Builders;
Reviewing the options to this point, I want to bring the comparison up to the point where every engine has a 5th bearing on it. These 5 paths present proven options for builders to follow, Again, there are options for each of the five, but this is easier to keep track of with the numbering system. Right now, Phil Maxson has worked out a spread sheet and is keeping up with the series, but at this point I would still like to keep builders focused on the discussion here. We can resort to a spread sheet when we get a lot more information to juggle.
The Traditional terms we use to describe stages of completion are “Closed case”, where the 5 engines are to this point. “Short Block”, which is a closed case with pistons rods and cylinders installed, and “Long Block”, which is taking it one step further by putting the heads on. In the articles so far I have used the term “short block” because I intend to take each of the five through that stage of completion in the discussion. Our DVD series aligns with these stages. Engine build #1 is the case closed, #2 is the pistons and cylinders, #3 is getting the heads on.
Engine options with 5th bearings:
Allan Able = $2,062
Bob Baker = $2,516
Chas, Charlie = $2,770
Davie Dog = $4,270
Eddie Easy = $3,157
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We are going to look at three piston and cylinder options and then apply each of them to each of the Closed Case systems above. That will give us 15 basic engine build paths.
Notice how the options expand geometrically as we get a little further along. 15 is actually something of a simplification, as I am not going to get into outdated displacements like 88mm, 90.5mm and 94mm bores. Don’t let the expanding possibilities overwhelm you. First and foremost, remember that it is the Corvair being adjustable to fit your exact needs. I am going to use the numbering system to make an easy to see, logical decision path, and I am going to highlight some common combinations like Allan Able building a .030″ over engine and Davie Dog opting for a 3,000cc displacement.
Yes, other engines come with options, The Rotax 912 comes in the 80hp 100hp and Fuel injected models. In Industry slang, these very expensive engines have nick names. 80hp = “Trust fund kid”, 100hp “Hedge fund Mgr.” and the Injected motor is “MMG” (more money than God). Obviously Rotax’s pricing isn’t really aimed at keeping homebuilding within reach of working Americans.
If you think their pricing is steep, you need to get a look at the typical cost of maintenance repair and overhaul to really understand why I refer to these things as ‘disposable appliances.’ There will be a Rotax ower who reads this, who will write in to tell me that I am all wrong about this, that he is very happy with his 912 engine on his $134,000 imported European S-LSA plane. To him and his budget, it is a great motor because all he wants out of it is that it is an acceptable appliance. He isn’t interested in learning anything about it nor working on it. It is a good match for his shallow needs, and he has the required bank roll. On the other hand, a typical homebuilder, a guy who wants to learn build and fly, a guy who got into homebuilding to get his hands dirty, will find the exact same 912 and the ‘support’ system for it aimed at pleasing wealthy appliance owners, a very frustrating proposition.-ww
Here is the number system for the next stage of engine building:
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Piston and rod group (1300)
1300- Piston set with wrist pins
1301- Ring set
1302- Connecting rods -6-
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Cylinder group (1400)
1400- Cylinders -6-
1401- Base gaskets -6-
1402- Head gasket set
Builders;
Builder ‘Eddie Easy’ is going to work with Roy of Roy’sgarage.com. Roy has his own 5th bearing design, and it is now flying on about a dozen aircraft. The bearing design requires builders to send their case and crank to Roy so that he can line bore his bearing to the case and he has to process the crank to install his 5th bearing journal on it.
Builders selecting Roy’s bearing design almost always have Roy assemble their bottom end for them. Also, Roy’s bearing design requires a special safety shaft and custom-made hybrid studs. (Dans 5th bearing uses parts straight from our catalog) For these reasons, an exact head to head price comparison isn’t possible, but we can come up with a reasonable comparison for builders. Since Roy’s set up utilizes a Moldex processed 8409 GM crank, It isn’t a fair match to compare it to ‘Davie Dog’s’ engine with a Billet crank. It is a better comparison with ‘Chas. Charlie’s’ short block. After we go through the numbers I will do some notes and comparisons at the end.
( CC stands for Clarks Corvair parts, SR stands for Summit Racing, ELS stands for Ebay Larry’s Corvair parts, and ECA stands for Ebay California Corvair parts.)
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Crank group (1000)
1000- 8409 crank, no gear ($500 )
1001- Crank gear (new, $150, installed in crank processing)
1002- Crank gear key (Included in crank prep)
1003- Crank gear gasket (Included in crank prep)
1004- Rear keys -2-(CC-#5858, $1.50, $3)
1005- Fuel pump eccentric (used, from core engine)
1006- Spacer (used, from core engine)
1007- Bronze distributor drive gear (used, from core engine)
1008- Oil slinger (used, from core engine)
1009- Main bearings (From Roy, $120)
1010- Connecting rod bearings (ELS-$59)
Cam group (1100)
1100- Cam ( CC, part 8800, $235 )
1101- Thrust washer (new installed by Clarks, $12.60)
1102- Key (CC-#5858, $1.50)
1103- ‘Fail safe’ Cam gear (CC- $94 + $25 assembly)
1104- Hydraulic lifter set -12 total- (Summitracing.com $2.99each, $36)
1105- Cam lubricant (comes with OT-10 cam)
1106- ZDDP oil additive (SR,$16)
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Case Group (1200)
1200- Case -2 halves with studs- (used, from core engine)
1201- Main case bolts -8- (used, from core engine)
1202- Pipe plugs for oil galleries -2- (used, from core engine)
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Special Items required in a Roy bearing closed case: The bearing itself; $1695, Hub modification $60, Difference in price for custom HS and SS; $30. Roy needs the case to be very clean, and he charges $120 for this service. It is not required, but Roy will assemble the lower end for the low price of $100. (during the bearing installation process he has to bolt the case together several times.)
The total of Eddie Easy’s engine parts on the chart above are $1252.10. To this must be added the bearing price, $1252.10 + $1695 = $2,947.10 . Add in the typical $120 case cleaning, and $90 for modified parts and the total comes out to $3,157.10. (Raise this to $3,257.10 and you get it back assembled.)
Chas. Charlie’s engine is identical, except it has a Dan Gen 2 bearing and it comes in at $2,770.10. $387 difference in the un-assembled form. There is some cost for shipping things back and forth, but it isn’t a deal breaker. For a builder who is looking for an assembled case, it isn’t the least expensive method, but it isn’t astronomically expensive either. There isn’t really a low-cost do it yourself option, nor a pay as you go approach that a guy like Allan Able can employ, but Roy’s product isn’t aimed at those builders.
Two things to frankly discuss: Roy has a very long waiting list, It has run over one year. Because of the hand done nature of the bearing, he can’t just phone up the CNC shop and order up another dozen bearings, and this leads to a long order time. Second, Roy has a background in working on things like Mercedes cars. To his perspective, applying the mercedes standard to the main bearing bores on a Corvair case means that 1/3 of cases are out of tolerance. This means you could need a whole new core case if he ‘rejects’ it.
To my perspective as an aircraft mechanic of 22 years, the GM tolerance is fine, and there is no need to arbitrarily cut it in half. Aluminum case opposed motors are traditional built a lot looser that Cast iron car blocks. Roy works with .0005″ as the limit of out of round on the bores. I have my doubts that all Corvairs passed this on the day they were made. The Gm new spec is .001″, twice as much. I have built many flight motors that were .0015″, They worked great.
For a reality check, Kevin and I once had about 20 140hp Corvair engines between us. These are Chevys high rpm/ high output engine. Inspecting many of these cases coming from 6,500 rpm engines which had 100,000 miles of beating on them, revealed that the main bores were often .0035, or seven times Roys tolerance. Yet none of these engines spun a main bearing. Thus I don’t agree that a Corvair between .001 and .0015 is in any danger of spinning a bearing or wearing out. You can ask any builder who has attended a number of colleges and seen 100 different engines that were torn down if he has ever seen one with a spun bearing, he hasn’t. In 20 years of working with Corvairs, I have seen two or three spun bearings, but they were all in engines that were literally run without oil.
At Embry-Riddle it was drilled into our heads that if the book said the allowable torque range determined by engineering was from 50 ft/lbs to 75 ft/lbs, then putting the item anywhere in that range made it air worthy. Mechanics that spent a lot of time trying to hit 62.5 ft/lbs were wasting effort and trying to prove something about their ego. If they would only be happy if it was between 55 and 70 because they were not sure about the torque wrench, then they were to get a new wrench. Guys who though they were making something ‘better’ by torquing it to 75 every time, were living under some illusion. In short, any mental justification that the mechanic used to put his own ‘custom’ touch on tolerance was to be frowned upon, because it probably indicated that the mechanic thought of himself as smarter than the engineer, or he did not trust the book. arbitrarily applying standards from one machine to another was really frowned upon. Less clearance isn’t always better, Closer fit in aircraft engine components isn’t always better, and neither is any arbitrarily set standard. The real issue with that kind of thinking is that you end up believing that you have a system that is ‘better’, and you stop looking at the field data that might suggest otherwise. No one gets smarter that way.-ww.
Builders;
Builder ‘Davie Dog’ is going to up the ante on Chas. Charlie by going for one of Dan Weseman’s new billet cranks with a Gen 2 bearing hub installed. He is going to choose to have a new gear on his crank. He is going to get a Clarks failsafe gear, installed by Clarks on a new cam, just as Chas. did. Deciding on a new Crank isn’t an impulse buy, so builders should study the information on it closely by reading the page for it on Dan’s site at the link below:
Although I have the price info here, Dan would like builders choosing a new crank to look at the package he has put together for the cranks. The primary structural strength increase in these cranks comes from having radiuses that are very large by Corvair standards. These radius need the bearings to be inspected for fit and the connecting rods to be clearanced to match. Dan is offering to take care of both of these tasks for builders selecting a new crank for a modest charge. If you look at his webpage there is a package listed at $3,100, but that price includes bearings and connecting rods and labor. To keep with the comparative format we are using here I am going to break down Dan’s price because we want to see the comparison without involving the rods yet. The information here will provide a fairly accurate cost comparison for builders.
Also to be noted is that the crank price of $2,450 with the new gear on is to allow the crank to be utilized in several different types of engines. In reality, Every Billet crank Dan has done has been delivered with the Gen 2 bearing hub installed. Dan pictures that almost every billet crank he delivers will go to the builder this way. Although the crank could have a Gen 1 bearing put on it, or be put in a car for that matter, I will give the price comparison at the end assuming the builder is going to have Dan install a Gen 2 hub so that it is a more direct comparison to the engine built by ‘Chas. Charlie.’
( CC stands for Clarks Corvair parts, SR stands for Summit Racing, ELS stands for Ebay Larry’s Corvair parts, and ECA stands for Ebay California Corvair parts.)
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Crank group (1000)
1000- Dan Weseman Billet crank. ( $2,250)
1001- Crank gear (new, $200, installed in crank processing)
1002- Crank gear key (Included in crank prep)
1003- Crank gear gasket (Included in crank prep)
1004- Rear keys -2-(CC-#5858, $1.50, $3)
1005- Fuel pump eccentric (used, from core engine)
1006- Spacer (used, from core engine)
1007- Bronze distributor drive gear (used, from core engine)
1008- Oil slinger (used, from core engine)
1009- Main bearings (ELS-$88)
1010- Connecting rod bearings (ELS-$59)
Cam group (1100)
1100- Cam ( CC, part 8800, $235 )
1101- Thrust washer (new installed by Clarks, $12.60)
1102- Key (CC-#5858, $1.50)
1103- ‘Fail safe’ Cam gear (CC- $94 + $25 assembly)
1104- Hydraulic lifter set -12 total- (Summitracing.com $2.99each, $36)
1105- Cam lubricant (comes with OT-10 cam)
1106- ZDDP oil additive (SR,$16)
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Case Group (1200)
1200- Case -2 halves with studs- (used, from core engine)
1201- Main case bolts -8- (used, from core engine)
1202- Pipe plugs for oil galleries -2- (used, from core engine)
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The total of Davie Dogs engine parts above are $3,020.10. For a more effective comparison, look at the price after installing a Gen 2 5th bearing system: $4,270.10. Chas. Charlie’s engine is identical, except that it has a processed GM 8409 crank, and it comes in at $2,770.10. This the price increase for going with a new billet crank is $1,500.
Is this a lot of money? Well, like most things, it depends on your perspective. Lets say you are going to build an absolutely magnificent Corvair with an overhauled MA-3, etc. and the total looks like $10K spent over 24 months. Deciding that you are going to build the engine around a billet crank instead is only a 15% price increase. For another comparison, my neighbor just had to buy a new crank for his 4 cylinder Lycoming. After careful shopping he found one on sale for $3,990. That’s the crank by itself. At Oshkosh I had a guy tell me that he had gone through an 0-200 bottom end from a 1959 C-150 for his homebuilt. He spent more than $5,000 on it to make it right. He said to me that he liked it more than a ‘car’ engine because he “didn’t want to use old stuff and he wanted an engine with big bearings,” Because I am a jackass at heart, I took the time to explain that his 1959 crank is older than any Corvair crank ever made and the main bearings on an O-200 are smaller in diameter than those in a Corvair. I restrained myself from pointing out that his top end will likely cost another $4K, his mags and carb overhaul another $3K. Maybe I am maturing and gaining a sensitive side….
Again, if any builder would like to have this assembled as a running start, we are glad to pick up the parts at The Weseman’s and take care of it for a modest charge. -ww
Builders;
Builder ‘Chas. Charlie’ elects to use a Weseman prepped crankshaft with a gen 2 bearing hub installed. He is going to elect to have a new gear put on his crank. He is going to get a Clarks failsafe gear, installed by Clarks on a new cam, so he can just take it out of the box and put it in the case. This option looks at trading more money to have new parts and less time involved in the case assembly.
(At the end I will cover some options and notes. CC stands for Clarks Corvair parts, SR stands for Summit Racing, ELS stands for Ebay Larry’s Corvair parts, and ECA stands for Ebay California Corvair parts.)
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Crank group (1000)
1000- Crank GM 8409 prepped by Dan Weseman with Gen 2 5th bearing hub installed. ( $1,350)
1001- Crank gear (new, $100, installed in crank processing)
1002- Crank gear key (Included in crank prep)
1003- Crank gear gasket (Included in crank prep)
1004- Rear keys -2-(CC-#5858, $1.50, $3)
1005- Fuel pump eccentric (used, from core engine)
1006- Spacer (used, from core engine)
1007- Bronze distributor drive gear (used, from core engine)
1008- Oil slinger (used, from core engine)
1009- Main bearings (ELS-$88)
1010- Connecting rod bearings (ELS-$59)
Cam group (1100)
1100- Cam ( CC, part 8800, $235 )
1101- Thrust washer (new installed by Clarks, $12.60)
1102- Key (CC-#5858, $1.50)
1103- ‘Fail safe’ Cam gear (CC- $94 + $25 assembly)
1104- Hydraulic lifter set -12 total- (Summitracing.com $2.99each, $36)
1105- Cam lubricant (comes with OT-10 cam)
1106- ZDDP oil additive (SR,$16)
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Case Group (1200)
1200- Case -2 halves with studs- (used, from core engine)
1201- Main case bolts -8- (used, from core engine)
1202- Pipe plugs for oil galleries -2- (used, from core engine)
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The total of Charles Charlie’s parts is $2020.10. This is a moderate increase over Bob Baker’s parts at $1,766. It will take less time to assemble, and it will all be bolt together stuff eliminating shrinking the cam gear on the cam at home. Many builders are attracted to the idea of having a new cam and the best cam gear, and I can’t argue with this, but traditional engines we have built that have a lot of flight time on them have had perfect service histories on reground cams and standard gears.
To get his short block up to the point of having a fully operational 5th bearing, Charles Charley will order the second half of the Weseman bearing, the Billet housing/bearing/seal for $750. This brings his total to $2,770.10. Again, if any builder would like to have this assembled as a running start, we are glad to pick up the parts at The Weseman’s and take care of it for a modest charge. -ww
Builders:
Now we get to the second engine builder, “Bob Baker.” He elects to use a Weseman prepped crankshaft with a Gen 2 bearing hub installed. He is going to keep his used gear from his crank. He is going to get a Clark’s standard cam gear that he is going to put on a re-ground cam himself.
Here is the logic in his decision making: He knows he is going to have a 5th bearing on his engine, so he wants to do it in the easiest way possible. He is also interested in condensing orders, so having the Wesemans take care of the crank prep and install the Gen 2 hub in one shot is appealing. The Weseman crank process takes care of removing the gear and replacing it for the builder, so he doesn’t have to track down a 20 ton press like Allan Able did. Later, Bob will have less work than Allan putting his 5th bearing on because the Gen 2 eliminates the most technical part of the installation. Even though Bob is looking to save the work on the crank, he still is willing to install his cam gear at home. If he changes his mind about this, Clark’s only up charges about $25 to install the gear for him.
Again, at the end I will cover some options and notes. CC stands for Clarks Corvair parts, SR stands for Summit Racing, ELS stands for Ebay Larry’s Corvair parts, and ECA stands for Ebay California Corvair parts. Lets look at Bob’s numbers:
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Crank group (1000)
1000- Crank GM 8409 prepped by Dan Weseman with Gen 2 5th bearing hub installed. ( $1,350)
1001- Crank gear (used, from core)
1002- Crank gear key (Included in crank prep)
1003- Crank gear gasket (Included in crank prep)
1004- Rear keys -2-(CC-#5858, $1.50, $3)
1005- Fuel pump eccentric (used, from core engine)
1006- Spacer (used, from core engine)
1007- Bronze distributor drive gear (used, from core engine)
1008- Oil slinger (used, from core engine)
1009- Main bearings (ELS-$88)
1010- Connecting rod bearings (ELS-$59)
Cam group (1100)
1100- Cam ( CC, part 8800R, $170 )
1101- Thrust washer (used, from core engine)
1102- Key (CC-#5858, $1.50)
1103- Cam gear (CC- $44)
1104- Hydraulic lifter set -12 total- (Summitracing.com $2.99each, $36)
1105- Cam lubricant (comes with OT-10 cam)
1106- ZDDP oil additive (SR,$16)
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Case Group (1200)
1200- Case -2 halves with studs- (used, from core engine)
1201- Main case bolts -8- (used, from core engine)
1202- Pipe plugs for oil galleries -2- (used, from core engine)
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The total of Bob’s parts is $1,766. A first, this seems like a really big bump from Allan Able’s $1012. But it really isn’t an apples to apples comparison. Heres why: Bob is already part of the way to his 5th bearing being done, because the Gen 2 hub is already on his crank. To complete his 5th bearing, he will need to order the $750 housing/bearing/seal from the Wesemans. Thus $1,766 + $750 = $2516. Allan Able is eventually going to get a Gen 1 bearing, and the cost is going to be $1050 for the whole bolt on kit. Thus Allan’s cost to the same point of completed case with operational 5th bearing is $1012 + $1050 = $2062.
So to get to a case with a 5th bearing Bob is only spending $454 more than Allan. He has less work, but to get to the point of closing the case Bob has to have about $750 more handy at the same stage.
Options Bob may consider: For $100 more he can get a new crank gear. For about $50 more he can have a “fail safe” cam gear. If Bob is looking for a running start at the next College, he can send his case to my hangar, and for a modest charge I will assemble the bottom end and put the Gen 2 bearing in place. This is an efficient process because I can pick up the builder’s crank and bearing from Dan after it is processed. Even with these options Bob can get his fully assembled case for less than $3,000. This is often the running start that makes the difference on getting an engine running at a 3-day College. We have presented builders with two options that are very different, yet we have only looked at 2 of the 5 examples. When you consider the sub options, we are looking at perhaps 50 different paths for builders to select.
Take a moment and think: How many different ways are there to buy an imported engine? In most cases, just one. How likely is this single configuration to be the perfect match for an individual builder’s budget, learning goals and project plane? Not likely at all. Almost all of those manufacturers offer their engine in a single configuration, not because it is the best for builders, but because it has the highest total revenue to their company. That isn’t evil, it’s capitalism. Works for them, and it works for any person who is willing to subjugate their own personal goals and individual plans to the available product.
Just looking for an appliance to turn a prop? No major loss to buy an imported, single configuration, “finance it don’t build it” motor. Did you get into this game to Learn, Build and Fly? Are you an individual who doesn’t fit the cookie cutter mold that many companies, organizations and magazines project as the “right” people for aviation? Then Corvairs are for you. … Keep reading until you define the engine that perfectly matches your goals in building and flying. Don’t ever change your dreams, desires nor plans because it would be more convenient for the large corporation to sell you something: That isn’t homebuilding, it’s consumerism, and it only makes shallow people happy for short periods of time. As an individual, you have to exercise your personal choice and will and effort to be happy for the long run. That is called being an Aviator. -ww
Builders,
Continuing here, we are going to look at one of the least expensive short blocks that can be built as a flight engine. This takes into account lessons we have learned over the years. Although this is inexpensive, it is far better than a handful of short blocks that I see during a year of Colleges, were some local expert talked a builder into doing it his way, and ended up grinding the crank radiuses off or not threading the crank for a safety shaft. Following the plan here will keep you on track even if you are on a very tight budget. At the end I will cover some options and notes. CC stands for Clarks Corvair parts, SR stands for Summit Racing, ELS stands for Ebay Larry’s Corvair parts, and ECA stands for Ebay California Corvair parts.
Crank group (1000)
1000- Crank Moldex, ($600 typical price for work)
1001- Crank gear (used, from core)
1002- Crank gear key (CC-#5858, $1.50)
1003- Crank gear gasket (CC-786A, $1.88)
1004- Rear keys -2-(CC-#5858, $1.50, $3)
1005- Fuel pump eccentric (used, from core engine)
1006- Spacer (used, from core engine)
1007- Bronze distributor drive gear (used, from core engine)
1008- Oil slinger (used, from core engine)
1009- Main bearings (ELS-$88)
1010- Connecting rod bearings (ELS-$59)
Cam group (1100)
1100- Cam ( CC, part 8800R, $170 )
1101- Thrust washer (used, from core engine)
1102- Key (CC-#5858, $1.50)
1103- Cam gear (ELS- $35)
1104- Hydraulic lifter set -12 total- (Summitracing.com $2.99each, $36)
1105- Cam lubricant (comes with OT-10 cam)
1106- ZDDP oil additive (SR,$16)
Case Group (1200)
1200- Case -2 halves with studs- (used, from core engine)
1201- Main case bolts -8- (used, from core engine)
1202- Pipe plugs for oil galleries -2- (used, from core engine)
Looking at the above prices, the total is $1,011.88, a very reasonable price to get the case closed. Some options: ECA sells an 1103 cam gear for $54 that is a USA billet item that I have not yet used, but I think this will turn out to be a $19 upgrade well spent. The 1100 cam here is a reground OT-10 from Clark’s. It’s pricey, but good. On an extreme budget, look at a ELS reground Isky 270 at $85. This isn’t as good as an OT-10, but it is far better than stock and better than a once proposed internet idea called using a ‘delta’ cam.
If you want to learn something about picking who has quality control on making cams or regrinding them, Read Harvey Crane’s website about the machines companies use. I have Known Harvey for 20 years, he is an airplane guy, lives at Spruce Creek and most people concede that he is one of the worlds leading experts on cams. OT-10s and Iskys are made on better equipment, and that’s what counts when it comes to reliability.
So a guy with a reground 270 and a gear upgrade is still only at $940 or so. To be fair the one issue here is that the crank gear has to come off before the crank is processed and later be put back on. The GM manual shows how to do this, but few homebuilders want to do this or have a 20 ton press. You can leave the gear on and let Moldex nitride it with the crank, but I am no longer in favor of this because people don’t take enough care to carefully clean the gear teeth later. There are literally more than 150 cranks flying that have had the gear nitrided in place, so there is a long track record of it working, but that shouldn’t prevent anyone from trying to do better today.
This isn’t the least expensive way anyone has gone. If you are lucky enough to find a GM factory nitrided crank that is still Standard size and you are planning on putting a 5th bearing on it, you could skip about $400 of the Moldex price because it would just need to be threaded, polished and Magnafluxed, about $200. I have an engine in the shop just like this right now, but it is a rare chance these days. But a builder with a GM 140/Turbo crank is good shape could get to the case closed stage for $550 or so.
I would not be afraid to fly such an engine, although I am going to work to later convince every ‘Allan Able’ builder to install a retrofit Gen. 1 Dan bearing. 5th bearings make sense for every builder, and the retrofittable nature of Dan’s Gen 1 bearing allows Builders to get started today, make progress, and work the bearing in later.
From my personal perspective I would rather fly any engine that was carefully built around a GM 8409, even one on a very tight budget, than any engine that was built around a Chinese crankshaft sold on the internet by a guy who advertised them as “great for aircraft” although he has never flown in a light plane himself. Understand that the very first one of these cranks put in a plane failed and revealed a hidden factory repair. They are Made in China, sold by a LLC, that is owned by a Canadian. (I have many friends from the frozen north, America made Jim Beedee, we take a back seat to no country when it comes to marketing rip off artists) That triple condition means that if anything ever goes wrong, no one is going to stand behind it. It is the perfect legal firewall for a guy who knows nothing about planes but wants your money to hide behind. No one would tollerate a person who has no medical training dispensing drugs or telling patients what is the best treatment. Likewise, no one should be tollerant of any person who has no aviation training telling people what is ‘best’ for aircraft builders to put in engines they will fly their family and friends behind. I am firm enough on this point that I will not allow anyone to bring a Chinese crank to a College. I am not Jack Kevorkian, I do not assist people in ending their lives. -ww
Builders,
Here we have a tiny group, the Case. I may later break down the case into smaller more descriptive elements, but for now, it gets the job done. Now, there are a lot of notes that can be applied here, but keep in mind we are just looking at the overview big picture. The one note that I want to point out is that the case has no machine work on a 2700/2850 but the six bores in the case for the cylinders must be machined larger on a 3,000 cc engine. Of course, this is done before it is assembled.
Case Group (1200)
1200- Case -2 halves with studs-
1201- Main case bolts -8-
1202- Pipe plugs for oil galleries -2-
Now, let’s get a look at the four parts so far and think about putting a case together. Using just these numbers as a check list and something of a road map, any builder can put together a plan to assemble their case at Corvair College #25. Actually all the effort to get to that stage goes into the prep work, cleaning and a little shopping. It you lay out all the properly prepared components from groups 1000, 1100 and 1200 in front of me on the bench, and get me an assembly stand and my trusty Snap-on torque wrench “Excalibur“, I can assemble the case in about 45 minutes.
Now I say this in bad conscience because I once took 2 days to do it. There was a tiny ding in one of the bearing surfaces that was putting a small amount of extra drag on the turning crank and bothering me. I took it apart 6 times to find it and make it right. Keep in mind, it’s not a contest, the winning score is being happy with it, and any amount of time it takes between 45 minutes and 48 hours is fine. BTW, everything we are talking about here is in our engine assembly DVD #1 that covers building up a case.
Going back to the first part of this series we talked about crank selection. Lets look at some samples bringing all of this together and see what large variations of choices are available to builders,
Builder ‘Allan Able’ elects to use a Moldex prepped crank, and put off a 5th bearing for now. Lets say his crank has a reasonably good gear on it that doesn’t need replacement. He is going to use the low expense route laid out in the Camshaft section of Part #4
Builder ‘Bob Baker’ elects to use a Weseman prepped crankshaft with a gen 2 bearing hub installed. He is going to keep his used gear from his crank. He is going to get a Clarks standard cam gear, he is going to put in on a re-ground cam himself.
Builder ‘Chas. Charlie’ elects to use a Weseman prepped crankshaft with a gen 2 bearing hub installed. He is going to elect to have a new gear on his crank. He is going to get a Clarks failsafe gear, installed by clarks on a new cam.
Builder ‘Davie Dog’ elects to use a Weseman New billet crankshaft with a gen 2 bearing hub installed. He is going to elect to have a new gear on his crank. He is going to get a Clarks failsafe gear, installed by clarks on a new cam.
Builder ‘Eddie Easy’ elects to send his case and crank to Roy at Roy’s Garage.com. Roy is going to rework his stock crank, install a Roy bearing and use a failsafe clarks gear on a new cam.
In the next few parts we will take a look at how Allan, Bob, Charles,Davie and Eddie are doing on their projects.-ww.
Builders,
Now that you have had an introduction to the numbering system, here is the second group. Keeping in mind that we are moving toward having the parts to close the case, this is the next group to collect all the elements of and check off as done.
Notice that the same list and the same numbers serves different builders with different budgets and goals. Builder ‘A’ may be on a budget, His cam is going to be a reground OT-10 from Clarks, P/N 8800R and a stock replacement gear. He is also going to get the lifters by shopping around for the best price on a set of sealed power HT-817’s. The 1105 lube comes with the cam, but make sure you get the 1106 additive from Clarks or another source. If he takes it apart carefully, the stock GM thrust washer can be used again. He can assemble it at home, but for heaven’s sake don’t follow the part of the assembly directions that tell people to hit it with a hammer.
Builder ‘B’ may have a different budget. He can call Clarks and buy a brand new OT-10, and get it with a billet fail safe gear already assembled with the 1101 and 1102 washer and key already mounted. This is much more money, but it is for each guy to decide. But notice the number system works for everyone.
To illustrate the flexibility of the system, consider this: I have given some thought to having the cam that Harvey Crane designed for us in 1997 put back in production, because I have found a giant national manufacturer who can make them in the US on new blanks. This part would still be numbered 1100. If I end up doing it, I think the best way of providing them is with a new fail safe made in the US gear already installed and part numbers 1104, 1105 and 1106 all wrapped up in one box that a builder can buy, and then just check “Camshaft Group 1100” off his list. Before anyone asks, I am not going to do this before the next two colleges, so don’t sit on your tail and wait. I mention this because I want to illustrate that having the know how to do something in this business is only half the battle. If builders are not clear on what exactly you’re talking about offering and what part of their build its going to cover, they will be slow to buy such a kit, and if you have a back porch full of them, you will find that you can’t BBQ them for lunch nor send them in as a mortgage payment. Having the numbering system does many things, not just organize builds that will be tackled at CC#25, but it also allows us to consider bringing things to the market without as much worry about how they taste on the grill.-ww
Cam group (1100)
1100- Cam
1101- Thrust washer
1102- Key
1103- Cam gear
1104- Hydraulic lifter set -12 total-
1105- Cam lubricant
1106- ZDDP oil additive
Builders,
I have a numbering system that I use for the engine parts that counts every single piece in the flight engine, and puts them in groups that make sense for builders getting organized to build their engines. In this series, I will introduce this nomenclature I use to keep track of in-house production engine to people building at home. When you see a little bit of how its organized, it will make a lot of sense. I am going to bring it in on each segment, and pause to discuss how it works as a system. I have had it for several years, and long-term I would like to integrate it into how builders plan out a build. Later on I will show you the critical path chart that works with it and a decision tree, but for now, lets look at the building block with the crank system as a “Group.”
I have the Flight engine broken down into 38 “Groups” Numbered from Group 1000 (Crankshaft) to Group 3800 (Carbs). As you look at the numbers below, note that all the numbers in the Crank Group (1000) fall between 1000 and 1099. Now, you don’t need 99 part numbers for crank things, I am just keeping a natural spacing. The next group in line is Camshaft Group (1100). We will get to that next. But for now, see how every part in the crank system is accounted for. Note that the rod and Main bearings are in this group because they are dependant on is the crank is new (standard bearings) or Reground (.010″ Bearings etc.) The list can function as a checklist for a builder getting everything ready for an assembly, or one just planning a very careful budget. In about a second, someone will kindly suggest an excel spread sheet, but keep in mind I am a real Troglodyte, and a sheet to me belongs on a bead and an attachment is something I have for my dog. For right now, lets keep the focus on the parts and system, and if individuals want to organize it a little later, that’s fine. There is a lot of later growth potential in the system, where we make short you tube videos for each section, etc, but for now, lets remember that the goal is to build an engine.
Crank group (1000)
1000- Crank (8409 GM or Weseman new Billet)
1001- Crank gear
1002- Crank gear key
1003- Crank gear gasket
1004- Rear keys -2-
1005- Fuel pump eccentric
1006- Spacer
1007- Bronze distributor drive gear
1008- Oil slinger
1009- Main bearings
1010- Connecting rod bearings
After a builder gets all the stuff organized, he can check off Group 1000 and move forward. To assemble a case, you need to have Groups 1000, 1100 and 1200 (Case) and we will get there shortly. If a builder has a specific question about a part, ask away, we will be able to refer to them by specific number. Notice how number 1009 doesn’t stand for a specific brand or size bearing. Today, the recommended main bearing is Clevite, and the size again, depends on the crank size. If next year there is a different bearing that testing shows to be better, then we can reference this in an update of the single 1009 number, but 1009 will always stand for the main bearings. Keep in mind that the goal is to give an overview of building the engine, and this little post is already 600 words. I have very detailed notes for every single part number, but I want builders to take in the big picture for right now. My flight instructor was very fond of saying “WAKE UP, IT’S TOMMOROW!” any time he caught you daydreaming in the cockpit. Same applies to making a plan for getting your own personal engine to advance.
If you’re looking at shipping your core crank out by Saturday, pull it out of the engine and get going. If you have a small gear puller you can remove 1005, 1006, 1007 and 1008 in one shot. Let the pro who is doing the crank take the 1001 gear off. Get a plastic bag, a few feet of old carpet, a strong cardboard box and a roll of shipping tape and get it wrapped up. What you do this week makes a difference on whether your working or watching at CC#25.-ww
Builders,
The season has started, and we are 90 days away from the first College of the year. If you have a core motor in your shop, or are about to get one, it is time to get going. In this ongoing series, I am giving something of an over view of the build process, but my real intention is to get builders in action. 2013 has started. Would you like to have a running engine this year? Like to see some undeniable physical progress? Is the midnight shift of magic elves laying down on the job at your place? Get out the wrenches, fire the elves, and let’s get going.
Every engine starts with a Crank. Three ways to go here: 1)Processed 8409 GM crank, 2)New Weseman Billet crank, or 3)”Internet Red Chinese.” For people who actually believe in the craftsmanship of workers at the $3 a day level and the business ethics of communist leadership, I suggest clicking on this link for my story on “Chinese Crankshafts“. If you still think these things are airworthy, and your going to put one in a pusher aircraft with a 70 mph stall speed, let me remind you of the adage “the pilot is the first person at the scene of the accident” really applies to pushers, and the engine often arrives .006 seconds later and hopefully doesn’t make it all the way to the instrument panel.
For the rest of the builders, it is Choice number 1) or 2). Lets cover #2 first. Dan tells me that 12 people have laid down the money and ordered a billet crank. Several of them have been delivered, and builders have seen these at CC#24. The last engine of the year, (see story:World’s Strongest 3,000cc Corvair, built by Greg Crouchley) had one installed, as well as the Panther Prototype engine. This is why I wrote those stories under the title of “The Panther’s engine, worlds strongest Corvair flight engine.) First question many people ask is “Who needs one of these?” The only answer is anyone who would like one. They add about $1,100 to the price of a first class engine. Looking at the first 12 people who ordered one, they do not all have the same airframe nor the same experience, nor the same style of flying. The only thing they have in common was they felt that it was a good value for the price. (I do also.) Speaking from a personal perspective, I would rather have one of these cranks in my engine than an expensive glass cockpit instrument panel. Some builders will choose both, others will choose neither. I will work with both builders. If you would like a bit longer story, I wrote one (Billet Cranks Made In The USA) but it is a year old, and you can just as well go to Dan’s website and get the most up to date information. When looking at the pricing keep in mind that it has things like a new gear and rod bearings worked in, first glance isn’t apples to apples unless you read closely:
One of the perspectives I have on the new crank is this: A guy who was looking at buying a Jab. 3300 or Rotax 912 has to budget about $20K for one. Same guy, willing to do some assembly and learning, finds out that he can build an absolutely first class, spare no expense, 3,000 cc Corvair for 50% of this. Yes he has to do some work, but some people got into homebuilding to learn, build and fly and they welcome that part of a Corvair. Same guy starts looking at a new billet crank as an upgrade; if it raises the price of the engine $1,100 or so, the engine only becomes 57% of the price of an import. Something to think about.
Above is a close up of a 2nd Gen Dan bearing journal on a re worked GM crank. This is a 2700/2850 ready case we put together and sold to Irv Russel at CC#24.
Ok, lets talk about option 1), prepping the GM 8409 crank. This is the most popular option by far for building a Corvair, and it will remain so for a long time.
First, you decide what kind of engine your building. note that 2,700, 2,850 and 3,000 cc engines all use the same crank. From there, several ways to go:
A) build a 4 bearing engine, and keep the option open of installing a Dan bearing later.
B) build a Dan 5th bearing engine.
C) build a Roy 5th bearing engine.
Option A) has been popular in the past, but it is important that builders understand that I am letting everyone make up their own mind, but I am whole heartedly recommending that people budget a 5th bearing into the building of their airplane. I personally feel that having a super nice paint job or radios or a glass cockpit on a Corvair powered plane that doesn’t have a 5th bearing is a judgement error in prioritizing. Think about this: I don’t build or sell engines for people unless they have a 5th bearing on them.
Option B) If you build an engine and you know that you are going to put a Dan bearing on it, you have two options; you can use a gen 1 retrofit bearing, but on a new build engine it makes more sense to use a gen 2 bearing, where the added steel bearing journal is fixed to the crank and ground concentric when the crank is processed. This is the system pictured above, and this in the one I currently use on all of our production engines.
Option C) Roy has been making 5th bearings for a number of years, and I have used them on production engines. They are CNCed, but they are hand fitted and line bored to each builders case. This means that the builder must send his case to Roy, and that Builders must be prepared to wait a bit because each installation requires a good deal of his labor, and this limits production. You can read more at Roysgarage.com. Roy has a specific process on the crank that is similar to a gen 2 Dan crank, but this process is handled by Roy start to finish for people who select his Bearing.
Back to the specific Item. You have a core crank, what’s next? Obviously, if you are going Option C), you are going to call Roy and send it to him. Looking at Option A), The best place to send the crank is to Moldex in MI. They have done more than 100 cranks over the years and they have a very good track record. At times, they process cranks in a few weeks, but at other times they have taken far longer.
Even so, they are vastly better than any local crank shop you are likely to find in your home state. Before the advent of 5th bearings or Excellent processing like moldex, A number of builders broke cranks in flight engines. There were a lot of factors that contributed to this, but I am going to flat-out tell everyone that two of the biggest factors was poor grinding, magnafluxing done by unqualified people. The first caused stress risers the second failed to detect preexisting damage. Both of these errors came from local shops. Builders going to Moldex for the last 5 years has made a very large difference in the Quality of 8409 cranks going into engines. If you are looking at Option A), I consider using a shop other than Moldex a hard decision to justify. There are a number of specific issues that go into grinding a Corvair crank, like getting it dead nuts concentric. On a V-8 with a timing chain, not so big a deal. On a Corvair where the cam drive is by finely meshing gears, a crank ground to V-8 concentricity can radically overwork the cam gear. Avoid drama like this, use people we recommend.
Last, Option B) As pointed out, you can start with option A), use that crank process, and later install a gen 1 Dan bearing. But the route that makes far more sense on a new build Dan bearing is to exercise the following process: Send your core crank to Dan. He will fully process it, thread, press cam gear off, stress relieve, grind, nitride, balance, polish and install his gen 2 steel bearing on the crank. In the process, he gives you a choice of reusing your stock gear if it is in good shape, or using a new one. This process and options are detail on this link to Dan’s website: http://flywithspa.com/corvaircomponents/new5thbearingcrankshaft.html
Note that you can have this service done to the crank, but delay buying the actual aluminum billet bearing housing part of the system until after your case is assembled. Using this system makes the installation far easier, because the alignment of the steel bearing surface, the part of the Dan installation that takes the time, is already done for you and it has been made fool-proof. The second half, the housing installation, is the far lower tech part of the process.
One more special note: For a number of years, we have been removing the cam drive gear/flange off the crank when it is processed. Year ago, when we had everyone’s local crank shop doing the work, I was concerned about having these shops press the gear on and off. (It requires some talent and specialized tools.) In that era, cranks went to nitride with the gear on. There was all kinds of theoretical debate about this, but thousands of hours were logged on cranks processed this way. In recent years, we have reversed this because with the use of centralized qualified people, the gears can correctly be taken off and put on. It is far easier to grind the crank concentric with the gear off. But a concern of mine is that builders that do not clean the gear teeth very carefully can have tiny hardened flakes of nitrided material end up embedded in the cam gear, potentially causing a lot of trouble. This is easily avoided by having the right people remove the gear before the crank gets nitrided. Both Roy and Dan do this.
OK, life got started yesterday. If you have a core crank in your shop, vow to yourself that you are going to have it in the mail to the process of your choice by Saturday at noon. If you are headed to CC#25 in three months, you need to get going. In this series, I am going to take builders forward step by step with a gen 2 Dan bearing engine build up, timed so people heading to the college can be prepared to make progress and get what they deserve out of this year.-ww
