Getting Started in 2013, Part #3, The Camshaft Group (1100)


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

Getting Started in 2013, Part #2, Group numbering system


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


Getting Started in 2013, part #1, Crankshaft process options.


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  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:

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