Jump Start Engines – part#3


In this part, let’s look at the sub-groups that will be in the assembled short block. One of the organizational tasks I put a huge amount to effort into in 2012-13 is our Group Numbering System, which logically breaks down your engine build into groups, and assigns every single part in the flight motor a number.


When I wrote the getting started series, I introduced the numberings system with this story: Getting Started in 2013, Part #2, Group numbering system. It is a good, short, introduction, but I later changed the system slightly. In the first system (which was used in the getting started series) You had Group 1000, (the crank group) but you also had part# 1000 which was the crank. Shortly I saw this was a little ambiguous, and decided to make the crank part number 1001, and bump all the part numbers down one digit. Not a big deal, but it makes it easy to understand that when we are speaking of 1000, 1500 or 2000, we are speaking of the whole group, not an individual part. Our regular catalog page:


Has all the correct part numbers as they are after the revision. Read and understand the getting started articles, but the numbers we use in this series will be the final ones that appear on our catalog page.


The catalog page has all groups, #1000 through #4300 on it. That may sound like a lot, but keep in mind that 3400 through 4300 deal with airframe installation components that you don’t need to get an engine running at a college. Also, there are a number of groups like the Front cover group 2300, that are deleted if you are building with a 5th bearing, There are two oil system groups, 2700 and the heavy duty 2800, and you only need one, and there are three 5th bearing groups, 3000 (Weseman), 3100 (Roy’s) and 3200 (mine) and you only need one. The numbering system has to cover a lot of options, but to build your engine you only need to use part of it. This series will guide you through with some examples.


If you look at it for a minute, you will understand that the “Catalog page” is far more than a list of items for sale. only a small fraction of the part numbers are items we sell. The page has a larger function as a checklist for your engine build. Rather than flashing back to it, consider printing one out and getting a highlighter and checking the items off as you collect and prep them. Even though I have been building the engines for 25 years, I still like to use a checklist to get everything organized.


I have a few hundred hours in Grace’s Taylorcraft. It is a very simple plane, but if you look in the glove box, it has a laminated, hand written pre-flight check list, and I still take it out and run through it and say the items aloud.  Make fun of that if you want, but I am never going to be the guy who took off with the fuel shut off, the plane radically out of trim, or the primer unlocked.  If you don’t want to be the guy who comes to a college to assemble and run his engine but doesn’t have lifters (#1105) or head gaskets. (#1403), use the checklist.




OK, below are the Groups we will be dealing with to build the Jump Start closed cases.( Getting Started in 2013, Part #7, ‘Chas. Charlie’ Short Block ) after this we will break it down to the individual parts in each group.


(1000) Crank group

(1100) Cam Group

(1200) Case Group

(2000) Rear oil case Group

(2400) Starter group

(2500) Hub Group

(3000) Weseman bearing Group


Reading for background:


To read about the Crank Group 1000

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


To read about the Cam Group 1100:

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


To read about the Case Group 1200:

Getting Started in 2013, Part #4, Case Group (1200)


To read about the Rear oil case Group 2000:

High Volume Oil Pump




“If two guys walk into my booth at an airshow and ask about engines, everyone should understand that I am going to be polite to the guy who wants to tell me about the 4 cylinder Corvair he had in high school, I am going to answer all the questions of the guy who has seen my website, but didn’t look enough to even hear about the number system, but I am going to invest as much of my time as possible with anyone who shows up with a printed numbers list, a highlighter, a pencil and a working knowledge of how we describe the engine now. There is only one of me, and there will be many people at an airshow as interested spectators. That’s good, but my mission is to teach builders, not entertain spectators. I am glad to talk to the later and do a little hangar flying if they are standing there, but mission #1 is to communicate with builders, and nothing says you’re a builder like having a written plan in your hand.” -ww


( Our booth at Oshkosh 2014 is #616 across from Zenith aircraft)




About William Wynne
I have been continuously building, testing and flying Corvair engines since 1989. Information, parts and components that we developed and tested are now flying on several hundred Corvair powered aircraft. I earned a Bachelor of Science in Professional Aeronautics and an A&P license from Embry-Riddle Aeronautical University, and have a proven 20 year track record of effectively teaching homebuilders how to create and fly their own Corvair powered planes. Much of this is chronicled at www.FlyCorvair.com and in more than 50 magazine articles.

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