Building a VW Aero-Engine

[lakeracer69]

Sorry, I should have said for a flywheel drive engine. I was just over there looking at those

 

[fly2kads]

FWIW, the vendor Pops linked to above, aircooled.net, is one of my go-to sources for VW engine parts. John, the owner, has been at it for years, and knows his stuff. It can take a while to get answers to questions, but his advice is solid. I have never had an issue with anything I have purchased from him, and shipping is prompt. No affiliation, just a satisfied customer.

 

[lakeracer69]

Pops,

To flesh out using the gland nut and flywheel prop flange some more. The 4130 larger gland nut options seem like a no brainer.
Will either a 42 or 44mm one still work when using a GP prop hub extension? Without having one in hand it is impossible to figure out the height of the nut, or if a larger socket will fit in the counterbore of the flywheel/ dowel pin area, or not protrude and interfere with the prop extension.

Also, with an 8 pin crank it would seem like a bigger nut is better. It also looks like GP has a regular bolt of some kind for theirs. Do you know offhand the thread size for the gland nut? It measures out around 29mm or so. I have attached a picture.



Hub ID is 2.293 with a shoulder depth of .146 Flywheel center counterbore is 2.570 and .648 deep.

Thanks for helping us understand this.

 

[Pops]

I don't know . Good question if you want to use the larger nut.

 

[lakeracer69]

Did my sleuthing yesterday. A 44mm socket will fit in the flywheel counterbore with a little room to spare, so the nut itself will fit fine ( diameter wise) The height of the nut is still unknown for now. I have ordered a 44mm 4130 gland nut to see if it fits under the GP prop flange. If it does, I believe that it is the way to go. Whether you use a 4 dowel crank and flywheel or an 8 dowel, the 44mm nut and washer will provide more contact area than a 36mm one.

Using one of these gland nuts to attach the flywheel flange/ prop flange to the crankshaft, is akin to the Jesus nut on a helicopter rotor hub. You'd better have faith in it. I'm ok with using the biggest/strongest one available. They also say you can torque it up to 400 ft/lbs and red loctite it on some aftermarket crankshafts.

 

[Pops]

I noted the change from 217 to 400 foot pounds. I still would like to come up with a way of locking the nut. On the shrunk fit prop hub for the pulley end of the crankshaft I used loctite on the nut and put a red paint mark on the head of the bolt and checking for movement was a normal preflight item to check. But, the shrunk fit hub is on so tight I don't think it would come off without the bolt.

 

[Pops]

The flywheel prop hub is finally finished by Bob Hoover's plans on his blog. I also cut the center out of a flywheel by his plans.

 

[Pops]

Forgot to add. The weight of the prop hub is 2 lb and 15 oz's. I would like to not add any weight but with the weight of the flywheel drive hub being a little heavier than the pulley end prop hub and the different engine mount maybe the total firewall forward weight my be a little more. Will be trying to same every ounce.

Dan

 

[karmarepair]

I still would like to come up with a way of locking the nut.

Would this work? Drill and tap for a small socket head cap screw, just inside where a spot face for the nut would land, so that the flat of the bolt will be tangent to the SHCS. I'll try and find a picture of what I mean. I found this trick in this invaluable book https://www.amazon.com/Fasteners-Plumbing-Handbook-Motorbooks-Workshop/dp/0879384069

Another way would be to use a thin jam nut under the main nut. Different fluid, but same principles Propeller Nut Myth Busting. If there is a washer under the hub nut, this might work better than my first suggestion. You might have to mill/grind your own jam nut. But the forces on this application are FAR lower than they would be on a drag racer dropping the clutch, so maybe Red Locknut and Faith In Jesus is enough....

 

[Pops]

The VW bottom oil plate is made from heavy steel. I made a plate from aluminum to save weight and added a small sump so when doing a hard slip It will not un-port the oil pickup tube. I have had good VW street cars where they would corner good enough that the the oil pickup tube would un-port and the oil pressure would fluctuate. I extended the oil pickup tube down in the sump so its about 1/2" off the bottom and cut at a 45 degree angle. The larger threaded hole is for the oil temp sensor.
I remove the pip plug to drain the oil.

Dan

 

[fly2kads]

The VW bottom oil plate is made from heavy steel. I made a plate from aluminum to save weight and added a small sump so when doing a hard slip It will not un-port the oil pickup tube. <snip>

I have made a mental note before that you have done this, but it is nice to see it in pictures. Thanks for posting that!

 

[Pops]

Welded an oil pickup extension tube to the VW engine pickup tube. A 4130, 5/8" dia X .035 slide up inside for a good fit. Not enough restriction to matter. Years ago I bought some of the aluminum boxes for a electronic project and one made a perfect oil sump.
From Zero Enclosures. Also used another for the engine case vent system.

Deep-Drawn and Fabricated Aluminum Molded Plastic Cases, Enclosures, and Assemblies - ZERO Manufacturing | ZERO Cases