Leaking flywheel... AGAIN!

[mike.smith]

So this weekend I am about to take my AeroVee engine off my plane for the THIRD time in as many weeks. I have been following the AeroVee installation instructions to the letter. The flywheel assembly is brand new (if you followed my post about the self destructing flywheel and alternator you know why). I put in a new rear seal. I used RTV on the hub and 8 pins holding the flywheel. Last time this happened (only a week ago), when I removed the flywheel I found the rear seal 100% intact, with no sign of even a drop of oil getting by. But the area of the 8 pins holding the flywheel was leaking heavily. We cleaned up everything down to bare metal. We lubed the rear seal. We put RTV on the flywheel hub and the 8 pins. We torqued the gland nut per specs.

There was no oil for the first couple of hours on the engine. After flying for an hour yesterday the back of the engine is a mess. There was so much oil that it filled the bottom of the air cleaner, and had half filled all the pores of the air filter. It's a wonder the engine was still breathing.

So I ask, WHAT THE HECK CAN I DO DIFFERENTLY SO THIS DOESN'T HAPPEN AGAIN!!! I have the AeroVee manual open through the entire process and follow every instruction. Why is it leaking!?

[merle reppert]

Make sure the oil drain passage in the case is not blocked by sealant ??

[mike.smith]

Make sure the oil drain passage in the case is not blocked by sealant ??

I ran a pipe cleaner into them to make sure they were clear. Oil pressure is the same as it's been for the last 80 hours, so no sign there is a problem with oil flow.

[vwglenn]

Well I don't know about the Aerovee flywheel but the regular flywheel on a VW has an O ring on it...



Usually when the main seal isn't leaking, the cam plug can be the culprit. Drips down, hits the flywheel and throws oil all over the place.

[mike.smith]

Well I don't know about the Aerovee flywheel but the regular flywheel on a VW has an O ring on it...
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Usually when the main seal isn't leaking, the cam plug can be the culprit. Drips down, hits the flywheel and throws oil all over the place.

The AeroVee does not use the O-ring. It relies solely on the RTV sealant throughout that area. I did look at the camp plug, and I didn't see any evidence of oil coming from there. I'll be re-doing the back of the engine again tomorrow, so I'll report back on what I find. I'm just not sure I'll be any closer to figuring out "why."

[SonexN76ET]

Mike,

I would still be suspicious of your rear main seal. You have to handle those things very delicately. You have to evenly and gently tap them into place and go no farther than flush with the case, maybe not even that far. Once in, you can not adjust it or re use it.

I don't remember for surer, but double check that their is not supposed to be an o ring on the flywheel. I just don't recall.

Also, when you pack on the RTV into the dowel pins make sure you give it plenty of time to dry before you add any oil!

Good luck! Happy Fourth of July!

Jake

[mike.smith]

Mike,

I don't remember for surer, but double check that their is not supposed to be an o ring on the flywheel. I just don't recall.

The manual says specifically that the O-ring has been omitted from the construction. I don't know why, but that's how they tell us to build it. As for the rear seal, I replaced it with a new one, and it was flush with the case; no further. When I re-do the work tomorrow I plan to replace the seal once again. Luckily I ordered an extra last time!

[nwyooper]

Red RTV is not the answer in my humble opinion. I used 1211 Sealant that I got from Amazon for about 25.00 for a 3.5 oz tube. My friend tried RTV 3 times and finally went tried my 1211 and it stopped his flywheel leak. Do need to make sure the drain hole is open

[rizzz]

Mike,
Check out this post on the legendary Bob Hoover VW blog:
http://bobhooversblog.blogspot.com.au/2 ... -seal.html
It might explain some things.

[mike.smith]

Mike,
Check out this post on the legendary Bob Hoover VW blog:
http://bobhooversblog.blogspot.com.au/2 ... -seal.html
It might explain some things.

Sounds like the AeroVee manual would benefit from some of these tidbits of wisdom!

I know my oil return hole is clear. I check that every time with a long pipe cleaner. As for installing the rear seal, pretty much everyone I know has done it with a rubber mallet or a mallet and a block of wood. I've removed 2 seals, and in both cases there was no damage, no nicks, no cuts and no sign of leaks coming from the seal. There was evidence of leaks coming from around the 8 pins that hold the flywheel. I'm letting the RTV set up for at least 36 hours (instructions say 24 hours) before trying the engine again.

By the way, for all us male type individuals, did you know there are "instructions" on the tube of RTV? And did you know that after applying RTV you are supposed to wait a full hour before tightening the parts and torquing them? This guy explains it pretty much like the instructions do:
https://www.youtube.com/watch?v=21CvanhKILA

I found the video made by the makers of RTV and Right Stuff to be pretty interesting, too, though if they say their Right Stuff is the best product to use, I'm not sure why they make all the other products:
https://www.youtube.com/watch?v=h_y9FTicNnM