Flywheel Seal - Major leak, owner prepexed!!

[Keith Lawrence]

I'm going to pull the engine out again tonight for the 2nd time (3rd time counting initial rebuild).

This is a fresh rebuild 1200 and it seems that the flywheel seal is no good. When running, I get a constant drip (at least 1 drop every second or two) from the flywheel area. It does not get to the clutch, just straight down. The FW seal looked great and I thought it was coming from the cam or gallery plug. I JB welded the cam plug and the large gallery plug, if nothing else than to ensure it was indeed a bad FW seal.

After that I tried to test it, but I could not get a leak when pressurizing the case to 35 psi (even sitting with the FW down).

The seal is the good red type and it was oiled every time the FW went on and was installed using a ring, not hammered in. I could not find any other areas of leakage - the case is being reused, never leaked and looking closely with a light I could not find any cracks. Crank endplay is .003 and using 3 metal shims.

Is there any other thing I may be missing? I'm going to replace the seal and see if that is it, but would like to check anything else since I'll have the engine out (AGAIN!!!). I'm using 2 qts (puts it 1/2 between marks) Valv 20-50 for engine break-in and tried to run in the rings yesterday thinking maybe blowby was a factor, no change.

Thanks
Keith

[SR Racing]

Don't know if it's a fresh flywheel or where you got it, BUT.. MOFOCO was selling some flywheels that had been turned down on the seal area. Thus, the seal never even touched the flywheel. As long as you are replacing the seal check that it fits your flywheel and rubs it.

BTW, it's not part of your problem but you want more than the VW stock end play. .008 to .010. .003 is too tight for a Vee racing engine.

Jim

[billinstuart]

Occasionally you'll get a leak through the end of the crank where it mates the flywheel. Try putting the paper/steel shim gasket there. You do need more end play!! The flywheel was tightened to 300 ft.lbs. or so, wasn't it? The stock 240 isn't enough.

[Keith Lawrence]

The FW and case are from the original engine, that had no oil leak issues.

It lost #3 rod bearing on the first outing becuase the last person to rebuild it, before it went into 15 years of storage, used case stud o-rings on a 1200 case. You could take the case studs off by hand, but it never lost oil pressure - or I shut it down fast enough before it went too low.

The new crank is a std/std with new bearings and no machine work was needed on the case. The seal seems to fit well before it was put into the case - no spring adjustment made.

Gland nut was tightened to 325 using torqmeister.


Thanks
Keith

[Larry Bradley]

Just a WAG but is it a new seal?
Is the spring in the seal?
The only time I had a FW seal leak was after balancing the FW and some idiot stamped a 1 on the FW at the seal point.
Any thing like that happen?

Larry

[Keith Lawrence]

This is a new, red seal and the spring is in it. It was laid on the FW to check and it looked OK (no spring adjustment made).
The FW surface is in good, shiny condition with no marks or dents...

I'm thinking the seal has a radial crack, but can't confirm without tearing it apart.

Would a leakdown test show high blowby? It may be worthj it to do before I go into a 3 hour engine pull..

Keith

[SR Racing]

>>Would a leakdown test show high blowby? It may be worthj it to do before I go into a 3 hour engine pull..<<

It may. But I still don't think that is your problem. If it's leaking while idling, you simply have a leak. Your case is vented in a couple spots, not to mention there is no front seal (at the pulley), so blow-by would hardly cause enough case pressures to leak at the flywheel seal. If it did, it would be blowing it out the dip stick tube and other places. Without an good inspection of the suspect area, I can't think of anything else it would be. But I am pretty sure it's not blow-by.

[billinstuart]

If the BACK of the flywheel is oily, it's the crank/flywheel seal. If the flywheel is dry, it's the seal in the case.

[brian]

Make sure the flywheel doesn't have a groove worn in by the seal. As Jim mentioned, MOFOCO ground some FW's to eliminate the groove and ruined the dimension reguired for seal. If there is a groove in the FW sometimes installing the seal in a slightly different location will avoid the groove. You mentioned the o ring and case torque thing, make sure the main bearing bores in cases are not out of round. Bill's mention of oil travel is an excellant idea for trouble shooting. Thanks.

[Keith Lawrence]

The FW is dry, so it has to be the case seal. I also checked the FW "runout" in 360 and foudn it to be less than .001, which I believe is more measurement error.

Also the cam plug looked like the JB weld had it selaed up tight. I'm going to try one of the double lip seals...

Thanks
Keith

[SR Racing]

Also the cam plug looked like the JB weld had it selaed up tight. I'm going to try one of the double lip seals...

JB Weld shrinks to some degree and in any case doesn't make for a good seal since it dries brittle and can crack. Use RTV for that purpose.

Jim

[Keith Lawrence]

Since the engine has been pulled, the JB weld is comning off and a new cam plug and FW seal are going in.

Keith

[billinstuart]

The runout may be true, but if it was turned undersize, it may be too small. Perhaps pull the flywheel, and fit the seal on the end to check for proper contact. You are gonna pull the flywheel to increase the end play aren't you??

[Keith Lawrence]

Yep! FW is out and the endplay will be adjusted accordingly.

I noticed that I have a B type FW - it's stamped on the inner face very small and the paint on the FW almost covered it completely.

A friend with a VW shop manual book (about 4 inch thick) says that this is a "later model" 40 hp flywheel with a conical surface and it requires a metal gasket.

I have been using no gasket for the FW/crank mating surface, so I'll try that and use a "test stand" set-up to run the engine before I waste another night in the garage to reinstall and then test run it.

Anyone familiar with this B type flywheel?

Thanks
for the help.

Keith

[SR Racing]

All 1200's (1192) should use the flywheel gasket. (either metal or paper) between the crank and the FW. If you install one on yours you will probably fix the leak and you will have .010+ end play which is what you want.

Torque the gland nut to a couple hundred lbs and check your end play. If is is between .009 and .013 you will be fine. If you have to much or little you will have to change either the flywheel shims or the FW gasket. When complete, torque to 325+ and it won't hurt to use red loctite on the threads. (Keep it off the center of the gland nut near the pin bearings. Do not over tighten the gland nut. It may crack and/or swell the end of the crank changing the main bearing clearances.

[Keith Lawrence]

8-hole paper gasket + very little Permatex Aviation = priceless.

Stopped my oil leak 100%.

See you at the Pittsburgh Vintage Grand Prix (PVGP.org) races in July.

Keith