Oil Leak - Main Seal

[vwnc]

I just overhauled my 1600 engine for my '69 Bus couple of months ago. I built the engine from a new case with a VW reground crank and cam. New bearings, pistons, reconditioned heads, carb.....etc.. Set the crank end play at .004 with 3 shims. Installed new oil seal flush with case with an oil seal installer. Also, I installed a new rubber ring in the flywheel. All went well the first 200 miles. Then, it starting leaking oil around from what appeared to be the oil seal as oil was dripping between engine case and transmission bell housing. Over a period of weeks, its gotten worse. Pulled the motor and the seal looked perfect. Talked a technician about it and he said not to install the seal flush with the case, but to go all the way back which is about 1/16 or so deeper. That is what I did with a new seal and even checked to be sure the return oil port in the block was not clogged in the oil seal area of the block. I got the same result. This is getting old and I don't what else do. I've built 20 motors over the course of 25 years and never experienced this issue. Any thoughts would be appreciated!

[busdaddy]

Did you grease or oil the surface of the seal that touches the flywheel during installation?
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[The Pilch]

[vwnc]

Yes, I applied stp to seal and flywheel neck.

[vwnc]

Flywheel neck was cleaned and had no grooves. Very nice and smooth

[SGKent]

the leak i get is at the part lines. Need a good sealant there.
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[vwnc]

The more I think about it, the more I think I may have a spunned main thrust bearing.

[SGKent]

[aeromech]

You have high breather pressure. How about a picture or two of the engine. I’ve been down this road before so trust me
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[vwnc]

aeromech, I just added photos of the engine. I like your thoughts about the "high pressure" issue. I checked the hose between the oil filler and the air cleaner and it was open. There are two flaps in the cleaner intake and one them is sticking a little bit. Wonder if that would be contributing to my problems.

[aeromech]

Thanks for the pictures. Looks OG to me which is good. It’s the aftermarket filler/breathers that are restrictive.

On mine it leaked after a high power hill climb.
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Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[vwnc]

Well, got the original air cleaner on. The breathing plate between gen. stand and block was installed as per the Bentley Manual.

[aeromech]

Is it possible that you have a cracked case or leaking galley plug behind the flywheel? You could add some UV dye to the oil and run it. Then pull the engine and maybe flywheel. Use a black light to inspect
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Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[skills@eurocarsplus]

what style RMS tool are you using? that shitty one that is a big washer or the nice machined one with the steps in it?

I use the latter. you draw the seal in till it hits the dowels. anyone who tells you the seal is flush is full of shit. every time you hit the clutch the f/w is going to get shoved rearward and the seal will catch on the "bell" part of the hub.

also, what flywheel are you using and are you 1000% sure the graphite o-ring is in there perfectly clean? I have spent upwards of 10 mins just cleaning that groove out.

you MUST replace that o ring any time you take the flywheel off.

you're not using any of the tin/paper gaskets on the dowel/tail of the crank are you?
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[telford dorr]

One other thought: some cases have drain passages for the seal area. It's super easy to get some case sealant into it and plug it up. You can clean it out with a stuff piece of small steel wire (like safety wire).

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[airschooled]

Skills said “graphite o-ring.” This is key. A few of the new o-rings I’ve bougbt have been some generic black rubber, like an epdm material. I have had to use Curil non-hardening sealant to get those o-rings to seal properly.

The diagnosis occurs when you pull the engine and look at the back (case side) of the flywheel. There are three diagonally-drilled holes. If they are wet, the o-ring is bad. If the flywheel is wet inward of those holes, the main seal is the source. Those holes are drilled to stop o-ring leakage from contaminating the clutch. One leak I’ve seen in the last few years was not cured without a 40-horse paper gasket between the crank and flywheel.

Case/breather pressure is important to note too, as well as the weighted flap on the stock air-cleaner which keeps a vacuum on the case to promote breathing through the stock pulley. Stock pulleys are not sealed; they have a spiral groove which acts as an air pump to keep crankcase air fresh. A sand-seal here can increase case pressure too. So can rings that are not sealing properly.

Good luck,
Robbie
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[vwnc]

Robbie,
Thanks for the tips. I'll look at all the suggestions you have made. Where do you buy your seals and "o" rings? Jay

[calvinater]

Yes where to get the graphite orings and elring seals ?
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[vwnc]

Yes, where do you get the o rings and crank seal?

[skills@eurocarsplus]

victor reinz 311 105 295A, Flywheel O-Ring and 113 105 245F, Crankshaft Seal I prefer the elring for this.

that groove in the flywheel HAS TO BE surgically clean. you'll find old rubber in there. use picks and dental tools to clean it. when you think it's clean....clean it again
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