I have a chronic oil leak on my VMC Speedster that appears to have its origin at the vertical seam between the case halves. See pic. Is this a common problem?
The leak has been there since purchasing the car new in December 2022. Do other folks have this problem?
Jason
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i dunno, maybe retorque the bolts in that area
Is it an actual leak? As in observable on the dipstick reading?
Or what I term "sweating" or "seeping".
They pretty much all leave their mark.
Torque the case bolts, if it stops, great. If it doesn't, put a tray or a piece of cardboard under the oil sump in the garage.
If it is measurable on the dipstick in a short time period, then maybe the case needs to be re-sealed. It happens.
@DannyP posted:Is it an actual leak? As in observable on the dipstick reading?
Or what I term "sweating" or "seeping".
They pretty much all leave their mark.
Torque the case bolts, if it stops, great. If it doesn't, put a tray or a piece of cardboard under the oil sump in the garage.
If it is measurable on the dipstick in a short time period, then maybe the case needs to be re-sealed. It happens.
It's more of a seep than an outright leak.
There's a bolt and nut nearly directly above the drip in the pic that helps retain the two case halves. I removed them and observed an oily film in the bolt hole and on the bolt, suggesting that oil was getting past one seam barrier. I thought perhaps the oil may then be migrating past the head of the bolt and/or nut so I cleaned them and applied a liberal amount of Gasket Maker to the contact surfaces. I'll check today to see if my gasket sealant has made any difference.
Jason
@jncspyder posted:
I've owned numerous air-cooled motorcycles and none of them leaked at the engine cases. So I'm a bit surprised that the VW cases leak. I use Yamabond exclusively to seal vertically split cases whenever I'm rebuilding an air-cooled motor and it's never failed me. That stuff is tenacious!
Reportedly the motor was built by Pat Downs, but it appears he doesn't use Yamabond. The residue around the case joint suggests Pat used Gasgacinch, which is good stuff but not the best for this application in my mind.
Jason
@DannyP posted:Torque the case bolts, if it stops, great. If it doesn't, put a tray or a piece of cardboard under the oil sump in the garage.
Yep, like the guy who used to work on my 911 used to say, “A quart of oil is $8.95. And engine rebuild is around $10,000. What do you want to do?”*
*It was 15 years ago. I think a head job would be about $10K now. When I was there last fall he had a twin plug 2.7 rebuild that he told me had just passed $25K.
@jncspyder posted:
Yeah yeah yeah, we know. You tell us about your great decision every opportunity you get. But you had to deal with John, so I get it. You made the best of a bad situation.
But a lot of us here are completely unconvinced of watercooled superiority. They're not superior. I absolutely love my aircooled and EFI type1. It's every bit as reliable as anything else out there. I could literally drive it to Cali, change the oil, and drive back. That's how confident I am.
Jason, I have always used Permatex Aviation sealant. Good stuff, always works for me. I've never tried Yamabond, but I know people have gotten good results.
@JasonC posted:… Reportedly the motor was built by Pat Downs, but it appears he doesn't use Yamabond. The residue around the case joint suggests Pat used Gasgacinch, which is good stuff but not the best for this application in my mind.
Curil T was the absolute go to before they changed the formula. Nobody likes it anymore. There’s no universally accepted sealant in its absence, so I’d be curious what it is between your case halves- but I’d be stunned it was Gasgacinch. I haven’t seen that stuff in 40 years. There are a lot of flange sealants out there.
The idea is to be able to split the case again without destroying the soft-metal sealing surfaces. Yamabond is tenacious, as you say, which makes it pretty much like glue, which is probably why Mr. Downs didn’t use it.
Any recommends to seal an aluminum valve cover onto the aluminum head on a BSA motorcycle ? I noticed that my 441 valve cover leaks a fair bit in one location about an inch long and likely the bottom of the valve cover or the top mating surface of the head or both may not be exactly true. Would I dare install two new gaskets to take up some space ? What might be a good sealant in this case ? Thanks.
@David Stroud IM Roadster D posted:Any recommends to seal an aluminum valve cover onto the aluminum head on a BSA motorcycle ? I noticed that my 441 valve cover leaks a fair bit in one location about an inch long and likely the bottom of the valve cover or the top mating surface of the head or both may not be exactly true. Would I dare install two new gaskets to take up some space ? What might be a good sealant in this case ? Thanks.
It sounds like the valve cover is not flat. I've had good results flattening Norton tappet covers using a sheet of wet/dry sandpaper and a flat surface, preferably a piece of glass.
Failing that I successfully used Permatex Right Stuff 90 Minute Gasket Maker on my 1966 MGB differential to seal the irregular sealing surface on the housing.
Jason
My brother had the same problem on a Norton 750 Dunstall (which, when it wasn't trying to shake/vibrate itself to death, leaked here and there).
He cured the valve cover leaks (for a while, at least) with Permatex Aviation Form-A-Gasket No. 3
The other case leaks he just put up with, like other Norton owners.
@DannyP i was a very competent VW person back in the day....probably not on your scale which i totally admire your automotive talent...and had my share of good times in my air cooled VW era...which FYI every one "seeped" oil....just goes with the territory..i also raced desert on huskys..and have had a couple harleys...and wrenched on all of them....all i am saying is at 66 i'm kinda over being a mechanic...i still have some knowledge should it become needed.....some like fiddling with carbs... valve adjusting etc etc ...all the things that come with air cooled...which is fine and dandy....liquid & air cooled both have their pros & cons....and i don't believe either or are more superior than the other....my point is i'd rather just drive and not tinker nowadays...that's all...and for the record...my Dr.Jekyll days really were way worse than almost any day i had working on VW's haa! happy motoring and happy thanksgiving to all our car guys 
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Jason, as you're discovering, drivers of these aircooled engines learn early on to distinguish between leaks and 'seepage'. Seepage is a leak you choose to ignore.
It's usually owners of new cars who are bothered by seepage because none of the more serious engine and mechanical problems that will inevitably follow have had time to surface yet. In time, you'll either pretend not to see the seepage altogether or wipe it off quickly with a rag while trying to figure out why the inside sidewall of one of your rear tires is suddenly covered with oil. And, by the way, if you get into the habit of not looking under the car, you'll never have to deal with seepage at all.
The creators of these engines incorporated seepage in the design as a means to sharpen our observational and deductive skills. Seepage never actually occurs at the place where the oil accumulates. The source is generally somewhere upwind or upstream, but not necessarily. Things as obscure as capillary action will move the oil around and I'm convinced that other forces not yet discovered by science are involved as well.
My particular car is subject to temporal seepage. Nothing ever seeps while I'm watching. I can wipe off the seepage after a drive and if it stays parked for two months, there's no subsequent oil accumulation. The more gullible will say that this means that small gaps open as the engine is driven and heats up, or that crankcase pressure is to blame, but I know the sources are supernatural.
The only good news is that most of us now have a pretty steady flow of Amazon boxes through our garages, and that is some of the most absorbent cardboard available.
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I dunno about that “Temporal Rift” thing-a-ma-Bob, @Sacto Mitch
My belief is that it is a Quantum Effect, kind of like the aircooled version of Schrödinger's cat. Maybe Schrödinger's Seepage?
It never seeps when you’re lookin’ at it, only when you look away.
So I guess then, maybe it might be like the “Weeping Angels”
(Google them)
Hmmmmmm….. That might be “Temporal”, after all.
Doctor Who would use his “Sonic Screwdriver” on it.
Wow….. Is that “Thread Drift” or what!?!?!?
Mischievous elves with Brad Penn 20/50 oil filled squirt guns live in my garage.
I wouldn't worry about it; that is minor. Just check it occasionally and replace the oil as necessary; you should see mine 
I guess I'm just one of the lucky ones. My 2332, sourced by JPS ca. 2006 had a pretty good leak at the rear crank seal that was fixed with two new seals applied. All good now and has been for many miles. The case does show some mild seepage (the source, as described above, is well hidden) which I rag off once or twice a year. There really is no dripping on the floor, which I will count as unusually good. My two prior 1600 P- engines ( a '56 Normal and a '61 S90) did indeed seep and drip a little oil on to the floor. The real deal with the S90 was that it was built to burn oil at the rate of a qt every ~500 mi. It came from the factory that way, set up loose for racing, with those ingenious (Devilish??) dimpled barrels. Eventually I retired those barrels and pistons in favor of cast iron ones as used on Super engines of that era. Theoretically, I lost a bit of compression, but never had to add oil again between changes. Retaining the S90 heads and carbs, I was hard pressed to notice any performance differences. I did not race the car, it was my daily driver and occasional hooner.
Gunk Engine Degreaser could be your new best friend.
Have used that product. Works. Just going over the bottom parts with a rag is fairly easy and less messy.
