Sand Seals

"Feel free to condescend."

Ah, Michael, you get it!

Yeah, they keep oil in as well. Berg claimed you needed to cut the case for a seal to fit properly, but that may have been just to sell the tool as well...

To work I go now. Yoda out

Don't you know anything Mike??

The sand seal keeps sand out by allowing enough oil to escape to flush the sand away from the crank pulley. Geeessshhh what a bunch of amateurs. Next thing you know Al will tell you to follow the oil.

Ok, now, that was really funny...

PS- This guy doesn't know what he's missing by leaving (not you, Michael- just thought I'd spell that out. I've caused enough trouble for 1 day)

I love this site! However, I don't have a thing to offer to this thread. Wish I did. Forgive me, Mike!

Robert M speaks for me.

In an effort to offer real advice I would suggest Mike you may want to PM Ted aka TRP. He had a real go around with his case as it had a sand seal when he got it and IIRC he was able to correct it. It might be more than you want to get into though if the amount of oil is negligible.

I guess that might not really qualify as advice but it moves your topic back to the top.

So what's the big deal...A little oil?

I'm running a 2,110 and whenever I push it hard (3,500+ for 2-3 hours) I get some weeping below the crank pulley.  Is no Big-a Deal.  That's what the designers wanted - to blow any dirt out of the crank/case interface behind the pulley.  

The bottom of the tin should even have a teeny-tiny spout in it to guide the little oil drips as they head for free-range-oil-land.   If I've been driving hard it gets a little wet at the bottom of the tin and maybe I'll get a drop or two on the ground after I stop, but it's certainly not enough to notice a loss in oil level.  It usually burns 1/2-3/4 of a quart between oil changes (3,000 miles) and that's it.  Besides - I grew up on VW motors that typically leaked from any of 30-odd places.  What was one more?

You should talk to or PM Ted - IIRC it took him a while to get his right, but I think he was satisfied in the end.  I don't think I would try to do this with the engine in (not a lot of room for tools down there) so you must consider that as well. Berg does, indeed, sell a neoprene nose seal (for $20 bucks) as well as the cutting tool (for $180 bucks) to relieve the case so the seal would fit properly.  You have to use the neoprene seal - using a steel-ringed seal will damage the case.

Good luck

OK, maybe I should leave well enough alone. I just thought maybe it would be an easy fix.

Mike,

I had a problem on my TD with this issue. Smaller engine 1641 but leaked anyway. Tried installing more engine case vents and that helped but still leaked. My engine builder told me to throw away the nice looking aluminum pulley and install an original German pulley ( he had an old one laying around ). Once done my leak in that area stopped. Seems the cuts in the original pulley throw the oil back inside much better. You might try both those options if you have not done so already.

Of course I still have a small leak at the rear seal. That will be fixed next time I pull the engine for some reason. always something...

Go to TheSamba, and they'll shout you down about sand seals being meant to keep sand out, not oil in.

I've always wondered though... if that's the case, then why are the seals aimed like they are keeping oil in?

A: Because, to some extent: they do. 

There's a longer/better answer here.

If you are involved in any discussion of anything for a certain length of time in the "ACVW online community", someone will eventually get back to "the sainted German engineer" who designed this or that perfectly, so that no modification could ever be an improvement. The entire oiling system is a Rube Goldberg contraption that relies on viscosity to determine oil temperature, etc., but discussing it in a rational manner with a true believer is a fool's errand. The cooling system is sacrosanct, it's the third rail of the subway-- touch it and die.

The lack of a rear seal will garner all kinds of ridiculous defenses from this crowd. "The giant hole RIGHT NEXT TO the oil level won't blow oil if the rings are tight, etc. It's fine just the way it is. Perfect, in fact."

When it was being designed 80 years ago, it all boiled down to economics-- in a size tiny engine in a time when oil leaks were pretty much just par for the course, getting away with a slinger and a pulley with oil grooves was "good enough". It wasn't ever intended to be the one true path, but don't say that in Samba-world.

Anyhow, the case is pretty small. Increasing the stroke makes it even tighter inside, to the extent that in some combinations the camshaft must be clearanced to miss the crankshaft. There's a lot of pumping action inside that case, creating a lot of turbulence. Each quarter revolution of the crank pushes a piston down into the case, creating a pressure wave-- of course, there is a piston going up as well, but the oil vapors inside the engine are moving around a lot, even with a super-tight engine. Increasing the bore and/or stroke increases the volume of this displaced air/vapor.

That would be enough, by itself, to warrant a seal. However, throw in the fact that no engine is 100% tight-- even race engines have 5-ish% leak-down. A standard "good enough" engine build will have more than that (a lot more). Keep in mind, these engines don't even have valve seals. With the case being pressurized by blow-by, and the entire mixture being pumped by the action of the pistons, it's kind've amazing that the thing doesn't blow oil worse than it does.

That's why we need case vents, etc. A decent PCV system would greatly reduce the pressure inside the case, but I'll be a monkey's uncle if anybody seems to be trying to make that work. Everybody seems to be happy just blowing oil like it's 1935. A seal helps, but it doesn't fix it.

I hate oil leaks-- I really, really hate them. I have a seal. I also dry-sumped my engine, in no small part because of my inclination to "THAT ought to do it" overkill. Drawing a vacuum on the case is a pretty good way to get rid of the pressurization. I've also got a breather box with about 3 gallons of capacity. To my way of thinking, the box has to be at least equal to the volume of the case to actually do anything. I'm running 1/2" hoses to it. It's not vented. I draw off the top of the (sealed) box, and run to a Moroso check-valve and a Bernoulli tube in the exhaust to draw a vacuum on the entire box.

It's pretty oil-tight, but it took redesigning the entire thing to get it that way. In more pedestrian engines (like my 2110), bolting on an extended sump and running the thing a 1/4" low on oil (don't freak out-- the pick-up is in the sump) seems to keep the oil level away from the crank-pulley hole, and give the case a bit more volume. I seem to spray less running it that way. But maybe I'm just deluding myself.

So... the short answer is "Yes, it'll help keep the oil inside the engine. No, it won't (by itself) fix anything. But a seal is just a good idea (kind've like a remote oil cooler)". If something can't hurt, and can only help, why would we obsess over if "it's really needed"?

That's my story and I'm sticking with it. Your mileage may vary.

In 2015 tooling around Northern Virginia in my Beck Speedster I heard a strange noise so I pulled over to discover the Crank Pulley nut had come loose. I have a CB 1915 with AC and didn't realize the nut had come loose until some damage was done. Carey sent me a new pulley with the AC pulley attached so I could go to Carlisle that Spring. I installed it but while driving up to PA and halfway there I smelled oil,it had sprayed all over the engine compartment. The loose nut had done some case damage. Carey and others suggested a sand seal pulley. It's basically the same crank pulley with a rubber seal. I put the sand seal pulley without an AC pulley in and have been driving the car for a year and not one drop of oil (knock on wood) has leaked since.

Yesterday, I installed a sand seal pulley with the AC pulley on that SE's Carey made for me and now have the AC running again (Just figured I might as well use it since I have everything in the car to do so).

So all that said in my case the sand seal did work.

Pete

Michael:

If you decide to move ahead, you might check out CB's Santana style pulley with the sand seal kit. Part #1917. They have others as well. Friend of mine has this one and solved his problem.