Sand seal, how do I tell?

Look into the bore of the case where the crankshaft emerges....  Is there a rubber lipped seal visible?   If not, your engine has probably not been machined for this feature...  If it does, you should be able to CAREFULY remove the seal and install a standard pulley with out a problem,as the seal bore should be only marginally larger than the stock bore....

As Leon said, there will be a seal in the opening if the pulley is cut for a sand seal (I will try and find the dimensions later, if I get a chance). There are seals that fit in the stock opening and then the case needs to be cut for the seal Gene Berg Ent. uses, so if it is bigger than stock I don't know about using a regular pulley and no seal. You could get the pulley you have turned down to the dimension of the one you pulled out. Make sure the machinist leaves a radius in the inside corner and polish the surface the seal will contact.

PS- I have seen aftermarket pulleys that are the stock dimension but with no oil throwing thread cut, so be sure of what you have. 

Hope this helps, Ted. Al

Hey Guys,

Yup, It had a sand seal in it. I pulled it out. I can see the case was machined to accept this seal.  I'll call ole GB on Tuesday to figure out my next move.

I'd like to not run a sand seal pulley.

Ted

There's two types of sand seal. Bolt-in or machine-in. The bolt-in type comes in a press-in carrier that sticks out of the front of the case about 1/4". No case mods are needed and can be installed with the engine assembled. This style uses washers on the upper and lower pulleys to maintain clearance to the seal carrier and a longer pulley bolt due to the extra depth.

The machine-in type is where they cut a groove in the case to accommodate a flush mounted seal. No spacer washers or longer bolts needed.

If the case has been cut for a machine-in type seal, that has removed most of the original metal sealing surface for the stock-style grooved pulley. I would think you would get more oil leakage if you tried. I suppose you could get a machined ring to install back in place of the removed material, but I've never heard of anyone doing it. Why do you want to go back to stock?

For those unaquainted with VW OEM front crankshaft oil seal technology, it involved a spiral groove machined into the crank pulley "neck" that carried oil back into the engine when required. The opening was shielded from crank case splash by the crank shaft design and bearing location...   It worked well below 3,500 rpm, and was reasonable at higher speeds....   The sand seal was adopted to keep dirt (sand) out, rather than oil in....

OK, so Justin gave us a great description of how a "sand seal" is added to a VW engine, and Danny P. gave us a bit more info and also that the "sand seal" keeps dirt out, not the oil in, so how, exactly, is the oil kept in the engine if it isn't "sealed"?

Well, that takes some ancient technology call "Centrifugal Force" and a clever use of it, developed during the early part of the Industrial Revolution.  Look here V....

This shows the internals of a stock, VW engine with the fan pulley on the far right.  

Just inside of the case from the fan pulley is a circular cavity that the crankshaft goes through and attached to the crankshaft inside of that cavity is a "Slinger Washer".  

That cavity has a drain hole in the bottom that allows any oil entering in there to drain back into the sump.  Just to the left of that cavity is the front (toward the pulley) main bearing, which has oil, under pressure, between the crankshaft and the bearing.  When the engine is running, that oil squeezes out on both sides of the bearing, mostly going back into the sump but some of it ends up riding the crankshaft into the slinger cavity, where it hits the washer and centrifugal force slings the oil outward into the cavity to then drain into the sump through the drain hole.

Pretty simple, huh?

And THAT explains why, when we have too much crankcase pressure (from an inadequate breather box) some oil gets forced out behind the pulley and leaks.  Too much for the slinger washer to handle, or the case pressure simply blows some oil out past the washer.  Either way, there is no "seal" there, just an oil management system that works well for a stock engine, less so for a larger displacement engine unless case pressure is more equalized.

I don't know (never worked on one) but I bet that a type 4 engine has a real seal behind the pulley....

Hope this helps.....gn

Sorry, Dan......I saw the Avatar of a Spyder and, you know.......

Well.....You're the "Spyder Man" aren't you?  

My now-on-Medicare mind just made the connection from the picture.

And I apologize to Leon, too.  You don't look like Danny at all.....lots more hair, too.

Like my new Avatar?  That's me after blowing out the driveway, yesterday.  Today, I get to re-rake the roofs, for the fifth time, now..........

Yeah, I guess all us Spyder guys are somewhat alike......

I have a really nice Berg Acheiver pulley I was going to install. I picked it up before I knew that my case had a sand seal. I have the machined type of sand seal, so  I guess I will go with a 7" sand seal pulley and install a new seal.

Anybody want a ripping deal on a berg pulley.

No biggie. I'll call CB on Tuesday.

Ted

You could always have the Berg pulley machined for sand seal use. It's all steel so no worries about the seal wearing grooves into aluminum.

Call a couple of "Jobber" type machine shops for quotes.....  It should not be too bad...