(I've cross-posted this to rec.autos.makers.vw.aircooled since it is becoming increasingly on topic for that group (and much less so for alt.autos.toyota). )
>>>> "Philip®" == Philip® writes:
Philip®> Dale Henderson wrote: >>>>>>> "MH" == MajorDomo writes: >>
>> Indeed today engines are built to closer tolerance then ever >>> before, but NO manufacture not even Ford machines a block or a >>> head so close that it could be assembled and run without a >>> gasket for even 330 miles, let alone 33,000 miles. Not even >>> 150K racing engines could do that, the only thing polished to >>> the kind of tolerance that would permit anywhere near that is >>> in nuclear equipment. To suggest the engine factory 'never >>> installed one on the right bank and it ran great for 32000 >>> miles' is just a bunch of BS, period. >>
>>> mike hunt >> Actually air cooled Volkswagens never used a head gasket. >> Philip®> FACTUALLY incorrect.
Philip®>
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"There is a Philip®> technical bulletin published by Volkswagen in 1990 that Philip®> describes a few changes they make upon reassembly. First, Philip®> eliminate the OEM head gasket and replace it with a 1.6mm Philip®> aluminum shim (#071 101 34), or a steel one, at the base Philip®> of the cylinder between the cylinder and crankcase. Philip®> Increase the piston / cylinder clearance to ..045mm Philip®> (.0017"), +/- .005mm. Cut a 1.5mm deep oil groove in the Philip®> large end of the connecting rods into the thrust surface Philip®> on both sides to splash oil on the bottom of the Philip®> pistons. For a more detailed description of these Philip®> modifications, send an SASE to Bob Donalds, and he'll Philip®> give you a copy of the bulletin." This site is about the 2L "pancake" engines used in later vans and type 3 and 4 VW's. I'm more familiar with with the upright engines that were used in the type 1's (Beetle, Ghia, etc.) which I still believe never had a head gasket. Perhaps my original statement was too broad.
Note however that the above section recommends "eliminating the OEM head gasket" this only strengthens my point that an engine can run without a head gasket. Note also that the shim mentioned doesn't replace the gasket since it goes between the cylinder and crankcase NOT the cylinder and head.
> And they weren't built to close tolerances.
Philip®> GENERALLY speaking, liquid cooled engines have pistons Philip®> fitted to less than .025mm (.001") these days. I was responding to the OPs statement that no engine was built to close enough tolerances to run without a head gasket when the VW, which had no head gasket (or the gasket could be removed), routinely ran without one. (I assume he meant the mating surfaces matched perfectly and this has nothing to do with piston fit.).
> So an engine running a long time without a head gasket isn't >> that unbelievable.
Philip®> Piston fit is not relevant to whether or not a head Philip®> gasket is required. You would make a better argument by Philip®> saying compression is *a* determinant of the need for a Philip®> head gasket. I didn't say it was. I was only making the point that engines *CAN* run without a head gasket.
> I'm not sure about a water cooled engine that was designed to >> have a gasket though.
Philip®> They are and do. Let me restate that: I'm not sure how long a water cooled engine that was designed to have a gasket would run without one. Probably not long.
> And just to further bedazzle those who don't know what air >> cooled means they didn't have radiators either. -- Dale >> Henderson
Philip®> Dale ... Air cooled VW *do* have a "radiator" (it's Philip®> called an oil cooler) and a fan. I'd say you need to Philip®> update your data base. ;-) --
Yes I know an oil cooler is a radiator (so is a heater core and an AC evaporator or condenser for that matter) and a vital part of the cooling system on an air cooled VW. But it is not what most people think of when the term radiator is used. Philip®> - Philip @ Maximum Torque RPM