cylinder to case tolerance

[VWporscheGT3]

Hi guys,
having a hard time finding it, but i am looking for the proper cylinder to case clearance... are we talking .005" here or what. I have some fairly early AA 94 mm cylinders and the step at the base is about .002-.005 too large for the bore. if I am not making sense let me know.
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Schnell, SCHNELL!

I like being wrong, Because, it is another opportunity to learn. If you stop learning from your mistakes than what is the point?

If you have any questions about Forged ICON 4032 VW pistons just shoot me a line.

[Brian_e]

I like the bore to be about .010" larger than the cylinder. Not sloppy, but not a press fit. This will help with differing hole spacing on the case and heads, and it will help the assembly go smoothly.

Brian
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www.type-emotorsports.com

[VWporscheGT3]

Thanks Brian,
I really appreciate it, I'm sure I've seen that before in the books but my mind just isn't registering. now lets get this case preppped!
_________________
Schnell, SCHNELL!

I like being wrong, Because, it is another opportunity to learn. If you stop learning from your mistakes than what is the point?

If you have any questions about Forged ICON 4032 VW pistons just shoot me a line.

[mark tucker]

many heads have a .030 clearance witch helps account for cases that have been done with those old handy dandy dripp press flycutters that many people seem to like to use with a hand drill or drill press and dont really have a clue what they are doing and get them off center...Ive seen some realy fucked up cases. I usualy try to do mine about .005" on the case. execpt for my old 2028 that used the old berg slipin 90.5's I bored the case to axcept the new std 92/90.5 size then steped the cylinder as I had to shorten them any way.but it's a very short step. zero leeks.

[RWK]

And more importantly, make sure your decks are flat and parallel. at least per side, any deviation here causes your cylinders to set crooked and not seal on the head.

nd more

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73 Type 181
63 Type 113
63 Type 261- 428 071
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[nsracing]

0.002 -0.005" is fine if bored w/ precision and good tools.

0.010" is kind of on the redneck side = butchery! It is typical tolerance w/ a berg cutter tool. But it should not be that loose w/ a proper mill and boring head.

[VWporscheGT3]

[Brian_e]

The necessary clearance on the case depends on how accurately the heads were machined. If the center to center bores on the heads are off, a tight case bore will cause some problems when you go to assemble it all.

In a perfect world, all these things would be..........perfect and correct. These engines are FAR from perfect in the machining department once aftermarket parts are introduced.

In the end...If the case bores were .100" to large, it really wouldn't matter one bit, as long as there was enough room for the cylinder to sit and seal. No it wouldn't be ideal or correct, but it would work just fine. What I mean is.....don't get caught up over +/-.003". A tiny bit larger is better in this one situation.

Brian
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www.type-emotorsports.com

[nsracing]

IF Bubba got hold both of the heads and case first, then all parts will have looser tolerance. You will probably use 3-4 tubes of sealer.

If Bubba only got hold of one then other part machined w// precision, it can be tighter on the last part machined.

If the parts were machined by someone w/ a stick up his ass w/ precision, then the tolerances will be much tighter.

It all depends on who cut it and w/ what tools. Machining VW parts comes in a variety of tolerances. HOw much gap do you want is the question.