Cylinder shim questions

[woodsbuggy1]

I am working on a 2276 build with a case that has been decked. I require .090 cylinder shims and .050 copper head gaskets to achieve .050 deck height on my turbo motor. Does anyone actually sell cylinder shims that measure what they are advertised at? The empi ones that I have measure larger and the CB ones that I received today only measure .0840.
Thanks
Kenric

[Piledriver]

EMW makes them custom in any size you like (for type4s at least) but they do T1 stuff as well since dirt.
aircooled.net IIRC carries a good variety, or used to.

To achieve same deck 2mm base shims and .060 head seals would be standard thicknesses and likely available off the shelf.

[Marc]

How much lower is your C.R. going to be if you just use the thicker EMPI shims? I doubt that it'll be enough to lose sleep over.
Unfortunately most cylinder shims are just stamped from sheetmetal and ± .002-.005" from nominal thickness is common. You've got to spend a bunch more for precision blanchard-ground spacers and I don't know where you'd get them for 97.25mm diameter (Berg only offers up to 96mm)...you might be able to sand 96mm spacers out to fit, but Pile's idea of stacking shims has merit. I've never encountered a problem with stacking them - even though it's admittedly not best-practice, it seems to work just fine in the real world.

The combination you're shooting for implies zero piston deck and relies upon the copper head gaskets alone for piston-to-head clearance, and that worries me a little. Any sliver of the head gasket that overhangs into the chamber could be struck by the piston so the I.D. is critical...2x.040" + .060" may not be the best plan for that reason. How 'bout just using the .084" cylinder spacers plus some ~.010" along with the .050" head gaskets? Or would that be about the same as just using the EMPIs?

If you want to stay totally anal about this, just for sh*ts & giggles you might try requesting a quote for some custom stainless-steel shims from these guys: http://www.phoenixspecialty.com/product ... om%20Shims

[Chip Birks]

Try Rimco, they can probably do whatever you need.

[ps2375]

http://carcraftstore.com/cylindershimsets.aspx

I haven't ordered from here yet, but if I decide to bump my CR, this is where I'm getting them.

[Piledriver]

Good find.

Wish T4 folks could get that kind of choice for that sort of price.

[woodsbuggy1]

Thanks everyone for all of the great input. I was trying to avoid stacking shims, but that seems unavoidable at this point. My new plan is to use .100 shims under cylinder and .040 copper head gasket that should allow me reach my goals of .050 dh and 8.6 cr with 66cc head chambers.
Kenric

[Tony Z]

you'll be better off stacking and not using the copper gaskets. Copper work hardens and will eventually lead to little bits glowing red hot and causing detonation.
Each to their own, VW removed them from the T4 for a reason

[Marc]

Agree with you there, if the I.D. of the head gasket is too small it can overheat from exposure and fail - even the laminated OEM Type IV head gaskets did (especially if used with overbores).

It makes no difference to the quench volume if piston-to-head clearance is due solely to piston deck height or to a combination of that plus head gasket thickness, so there's no performance advantage either way.

I've never been a proponent of copper head gaskets in most N.A. applications, but you can make a case for them in a turbo motor. They can act as a "fuse" at the cylinder-to-head seal - if you shut down at the first sound of compression leakage, there's a better chance of the heads & jugs being salvageable than if they were run in direct contact.
If you're drag-racing near sea level one week and in Colorado the next, you might want to be able to change the C.R. to maintain consistency without changing heads or yanking the jugs...head gaskets do offer that option.

I don't use 'em for what I do, but I can still appreciate why others might choose to if they have a good reason.

[woodsbuggy1]

I received some .098" Scat cylinder shims today from Gary Davis and they actually measure .098" , that allowed me to finally get my deck height sorted out.
Cyl 1 .0095"
Cyl 2 .0085"
Cyl 3 .0125"
Cyl 4 .0120"
If I use the .040 copper head gaskets that I already have it will give me right around .050" deck which should be great for this turbo engine.
Thanks
Kenric

[Piledriver]

Are the rods different lengths, or are you getting the case decked to fix that?

[Chip Birks]

I'd have a hard time paying a machinist to perform the setup required to deck that case .004. Just run it as is, you'll be just fine.

[woodsbuggy1]

The case had been decked, but not correctly so I had to machine the cylinders to compensate for this(my first time with cylinders in a lathe) so I think that I can live with what I have. I am a big fan of copper head gaskets and would not build an engine without them. Thanks Again for all of the help.
Kenric

[machineshopjohn]

problem is that not all cases are the same height from the centerline of the crank to were the cylinders sit

check your rods with a dial caliper take 1/2 pin dia and 1/2 housing bore dia and the length between the pin bushing and the rod bearing bore add together and then check to each other
new rods will be within .001 thou

reconed rods can be as much as .005 or more difference on rods from center to center

rimco will make you shims at what ever thickness that you need

i don't like to stack shims because most all the shims are stamped out and have a rounded side and a flat side and as you stack them its just another place for an oil leak..