Are thick head gaskets legal for compression correction?

[Flyinglizard]

I have a few old race cars that could be over the compression limits for IT rules. Can I stack the metal head gaskets to get back under the legal limit?
Thanks, MM

[Greg Amy]

Read the rulez, newb... ;)

"Cylinder head gasket(s) may be replaced with any gasket(s) having the same compressed thickness as stock."

[Flyinglizard]

So, no provision to save all of these old race engines?
Plus, nobody knows what the OE size was/ is.

Maybe one of you insiders can write a letter to correct this oversight.

[gran racing]

Maybe one of you insiders can write a letter to correct this oversight.

If you want the rule changed and you're knowledgeable, why don't you write the letter?? ;)

[chuck baader]

Note, some manufacturers, namely BMW, offer two thicknesses head gaskets. I think they are 2mm (stock) and 3mm, just for the purpose of lowering the compression ratio if the head is milled too far. I would think the rule was written to prevent thin gaskets to raise compression.

[gran racing]

What would make that a bad thing instill of milling the head?

[Dano77]

My AS car had the heads milled too thin by "accident" we used 350 gaskets on the 305 to lower the limit, same compressed thickness different bore. The fire ring was .250 larger on the 350. Brought it from 11.0-1 down to a paltry 10.3 ish. got below the limit though.

Not saying its right, just that its an option. There must be a larger bore gasket for a VW out there with the same block?????

[Greg Amy]

Maybe one of you insiders can write a letter to correct this oversight.

"Oversight"?? For four decades...?

See, I told you guys: allow removal of washer bottles and suddenly everyone wants their own pet peeve 40-year-old reg changed.

I told you, I told you, I told you...

[iambhooper]

"Oversight"?? For four decades...?

See, I told you guys: allow removal of washer bottles and suddenly everyone wants their own pet peeve 40-year-old reg changed.

I told you, I told you, I told you...


Actually, before they did away with the washer bottle rule they did away with the VIN and sub model rule (the one that now lets you make an Si out of a DX). So if you REALLY want to talk up told you so's...:026:

[Greg Amy]

Actually, before they did away with the washer bottle rule they did away with the VIN and sub model rule...
Holy crap...YOU'RE RIGHT! I *TOTALLY* missed that!

So it WASN'T the washer bottle...that...was just a diversion! Dammit those guys are smart...

[iambhooper]

That one was kind of ridunkulous anyway. What really seperates a 4 cylinder fiero from a v6? 1 transmission and 1 motor, other than that everything is interchangeable, so it made no sense to keep a guy from building a perfectly fine ITA car out of a tub that came with an iron duke.

[Flyinglizard]

The 305 AS with 350 gaskets is should not be legal. The bigger bore gaskets may unshroud the valves a bit and increase low lit flow.

I have the customer that wants to make sure that his engine is under the limit . I advised that i expect it to be over by around 1.0 compression value. Stacked MLS gaskets can reduce that value to the legal limit.

I will have him send a letter and just put this together as is , as it has been run for 15 yrs.
If somebody on the board can respond with a valid answer ,it would be nice.
Thanks, MM

[jumbojimbo]

The 305 AS with 350 gaskets is should not be legal. The bigger bore gaskets may unshroud the valves a bit and increase low lit flow.

I have the customer that wants to make sure that his engine is under the limit . I advised that i expect it to be over by around 1.0 compression value. Stacked MLS gaskets can reduce that value to the legal limit.

I will have him send a letter and just put this together as is , as it has been run for 15 yrs.
If somebody on the board can respond with a valid answer ,it would be nice.
Thanks, MM

Clarify: Does the customer want to be under the limit or does the customer want to be legal?

To be under the limit, then go ahead and stack the gaskets and move on.

To be legal, you (or the customer) have to write a letter. It seems like a reasonable request is to have the wording changed to "Cylinder head gasket(s) may be replaced with any gasket(s) having at least the same total compressed thickness as stock."

Keeping in mind that someone may argue that milling the head down and then increasing the gasket thickness would be an advantage on some car(s) and therefore shouldn't be allowed. In which case it could be rejected. And then the answer to be legal is "new head". If this is the result then please do not come back here and whine about SCCA.

[Bill Miller]

Clarify: Does the customer want to be under the limit or does the customer want to be legal?

To be under the limit, then go ahead and stack the gaskets and move on.

To be legal, you (or the customer) have to write a letter. It seems like a reasonable request is to have the wording changed to "Cylinder head gasket(s) may be replaced with any gasket(s) having at least the same total compressed thickness as stock."

Keeping in mind that someone may argue that milling the head down and then increasing the gasket thickness would be an advantage on some car(s) and therefore shouldn't be allowed. In which case it could be rejected. And then the answer to be legal is "new head". If this is the result then please do not come back here and whine about SCCA.

No more calls please, we have a winner.

[Flyinglizard]

¨ It seems like a reasonable request is to have the wording changed to "Cylinder head gasket(s) may be replaced with any gasket(s) having at least the same total compressed thickness as stock."
Should include less than .100 total so as to keep my angle milled head shim out of play. Stacked stock style gaskets should be allowed for any car 20yrs or older.

[Greg Amy]

¨ It seems like a reasonable request is to have the wording changed to "Cylinder head gasket(s) may be replaced with any gasket(s) having at least the same total compressed thickness as stock."

That's a rule change, and a change in the basic philosophy of the class. Regardless of if/when the request is submitted, note that it cannot be approved prior to the 2015 racing season.

No one else is interested in the idea. If you want it, write your letter to the CRB and it will be considered.

GA