shaaark89

changing (or rather changed) heads in one of the racecars (heads were cracked.)
noticed some discussion here that the 2r and later had longer bolts. the old heads were 1r new 3r. can i still use the same bolts?

James Bailey

Most are the same length but the thicker boss on a couple holes use longer bolts . I do not have PET up but just check it....

DR

Hi Tom,

There is 19mm differential between the early and late head bolts (130vs149, 180vs199). In the world of head bolts I would call approx 3/4" pretty substancial.

See Pet 87-91 Illustration 103-00 and according to it this includes all head bolts..

blown 87

Hi David, that change started withe the S4 R2 heads, is that correct?

DR

Yes, starting in early 89 Production with Engine #81K 00121 (manual) and #81K 05328 (auto)

blown 87

Do you know what the modifications were to each revision?

This R1-R4 has a lot of folks confused, like was there a head before the R1? Was that the 85-86 heads and the first revision R1 heads were the S4 ones.

Here is what i think, nothing to back it up at all.

The 85-86 heads were a no revision number head
The R1 heads were 87-88, they are short bolt heads.
The R2 were from 89-? and were the same as the R1 heads but had more thickness in the areas prone to cracking and used the longer bolts.

The R3 heads were ??????, I have no idea.

The R4 were the last revision and had the so called steam holes.

DR

That's getting into "Greg Brown territory", I would trust his extensive hands on experiance/observations more than the Porsche documentation and/or mine.

White Lightnin'

David... PM sent on unrelated matter.