Differences in 964 engines
Discussion
Hi all
Would I be right in saying that there was an improvement in the engine sealing approach from 964s after 1991? Thus, if one is looking for a 964, you'd be better to get one as late as poss (like a 1992/3)?
Do these late ones still need top end rebuilds, and does the addition of a Cat for post 92 cars create any drop in power?
Ta
Benj
Would I be right in saying that there was an improvement in the engine sealing approach from 964s after 1991? Thus, if one is looking for a 964, you'd be better to get one as late as poss (like a 1992/3)?
Do these late ones still need top end rebuilds, and does the addition of a Cat for post 92 cars create any drop in power?
Ta
Benj
Benj,
I guess, in a perfect world you would aim for one of the post 91 models with the head seal ring (it's not really a gasket) but there are plenty of pre-91 cars which don't have a problem - and there are plenty of post-91 cars which do!! The requirement for top end rebuilds is not directly an issue of whether they have head seals or not - it's more to do with valve guide wear and the general condition of pistons rings etc. leading to poor compression. Many owners have had the old style heads machined to accept the new seals but the newer heads are different (with more "meat" around the seal area) so there is a chance that machined "old" heads might be susceptible to some other type of failure. The only real solution (if you need one) is to fit new heads and barrels - but it's a pretty expensive solution.
There was no catalytic converter added in 1992 - the 964 had a cat from the outset in 1988 (1989 MY). It's just that you can remove the cat on pre-92 cars since the CO limit is very different.
Regards
Dave
I guess, in a perfect world you would aim for one of the post 91 models with the head seal ring (it's not really a gasket) but there are plenty of pre-91 cars which don't have a problem - and there are plenty of post-91 cars which do!! The requirement for top end rebuilds is not directly an issue of whether they have head seals or not - it's more to do with valve guide wear and the general condition of pistons rings etc. leading to poor compression. Many owners have had the old style heads machined to accept the new seals but the newer heads are different (with more "meat" around the seal area) so there is a chance that machined "old" heads might be susceptible to some other type of failure. The only real solution (if you need one) is to fit new heads and barrels - but it's a pretty expensive solution.
There was no catalytic converter added in 1992 - the 964 had a cat from the outset in 1988 (1989 MY). It's just that you can remove the cat on pre-92 cars since the CO limit is very different.
Regards
Dave
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