Re: [T3] Compression Woes

[Jim Adney <jadney@vwtype3.org>]

On 6 Jul 2006 at 20:17, knowonelse@sbcglobal.net wrote:

> Looks like I'm in the market for a pair of heads.
> Photo of the head is at:

> http://www.thesamba.com/vw/forum/album_search.php?search_author=Jeff67sqbk

Looks to me like you just need a valve job. The heads themselves are probably 
fine.

Clean 'em up, put in new exhaust valves and guides, machine the seats, and 
you're back in business.

Once you get them cleaned up you should check where the loose head was hitting 
against the low compression cylinder. If it has been loose for long, the 
cylinder may have banged a depression in the head. If that's the case, all 4 
cylinder spigots should be flycut the same amount, just to keep the compression 
ratios equal.

If the heads don't appear to be a matched set, then you might want to measure 
the chamber volume on each one and adjust the flycut depth to even them up, but 
keep in mind that you want to flycut both spigots in a given head to the exact 
same depth.

Don't take off any more than you have to.

BTW, you should also make sure the case studs aren't pulling out. To test them, 
you actually need to overtorque them and make sure they don't strip. Don't 
overtorque too much, perhaps 5 ft-lbs, but someone else here may know the rule 
of thumb. You need to do this because the studs actually get tighter when the 
engine is warm.

Of course, once you're actually assembling your engine you should torque them 
to the factory spec.

-- 
Jim Adney
jadney@vwtype3.org
Madison, WI 53711-3054
USA

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