[V8] '92 with a broken timing belt

[DasWolfen at aol.com]

In a message dated 1/7/04 3:16:31 PM Eastern Standard Time, 
Anthony.Hoffman at tinker.af.mil writes:

> On the subject of a broken belt, If you were to change the affected 
> head(s),
> are the 4.2 and 3.6 heads interchangable? If not, what are the differences?

 No they are not interchangeable. All the parts with the exception of the 
casting are identical. The 4.2 uses a different bore spacing than the 3.6 so 
4.2's have revised combustion chamber locations and coolant passages. Audi went an 
extra step to ensure that you don't try it either, they moved the locating 
pin locations on the block/heads.

 Rebuilding a V8 head isnt any more cost prohibitive than any other head. A 
couple of intake valves, maybe some guides if the valves really got whacked 
hard and new lifters for the bent valve positions. I recently had a pair of 3.6 
heads rebuilt, including 32 new guides, 32 fresh valve seals, 
resurfacing/pressure testing, and a valve job, for about $500 parts included. Intake valves and 
guides are cheap if you shop around.

 On the subject of "while you're in there" work.... If you have a head off 
for valve replacement.....rebuild it! Its too cheap and easy to do it right and 
even if you sell the car you can use the repair bill to justify your 
bargaining position. Better yet rebuild them both, the cost of an entire top end gasket 
set is cheaper than trying to peice a set and since the engine already apart 
that other head is easily accessable.

 Pick the right parts source/machine shop and the DIY cost should end up 
around $1000 including all the parts to do the timing belt CORRECTLY.

KT