Re: GTV6 valve guide replacement

["Obie Fayth" <bibendum59@domain.elided>]

	Joe Elliott asked a few digests ago exactly what was involved in replacing 
the valve guides in his GTV6. I rebuilt the engine in my GTV6 last summer to 
cure James Bond-esque levels of smoking and while doing so had the guides 
replaced so the procedure is still pretty fresh in my mind.
	To replace the guides you have to remove and disassemble the heads. Then 
you have to completely remove all of the valve train hardware: keepers, 
springs, etc... To do this you need access to a valve spring compressor. 
Because the valve springs in the alfa heads are set deeply within the 
casting the standard C-shaped jobs will not work without some modification. 
I ended up fabricating an adaptor to extend the jaws (IAP sells adaptors if 
you want to buy one), but even with the adaptor and unusually high levels of 
cursing I was unable to disassemble the valve springs. The compressor kept 
flexing, I think the adaptor I welded up might not have been perfectly 
square. I ended up taking the heads to a local machine shop that was 
recommended on the list.
	I don't have their bill handy, but I think they charged around $25 to 
disassemble the heads and another $25 to reassemble them (without setting 
the clearances). If you have any other upper end work that needs to be done 
now is the time. To remove the old guides you can tap them out with a big 
punch. To put in the new ones you need a special punch to avoid mushrooming 
the end. After the new guides are in place they need to be honed to ensure 
the correct clearance between them and the valve stems. While the heads are 
apart it would be a good idea to have the valve sealing surfaces cleaned up. 
I think this is actually required when replacing the guides as the 
centerline of the old guide and centerline of the new guide may not be 
exactly the same which would cause poor sealing if the seats were not recut. 
You should also have the heads surfaced if they need it to ensure that you 
won't have any head gasket leaks after you reassemble the engine.
	I think I paid around $350 to have the heads cleaned, disassembled, valve 
guides replaced and the new ones honed, valve guide seals installed, valves 
and seats recut, cam and distributor seals replaced, heads reassembled, 
painted and surfaced. Then you have to buy the head gaskets, cam seals, 
etc... which will be at least another $150.
	Before you pull the heads to have the guides replaced you should do a leak 
down test to see is the valves are sealing well. If they are you might 
consider replacing only the valve guide seals. This is a procedure that can 
be done without removing the heads from the engine according to the factory 
manual, though I've never tried it. Anyone on the list done this before?

Hope this helps,
-Obie
Tacoma, Wa.
'91 164S
'83 GTV6



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