Can you replace valve guides without doing total top- end job??

[vincenza]

Just wondering if a total top end is necessary to replace valve guides only ?? And can anyone tell me what the average cost of just replacing valve guides would be .



Thanks

Vinnie from Ventura
1989 3.2 911 Silver Anniversary

[Superman]

Well, to replace the valve guides, you need to remove the heads, and remove the valves. And while the valve are out, the stems should be measured, particularly near the base where the guide rubs on them the most. If they are thin, then it's a good idea to replace them. Particularly the exhaust valves. And then, as long as everything is apart and especially if guides and valves are changed, then the seats need to be resurfaced. That's a complete head job. And frankly, as long as the heads are off, I'd look at the rings. At 183K miles, my valve stems were worn, and so were my rings. But the cylinders (Alusil) were not, so I replaced rings, valves, guides, seals, reconditioned the seats and changed rod and main bearings. It was a "budget" engine refresh.

Short answer is this: If you guides are worn, your valve stems probably are too. And you can replace those pesky Dilivar head studs as well, and have a reliable motor for years.

[Por_sha911]

What Super said. Doing just the guides is right up there with doing an oil change but not changing the filter. You could but, why would you want to?

[vincenza]

Thanks Superman ,
my 89 has 180,000 miles ( I put on 90,000) 2nd owner .
I found records in book when I purchased the car that the original owner replaced valve guides and work cost $ 2,100 in 1996 . Does that sound about right

Vinnie from Ventura

[vincenza]

Joe,
the reason that I am asking is that so many threads taliking about burning oil stems from worn valve guides . The answers that I see the most is that your ready for top end because your valve guides are worn . Wouldn't just changing the valve guides help correct that oil consumption problem ?


Vinnie From Ventura
Just a Salesman that loves 911's

[Superman]

I'd check that out further. Perhaps call the place that did the work. Hard to imagine replacing guides and nothing else. That's $30 in parts, and $2000 in labor.

Then again, it might not have had many miles. And Carreras had a reputation for weak valve guides. Could be that it was a necessary upgrade, and nothing else was necessary at the time.

[john walker's workshop]

you replace a guide and the valve will no longer seat/seal. it probably wasn't seating real well anyway, before the job, because when a guide wears, the valve wobbles around and beats up the seat in the head until the seat is no longer round and true. often when i grind seats, after replacing the guides, only half of the seat is actually contacted by the grinding stone. it takes a while for them to clean all around. so yes, you always do the whole job.

[vincenza]

Thanks Guys ,
always a pleasure exchanging ideas and comments .

Sincerely,
Vince Spagnuolo
AKA Vinnie from Ventura 89 911 silver anniversary