brutus

I was not questioning that you paid for a valve job just IF you really needed one. One recent study of auto repairs found that 50% of work done was not needed. But misdiagnosis or fraud is quite common in that industry. What you know for sure is you were told you had bent valves, which is very unlikely.

hacker-pschorr

This discussion really gets interesting if you have witnessed a car pass a compression test on every cylinder with bent valves.

The car ran perfect until high load above 3,500 - 4,000 rpm (not a 928).

The engine did fail a leak down.

Vavles were bent due to a missed downshift (5th to 2nd) = valve float and piston contact.

Jon B.

Yep, I was clarifying for him specifically for 928's considering that's what we're talking about here.

danglerb

Greg Brown doesn't make those mistakes.

Beyond the interference issue, what 100k+ mile 30 year old 928 doesn't need the heads rebuilt?

Tom's 87 928 S4

What I was told by the shop doing the repairs. I was in the middle of a divorce at the time, and the ex-wife had the car, so I could not go look at it, and had to take their word.

Ducman82

My 81 is an SOB. Semi old bugger. Can't wait to test this hybrid to see if it will be a interference setup. Never got that figured out

danglerb

On a Euro hybrid motor you decide if its interference or not by the depth of the fly cuts. That said I can't say for sure if the normal practice is to cut them deep enough for non, but I think so.

Ducman82

i plan on bolting everything up complete (don't torque head gasket or anything) and clay the pistons... see what happens.

brutus

All which have had the coolant changed at reasonable intervals should be just fine. The low RPM nature of the 928 equates to very long valve, springs, seat and seal life.
And sadly there is only ONE Greg Brown working on 928s.

dprantl

How many 928's are on this list with 200k+ miles and no head work? As long as you change the coolant and oil at the proper intervals, they will be fine. 240k+ miles and counting here. Oh, and my GT cams look very good as well.

Dan
'91 928GT S/C 475hp/460lb.ft

hacker-pschorr

I don't care how well you take care of your 928, nothing will keep the valve guides and seals from wearing out.

If I buy a 928 / 944 with close to 100k and the heads have never been off, I'll plan into my budget a valve job just to replace the guides and seals.

Lizard928

243,000 miles now and I am planning on removing heads and replacing guides and seals.

brutus

Engines do not know how many miles they have been driven they only know how many times the pistons went up and down, how many times the valves opened and closed. The low RPM gearing of a 928 and it's relatively short stroke (compared to a 944) and ample torque simply means it can last a very long time as it need not be reved up as much. The 2:20 geared cars just are idling along at 65 mph.
But yes not knowing if the coolant was changed when you buy a older car or engine you should not be surprised if it was neglected.