Definitive Answer on Interference Engines?
#31
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.
#32
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.
#34
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.
Beyond the interference issue, what 100k+ mile 30 year old 928 doesn't need the heads rebuilt?
#35
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.
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.
#37
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.
#39
And sadly there is only ONE Greg Brown working on 928s.
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Jakalu (03-27-2020)
#40
Dan
'91 928GT S/C 475hp/460lb.ft
#41
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.
#42
243,000 miles now and I am planning on removing heads and replacing guides and seals.
#43
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.
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.