[Rennen]

...on the face of virtually every piston. The is very discouraging to me since I had grown cautiously optimistic when I discovered that all valve clearances could be adjusted within spec. One other discouraging sign is what appears to be oil inside cylinder 6 which leads me to think maybe the valve guide was hosed on that cylinder as well. I'm seeking opinions on what to do next? Since I had the one valve adjuster retaining nut off and that adjuster backed way out, I'm inclined to put the thing back together, fill it up with oil, and fire it up to see how it's running. Another part of me is saying don't waste my time, start making plans to pull the motor and pull off the heads.

Thoughts?

[cmartin]

Drop the motor and rebuild

[roundel]

Do I have this right?

You missed a shift, meaning caused a mechanical over rev.
The car clacked and ran like poop.
Upon inspection, you have oil in a cylinder and evidence of valves striking the piston.

I think it is fair to assume your valves are bent, guides have been damaged, and maybe some debris has been released into the cylinders. I think starting it will just result in further damage but certainly will not result in a healthy engine.

Drop and rebuild x2

[slbates]

Time for a rebuild. If you can see the kiss on the top of the piston, the valves are inevitably bent. How bad was the over-rev? Excercise caution if you only do a top end. The over-rev can also cause the rods to lose a bit of their shape resulting in insufficient bearing crush (not to mention stretched bolts). A friend bought a car with a fresh $7k documented top end rebuild (seller disclosed was the result of a missed shift) and 2k miles later he lost a rod. tear down found 2 spun bearings in addition the the thrown rod! Diagnosis was loss of bearing crush from the original over-rev.

[Rennen]

Originally Posted by slbates

Time for a rebuild. If you can see the kiss on the top of the piston, the valves are inevitably bent. How bad was the over-rev? Excercise caution if you only do a top end. The over-rev can also cause the rods to lose a bit of their shape resulting in insufficient bearing crush (not to mention stretched bolts). A friend bought a car with a fresh $7k documented top end rebuild (seller disclosed was the result of a missed shift) and 2k miles later he lost a rod. tear down found 2 spun bearings in addition the the thrown rod! Diagnosis was loss of bearing crush from the original over-rev.

It is possible to diagnose these things while I've got it out and apart if I'm only planning a top-end rebuild or are you suggesting a full tear-down is the kind of caution I should take?

[slbates]

Dave,

Did it happen at the track? Do you have an in-car video showing the magnitude and duration of the over-rev? If so, show it to a professional wrench and get his opinion. If not, what it your opinion? Did it zing to 9k rpms? Did it sound bad? I have no real opinion or sage advice, but if you can see a shiny smile on every piston it must not have been slight. If you plan to keep the car, you may want to consider a full rebuild. Have the rods checked and if they are out of round on the bottom or top end, toss them. Do not have them resized/reconditioned. If the length and size/ovality check out, at least replace the rod bolts, have them magnafluxed and stress relieved. A quality forged rod will stretch (permanent set) and not break. However, it will be weakened and when overstressed again it can let go in spectacular fashion.

[Rennen]

Originally Posted by slbates

Dave,

Did it happen at the track? Do you have an in-car video showing the magnitude and duration of the over-rev? If so, show it to a professional wrench and get his opinion. If not, what it your opinion? Did it zing to 9k rpms? Did it sound bad? I have no real opinion or sage advice, but if you can see a shiny smile on every piston it must not have been slight. If you plan to keep the car, you may want to consider a full rebuild. Have the rods checked and if they are out of round on the bottom or top end, toss them. Do not have them resized/reconditioned. If the length and size/ovality check out, at least replace the rod bolts, have them magnafluxed and stress relieved. A quality forged rod will stretch (permanent set) and not break. However, it will be weakened and when overstressed again it can let go in spectacular fashion.

I don't have it on video so I'm at a loss there. If I recall, it went to about 8500 RPM. Dang....full rebuild....this just keep getting worse and worse. I may need to get a professional to look at it to help me decide.

[Jase007]

Compression and leak-down tests done?

Got numbers?

[Rick V]

The only true way to see if you have damage to the lower end is to pull it apart, sorry but it is. By the time you figure a top end, the rest of the engine isn't that much more, as long as you don't need any of the hard parts. (rods crank ect) It would be better to excersize some caution here. If you only do a top end, you are chancing throwing all that money away should you develope a lower end problem.
Theres always Motor Meister. (I'm going to duck now)

[Rennen]

Originally Posted by Rick V

The only true way to see if you have damage to the lower end is to pull it apart, sorry but it is. By the time you figure a top end, the rest of the engine isn't that much more, as long as you don't need any of the hard parts. (rods crank ect) It would be better to excersize some caution here. If you only do a top end, you are chancing throwing all that money away should you develope a lower end problem.
Theres always Motor Meister. (I'm going to duck now)

Makes sense. Then there is always the "while I'm in here" stuff I'll probably want to do as well. Now I just have to decide if this is something I want to take on doing myself....