samajam

Thought I would post a few pics of what was found on the left side of the during an engine out valve adjustment. The car is a 90 C4 with apppx 145,000 miles, right side was taken to the case in '03 at 110,000 miles due to bent valves, loose cam gear was noted as the cause and left side is original. Will replace the cams with a regrind from Dougherty and all rockers on the left side. Other than the valves is there anything else I should have checked that might have contributed to the damage?

ja78911sc

Could this be cam damage caused by the new oils without ZDDP?

FeralComprehension

1. that's a mess
2. I think your cam source is one that's lauded on Pelican for his quality and skewered for his turn times and periodic bouts of non-contactibility. Caveat emptor.

Makmov

Could be.

Beware of off the shelve synthetics. GL5 2005 significantly reduced ZDDP levels in synthetic oils... and most cars it's not a issue.

Usually oils with enough ZDDP are labled for off road use only or racing.

touque

samajam, I had damage to a few of my rockers (not the cams) from a plugged hole in the spray bar. When I put a thin pick in there, I heard and felt a crunch where the oil had turned hard and crusty. Quite a few miles later, my new rockers are just fine.

Rocket Rob

I agree with Makmov. When I disassembled my cab's engine. I found some pitting on the cams too. Talked to Steve Weiner about it and he speculated that it was damage caused by oil with low ZDDP. I'm now running Mobil 1 V-Twin 20W50 in my cars.

Good luck with the repair.

Porsche964FP

Thought about cup cams?

samajam

Thanks for the responses, I have heard the ZDDP argument from a few sources now and been recommended the V-twin by a well regarded tuner. 145,000 miles is a lot of revolutions and I am sure that many of them were completed in less than ideal oil conditions. I have been using std Mobil 1 but will move over to either Motul or Penn since they are readily available in my market.

samajam

I will make sure that the teck looks at the spray hole. It seems curoius to me that one went bad and the others are still very smooth. The initial thought was of bad springs or stuck/sticky valve increasing the pressure on the cam but all seems good there so lubrication is the more likely culprit.

samajam

Thanks Frank, you have a great sig line. I did consider cup cams, if for nothing else than the cool name, but through all my forum searching the Dougherty 993-SS seemed like a good compromise for a mostly stock engine and as an added bonus they are cheap compared to stock. I do want more performance in the future but might swap for a C2 before I commit to more engine. Besides, I have recently picked up three go-karts for me and the boys(8&11 yrs) and that is where my motorsport aspitarions are focussed at the moment.

samajam

1. agree
2. eyes open, and add to that the border issues and it could be a PITA but my nature is to make a decision and not look back, otherwise I would not own an older car and almost certainly not be married.

Thanks

Porsche964FP

Yeah I ditto what has been said before - get those oil spray tubes nice and cleaned out. A block is what caused damage to my rockers which resulted in debris...

Geoffrey

I would use Elgin cams if it were me.

samajam

Geoffery, is that based on profile or quality? please pm if you prefer. Thanks

Makmov

What weight Mobile 1, a lot of the standard Mobile 1s are too low in ZDDP now days.