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I'm leaning towards reversion, 600hp big block
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The broken springs have nothing to do with reversion. You either got bad springs, wrong springs, or they are not set up right.
Milky oil under valve covers can be from running the engine for short periods and never getting the oil good and hot. Same goes for too low or no thermostat. You never get the oil hot enough to get rid of condensation that naturally occurs in the valve covers. If you have reversion and water getting back into the cylinders when shut down you'd see it in the oil or bent connecting rods. Idle being too slow can also show signs of reversion if the cam is big enough. The corroded valves makes me wonder if they're really high quality stainless. As for the taller risers, they'll only help a reversion issue if the point where water enters the exhaust is farther down stream than it was on the shorter ones. |
Originally Posted by Smitty275
(Post 4870643)
The broken springs have nothing to do with reversion. You either got bad springs, wrong springs, or they are not set up right.
Milky oil under valve covers can be from running the engine for short periods and never getting the oil good and hot. Same goes for too low or no thermostat. You never get the oil hot enough to get rid of condensation that naturally occurs in the valve covers. If you have reversion and water getting back into the cylinders when shut down you'd see it in the oil or bent connecting rods. Idle being too slow can also show signs of reversion if the cam is big enough. The corroded valves makes me wonder if they're really high quality stainless. As for the taller risers, they'll only help a reversion issue if the point where water enters the exhaust is farther down stream than it was on the shorter ones. Springs are Comp Cam 929s with only about 90 hours on them BUT they might have been produced around a quality issue about 5-6 years ago. I'm thinking of adding an oil thermostat (water thermostat is 140) Cam has potential for idle reversion (237/243 .610/.627 112degree) with original Gil risers...and I have a few long idle zones I traverse near my house. Comp Cam SS valves...in salt water environment. Probably not running the motors hard/hot/long enough. Finally, I just found traces of slight/minor water leaks from previously repaired/welded ports...so I believe it was a perfect storm :-( https://cimg9.ibsrv.net/gimg/www.off...839ea2ad33.jpg https://cimg2.ibsrv.net/gimg/www.off...485e835909.jpg |
I have never used Comp valves. But I learned the lesson the hard way an will only use Manley or Milodon Severe Duty valves and PAC springs. Always made great power with Manley springs but had issues with them breaking. Went to PAC Springs and not a broken one yet.
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Originally Posted by Smitty275
(Post 4870688)
I have never used Comp valves. But I learned the lesson the hard way an will only use Manley or Milodon Severe Duty valves and PAC springs. Always made great power with Manley springs but had issues with them breaking. Went to PAC Springs and not a broken one yet.
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That’s too much cam for standard height gill exhaust. Merc had issues with those on the HP500’s and soon went to much taller risers. Search HP500 Gill Risers to see what they went to.
Yes, too low idle speed incurs reversion earlier also. Every 100rpm makes a huge difference. Found a pic: https://cimg2.ibsrv.net/gimg/www.off...bfcf54baa7.jpg |
Originally Posted by SB
(Post 4870694)
That’s too much cam for standard height gill exhaust. Merc had issues with those on the HP500’s and soon went to much taller risers. Search HP500 Gill Risers to see what they went to.
Yes, too low idle speed incurs reversion earlier also. Every 100rpm makes a huge difference. Found a pic: https://cimg2.ibsrv.net/gimg/www.off...bfcf54baa7.jpg |
I think your manifolds are good, Tom. Just switch out to the big cam HP 500 riser from Hardin and that'll help a lot.
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Originally Posted by TomZ
(Post 4870729)
I think your manifolds are good, Tom. Just switch out to the big cam HP 500 riser from Hardin and that'll help a lot.
Pictures of concerns... https://cimg0.ibsrv.net/gimg/www.off...6d02f10890.jpg https://cimg9.ibsrv.net/gimg/www.off...f8325dd34d.jpg |
Yeah, they may be done.
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