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Original Message
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| Wear From Positive Seals |
| By John - 05/11/2001 5:00:08 PM; IP 142.177.55.144 |
| I am in the process of rebuilding my 428 after an unknown reason caused the main bearings to prematurely wear. It was either an internal antifreeze leak or the pump sucked air. I never was quite sure which one, but the block had developed a crack in the Valley area water jacket. As long as it was apart I decided to have the positive type valve seals on the heads changed. Strange thing is, that all the exhaust valves showed excessive wear in the area where the seal rubs against the valve stem. The intake valves were OK and all bronze guides and the rest of the valve stems were OK. I used all Crane components, cam, solid lifters, dual springs, etc, except for the seals. I had purchased them, but apparently the machine shop didn't use them because they didn't have the right tool to turn down the guides, if I remember correctly. The engine only lasted a little over 2000 miles. Also, it was smoking quite a bit for the last 1000 miles, which was suspected to be because of the valve seals. The seals looked the same as the Crane ones (for what that's worth), and the Machine Shop said they use them all the time(although probably on Chevs, no doubt...hmmm..isn't there a tiny bit of valve stem diameter difference between chev and Ford valve stems?). Anyone have any idea why the valve seals would wear the valve stems? |
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This thread, so far...
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