Need ideas
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whats causing this??
Hi. the info" 2003 F-550,4x4, V-10, w/whipple supercharger. The problem: Less than 3000 mi, Labor Day to be exact, pulling my 16,000 fifth wheel, I lost #4 and #5 cyl. Out of warranty, Ford refused to look at it cuz of the whipple, took it to a Hot Rod shop( good rep in the area I was in) and they found that the valves had "stretched". one was .14 and 1 was .19 longer than stock. Replaced and off I went, Of course 2200 dollars lighter in the pocket. Wendesday, hooked up to move to new job, less than 200 miles down tghe road, same thing!! only this time, 4,5,9,10 are out. Its in the ford house here(small N.C. town, seem to be good folks. So far no reasons as to why . The mech says the whipple couldnt do it, I only have 5-6 lbs of boost, but yet he doesnt know why. Any ideas? I would like to keep the truck, as it is set up now the way I want it. But, I have to have something dependable and the 10 just aint cuttin it. TIA
Last edited by deanndeb; Jan 22, 2006 at 11:50 AM.
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From: Northwest Indiana
I guess it could happen, but it seems hard to believe the rpms these motors turn, even with chips and tuners, could do much to hurt the valves. I imagine you're running hotter combustion chamber temps than stock, but if high temps caused a problem with the valves you'd think the pistons and cylinder walls would be hosed as well. Did they show you the valves? Are they physically longer than new ones or did they measure the difference in deck heighth compared to the others? If the deck heighth was different, it's possible the valve seats somehow recessed into the head. But again, it's not like you're running anything terribly radical with single digit boost pressures.
Last edited by T- Squared; Jan 22, 2006 at 10:42 PM.
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What valves? Intake or exhaust?
If it's the exhaust, sounds like a lot of backpressure and/or unburnt fuel overheating the valves and stretching them, although I would think the seats would be burned too. Like T-Squared said, were the valves really longer, or were the retainers worn or the valve seats recessed?
Maybe you have a bad run of valves? Hard to believe, but possible.
Again, which valves, intake or exhaust (or both) ???
How high are you running the revs?
If it's the exhaust, sounds like a lot of backpressure and/or unburnt fuel overheating the valves and stretching them, although I would think the seats would be burned too. Like T-Squared said, were the valves really longer, or were the retainers worn or the valve seats recessed?
Maybe you have a bad run of valves? Hard to believe, but possible.
Again, which valves, intake or exhaust (or both) ???
How high are you running the revs?
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