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Old 01-07-2013, 07:36 AM   #1
Join Date: Jan 2013
Location: st pete,fl
Posts: 3
Stuck Valve: what caused it?

The story:
2000 4.0 with cracked head drove it for years. Had engine rebuilt at 74,717 miles. Mech could not understand the head thing or why he could not fit the coils to an old head he rebuilt or why he could not find a used 2000 head. I went to Clearwater Cylinder Head and bought NEW head with valves in it. Jeep ran good. 357 Days and 6,196 miles later WHAM #6 intake valve is stuck open, push rod bent. Take head to Cleawater and they say all the intake valves were sticking and galled BECAUSE of a way too rich air/fuel mixture is washing the oil off of the stems. I see no indication of this: no smoking, spark plugs light tan except for #6, MPG is good, No check engine light before the valve stuck.
What do you think?
What should I do next?
Thanks - allen

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Old 01-07-2013, 09:19 AM   #2
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Location: San Diego
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Sure sounds like a BS excuse to me. I would suspect oil pump / pickup / pressure issues. Raw gas is supposed to spray on the intake valve stem. The difference between a stoich mixture and a rich mixture shouldn't affect the oil control on the valve stem in any way. There would have to be raw fuel coming out the exhaust / backfires, horrible running, etc for that comment to have even the slightest truth to it.

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Old 01-07-2013, 10:56 AM   #3
Join Date: Jan 2013
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Thanks. I was speechless when he said that. I am wondering if I should check the guide to valve fit when I get it back. I've never done it before but I recall you clamp a micrometer and measure the side to side play at the top of the stem. Is that right?
thanks - allen
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Old 01-07-2013, 09:31 PM   #4
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I was an auto tech for many years and that was a total bs story that they fed you. I can not tell you how many times I have seen shops make up some off the wall excuse to cover up their mistake.
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Old 01-08-2013, 10:07 AM   #5
Join Date: Jan 2013
Location: st pete,fl
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FYI: oil pressure has been good, new Mel. high volume pump, 4 oil changes, new rocker arms have almost no wear. maybe the stem oil seals are wrong. I may change the O2 sens. we will see what they say when I pick it up.
thanks again - allen
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cracked , head casting problems , head unit , stuck , valves

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