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Old August 26th, 2011, 08:44 AM   #21
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intake and its usally just air/fuel once and a while its a flame, cam is good i checked push rods are stright what would be worng with a lifter that would cause that
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Old August 26th, 2011, 06:32 PM   #22
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timing or intake valve related both will cause a backfire into the manifold. like mentioned do a leak down test the valve may have a small notch or bend in it still allowing it to build compression. a leakdown test will show that crack and will not hold pressure if it is cracked or bent
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Old August 26th, 2011, 06:44 PM   #23
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well it could be a burned valve but I tend to think its either a broken valve spring of a wiped exhaust lobe at this point. I would put on a set of oil deverters on the rocker tips(keeps oil from spraying) and fire up the engine with one valve cover removed at a time. watch for anything not moving or very little movement. if its blown lifter the rocker could imitate the effects of a wiped cam lobe. the trick is a blown lifter can be compressed by hand.
the other thing to watch for is an intake valve with a very worn stem. it will "rim" the seat before it settles in to seal and can act like a burn't valve. in most cases will even pass a leak down check.
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Old August 27th, 2011, 12:37 PM   #24
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i looked at the cam when the intake was off and did see any bad lobes. but never looked/fondled the lifters. i may just start pulling spark plugs and witch cyl is bad
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Old September 2nd, 2011, 03:48 PM   #25
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what is the timing set at??
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Old September 2nd, 2011, 05:10 PM   #26
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curretly at 8 btdc
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Old September 13th, 2011, 06:08 PM   #27
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well i fingered the problem all intake valves are pitted and one has a obvious bad spot where it leaks thanks guys for help
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