l98 (408ci) lifter noise?
#1
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Hi Guys!
ive got a 408ci l98 which was a brand new crate motor that was pulled down and built up. it runs a 242/251 112l/s and 638" lift cam, stock lifters (not the ones that can drop cylinders) and yella terra ultralite rockers 3/8 shaft mount.
the lifter noise is intense on first start and only marginally quietens down after it gets oil presure (50psi at ide 45psi idle warm (upgraded oil pump)
the engine has donw it since day one and the engine builder could never find the prob. the preloads are set down 3/4 of a turn. i went 1/4 then ran it than another 1/4 ran it then another 1/4 noise never changes.
im suspecting either a couple of dud lifter, definatly more than 2. or the valve spring pressure too much and overcoming the hydraulic lifter plunger. ive noticed that everhy time i take rocker covers off i can push down on the lifter side of the rocker a couple of mm. i thaught they should be still pumped up .. let me no your thaughts. thanks
ive got a 408ci l98 which was a brand new crate motor that was pulled down and built up. it runs a 242/251 112l/s and 638" lift cam, stock lifters (not the ones that can drop cylinders) and yella terra ultralite rockers 3/8 shaft mount.
the lifter noise is intense on first start and only marginally quietens down after it gets oil presure (50psi at ide 45psi idle warm (upgraded oil pump)
the engine has donw it since day one and the engine builder could never find the prob. the preloads are set down 3/4 of a turn. i went 1/4 then ran it than another 1/4 ran it then another 1/4 noise never changes.
im suspecting either a couple of dud lifter, definatly more than 2. or the valve spring pressure too much and overcoming the hydraulic lifter plunger. ive noticed that everhy time i take rocker covers off i can push down on the lifter side of the rocker a couple of mm. i thaught they should be still pumped up .. let me no your thaughts. thanks
#2
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PS one full turn from zero lash is roughly .047" preload on the metric rocker arm bolt. That is prob where you are off. For the LS7 lifter, people usually aim for .050 to .080 ish preload.
#4
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The LS7 lifters are the standard lifter, not the active fuel management lifter or the DOD lifter (same thing some people use diff terminology). They are the normal lifter. And 1 turn normally gets you in the target zone. You can do it exactly if you wish though with an angle meter also. Roughly 30* extra will give you your target range of between 55 and 65 if that is what you want to run them at. Some say more, some say less.
Most of the info I am using for the 1 turn theory is based off of a write up that thunder racing posted quite a while back. It gets recycled on here alot, but is very helpful.
Most of the info I am using for the 1 turn theory is based off of a write up that thunder racing posted quite a while back. It gets recycled on here alot, but is very helpful.
#5
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Thank gektec
Ive spend night after night researching the forum ready threads and ive found people with the same issue but has never been fixed properly.
i gues ast question before i rip the heads off is: after i switch the car of, remove the valve covers, i can push down on the pushrod sode of the rocker
is this normal? like they have collapsed
listening to the noise it is mos evidend if you put your ear or stethascope on the inet manifold.
Ive spend night after night researching the forum ready threads and ive found people with the same issue but has never been fixed properly.
i gues ast question before i rip the heads off is: after i switch the car of, remove the valve covers, i can push down on the pushrod sode of the rocker
is this normal? like they have collapsed
listening to the noise it is mos evidend if you put your ear or stethascope on the inet manifold.
#6
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Are you sure you put the camshaft in correctly? If you are off by one tooth that would accidentally over advance the cam by roughly 8 degrees or more, and can cause your valvetrain noise as well.
#7
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cam is definatly in correctly, tripple checked. ps noise was there before cam repacement, has been in engine since new, engine buiilder couldnt even work it out has done 1500kms now
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#8
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Ive got some comp cams hydraulic roller lifters order, might pull her down, replace and work my way up. i dont think i have an oi pressure prob as its got 50psi colt and around 42 hot. noise does get slightly worse hot.