New valve lifters?
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Senior User
Joined: Dec 2002
Posts: 105
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From: Salem, Oregon
New valve lifters?
150,000 miles on 351-m engine F-150 4X4. Engine still runs good but has tappet noise on start up for about five minutes. Would it help to put in new lifters? Thanks; Webster
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Joined: Aug 2000
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From: (near) Denver USA
New valve lifters?
In 335-series engines (351C, 351M, 400), lifter noise that occurs briefly immediately after start-up is usually caused by a worn out rear main bearing. Excess clearance in the main bearing allows oil to drain down from the left side lifter gallery when the engine is shut off.
In 335-series engines, the right side lifter gallery is a main distribution passage, and it is pressurized immediately when the oil pump turns. The left side lifter gallery is fed from the rear main bearing, and it is the last part of the system to receive oil.
In 335-series engines, the right side lifter gallery is a main distribution passage, and it is pressurized immediately when the oil pump turns. The left side lifter gallery is fed from the rear main bearing, and it is the last part of the system to receive oil.
Thread Starter
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Senior User
Joined: Dec 2002
Posts: 105
Likes: 0
From: Salem, Oregon
New valve lifters?
Yeah; those bearings have been in there a long time. 22 years. Only thing of note is that most of noise seems coming from the right valve bank. It does get me thinking of building up a new block. Thanks a lot for the info. Webster
