Top end noise
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Top end noise
I am not a mechanic to start off. I have a 78 F150 4x4, with a 351M in it, with a top end noise. Have done alot of work to the truck, with the exception of the motor. Got a new exhaust put on , and the guy who did it did not want to put in new manifold gaskets for fear of breaking a bolt off. I asked him prior to doing the exhaust if he thought the noise was an exhaust leak, but he said he didn't think so. Had my mechanic look at it prior to that, and he put new valve cover gaskets on it. I had asked him to adjust the rocker arms because I thought I heard something tapping. He gave me the truck back, said they didn't need adjusted because they don't loosen up. I thought this was odd. It seemed like he didn't want to mess with it. What do I have to do to figure this out for myself? I have the torque settings for all the engine components. Should I just check the torque on all the rockers to start? Can someone help me with this? I don't think anything is drastically wrong, but the motor is noisy, so I would like to fix it.
Lead Driver
Joined: Nov 2000
Posts: 6,625
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From: Albuquerque
There is no adjustment on the valves for this engine. If the lifters are making noise the only cure would be to replace them (or maybe a good dose of Sea Foam or MMO, heavier oil helps). Lifters would make kind of a uniform ticking noise (unless it's just one or two of them). An exhaust leak usually is more of a loud noise that increases with load on the engine.
Can you be more discriptive of the noise?
Can you be more discriptive of the noise?
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I understand the lifter noise is a ticking, since I have heard that before while someone was adjusting some in his motor. This seems to be louder than that at idle and does get louder when stress is put on the motor. I think it could be the exhaust. It seems like it is from one side that I hear it from.What is sea foam, and what type of oil would you use? Thanks for your help.
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The dilemma is that this truck runs great, with the exception of running a little rough, which I am gonna investigate with a carb cleaning and such. I really dont think I am anywhere close to a rebuild.
Cargo Master
Joined: Apr 2001
Posts: 2,364
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From: Eustis FL
Also check the exhaust connection between the manifold and the down pipe. It may be cocked to one side or might have a broken doughnut (if used).
You might feel the exhaust escaping if it is the manifold gasket with the back of your hand. (do it while the engine is still cold before going near the manifolds!) lol
You might feel the exhaust escaping if it is the manifold gasket with the back of your hand. (do it while the engine is still cold before going near the manifolds!) lol
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