460 tapping sound
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460 tapping sound
This is my first post. I just bought a '77 F-150 with a 460. Im hearing a tapping noise from the engine. From under the hood it sounds like it is coming from the back of the passenger side valve cover. My first thought is that it is probably a bad lifter. I ran some oil detergent in it to see if it might clear it up but it hasnt. Today I decided to see if it could be an exhaust leak. I can hear the tapping sound very loud underneath the truck, even away from the engine compartment. How does one diagnose or locate a exhaust leak? I hope it isnt a lifter. This truck takes me to work and I cant afford to pull the intake off. Thanks!
Fleet Mechanic
Joined: Mar 2004
Posts: 1,398
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From: Hesperia, CA
I have to re torque my exhaust manifolds every six months. The heating and cooling loosens these things up. This is quite common with the 460. If it hasn't been too long you might possibly get by with just re torquing the manifold. Just make sure you re torque them as regular maintenance.
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I suppose I should have mentioned that it does have headers and not the stock manifolds. This may or may not be a dumb question, but since I dont know I had better ask. What should the bolts be torqued to? I have some cold weather problems as well, but I have adjusted the idle, got a new distributor cap and rotor and cleaned out the carb. That has seemed to help, but it has been warmer the last few days. If it continues I will tighten the choke pull-off. It starts great when cold, but after I drive a few miles it will die at a stop sign or light if I leave it in gear. Anybody else that has these problems may have a different answer.
Senior User
Joined: Feb 2006
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From: Sonoma, CA
Try a piece of rubber hose to probe around the mating surface of the header and the head and stick the other end up to your ear. Odds are it's an exhaust leak and headers are even more common leakers.
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Thanks for the help and the torque specs. Bought a used Chilton on Ebay and havent received it yet. I think I will try the hose trick just because Im curious to see if I can find it. Either way Im going to retorque those bolts and see if that helps. Thanks again!
