Hello Folks,

I have a 77 f-150 with a 351m, that is making a strange ticking sound. When the truck is idling and in park, it will only do it if you give it a lot of throttle really fast. If you just roll on the throttle no tick at all. Or, when you are driving, it will consistently tick while accelerating. If you let off the gas, it does not tick at all. I just replaced exhaust manifold gaskets, but the stock manifolds were pretty beat on the sealing surface, so I have a suspicion it may just be an exhaust leak. I did order some headers, so I guess I will see if that changes anything next week. I also took a stethoscope to both valve covers, and the oil pan, and neither spot seemed to magnify the sound. Has anybody here ran into a similar situation, or have an idea of what this ticking sound might be? Any info is greatly appreciated.

Thanks,
Nick

 

An exhaust leak, especially at the head to manifold joint can make the tick which strangely sounds mettalic. A stuck or collapsed valve lifter also... or other valvetrain issues. Installing manifold gaskets with a thin coat of high temp RTV could help determine if it is a leak.

Also, assuming auto transmission, it wouldn't hurt to check/tighten flex plate bolts. Loose bolts or a cracked flex plate can do it also.

 

Check the freeze plug on the front left corner of the engine, front side of the head behind the alternator. It's only 1/2" diameter. Mine was rusted and had a pinhole that produced a ticking sound. If yours looks rusted, just remove the alt and tap it out with a screwdriver and hammer.