Plaineman

I just put new heads, lifters and exhaust manifolds on my 2000 GEN VI 7.4 merc and got her started today but she is making a hell of a lot of noise. Sounds like lifters but I put a whole new set on. Is there something I am missing or may have done wrong? I'm afraid to keep running it like this. Any help would be greatly appreciated.

Thanks

Griff

No way to tell without looking at or hearing it. There's about 50 things that could be done wrong.

niceguy

Is the valve lash set correctly?

Like Griff said, it could be quite a few different things.

Plaineman

I did all by the book and it seemed like all went well... I have been working on cars my whole life and have completed big jobs like this with great results. As for the valve lash I did find it strange that all the book said to do was to tighten the rocker nuts down to spec and it was done. The computer is not putting out any codes and oil and temp seem to be good. The water flow is fine and she even seems to be making good power. I am stumped on this... if the valve train was so far out that it was making this kind of noise would't she be running extremely rough? I have been reading some other posts and found some people complaining of a similar type of noise and found it to be the exhaust flappers. She sat all last year so maybe I have other problems all together. Wondering if maybe one of the belt driven components is shot and making noise. I'm gonna go run it for a second without the belt and see. Thanks for reading guys.... Wish me luck.

B

Griff

If you used stock heads and lifters, then you should be able to just snug up the rocker bolts.

Internal Exhaust flapper noise is usually kind of inconsistent and will the noise will go away with a little more rpm.

Plaineman

Yeah... it doesn't go away and only gets more intense with RPM. I just can't see how I would have noise due to lifters or valve lash but that is what it seems like to me... Could it be that the lifters are not the right ones for my app... maybe too short? These engines have roller lifters and seem to be the exact fit... maybe my cam was shot but then again I would be having a rough running engine and she seems strong... just making a hell of a lot of noise.

Thanks for input guys... I will be at all day.

B

niceguy

On my HP500, I had two different length pushrods for intake and exhaust.... I don't know if yours is the same, but make sure you have them in the right spot. Too short of a pushrod would cause the lash to be off making the rockers really noisy. But I would think it is was too short the motor wouldn't run very well. Just a thought.

And you're sure the noise is valvetrain related and not a lower end issue?