Substantial Noise from Valve Bank

[jvwfd51]

Hello all, hopefully you guys can help me out with a little problem. I have recently replaced my engine in my 30' Cruiser. Its a Ford 351 rebuild. Now after breaking it in I experienced some noise coming from under the valve cover on the 5-6-7-8 bank (Looking toward front of engine, Left side). The "klacking" as I will call it is only experienced when I am running the engine between 2800 and 3000 rpm. I am 99 percent sure its from the rocker arms. Now heres the kicker. Occording to my owners manual, this engines cruising rpm is 3600. This boat was passed down to me so my question is that if the prop was replaced and is not the correct pitch such as not enough, could the load put on the engine not be enough? Esentially overreving the engine without enough load could be just as bad as to much load right? Any help would be great.
Thanks

 

[Bondo]

Re: Substantial Noise from Valve Bank

Are you saying it will Only run to 3000rpms,..??.......

I believe WOT, rpms should be up around 4200/ 4600rpms for that motor........

 

[jvwfd51]

Re: Substantial Noise from Valve Bank

You are right. That is the wot rpm. Cruising is stated to be 3600. I havn't gone that high because of the Klacking noise from the valve bank. Is that amount of noise a normal thing for these engines?
Thanks

 

[Bondo]

Re: Substantial Noise from Valve Bank

Is that amount of noise a normal thing for these engines?

Nope,....... Something is Very Wrong........

 

[mkpj1]

Re: Substantial Noise from Valve Bank

Could be lots of things especially on a rebuild. Who rebuilt it? Take it back to the builder and have them look at it while it's running. You have a warranty? Did you break it in or did the builder?

Could be something as simple as a poorly adjusted valve train or more complicated as ... wrong springs, lifters, bad cam etc.

Ken

 

[jvwfd51]

Re: Substantial Noise from Valve Bank

Ken,
It is a rebuilt from Firstmate Marine engines. It is under warranty and I have started the process with them. They would not tell me weather the pushrods, rocker arms, or cam are new or reconditioned. I guess I need to talk with someone in tech support to find that out.

"Something is very wrong" seems to be the general consensous with everyone I talked to. Including a friend who owns a machine shop and has been in the field a long time.
Thanks

 

[Bondo]

Re: Substantial Noise from Valve Bank

Are you Sure it's Valve Clatter,..??..??....

I'm thinking a Lean running motor will Dentonate quite easily,+ Spark-Knock could be What you're hearing.......

Not being able to pull over 4000rpms at WOT is of Concern enough to warrent some extensive Diagnostic time.......

 

[mkpj1]

Re: Substantial Noise from Valve Bank

Exactly right Bondo, Could be lots of stuff but if it was mine I would do exactly what you are doing. Sucks, but hey a new engine is alot of dough! They will probably have you take it to one of there contractors for examination. Hopefully just a simple fix and you will be out on the water!!!

That is my whole soap box about remans. You pay a little extra to build it locally but you know what you are getting. I met up with a builder/machinist when I needed a rebuild and talked it over. Then took it to him and had him do the technicals and I polished it off. I knew what I had and it was "high" quality new parts. Plus, I got a good friend out of the deal! JMHO?

Good Luck!!