New Heads , New Noise

[Rapid]

My new Edelbrock heads are on. I am very pleased so far with the results but will have numbers from the dyno soon.

Problem is that after it has idled for about a minute, I get a "rattle" from around the Number 2 cylinder tword the center of the intake. It goes completly away with any RPMs added and I don't hear it while driving at all. I can not tell that there is any other problem, like a vibration to go with it. I adjusted the valves from zero lash and added 1/2 turn and checked the guide plates tp make sure they were lined up properly. I could see no issues when I turned over the engine and watched the rockers. I also rechecked the locks on the roller rocker adjust nuts.

I can only come up with a lifter that is bleeding down at idle.

Any ideas before I tear back in???

 

[65fastbackresto]

Look up apost started last year

Has "water hammer" in the title by 68conv4sp.

Funny thing, you, me and him all have the same issue. We also have Edelbrock heads.

You wouldn`t happen to have the old style block would you? With the 2 peice rear main seal?

One other thing too, did you "burp" your motor when you filled it with coolant?

 

[Rapid]

Yes, I have the old style block and no I did not burp the cooling system. I did fill it slowly and gave it time to bleed air. I had to drill the steam holes in the block as well. Did you figure out the problem?

 

[Rapid]

Thanks,

I read the old thread. I'll install a filler neck for flushong and try to make sure there is no air trapped. Are you happy with your heads otherwise?

 

[TOM B]

I too have the Edelbrock RPM heads and I they work great.
The rattle you have might be the pushrod guide against the pushrod, as it may need adjusted. remember that when the engine is at idle you have the most vibration, so that said, look for something loose like a header bolt or exhaust as noise will travel and make it sound like its coming from somewhere else.
Leaky lifters dont rattle, they tap, like taking 2 spoons and taping them together.
Hey, one last thought, did you install the heat riser block off plates as some gaskets still come with them, I think that the Edelbrock Performer heads have the heat ports and if you installed the plates one might have fallen into the port.

 

[Rapid]

They are the RPM heads w/o the riser port. Good idea though.

 

[65fastbackresto]

I`m still working on my problem.

Putting new edelbrock water pump this week, hoping that will cure the overheating issue. The hammering noise went away after running the motor a few hours. I`ve had it almost a year and have only run one full tank of gas thru it so far, so its still breaking in.

But I love the heads, O got the rpm`s with the 1.90/1.60 valves, and this thing is pretty stout.

 

[Rapid]

We have similar engines and I haev the Edelbrock water pump. I am running the 500 cfm carb. Which pistons are you using? Do you know your CR and have you dynoed it? I plan to go this week to see how much it has improved.