I replaced the fuel pump, hoping it was the pushrod against the cam due to a faulty spring in the pump. Unfortunately the noise is still there. The noise is not continuous, there are a couple of seconds between each series of raps, at idle. I'm looking for any more suggestions before I remove the timing cover, which is where it seems to be coming from. The previous owner showed me the box from the Cloyes timing chain set and the number seems correct (9-1110). Any more suggestions before I remove the pan and timing cover would be appreciated. I would hate to do that and find everything in order, but I guess that's the only way I'll find out. Is this the type of noise a faulty timing chain would produce?
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Re: '66 BB RAPPING NOISE CONTINUED
I had a 427 years ago that had a noise up front around the timing cover, turns out the balancer had a crack by the keyway,look at the balancer close, If it is a internal problem you might see signs in the oil filter, cut the top and bottom off and streach it out and look for any metal. -
Re: '66 BB RAPPING NOISE CONTINUED
Rob did you try the excellent test that was recommended to you in a eariler post where you would remove the fuel pump and with the fuel pump rod not in contact with the camshaft, start the engine to test for the noise?
I installed a Crower cam in my 64 and remember that the cam and lifters came with a round wood piece that was installed at the end of the camshaft to keep it from walking forward, did you use something similiar when you rebuilt your engine?Comment
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Re: '66 BB RAPPING NOISE CONTINUED
Rob, Has the exhaust manifold been off this engine recently?Comment
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Re: '66 BB RAPPING NOISE CONTINUED
Jim,
I figured by installing a new fuel pump, it would accomplish the same test. Even though the lever on the old one seemed to have very strong tension, I tried a new one. Are you thinking it could still be the pump, or the push rod? I did notice that when reinstalling the pump push rod, the noise it makes against the cam sounds like the one I'm trying to eliminate, however, there is no noise coming from the fuel pump housing with the engine running.Comment
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Re: '66 BB RAPPING NOISE CONTINUED
The exhaust manifolds have not been removed recently.Comment
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Re: '66 BB RAPPING NOISE CONTINUED
The cam was installed without a thrust plate. Supposively, the flat lifters and the cam are ground in such a way to rotate the lifters and keep pressure rearward and not allow the cam to walk forward.Comment
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Re: '66 BB RAPPING NOISE CONTINUED
Rob
Just a thought,if the distributor shaft was bent it might bonce from the alternating free then resistance ,same thing for the oil pump,or if it had ate something ,like my friends 350 after he bottomed out on a street marked "dip"
Low oil pressure and a knock,during tear-down I found that the Oil pick-up tube and screen where not on the pump,but some of the screen was in the pump but mostly in the timing chain and as it turned whacking the timing cover.
Gaskets and oil are cheaper the Fat Blocks!
2 centsComment
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Re: '66 BB RAPPING NOISE CONTINUED
Rob,
How much time do you have on the engine since the rebuild? I hate to suggest this but your rapping noise sounds like what turned out to be a cam failure in my big block about a month ago.Comment
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Re: '66 BB RAPPING NOISE CONTINUED
John,
There are 500 miles on the rebuild. The engine runs smooth and strong without a miss. I assume the noise I am describing is what you heard on your car. Was your engine missing or running poorly, and what did you find was the actual point of interference causing the rapping noise when you dissmantled your engine, if you did yet?Comment
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Re: '66 BB RAPPING NOISE CONTINUED
Rob,
The noise that I heard was a rapping noise that sounded like it was coming from the right cylinder bank. I couldn't tell if it was front or back. I also didn't think to check the fuel pump. After pulling the pan and inspecting the lower end I discovered some small metal shavings in the oil. We then pulled the engine. In tearing it down, it was discovered that one cam lobe and the acompanying lifter had extreme wear with the cam lobe being almost completely worn away. This was really surprising to me as the engine had been running very strong without any miss and the knock had developed very suddenly. Clem Z. informed me in response to one of my posts that the problem could have developed from improperly breaking in the cam. I have also been informed since that it is more likely that this was the result of idling the engine before it warmed up and not having enough oil thrown up on the cam. In fact, several people recommended that I install a roller cam to avoid this problem which I did. What really surprised me about all of this is the fact the problem deveoped right about the time I had 3,000 miles on the last engine rebuild.Comment
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