Thread: Engine noise...

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Here's another challenge for you guys. I've been around race motors most of my life, but have never seen this before. I have a 496 c.i. gen 6 block, 13.5 : 1 J/E pistons, Eagle rods/ crank, Dart Pro 1 heads, aggressive cam (770 lift, 300 dur. approx.). This has just been assembled by a local engine builder, with some notoriety for building race motors. The motor starts, idles, and seems to be running fine, except for one problem. I hear a disturbing internal noise...hard to describe...kind of like a vibration, or slight binding, which fades in and out with the engine idling. I thought it was trans. or convertor noise, but I have nothing behind the motor, except the flex plate, and the noise is still there. The water pump is electric (CSR), and the noise seems to be louder on the driver's side of the engine. Any ideas? The rotating assembly was used in another block previously, with no problems, and it is almost new. Is there any possibility that this thing is slightly out of balance? Before you ask....it has the correct balancer and flex plate for an internally balanced motor. No balancing weights on either. Keep in mind....this is a newly built motor, which all the components except the block and the cam were used previosly with no issues similar to this. Thanks for your input.

Check the crankshaft end play.

Johnretired

Does that cop still hide there and give tickets???Chatham was the first speed trap in the country

Jerry Clayton
from Scottville

Problem solved.....have you ever heard of a harmonic balancer named "The Rattler"? I guess some genius came up with this theory that it would somehow help the harmonics through the crankshaft???....over my head. Anyway.....it is a SFI approved balancer, and the builder used it, because it is the only one he had, at the time. The strange thing is.....to listen to the noise, you would be convinced it is coming from the oil pan. That balancer is headed to the trash can.

Originally Posted by lodilobo

Problem solved.....have you ever heard of a harmonic balancer named "The Rattler"? I guess some genius came up with this theory that it would somehow help the harmonics through the crankshaft???....over my head. Anyway.....it is a SFI approved balancer, and the builder used it, because it is the only one he had, at the time. The strange thing is.....to listen to the noise, you would be convinced it is coming from the oil pan. That balancer is headed to the trash can.

Doesn't sound like such a great engine builder if he is using a junk balancer because its "all he had". What if he needed 1/2" bolts but all he had was 3/8" bolts??? Just a thought... Guarantee he wouldn't have used that balancer on his engine...

TCI typically makes a good product.

"The Rattler® a pendulum absorber developed to control amplitudes of vibration and angle of crankshaft twist like no other design. Its ability to absorb rather than dampen is the key to its success. The Rattler® is effective for the entire RPM range, and extends crankshaft and bearing life."

"Inside the Rattler® are steel rollers that fit loosely into a specific number of holes. By using an exact mathematical relationship, the rollers will roll forward during compression strokes and roll backward during the power stroke to keep the engine speed variations and vibration, to a minimum."

"The only time you may hear the Rattler® is when starting and stopping the engine. When you hear the slight "click" you know the Rattler® is ready to work. The slight noise could have been eliminated but TCI® decided to keep it as a distinguishing trademark."

So - it may have been working correctly. It's too bad your builder didn't explain the nuances of the thing - the noise would have caused me concern as well. Knowing what it is, you may want to rescue it from the trash.

Regards,
Glenn

I did a little research on the rattler, myself. That all sounds good, when explained, but I think I'll stick with a nice 7" conventional balancer. Thanks for the input.

Roger that!! I hate things that "just don't sound right"... I had a friend that insisted on a gear drive. We put in a real good one and it was noisy beyond belief. He ran it for a while and got tired of the funny looks at stop lights. I think it's in a box in his garage - never to be mentioned again!!

Hot roddin is really fun, eh?

Regards All,
Glenn

....lol!....I did exactly the same thing with a "noisy gear drive". In fact...I think I'll store that balancer and the gear drive together.

Don't ya just hate strange noises. Even if it's supposed to make that noise. In the back of your mind you are just waiting for the exploision. I've thrown a few things away over the years because I didn't like the way it sounded. My buddies would say, "It's supposed to make that noise". But there is definately somthing to be said for "peace of mind". And I really hate walking.