eng viberation

[lboos]

I have a 72 super bug, I just had the eng. rebuilt to a 1776 cc a few Mo's ago, it has plenty of power and runs great, but when I accelerate and reach a higher RPM in any gear it sounds loud and rough like a metal to metal vibration, when I let off the gas to a lower RPM it gets quiet and smooth. it is all stock except for the 1776 mod. it has a stock muffler and exh.
I thought it might be a out of bal. cooling fan so I changed it, no help, same thing.
During normal slow driving it's smooth and quiet, any idea's ? Thanks.

[mcdragracer]

Sometimes the bracing ribs inside the shroud become detached over time from the outer skin of the shroud
and you will get that metal to metal vibration, try disconnecting the belt and drive it the same way
and see if the noise/vibration is still there, remember don't drive it a far distance with the belt off.

[lboos]

Sometimes the bracing ribs inside the shroud become detached over time from the outer skin of the shroud
and you will get that metal to metal vibration, try disconnecting the belt and drive it the same way
and see if the noise/vibration is still there, remember don't drive it a far distance with the belt off.

Thanks mcdragracer,
If that is the prob. will it damage the eng. to drive it that way ? or just a noise you put up with.

[Marc]

You an drive a cool engine for a couple of minutes without the fanbelt (long enough to see if the vibration is in that area) but I wouldn't advise going further than around the block.