327 noise.?

[ChopChop]

Hi all, i have not had allot of experience yet with camaro's and hope someone could point me in the right direction? Now i have a stock 69 convertible with the original 327 with 2bb. the engine runs fine and sounds fine when stationary, however when driving and i plant the foot and load up the engine there is a distinctive "rattle" sound, at first i thought it was a loose baffle in the muffler, but now im not sure. The sound only appears when there is a good load on the engine.

i know its very hard to diagnose over the net but any thoughts?

[Sauron327]

Does the noise occur when the car is parked and you crack the throttle? And can you hear it under the hood coming from the motor? Is it a steady or inconsistent sound? Yes, it is difficult as a "rattle" would indicate something other than the engine. Pointing more towards a loose baffle as the change in flow of exhaust and the motion and torque while driving distrupt the innards.

[jdv69z]

Could it be the pinging you can get from too low octane gasoline?

Jimmy V.

[ChopChop]

No "rattle" when its in park and you stick the foot down, it sounds very clean. It only seems to do it when im driving under load\accelerating hard. I thought a baffle at first but if it is a baffle wouldnt it do it in park as well..?
As it only does it when moving i cant pick exactly where its coming from, its somwhere in the front half and thats about as good as i can get without a little stunt driving.... 

[ChopChop]

I'm just using reg unleaded, i havnt tried anything with a high octane level, i did try using some lead additive but it didnt make any difference

[JohnZ]

A "rattle" under load is generally "pinging" or detonation - check your ignition timing setting and make sure your centrifugal advance weights in the distributor aren't stuck.

[Sauron327]

 Good call John. Did not think to use pinging for synonym for "rattle"

[ChopChop]

i shall check the timing and distributor, ill let you know how it goes....Thanks

[ChopChop]

Well johnZ you were spot on the timing was too advanced, running well now thanks for the advice...