Rattle on Light Acceleration
 

My 86 has a rattle sound from the engine when warm on light acceleration and ut drives me nuts. It goes away if i push harder on the gas and i dont hear it any other times. I have an all original 305 with 169k and was wondering that the noise could possibly be valvetrain. Even with hydraulic lifters does lash ever need to be adjusted? Any other ideas?

Re: Rattle on Light Acceleration
 

Could be excessive vacuum advance. Try disconnecting the hose from the vac can and the plug the hose, and see if it goes away.

Re: Rattle on Light Acceleration
 

Thats an easy check, will do. Its been doing it since i bought it in 08 with 105k, just bugging me more lately

Re: Rattle on Light Acceleration
 

A rattle like spark knock, or something external to the engine like a heat shield buzzing, etc?

Does it occur any time you are at a particular engine RPM, or is it load dependent?

K

Re: Rattle on Light Acceleration
 

I was originally thinking spark knock but octane and lowering timing never changes it. It could be that still tho. Its not external and happens on tip in like when i come to an incline, where you give it just a little more without down shifting or opening secondaries