Engine noise-Confuseing
 

Just built a new 389 for my 66 GTO. It runs great,edelbrock cam.kaufman heads etc.
When I start the motor and only when started I hear a Rattle in the lower end,think thats where it is. only last a mili second then all is fine. I have never had this before in any engine I built and I have built many. It has me confused.
Has anyone had anything like this??

Auto trans.? If so, check flexplate bolts. Even one a bit loose will make a noise like you said you're hearing.

Hard to diagnose on the web...Maybe the starter??

I was thinking the same things. Also check your kick down cable, tranny dipstick, If you have it on, check in the tranny dust cover, maybe something sitting in the bottom of the pan. Hard to say it could be a bunch of things. I would go over the obvious things first.

Just had another thought. Is your starter gapped properly? I usually can tell by placing a safety clip in between it and the flexplate. Maybe the starter is staying engaged too long.. Is your flex plate new? Did you install the metal gasket that goes in with the flex plate. It was put in from the factory to stop any potential vibration and noise that might come from the flexplate not being perfectly in rotation/balance.

engine noise
 

Thanks for the input guys
Ant's diagnosis was it. the starter was staying engaged a second longer after the engine started.
checked as told and the gap was to tight, shimmed it and the noise went away.
thanks again all for your help.
FRED

Nice to know that it wasn't something internal, huh!

Had the same issue, check the starter shims and increase if necessary.

Brad

engine noise
 

Hi Brad & Alan
Yes,there is no doubt bout it that when the starter shim solved the problem,I breathed a sigh of relife. We shuddered when taking this motor out the 1st time let alone having to take it out again because of possibly something we screwed up on the lower end.
All I dreamt about was the crane failing and my paint job becoming a disaster.
Thanks to you guys thats all just a memory.
Check it out at FREDSGTO.com
Thanks
FRED

Freddy,
Glad I could help. Feels good to sleep at night right, lol. I just went through a major 462swap in my 67 so it was all still fresh in my head. I am going to check your site now.

Wow! That car is sharp. The stance, paint job, color and motor just look incredible. Best of luck with it! Drive it in good health.

I agree with Ant. Nice car Fred. The page signed by your family is priceless.

Enjoy it!!!!!!