hey guys

my roomate has a 86 coupe 2.8 v6 ride. The car got a hole eaten in the timing cover due to corrosion and it over heated with him. I found the problem change the cover and flushed out the oil. The car has ben running good up intill the other day then it started rattling. if you crack the gas and let off you can hear something bang around. But if you rase rpm's slowly it does not rattle at all ( i had it up to 2k no rattles) but how ever if you turn on the A/C it really starts talking to ya. i was told broke crank but the motor runs to smooth. also it rattles with it in gear too!


help this motor has only 40k on it.

could it be the harmonis balancer?

 

Harmonic balancer, the motor will shake and vibrate, and gradually get worse as the rpms raise. These cars had neutrally balanced harmonic balancers....so for one to fail is fairly improbable, and the car should work just fine without one at all. All the balancing is achieved on the crank and I believe the flywheel too.

Have you checked the timing chain and gears? Maybe the chain is toast and what you've hearing is it whipping/flexing. Extra chatter with the A/C system is probably a shot compressor.

 

Overheating with the timing cover having a hole? Why do visions of toasted bearings dance through my mind?

I'd say its rod knock, albeit light. Crank ran low of oil, wiped the bearings - now you have too much clearance, and it rattles. Wouldn't know without hearing it first..

 

If you broke the crank then the motor will not run worth a penny. I broke mine in half and could get it to barely start and run on 3 or 4 cylnders. Needless to say it didnt sound good at all while running. CLANK CLANK CLANK SSSSRRRRUUUCCCCHHHHHH CLANK CL CL CLLLLLANNNK BOOOM POP POP KLUNK. sounded something like that.

 

What your are describing to me in your post is exactly what happend to my G/F's friend 86 2.5L celebrity. She brought it over, said the oil light was on and making a funny noise. At idle it was fine, as soon as you gave it a shot of cars you could hear a knocking noise. The engine was toast. I hope its not whats wrong with your friends, but I would say its probably what the problem is.

 

thats classic rod knock

you have a bent rod