Your opinion on engine diagnostic
 

Hi everyone, just wanted some opinions on what is going on with my 68 Coupe. First off its a 289, Holley 650, Edelbrock RPM manafold, milage unknown but receipts say it was rebuilt in 1991. I have some smoke out the breather tube and the exhaust under acceleration. Otherwise it runs great. I have set the valves, carb. and put in new plugs.

Vacuum reads 18 steady.
Compression reads,
1 120 lbs. (150 with a teaspoon of oil)
2 135 lbs.
3 145 lbs.
4 145 lbs.
5 135 lbs.
6 130 lbs.
7 125 lbs.
8 135 lbs.

I am thinking that #1 and maybe # 7 piston has bad rings. Your thoughts?

Re: Your opinion on engine diagnostic
 

30 lbs is a big increse wet, too much.

With that much of a increase with oil, the rings are leting alot of pressure by. Rings for sure.

Im just guessing, but I bet the motor was re-ringed and not bored.

Nowz the time to get a 5.0 roller motor.

Re: Your opinion on engine diagnostic
 

Big increase with the oil. Definatly bad rings. As stated above, good chance that someone threw a set of rings at it without boring and honing.

Time for a rebuild.