Your opinion on engine diagnostic

Blue68Coupe · 05-08-2005, 04:18 PM

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?

mustangII460 · 05-08-2005, 05:56 PM

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.

Gearhead999 · 05-09-2005, 08:32 PM

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.

05-08-2005, 05:56 PM	#2
mustangII460 Factoy Five Roadster Join Date: May 2000 Location: Sevier Co,Tennessee Posts: 1,681	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. __________________ Frank

05-09-2005, 08:32 PM	#3
Gearhead999 Registered Member Join Date: Sep 1998 Location: Oviedo, FL Posts: 992	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. __________________ "Support our Troops" Dave 1968 Cougar 2004 Thunderbird 2007 F150 Harley-Davidson, SuperCrew 1986 LTD 1997 Ranger 1992 Honda Civic

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05-08-2005, 04:18 PM	#1
Blue68Coupe 68 Coupe 289 Join Date: Apr 2005 Location: North carolina Posts: 44	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? __________________