MustangWorks.com : Ford Forums - View Single Post - not a 351, but 302 problem i need answered

84LX89GT · 01-26-2006, 05:29 AM

starting with the simplest thing: Is the oil level correct, is it overfull?
Now to the not so simple things:
It sounds like oil is getting past the rings - I'd blame the valve guide seals if it happened under deceleration, or after sitting from a stop when there's vacuum. I'd blame oil rings if it's under acceleration. you'll get oil up in the intake from the scavanging pulses in the intake sucking back oil. Especially with oil on your plugs i'd say oil control rings/bottom end problem. What is odd is that it's on all the cylinders....hmmm.....Did you double check the clearance between the pistons and cylinder walls, or post-machining measurements on each cylinder? I've heard of alot of rebuilt engines having problems real fast because of slight machining errors/miscalibration.
The problem with compression testing a vehicle with an oil bypass problem is that the oil itself with help seal the combustion chamber.
....this is all i can think of.

01-26-2006, 05:29 AM	#2
84LX89GT Mustangs Join Date: Jul 2000 Posts: 1,938	Re: not a 351, but 302 problem i need answered starting with the simplest thing: Is the oil level correct, is it overfull? Now to the not so simple things: It sounds like oil is getting past the rings - I'd blame the valve guide seals if it happened under deceleration, or after sitting from a stop when there's vacuum. I'd blame oil rings if it's under acceleration. you'll get oil up in the intake from the scavanging pulses in the intake sucking back oil. Especially with oil on your plugs i'd say oil control rings/bottom end problem. What is odd is that it's on all the cylinders....hmmm.....Did you double check the clearance between the pistons and cylinder walls, or post-machining measurements on each cylinder? I've heard of alot of rebuilt engines having problems real fast because of slight machining errors/miscalibration. The problem with compression testing a vehicle with an oil bypass problem is that the oil itself with help seal the combustion chamber. ....this is all i can think of. __________________ 2005 Suzuki Hayabusa GSX1300-R 1980 Ford Thunderbird - 255 V8 ported heads, 5.0L ported stock headers, O.R. H-pipe and Flowmaster 2-chambers, dual roller timing chain hi-po Mack Truck hood emblem 1985 Mustang GT 5.0L T5, F-303, GT40p, headers, off-road h, flowmasters, MSD stuff, etc. Sold 02/06/04 1989 Mustang GT ET: 13.304@102.29 mph (5-24-03) Sold - 1998 Mustang Cobra coupe, 1/4 mile - street tires: 13.843@103.41 (bone stock)