Need help asap 302 engine problems!!!
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Freshman User
Joined: Apr 2004
Posts: 41
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Need help asap 302 engine problems!!!
I just got the 302 all back together in my 1991 ford f-150 4by4.I replaced everything in the motor minus bearings and rings.The reason for not replacing the rings is there was a ridge in the cyl. but ran good in the donor.It was running great,then I was on my way to New York to pick a car up for a friend and my motor made a noise I was thinking a rocker or pushrod etc.Starting running on like 7 cyl.I starting having blowby and going through oil and oil into my breather and out my rear main seal.I went through about 10 qts in 1400 miles.It made it home seems to run better now and got blowby out my oil dipstick tube.It seems to have all its power still using oil mainly leaking I am thinking.I had to heads checked when I did the motor and a valve job done.The truck doesn't smoke out the tail pipe.What do you guys think happened?Think a ring broke?I was going to take the valve covers off and look but its running pretty good and no noise at all right now.Just the blowby from the oil dipstick tube.You guys think the motor is trashed if so I will build a new 306 for it.Please reply really need this fixed.
Hotshot
Joined: May 2004
Posts: 12,170
Likes: 5
From: The hills of No. Calif.
As an engine runs, and wears, all the parts work and wear together, so to speak. When you do a valve job on a high milage engine, you are eliminating all the cylinder pressure leakage that occurs past the worn valves. This put more stress on the piston ring seal, and often you can get symptoms like you descirbe. I've even seen it happen just from replacing a blown head gasket. For a low buck rebuild, it's worth it to replace the rings and bearings as well. Use cast rings, not moly, as they will wear in better and conform to the out-of-round cylinders. But it's a lot of work for a very temporary rebuild, and it still may not seal very well. I think it's time for that 306 you mentioned. -TD
