looking for some input on a blow by problem i have with my 302 motor. i have a 72 comet GT with the 302 in it. i just bought the car a few weeks ago. the car ran horrible when i got it. you could smell real bad gas comming from the car. i dropped the tank, flushed and flushed lines, motor now has factory new carb, new filter, new complete tune up, new plugs, wires, cap, rotor, points condensor, hoses ,heater core, radiator flushed, new 180 thermostat...... motor runs great now, very strong, chirps the tires when it shifts into second stage, motor is stock with stock c4 trans. my problem is i have bad blow by. when i accelerate oil comes out of dip stick tube, oil also comes out of pcv housing, and the blow by blows the foam breather element out of the housing that attaches to inside of air cleaner base. car does not smoke, no lifter noise or engine noise. motor has 20 inches of steady vacume at idle and drops as it should when you rev the motor but it still stays steady. old plugs were oil fouled. there is very strong exshaust fumes not smoke but fumes. after i drive the car for awhile and go in the house i smell like i have been in a garage with the door closed and the car running. i feel that it is bad oil rings on the pistons????? its just strange that the motor has such strong vacume and no smoke and runs so strong?????? does anyone have any thoughts. thanks tim....... pcv valve is working and is the proper valve....
Sounds to me like you've got too much oil in the motor.And/Or the oil drains in the heads are plugged and allowing oil to pool in the rocker galleries. Some of that would get sucked into the valvestems(from inadequate valve seals) and foul the spark plugs.
Sounds like rings to me. I am suspicious about the car smelling like fuel. Maybe it was flooding and the rings/cylinders got washed. I would do cylinder pressure testing to see if there is any leakdown.
usually if it smokes all the time its rings,if it smokes when you start it up and if you give it gas and let off it its valve stem seals or burnt valves, blowby usually is rings, try a can of seafoam in the gas tank, run it through it ,then change the oil to see if it helps
heres the problem. a few members told me to pull the plugs again and check them. i just did that today. the plugs are perfect. i mean they are light tan in color no carbon or oil or fouling. if this was rings at all wouldnt the plugs be discolored, wet, or black???????? the car does not smoke at all. when you start it or rev it up it runs clean as far as smoke..... could this be bad valve seals or bad valve guides????
I wouldn't think so. I think compression can bypass the rings without the plugs showing any indication of oil because the oil is not going into the cylinder under a vacuum. I am wondering if the "oil fouled" plugs you said you had wasn't oil run off from the valve covers or something cause now your saying they are clean..? All I can imagine is compression escapeing into the crankcase. Either the rings or maybe a exhaust valve issue. But toy say the motor runs "very strong". Any time I had valve issues I had rough running and other issues so I still lean towards rings till readings are made. I don't claim to know everything and it has been a looong time since I was mechanicing so I may be wrong..
If the car was sitting for a while maybe the oil rings are stuck. they are a 3 piece ring and could be stuck together with sludge. Might try rinning one of those additived they sell for sticking lifters and see if it frees up the rings.
Does the PCV system work properly Tim? Valve is flowing and the fresh air intake side is free of restriction?
If there was bad gas in the tank, I would think the motor had not been run in a very long time, dry start, scoring, Stuck oil rings, plugged oil passages, dang tough call for me, but I think everybody here has covered all the bases. When I was a kid my friends and I would buy cars for 50 bucks, (late 60s early 70s No I was not at Woodstock) we would pull the plugs and put oil in the holes, wait over night then turn the motor over blowing oil eveywhere. No dry start. WE were dumb kids.lol Good Luck.
