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Ford Bronco

1986 Ford Bronco w a 351W why do you keep getting blow-by even after changing the PCV and doing a complete tune-up?

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Wiki User
2006-09-13 14:30:16

Blow-by is an indication of worn rings. While the PCV valve can

take up SOME of the blowby gasses, it can't take care of a lot,

especially if you have severe blow-by. If you're still getting too

much blow-by, it's time to rebuild the engine. Don't just do rings,

have the cylinders bored and get new pistons, and while it's apart,

replace the oil pump, have the Camshaft checked, replace lifters,

polish and/or turn the crank, new bearings, new exhaust valves,

replace or recondition all valve guides, and have the head

surfaced. It's not very cost effective to just replace the part

that has failed. Everything in the engine has worn severely over

time, and you'll actually save in the long run if you do the engine

right. BTW, don't ever let an engine overheat, that can lead to

collapsed rings. Also, keep the oil and filter clean, and make sure

the carburater is adjusted and working right and that the air

cleaner is doing its job and is clean. Dust in the engine intake

can cause rings to wear, resulting in blowby. In general, just make

sure the NEXT engine is properly maintained and you shouldn't have

blow-by problems.

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