Is this ring blow-by?
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Is this ring blow-by?
Newbie here.
I have an 83 f250 with a 351W that has a lot of oil coming through the crank case breather into the air filter via the rubber tube. Is this an indication of oil blowing by the rings and through the valves? Or could it be a head problem? She also uses coolant up.
After I find out for sure if this is ring blowby , I think I'm gonna get a long block. This truck has a very ,very good body on it and would like to keep it a while. Will an older motor,79 or earlier fit the same? I dont see a reason to loose power through smog engineering in the heads.
Thank You,
Mike
I have an 83 f250 with a 351W that has a lot of oil coming through the crank case breather into the air filter via the rubber tube. Is this an indication of oil blowing by the rings and through the valves? Or could it be a head problem? She also uses coolant up.
After I find out for sure if this is ring blowby , I think I'm gonna get a long block. This truck has a very ,very good body on it and would like to keep it a while. Will an older motor,79 or earlier fit the same? I dont see a reason to loose power through smog engineering in the heads.
Thank You,
Mike
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Welcome to the site
Yes that is a telltale sign that the rings are wearing out.
It shouldn't be using any coolant though.
Is the oil milky looking ?
I assume this is a carbed or TBI carb truck ?
An earlier 351W will do fine in this truck
Yes that is a telltale sign that the rings are wearing out.
It shouldn't be using any coolant though.
Is the oil milky looking ?
I assume this is a carbed or TBI carb truck ?
An earlier 351W will do fine in this truck
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Thanks Dennis. Thats what I was afraid of. Oil actually looks good and so does the coolant. And yes it has an old 2 barrel that someone put a man. choke on.
OK. Now to plunk down 1350 for a long block and another 700 to wrap all the rest of the stuff in so it's new( rad., water pump, power steering and a carb...)
So, no problem with bell housing or mounts ligning up, then older it will be.
Poor truck has 246,000 , time for some lovin'.
Thanks again.
OK. Now to plunk down 1350 for a long block and another 700 to wrap all the rest of the stuff in so it's new( rad., water pump, power steering and a carb...)
So, no problem with bell housing or mounts ligning up, then older it will be.
Poor truck has 246,000 , time for some lovin'.
Thanks again.
Posting Guru
Joined: Nov 2004
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From: Asheville, NC
If your PCV valve is clogged, it will do what you describe. Any coolant leaks anywhere on the engine, or heater box?
I got 385,000 out of a 351W that still ran great when I sold it. Its still running, as I sold it to a former Chekrolet owner.
I got 385,000 out of a 351W that still ran great when I sold it. Its still running, as I sold it to a former Chekrolet owner.
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I have changed the PCV. No luck. I am going to do a compression test on the truck this Sunday and that will be the final determination. The way I understand it is compression should be 80% or better of maximum.
What is max. for a 83 351W stock , 2brl carb?
If one or more is low and a little oil in the plug hole brings it up then it's blow by, if it stays low then it might be a valve not seating? Does this sound correct to you folks?
I dont think it's an exhaust valve , no smoke , or an intake , no miss. But what do I know?
Thanks again folks.
What is max. for a 83 351W stock , 2brl carb?
If one or more is low and a little oil in the plug hole brings it up then it's blow by, if it stays low then it might be a valve not seating? Does this sound correct to you folks?
I dont think it's an exhaust valve , no smoke , or an intake , no miss. But what do I know?
Thanks again folks.
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Oh yea. The coolant leak I described is about 4 inches in the radiator in a month. Its going somewhere but with an oil covered engine compartment its hard to see what if any thing is leaking.
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One way to determine valve or piston rings is to insert an special air valve in the spark plug hole.
Remove valve cover
Make sure both valves for that cylinder being tested are closed.
Then Pressurize the cylinder with 100 psi.
Listen at valve area of head - sound of air means bad valves
Listen at PCVV hole or Oil filler hole or oil galley holes- sound of air means leaking piston rings into crankcase
Remove valve cover
Make sure both valves for that cylinder being tested are closed.
Then Pressurize the cylinder with 100 psi.
Listen at valve area of head - sound of air means bad valves
Listen at PCVV hole or Oil filler hole or oil galley holes- sound of air means leaking piston rings into crankcase
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