I recently had the 351 Windsor in my 1990 F-250 stroked and mildly modified. Just about everything is new including the fuel injection system and a bigger fuel pump. It runs great. I wanted it built for power at highway speed. I had it tuned on a wheel dyno and it reaches a peak of 310hp to the ground @ 2750rpm. It'll run sweet up to 6000 but all your doing is making alot of noise and gaining nothing after 2750. I broke it in like I was told. I didn't baby it but didn't abuse it. I ran it for over 2000 miles and it never quit burning oil. About 1 qt./250 miles. It is going out the pipes. If I get on it, there's blue smoke behind me and it ain't comin' off the tires. We pulled the engine out and put new rings and rod bearings in it but my engine builder said that everything looked good. The intake was full of oil however. I lengthened the vac. hose from the pcv to the intake because I had heard that Ford had a problem with that in some of the 302's. We reinstalled it and I now have over 700 miles on it again. Break in oil changed at 100 miles. It still is using oil. 2qts./325 miles. I love the power but this oil thing is driving me crazy. Any ideas out there would be greatly appreciated!

 

Does the engine have good/equal compression on each cylinder?

Where the heads modified in any way? Were new valve seals put in? Bad valve seals could let oil into the intake & combustion chamber.

 

I didn't do a compression check. To be honest with you, I never thought of it. Is it common practice to check compression after an engine is assembled? My engine builder may have, but I'll have to check with him.

The heads are brand new RHS (Racing Head Service) Model#35303 cast iron 64cc, 215cc. I don't get that telltale puff of smoke at startup so I think the valve seals are fine. I am open to any and all thoughts, so please keep em' comin'.
Someone out there has the answer. I just know it!

 

Is it possible the intake gasket between the intake and head was damaged when it was assembled?

 

My engine builder didn't think so, but we'll keep it in mind.

Does anybody know of some other sites that I could post this problem? I just can't be the first person that has had this problem with a beefed up Windsor.

Thanks for all of your help!

 

Did you do a compression test to be sure?

There is an outside chance that the gang at www.mustangforms.com may have a section that could help.

 

Was the engine built with chrome rings? cast? If the engine was run long enough, usually you'll see a 'washed area' around the piston edge/s if the oil is coming up around the rings. A bore scope may help to verify if one cylinder, or all are evenly pumping/using oil. If your builder honed the bores with a more aggressive hatch and used chrome rings it may not be seating the rings, and may not show up in a comp. test. Did you buy bare heads? and have the builder put them together (positive seals) or complete assemblies from RHS.. All the plugs 'clean' or any that seems to burn oil more than others?

 

He used chrome/moly rings & originally crosshatched the cylinders with a #280 stone and followed by plateauing the cylinders. The second time around, he used the #280 stone with no plateauing. The heads were bare and he believes that he used positive seals but would have to check. He is stopping in tomorrow to scope the cylinders. We'll let you know how the plugs & cylinders look.

 

He scoped a couple of the cylinders. Everything looks good. You can tell that the oil is going through the cylinders. The plugs are a little black. He said to run it for about 10,000 miles and we'll see if it gets any better. He said that sometimes by changing to a different brand of oil helps, but he doesn't believe that the rings are seated properly yet. He welcomes any suggestions that someone may have. We were hoping to hear from someone who has seen this before. This is the second set of rings and he always uses Chrome/Moly rings with no problems. It may not be the rings. But then, what can it be?