Thread: Completely Rebuilt 427 FE - Still smokes!!!

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Me and my father completely rebuilt a 427 fe motor, including all new gaskets, bearings, rings, oil pump, cam, lifters, valve seals...etc. At this point, it is as close to new as we can make it.
The only problem is the same problem we had before we rebuilt it, it still smokes... blue oil burning smoke.
Can anyone offer any advice or solutions to this problem?
Thank you.

My line of thought is figure out at what point the oil is getting in to the airflow.
Is the oil getting in past the intake valve stems?
Are the plugs oil fouled?
Are the rings sealing correctly / seated in?
Is the oil coming in through the exhaust valve stems?
Is the crankcase dealing with positive pressure?
Is the oil draining back properly from up around the rocker arms?

What was the piston to wall clearance? What did you set the end gap at, and how did you position the rings??? How were the valve guides?

Originally Posted by Lord Antagonism

My line of thought is figure out at what point the oil is getting in to the airflow.
Is the oil getting in past the intake valve stems?
Are the plugs oil fouled?
Are the rings sealing correctly / seated in?
Is the oil coming in through the exhaust valve stems?
Is the crankcase dealing with positive pressure?
Is the oil draining back properly from up around the rocker arms?

The heads are not cut, block is not cut, intake is from a different(same year and make) motor, do not know if it was cut though.
Could that be the problem?
Thank you for your advice.

You say you "completely" rebuilt the engine, but it doesn't sound like that. More like you freshened it up with rings and bearings. Did you have the block professionally machined? Did you have the heads redone?

There are many degrees of "rebuilding" an engine, and if you didn't have the block and heads brought back to specs by machining there is your problem. A "completely" rebuilt engine would have the block hot tanked, new cam bearings installed, the head mating surface decked, the main bearing mating surfaces align bored, the cylinders bored enough to remove any wear and true them up, etc.

Don

Check for intake gasket leaks. They are super common on FE engines. The angles of the gasket surface between the heads and the manifold need to be within .010 in order to seal.

1. Also check the "tubes" that the pushrods run through. I've see porosities through those that introduced oil right into the runners.
2. Remove the rockers & valvetrain.
3. Make certain you've disconnected & plugged all vaccuum hoses or you'll pop the diaphragms.
4. Cobble up a carb plate for the top that'll let you put a couple psi (not much!) of air pressure into the intake with a radiator pressure tester.
5. Brake Cleaner and a strong/small flashlight...

Like Dave said how did you position the rings?
Second did you have the block and the heads magnaflexed. {Spelling}
The only problem is you said it smoked before so you should have had that done
to check for any cracks in the heads or the block.
Kurt

are you running an automatic trans .. perhaps the modulator valve is leaking .. sucking trans fluid into the motor .. makes pretty blue smoke .. if so unhook it and see if it clears up ..

Originally Posted by HOSS429

are you running an automatic trans .. perhaps the modulator valve is leaking .. sucking trans fluid into the motor .. makes pretty blue smoke .. if so unhook it and see if it clears up ..

Running a 4 speed manual.
Do you have any other solutions?
Thank you for responding.

I appriciate all of you taking the time to help me with this problem. Sorry it is taking me so long to respond. I am talking it through with my father trying to figure out what has and has not been done to the motor. But we do not live together so the conversations are taking place over the phone. I will reply to all comments as soon as we get our information straight.
Thank you all so much for your comments.

When you say valve stem seals, did you actually measure the fit of the valve to the guide? Knurling them will fix the problem for a few miles - maybe, but replacing the guide is the only sure repair. Fords are notorious for wear and just replacing the seals will not cure the problem. These engines are not friendly to work on with that monster intake that is actually is part of the head. Gaskets easily move or are damaged - then oil consumption and/or vacuum leaks. Often you can hear hissing or see excessive oil fill tube vapor if a gasket is a cause

I had some pretty tired 427's years ago. Down on power due to bore wear but
with .025 ring gap still did not smoke.

THERE IS A LIFTER VALLEY COVER. did you install it when refreshing the engine? did you check the pistons for cracks or breakes???the intake is used,has it ever been milled??? how about the heads???how about the oil drain holes are they clear???if i were building a 427 i would do a complete rebuild.don't forget to tighten the cross-bolt mains in order

is the intake match the heads ??? low.med. and hi rise heads all use different intakes.