Burning Oil

The rebuilt F head in my '56 smokes like crazy only after I let off the throttle from going up a hill or pulling the plow. I have no idea where to start with this one. I'm thinking I should pull the plugs and see if the oil is getting by the pistons first.

 

PCV baffle?

disconnect the PCV and see if it happens.. might be sucking oil under WOT

 

Compression test and vacuum test would be quick and cheap to see if one cylinder is bad.

But usually bad oil-smoke is the reverse... worse upon hitting the gas after coasting down a hill. Are you sure it's not a fuel-rich condition? (Is the smoke blue, or black? Are the plugs oily/cruddy, or sooty?)

 

Valve guides or bad valve seals if it had any

 

Aren't they likely to act up more in a high vacuum situation, rather than after heavy loading?

 

He said: " only after I let off the throttle"........where vacuum would be present.................might be coming down the valve stem from the overhead into the combustion chamber and out the exhaust valve? ..............................Only a guess?

 

It doesn't smoke when it starts.

 

I don’t know how many miles it has. Daryl drove it around quite a bit after he rebuilt the engine. I’ve only driven it around the yard.

 

Smokes after being under load, or under load as in dropped a gear and running high revs? Possibly pumping rocker box full of oil, then sucking it past the valve seals when you let off and vacuum goes high? Anything blocking drains from top of head back to crankcase?

But since this is freshly rebuilt it seems odd to have valve seal leaks. Rich condition seems more likely. I dont know what carb you have or how it works but if it was a motorcraft 2100 I'd be thinking of a power valve that comes on later (lower vacuum), if in fact it is rich mixture and not oil.

 

Mine smokes like a chimney upon goosing the throttle and under a load. I have no idea what is the issue with mine. I am afraid of going down the rabbit hole so to speak. Mine is a whitish blue smoke.

Mine smoked using both stock Fuel/Vacuum pump and aftermarket pump without Vac for wipers.

 

Do you have the combination fuel/vacuum pump? If there is a crack in the vacuum diaphragm, oil can be sucked through the diaphragm and into your pcv system. This happened to me and it took me a while to figure out how oil was being burned!

 

I rebuilt the vac/fuel pump. I can disconnect the vacuum pump and see if the problem goes away.

 

With my f-head I had the issue where the exhaust back pressure and intake pressure was entering the crankcase thru worn valve guides that have no seal and pushing everything out the breather which would go into the oil bath. It got 1 mile per quart of oil so that was rather extreme and unlikely under normal circumstances.
But this was under load and wide open throttle.
Edit:
I would suspect an issue with the intake guides allowing oil to be drawn into the intake, or a pcv issue (it is positive crankcase ventilation)

 

Does your oil dipstick still have the baffle?