What would cause a newly rebuilt OHC to put out lots of white smoke and use a quart of oil in 20 miles? Is this a normal break in problem for these engines? Otherwise it seems to run fine.

Passbob
'68 Sprint

No, it's definitely not "normal".

I can't imagine going 20 miles blowing smoke, maybe 20 feet.

Have you pulled your radiator cap and checked for tan foamy residue on the cap seal or the radiator neck? And have you checked the dipstick for the same?

My guess would be head gasket.

The oil on the dipstick looks clean and the water looks clean too. Could there be a busted ring?

I defer to the engine experts...

In my experience, white smoke is usually trans fluid (bad vacuum modulator) or coolant entering combustion chambers (smells like antifreeze if antifreeze is used).

Blue smoke with odor for oil.

yes,white smoke would be tranny fluid hitting exhausts, usually

Rings didn't seat properly. Poorly assembled or wrongly machined. As long as you don't see oil dripping off the engine then it's internal and probably a major problem.

I agree with the others... Fill the engine back up to normal, place a clean pc of cardboard under the engine, get out the compression testing equipment...and start it up. Look for fresh oil on the cardboard underneath, and check your compression for each cyl. How do your plugs look?

First, I would get in touch with whoever rebuilt it..... A bad ring can score a cylinder wall to the point of having to rebore....

Didn't Passbob rebuild it? If not, yeah, call up the shop... I guess I thought he rebuilt it himself. If he's already driven it 20 miles...is the damage done already?

Probably not yet.

Passbob has taken our sons camping and and left me (wife) in charge of the Sprint. The OHC was rebuilt by a racing shop and then reinstalled by a mechanic friend. Bob hasn't had time to check compression or plugs. I would love to drive the car to a club meeting but you have me scared now! I don't even want to think about having the engine pulled again. It took forever to get it done the first time.

Would it still run good if a ring was bad? It smokes just a little at idle but really boils out when the accelerator is tromped.
Liz

Liz,
It would still run good until the plug/plugs foul. This could be a PCV problem causing too much pressure inside the block. There's a chance that if you run it some more that some seals could be permanently damaged.

Does the smoke continue after the first few seconds of acceleration? Any details on the invoice regarding the type of valve seals and/or new valve guides?

in my opinion, you might have the rings improperly set. I mean the ring's have to be off set when installed. this way the engine will seal and no oil will pass. or the valves were improperly done. I would bet on the rings.


good luck 68 400ho4spd to go!

I talked to the mechanic today and he DID NOT replace the PCV valve when he reinstalled the engine. (That seems like poor workmanship to me). He had me check the metal tube at the bottom of the hose and there was oil on it. He is too far away to work on it so can someone explain how to get the PCV valve off of the car so I can replace it? I think he didn't do it because it is really stuck. Do I need to remove the breather and what type/size wrench to use would help. It has power brakes.
Thanks,
Liz, (who is mechanically challenged.)

My PCV is screwed into a fitting on the intake manifold. A 3/4 inch wrench should work. Saw one on ebay,maybe take yours off and clean it but, I read somewhere that there may be an oil baffle on the block by the pcv hole ,could he have broken it off?Good luck, Try the overheadcam forum to they might help you over there.

Also be sure that your oil tube cap is a breather type, not a rubber plug type.

Primatech Motorsports has the PCV valves if you cannot find them locally, http://primatechmotorsports.com

Yep, the PCV is threaded into the intake manifold behind the carb.



The oil cap depends on the type of breather used. There are two, an open oil filler breather cap and a closed oil filler cap.



Pictured above is the closed breather. My factory (top hat) cap is missing so I have a rubber stopper. venting is provided by the tube that is connected to the air cleaner and the oil filler neck.

The open breather doesn't have the connecting tube to the air cleaner and has a plug on the oil filler neck. This requires the breather type oil filler cap.

My Sprint has the closed oil filler cap/system. When we bought the car it ran good and didn't smoke so I'm really aggravated that after spending lots of $$$$ the rebuilt engine smokes like it does. I couldn't break the PCV valve loose. Maybe that's why the mechanic didn't replace it. I wouldn't think the baffle would be broken since it didn't smoke before the rebuild.
Liz

The PCV's check ball may have gotten stuck while the motor was non-operational. I hope thats the case for your sake. Keep us posted on what you find.

The PCV valve (NAPA) was replaced today. The old one rattled but seemed a little sticky inside. Compression was checked and all cylinders were good. All spark plugs are clean. No oil leaking underneath. So.... I guess we will drive the car and see if the new PCV valve fixes the smoking problem. Thanks, Liz