Rebuilt engine smokes

Hi,
I have a 1960 CJ-5 with a freshly rebuilt stock engine, approx. 150 miles since rebuild. It runs great but blows big clouds of white smoke when cold. Once up to temperature there is no smoke. The rebuilder said there were some cracks in the block that were "fixed", but coolant could be leaking through. He suggested I run some magic potient through the cooling system to plug any leaks. The coolant level hasn't dropped noticeably, but I havn't put a lot of miles on it either.
Does anyone have any suggestions? Thanks for any help.
AL

 

sounds like a head gasket might be weeping. IF the cracks were fixed, they wouldn't leak.

 

If it was me, I would have pretty big issues with my rebuilder telling me I needed a can of Magic Enginer Fixer.

 

As the motor warms up the metal expands and is closing the leak. It could be a micro crack somewhere in he head, block or the head gasket is not sealed.

Some of the big 3 auto makers even use that magic stuff in new cars as I am told.

Suggestion:

A bottle of bars leak in the radiator should take care of the problem. But before you do it, be sure to let the engine rebuilder know what you are thinking of doing. So he won't have anything to come back at you incase it does not work. I am willing to bet it fixes it.

Question: Are you sure it is white smoke and not blue. With a new rebuild, it is normal to have a little blue smoke from the new rings not seating well. In that case, I like to put some marvel mystery oil in the crankcase. It loosens up the rings around the pistons and allows them to flex a little bit more.

Anyhow, I would drive for at least a 1,000 miles before you do anything to the motor. I bet it clears up. Or at least you might learn to live with it.

 

I have never seen this with any rebuild I have done. Something ain't right. Next idea would be to leave it alone for a day or two, and then pull the sparkplugs to get a idea which one is getting coolant. Stopleak might work, but I am leary of causing more harm than good. I used a product that contains micro cellulose. Works good, and does not plug things up.

Good luck.

 

If the rebuilder was paid, I try and get him to fixed it. He knew there were cracks and if they were fixed a mag-test should tell if he missed some. Why did he not pressure test the repairs in the water jackets? I'd take it back (if it is white not blue) and ask him to rebuild it right. I would not use magic in a bottle for a newly rebuild motor, your should have to fix a new motor.

 

This isnt normal. I have built many engines and let me second the fact that smokin new engines arent right. I would undrstand if the rings were causing a little blue smoke from not being seated, But that should correct itself,but not a water smoke. It aint right. if this was a paid engine builder, either get him to repair it, or get your money back.

 

Al

I just re read your post. Big clouds of white smoke until it gets warm. I am just wondering if head gasket might be letting some water seep into one of the exhaust valves and water is coating the inside of your exhaust manifold. Do you see any water coming out of the exhaust pipe. Is it wet on the inside when you first start it.


As mentioned above, the first culprit hopefully is the head is not torqued down to specs. Might want to recheck the head bolts. If it still acts up pull the head and replace the head gasket. Just my 2 cents. I love working on jeeps and have been doing it many years, but I don't really consider myself an expert.

Some of these guys probably will have some better ideas. Let us know how you come out. We all have our fingers crossed for you.....

 

Thanks for all the suggestions and advice. The rebuilder is a friend who built high performance race engines for many years. He is concerned and will stand behind his work. I'll ask if he pressure tested the cooling system.

Sounds like the next step is to check the head for proper torque. If that's not it I'll probably try some stop leak.

The jeep is 150 miles away from me at my hunting camp, so I won't be able to do anything for a couple weeks. Thanks again, I'll let you all know how it turns out.
AL

 

Yes it's an F head. I'll check those bolts. Thanks.