Smokey exhaust

wow i was at a fast food drive through yesterday and wow there was like a cloud of smoke coming from my exhaust. Iv never really seen it before. first time i had seen smoke before. I had I did notice that i had been loosing oil and have no leaks. theres only 7-10,000 miles tops on my new motor. i dought the valve seals are bad? or piston rings are leakin oil into combustion chamber?? what do you think.

Jeepster4wd said:

what do you think.

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I think you should pretend we know absolutely nothing about your Jeep...other than you have 7-10k miles on your new motor.

What year? What engine? Details, son, details!

haha, its 93 cherokee 4.0 with crane cam, performance lifters. intake, exhaust.

What color smoke?

couldn't tell it was dark but i think it was more dark grey i didnt see any blue. I just went and started it up and it was clean as a whistle no smoke at all so im not sure. it was quite hot over 210 degrees but not to much over i dought that has anything to do with it.

What did your exhaust smell like?

I was in traffic last week behind a Nissan pickup that was pouring not smoke, but steam from the tailpipe along with a steady trickle of coolant. I can't even imagine how the motor still ran. The driver was using the "ultrasound" diagnosis technique.....just crank up the stereo and sing along loudly.

yea it smelled wierd. im possitive it wasn't coolant. it was def coming from the tailpipe. pretty sure it was oil. because iv been loosing oil at a very slow rate. I have never noticed it smoking before and it was like a thick cloud. kinda like when its very cold outside and you can see the exhaust smoke but thicker. i could see it quite clearly at 11pm thru a drive thru. i looked behind and saw aton of smoke and was like wtf is that. im puzzled

Jeepster4wd said:

yea it smelled wierd. im possitive it wasn't coolant. it was def coming from the tailpipe. pretty sure it was oil. because iv been loosing oil at a very slow rate. I have never noticed it smoking before and it was like a thick cloud. kinda like when its very cold outside and you can see the exhaust smoke but thicker. i could see it quite clearly at 11pm thru a drive thru. i looked behind and saw aton of smoke and was like wtf is that. im puzzled

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What's you air filter look like? You could have a bad PCV.

What you are experiencing is extremely common on rebuilt motors. When they reworked the head, the valve guides were worn. They took the cheap way out and knurled the valve guides. This lasts for around 10,000 miles in stock engine. With a higher lift cam, they last even less. The guides get worn and under high vacuum situations, oil gets sucked by the guides and burns as smoke. It is most normally noticed after driving and getting it hot and then sitting idling in a fast food line. At an idle, the vacuum is the highest.

A bandaid can be to replace the valve seals, but normally you need to pull the head, have the valve guides sleeved with brass/bronze inserts and then reamed to size. Check you engine warranty. It should cover it, but if they find out you are running a hot cam, they will most likely void your warranty.

This is why I preach against getting a crate rebuild. A long block is fine, but never get a rebuilt head. Have your old head redone locally where you can guarantee that the guides are sleeved, not knurled.

yeah you sound like your dead on there. I purchased the short block from a local engine rebuilder, they ended up being a new factory shortblock motor not bored out. strait from factory. i did end up reusing my old head and had them do a valve job on it aswell as all new exhaust valves. along with my mopar higher lift springs that were needed for the hotter cam. if it only lasts 10k miles then thats retarded. they might aswell do it right the first time.