Smoking

intimidator3

New member
Just assembled a box stock and the thing is smoking excessively out of the overflow tank. It is watery not oil. It isn't smoking any out of the exhaust just of the valve cover and through the overflow. WHAT COULD CAUSE THIS?
 
Out the valve cover? Did you shake the engine around a bit to make sure oil got to the valvetrain and in the cylender a lilltle so as not to have a dry start? Sounds like you started it with the cylender and valvetrain completely dry of oil, thats the only thing IV ever seen cause smoke to come out the vent in the valve cover.
 
Excessive blowby orit could be as the engine warms up or gets hot and is about to seize the rod to the crank, the excessive heat will cause the oil to smoke, the only exit it has is throughthe crankcase vent.
 
Well I decided that the rings might have been my problem. I thought maybe they weren't lined up correctly. I took it back apart and put a different piston with new rings. IT IS STILL SMOKING OUT OF THE VALVE COVER! I have no clue why and have never experienced this before. The motor is a brand new box stock. Any other thoughts on what could be going on with it. I am wondering if it will just go away after running a while or if I have something major going on. It is just frustrating because everything is new.
 
What is your piston to cylender wall clearance and what is the ring endgaps? You may have too much ring gap that is letting oil by the rings
 
other than checking the ring gap for problems, the only other cause that i can think of for smoke is excessive heat...which means something is dry and friction is causing the oil to burn. are you running enough oil in it? 14-16 ounces usually is enough to adequately lube everything up. i'd be more worried about a rod bearing seizing....did you lube the cylinder walls prior to installing the piston? did you tighten the rod bolts to spec? maybe your valve guides and/or seats are bad...one valve not seating or oil by passing the valve guide MAY cause the oil to burn....is it a white smoke or a dark smoke? does it smell like something burning or what? believe it or not, your nose is a good tool to use...it's like starting a race car engine and smelling the clutch burning up...once you know what it smells like, you'll remember it! :)

i'd be very careful with this motor...not because you've done anything wrong, you probably did things right and this is just one time that it's not working as you want it to...but i'd be careful so that you don't lose the motor altogether...
 
I will try to check the ring gaps. Rod bolts are torqued to specs. I run 12 ounces of oil. Should I be running more? The smoke is white and is watery not oily.
 
seeing that it's not oily, but kind of watery....can you smell any odor of fuel in it? you might be leaking fuel from the intake runner into the head/valve cover area. 12 ounces is good depending on the track and what your running. for me, i'm on a medium banked track, but it's big and we're wide open all the time with high speeds going through the corners, so we need the extra few ounces to get it up to the head....

also, you didn't say if you were down on power or if it was just smoke...it it light or like a mosquitoe fogger?
 
I didn't really smell fuel, but I will try it again later today and double check. It is a heavy smoke killing all mosquitoes in its path.
 
You really need to tear the engine down and go over everything with a fine tooth comb, examine and inspect every part inside and on the engine for the cause of your issues. If your ring gap is too loose, especially on the oil rings, your going to get some oil on top of the piston and in the chamber, which will result in some smoking. Also check to make sure that you did not install the 2nd/scraper ring upside down, that will cause any engine to smoke like a train
 
Tried different valve covers. If my bore was off wouldn't that result in smoking out the pipe? I'm not getting any smoke out of the pipe. I ran it again yesterday evening and the head was building pressure in it. It was nearly blowing off the fuel line off the pulse fitting. Took it apart and the checked everything from top to bottom. The only thing I could find was the intake valve appeared to have a bad grind on it or warped or something. I took another valve from another head and tried it again. STILL SMOKING! STILL BUILDING PRESSURE IN HEAD! I decided something must be wrong with my head so I swapped heads. Try to start it and suddenly I couldn't even pull the rope anymore. I gave up and went to bed. Someone told me I may have sheared my flywheel key. They said it makes it impossible to start. So when I get home I will check and change key if need be and see if changing heads solved my problems.
 
This almost has to be due to excessive blow-by past the rings creating pressure in the crankcase with each stroke of the motor. I'd be checking the "round" of my hole as was suggested above. I would also be talking directly with whomever I bought the motor from to see if they are familiar with the problem. Best of luck with it.

Dan
 
the only thing that i can think of that would BUILD pressure in the head is that you have a bad lob on the cam. something is not allowing the exhaust to fully escape...maybe a bent pushrod...this doesn't explain the white smoke, but them maybe it does...if the exhaust can't escape it has to go somewhere....back through the intake and maybe it's blowing past the valve guide and oil seal....personally....before i worried myself sick on this problem, i would get another head (completely new head) and slap that puppy on. rule out the head or the bottom end before you start having nightmares!

check the compression release on the cam when you look at it too....pull the plug and see if it gets easier to turn over....
 
PROBLEM IS SOLVED FINALLY, NO MORE SMOKE. I replaced the head, reset the timing, and ended up taking off the lash cap that came with it on the exhaust side. It didn't act right with it on. It made it really hard to start. I don't know which one was my main problem, but the nightmare is finally over and I really don't care which one it was to be quiet frank because it is running and sounds great.

Thanks for all the help!
 
You need that lash cap on the exhaust valve or you run the risk of the retainer popping off and dropping the valve, which will cause worse problems than a little smoke. Good that you figured out the problem though but i doubt the lash cap was the cause of the problem, was likely something to do with the valve seats or valves in the head or the timing. Try another lash cap if you have to, some are taller than others
 
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