Light blue/white smoke

P

Pavehawk

New member
I have a 20 over steel bore engine that smokes like some kind of james bond car when your in the throttle. At idle its fine. Warm or cold doesnt matter it. What would cause this? We dont race fh much so i thought i would give it a go at fixing it.
 
I ran it last season, the last race it started smoking pretty good. Started it over the winter a couple of times and this last time I could not see across my shop in about 30 seconds. Can this be valve related or it just a ring issue? The piston looks fine on the top, no cracks, fits in cylinder with what I would call very little play and the cylinder looks good with some lite hone marks still present.
 
So if the piston is .020 over i am sure getting rings is not as easy as ordering a .020 set huh... Thanks for your help on this.
 
Have you checked for a broken ring? Check top ring gap, should be less than .010 (only .001 - .002 needed for new ring). If you replace the rings order 1 size bigger and file fit them to the bore. -- Chuck
 
Chuck, I just took the head off to look at the piston size and bore condition. How are rings sized by bore size?
 
Yes, the rings are sized by bore size but if you buy rings the same size as the piston you will have too much end gap to start with. The next oversize will require you to file the ends to get the gap right. Check the gap in several locations in the bore in case your bore is not straight (tapered). While you have it apart you should at minimum do a light hone, if the bore is pretty straight a 600 grit ball hone will help with break in. -- Chuck
 
White smoke is what happens when oil gets into the combustion chamber. Black smoke would be too much gas.

There's more than one way for the oil to get into the combustion chamber. Bad Rings and loose valve guides being two of them.

From the desk of Al Nunley
Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory.(Al Nunley)
 
It's an alky motor al. I'm just looking for a ring size recommendation. I found two types on the web. One that says .020 over then the others go by bore size. I will have the guides replaced by a shop most likely.
 
What piston do you have? Raptor III or earlier (full skirt)? The piston should have a oversize stamped on the top, if it is a R III has a stamp saying std, to older style full skirt piston in standard size is not stamped. The rings for the R III are narrow compared to the old style. -- Chuck
 
std bore is 2.56.
piston says 020 should be a 20 over piston.
better recheck bore.
Is this an aluminum bore?
 
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