White smoke

F

Fasteddie84

Member
I have a flathead that is smoking white now big time , last year broke 2 compression rings, 2 weeks in a row never found out why....just replaced rings again I have not checked with bore gauge yet but ring gap is within .002 everywhere in cyl it's checked.... .010 piston skirt clearance. ( like to see .004 but don't think prob)
.005 compression ring
.013 for scraper
.030 on oil
Guides look good .....

Now headgasket was leaking near exhaust valve , I know it will make a ohv smoke but what about a flathead,

Just seems weird , lots of oil on piston and valves when I remove head .

Also broke engine in on electric break in stand
 
Guides look good , but are they? they need to be around .002 to .003 clearance to stem to not let much oil get by them. .030 is a lot on the oil ring , that's not helping any. .010 is a lot with a raptor piston, but not the main cause of the oil smoke. Does it smoke like a freight train all the way around or just off the grid and then clear up? I've had some fast motors that smoked some when you first got in the throttle. Your moving oil top the top end either thru the guides or past the oil control rings. Jon
 
Very little smoke at idle, but constant when on throttle, ........

Both times there was also significant leakage from head gasket near exhaust valve on cluch side, i replaced the comedic Burris gasket with a soft style oem gasket and seemed to run good for 5 min until it blew a small hole in that gasket,...

Would a bad headgasket cause it to smoke.... Almost like it's sucking air in and over pressurizing the base......
 
Fix the head gasket problem first -- address that, then try to diagnose the white smoke issue. Deck problem, head problem, what is the cause of the gasket failure?

.010" is WAY too much piston/cyl. clearance and COULD be the culprit - as the piston rocks, it unseats the rings.

Back to the head gasket -- is the engine over heating? DO you have a whole lot of ignition advance in it? Detonation? White smoke could be caused by over the timing being way off or even simply over-fueling.


Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Chassis
Vector Cuts
(25 years full time serving the karting industry)
www.CarlsonMotorsports.com
215 N. High St.
Linden, IN 47955
765-339-4407
bcarlson@CarlsonMotorsports.com
 
White smoke is oil, black smoke is fuel.

.010” is a lot of piston clearance!

Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory. (Al Nunley)
 
On an alcohol engine that's out of time (ignition), it's common to see a cloud of white "smoke." It's actually unburnt fuel that you see coming out in a cloud.
Alcohol burns very cleanly. Rarely does an alcohol fueled engine emit black smoke. Diesel maybe. Gas slightly. Alcohol? No.
 
Found small hole in piston, couldn't see it until lol used plastic scrubber and cleaned all the discoloration off piston .... Weird enough in was in the center of the "0" in .20. New piston and cleaning hone and it's all good even Skirt clearence. No more smoke!!
 
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