Smokey engine

[john wyatt]

A guide or guides sounds likely, hard to imagine a decoke is required after 4k, if the car is not turned over and sits for a while a cracked ring sounds equally likely, if so inclined there is another product generally available called "10k power boost" this is designed as a "decoke in a can", it is about ?20 per can and can be bought from halfords, I have used it on many cars but most dramatically on a Bentley S1 where results were nothing short of amazing, a well respected tuner told me recently to run an old engine on running in oil to remove glaze from bores, I have doubts on this but would be glad to here if anyone else uses this method.

[Mark Gordon]

I can't imagine putting that into an engine. I can see how it might remove the glazing, but it would surely wear valve seats, rings, cylinder walls, etc.

Mark

[mgcjag]

Hi All........Just getting back to a diagnosis.....am i correct in thinking that smoke on acceleration points to rings/bores wrere as smoke when backing off/changing down points to valves/guides.....Thanks Steve

[christopher storey]

Well, it can do, if it persists during the acceleration . If it just happens for a second or so when you accelerate after having been on the overrun, it generally still points to valve and guide wear . What happens is that under high vacuum on the overrun , oil is sucked into the cylinders , and then when significant combustion resumes on subsequent acceleration, the oil gets burnt. If however, you get blue smoke during say 6 or 7 seconds of acceleration , then the likelihood is that oil is entering the cylinder from the bottom end either by worn bores , or worn rings, or sometimes as a result of worn lands on the piston itself allowing the rings to "work" in the piston and pump oil up the inside of the ring