With a minimal investment, you can assure good oil control by installing valve guide seals Text & photos by John Dianna 0:00 / 0:00 ...

The 139QMB scooter engine is a popular small engine used in many scooters and mopeds. In this detailed video, we break down all the critical components that make up the 139QMB engine, from the ...

The machine work involves using a cutter that indexes off the valve-guide centerline to reduce the outer diameter (o.d.) to either 500 or 530 inch. As an example, stock small-block Chevy valve ...

The common suggestion that most hot-rodders make when faced with this problem is that the valve guide seals are weak or non-existent. But the heads were freshly rebuilt using Viton rubber positive ...

It can leak past worn valve guides or it can be coming past piston rings. If the oil is being consumed during stop and go city driving, the valve guides or their seals are the probable culprit.

Replace Valve Guide Seals This is another fix that involves a cheap part, but the labor is the killer. The valve guide is an integral oil seal between the combustion chamber and the cylinder head.

What happens is that the valve guide seals or piston rings are worn out, and oil is leaking past from where it should be lubricating the moving parts, to the combustion chamber where it’s being ...

When valve-guide seals wear out, motor oil can leak into combustion chambers and the engine will literally start burning oil.

Generally, replacing all of the valve guide seals will remedy the oil smoke. Although at this point, since the smoke so infrequent, you might want to wait before you spend the money on the repairs. Q.