Hi, from down south!
Would like to know if any one has ever found out why some gassers will exhibit more compression while hand rotating the prop clockwise instead of the normal operating mode, counter-clockwise??
It occurs with or without the crankcase back plate bolted on, so I have discarded crankcase pressure.
Thanks for any enlightening comments.
Juan

It depends on which side the ring gap(s) is on

+1 on ring gap

+2</p>

As long as we are on a discussion about compression why do the Chinese Engines have so little while my 3W Engines have so much when cranked by hand?

your kidding rite.

China made engines lack precise fitted parts.Sometimes too large of a ring end-gap. Cylinders can be out of round ...rings cannot seal good. Cylinders can have a taper...again rings cannot seal good. Ring material can be to hard...rings do not seat good. Ring could lack good machining...poor fit.

Im kidding a little. It's funny though that I have weed eaters and chain saws that are not top of the line but they have good compression.

I have numerous Chinese Engines that run well but have little compression when hand cranked. My two 3W Engines on the other hand really get your attention when you hand crank them. I'm sure they have much better tolerances and fit. I'm sure thats some of what the extra cost gets you.

you have a point that I have made in the past.you can go out and buy a 79.00 weed eater feed it the cheapest oil you can find.it has great compression and never a problem with bearings and it just keeps running.

Maybe all of the above. Notice my new DLE 35&55 RA have much better compression feel than the older ones. Bowman rings in both.
BCCHI

The more I read about all the problems with a lot of all these engines of various brands, I think it would be better to get a good conversion RC engine from one of the guys that know this stuff in the first place. They know by experience what goes wrong & rebuild/convert them to be more trouble free................

3Ws have dual piston rings.....that might contribute also

I don't think ring gap has anything to do with it as ABC-type engines have the same characteristic. Perhaps it has something to do with intake and exhaust timing.

Thanks for returning to the original thread subject, ie: CW and CCW compression!!!
The subject still baffles me.
Juan