A friend gave me a Saito 56 that has been sitting for a couple of years. Put it in the crock pot to free it up. Put the plug back in & noticed no compression. Had already adjusted the valves so that's not the cause. The question is: the engine ran fine 2 years ago, could the valve springs have lost some of their springiness due to possibly sitting compressed, or could the crock pot weaken the springs? Tried gently lapping the valves with no luck. Any ideas?

Did you tear the engine down before it went into the pot?

Is the piston ring stuck in its groove?

Are the valves and tappets free to move without any sticking?

Is the wrist pin free in the piston and con rod?

Listen in the exhaust and carb areas for a leak

listen at the crankcase vent

If the carburetor is closed it will not have any compression

Fuel it up and start it some enigens ive ownd have no compression when turnd over by hand. Once it is running the the fuel iginting will push out the ring.

I had this happen on one of my Saito 56 engines. I didn't notice the lack of compression until I went to back the prop up against compression to put the starter against the engine. I stuck the starter against it anyway and it started right up. I flew the thing 5 or 6 times that day

I'm pretty good with engines. It is narrowed down to the valve train. I took the cylinder/head off, filled it with fuel & watched it run out of the intake port within 10 seconds. So it''s not the pison ring. With the cylinder on I can cover the intake port & get compression.

I also have had some low compression engines run but this one will not. Could it be the springs?

Best thing to do is look under the intake valve cover and see if the pushrod is out of the rocker arm socket if not then .. .. . .

The intake valve is either stuck in the guide or the lifter is stuck in it's guide

Put some WD40 on the parts to free them up

Hello; I have had that same situation; These engines rely on oil to aid compression and help sealing. Your compression will return after a tank or two. In the two or so years that the engine has been sitting, what oil it had in it has evaporated or otherwise escaped leaving a soapy residue to prevent rust, it won't be liquid enough to provide a compression seal.
I have my first ever engine (a Saito 45) it doesn't show any compression either, but I know every part of that engine is in a healthy serviceable condition. I wouldn't hesitate to use that engine, but others have picked it up and spun it over then put it down and told me that it's hooped, or it needs a new exhaust valve, or the ring is broken. Yet it starts first flip and will idle all day at 1800 rpm.

It will not run. Way past checking valve clearance

Look under the intake valve cover it might have a broken spring or one of the other things we mentioned.

Did you have the engine apart like in take the cam box off the crankcase?

I have heard for years the if you keep a steel spring compressed it will loose tension. This old wives tale must have sprung form bow and arrow day in that if you didn't unstring your wooden bow it would loose tension. Very true for a wooden bow - not so with steel springs. My father had a Cadillac sitting for 6.5 years and with a new battery fired right up and still runs fine. If anything your valve guides and stems could be gummed up with old castor. If it were not for castor's durable film strnght at high temperature there would be not reason for a sane man to use the stuff.

Bill