I am trying to get this 216 on its feet and nothing is working for me. Timing is good, valve lash set. I tried soaking the cylinders in Marvel to raise compression. I am having starter issues. I think it is cranking slow and the switch gets smoking hot. Could it be that it’s not fast enough to generate compression? I am only getting 30-50psi across all 6. https://youtube.com/shorts/CFNPbMgEbJc?si=qsAAZQJsfLPho9HS
Dunno...might double check valve lash settings. Not adjusted correctly or could be too tight, keeping the valves from closing completely.
As much as I hate to say it, the rings can still be stuck, or might even be wore out. Are you doing the compression test with all the spark plugs out of the motor? The motor turning slow with all the plugs out could be caused by a starter that has a problem, or it could be a crankshaft issue or some other internal motor problem. How does the motor turn by hand by grabbing the fan blade and turning it with the plugs out? A motor with no plugs should turn over pretty easy by hand.
Have you tried a "wet check"? A tablespoon or so of oil in each cylinder can tell you if you have ring problem. If the oil raises compression that indicates worn or set up rings. If that doesn't change it try backing off all the rockers a turn and that'll tell you if valves are adjusted too tight to close. I had a similar problem with an OT tractor after I did the valves. It sat for a couple years and after I got it back together it wouldn't make more than 30-40 psi compression. After I fed all the cylinders some oil and gas in the carb it fired up reluctantly. I ran it for about 20 minutes, shut it down, and rechecked compression. Was back up nearly to spec and ran strong/started good after that. My theory is that the cylinders and rings just got dried out after a couple years of inside storage. It also shows the rings were worn, but it's still running strong 4 years later. I know you used Marvel in it but that is quite low viscosity compared to oil. That might keep the rings from sealing well on initial startup. If this motor sat for a long time the rings may need a little help to seal until it runs for a while. If they're completely set up you know the drill.
How did you set all your valve lash? There is an easy way to be sure by bringing number 1 up on TDC and setting both intake and exhaust lash. Then set #2 intake, #3 exhaust, #4 intake #5 exhaust. Then bring # 6 up on TDC and set both intake and exhaust. Follow that with #5 intake, #4 exhaust, #3 intake and then #2 exhaust. That's how I've done my 235.
I did it the same way, has to be the fastest. Since it has to be done cold I went .010 intake .018 exhaust.
Operate the starter directly (with a hand switch ) so you don't cook your starter switch. You can crank the 6V starter with 12V, so at least you can get it spinning faster. Wet compression test will tell you if you have any rings left. An air fitting through an old spark plug, screwed into the plug hole and with air going through it, will let you hear if you have any air leaking past the valve seats (with that cylinder both valves closed ) when you put a bit of hose into the manifolds and listen to the other end .
Well with a wet compression test it went to about 90 psi and with it would run for half a second or so on starter fluid so I hooked up the fuel line, cleared the carb of mud dauber nest and with a bit more struggle got it running! https://youtube.com/shorts/_xnktli5zK0?si=rXMkuUucxYrKf_mP
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