AMC 401 engine problem

Just an odd thought... If you have an old set of timing gears, you can check the keyway clocking to timing marks compared with your timing set. There was some discussion about off timing marks long ago.

I have my set that I pulled with a good running engine. Can post a picture, to give some indication that might be the issue.

I had a new set of gears long ago with what looked like a timing mark on the reverse side. Which did install proper, but threw internal engine timing off.

I think your leak down is on the high side... When you re-lapped the valves after my last post, did you do a blue check? There's only so many causes for losing compression... Valves not sealing, valve(s) open (valve train issue or overlap) , rings not sealing, head gasket not sealing.

I read a few posts about rounded off cam lobes. I do not believe that would cause your issue. That would open the valves LESS and start your valve motion slower and end sooner...

I read a few posts about timing chain alignment. Keep in mind the alignment marks should be near each other. I rebuilt a Pontiac one time and the alignment marks were supposed to BOTH be at the bottom of the gear in the same vertical plane. Very strange to this old AMC guy.

I think you need to stay focused on combustion chamber sealing...

At this point, I think you need to look for something simple that is wrong with your set up. make sure your distributer cap is wired correctly-the firing order goes in a clockwise direction and is 18436572 just like a chevy. the EVEN numbered cylinders are on the passenger side of the engine. I have seen engines with the firing order wrong and they ran all crazy...but they ran. try a different distributer if you have one. Use a different timing light if you have one too.

Morten - when you refreshed your engine, did you pull the piston and replace the rings? If so, is there a possibility that [with the exception of #1 Cylinder] the rings were not staggered, but with the ring gaps aligned, allowing compression blow-by.   

Hi guys.

I guess its time for a little Update, not that there is much new to tell. Its for sure still pretty dead.

Vi took the the timeingcover and intake manifold off. Had a degree wheel installed on the crank and a gaugeclock on the intake valve on cyl 1. The timing chain were installed as default, with cyl 1 at TDC and the dot marks alligned faceing eachother. Recording to my cam card, my intake valve should begin oppening approx 1,5 degree before TDC. Well it was nearly as spot on as you can get. So i know for a fact my timing gear and cam are working as they should. Than we tried cranking the engine, and hold our hands over the each intake, and the was alot of sucktion/vaccum. Maybe a little less on cyl. Nr 7 but not much. than we took another compressiontest. Strange thing happened. Now we have approx 5,5 - 6 bar / 80-90 psi on all cylinders. I guess this would be an okay (not what i could wish for) but on a cold engine with a mild cam this would be enough to crank and start the engine. We than reassembly the timingcover, and intake, and took another vaccumtest on the intakemanifold, again on the starter. Again not much vaccum,- around 3-5 in/HG on the starter. We than installed the ignition, distributor, coil a.s.o. Testing that we have fuel, spark and of course free air flow. We know had had some sort of compression. Cranking the engine with fingers crossed, but not even a little fart..    Doublechecked ignition, timing and pulled all spark plugs out. We can see all cylinders get fuel, except cyl 1 and 2 at the front. Thoose two, were not wet of fuel of some reason i dont understand. Than we tried again, but this time with a little help from a spray of "diesel start" - but still nothing. We tried many different positions with the distributor, but nothing would even give us a little indication of an ignition. So this is basic were i am right now.. i ordered a new High torgue starter Yesterday, because the my current one never had turned the engine in the speed i wanted it to, and after using it pretty hard last 3-4 weeks its getting even worse, so my cranking speed is very slow, and after 4-5 sec of cranking, its like its giving up. Battery is New, and since i dont know the age and origin of the poor bastard - i give it go. I also ordered a New distributor gear for my old dist. and im going to try installing the old ignition controller, and maybe buy a New coil. Well i am simply just lost for now.., if the things i Wrote dont seems to do magic, i'll might just buy a bag of marshmallows and make me a great fire...