At stand still

Sounds like to me the bolt to the harmonic balancer may be loose or is spinning on the crankshaft. Have you read service information on replacing a timing chain?

Have you used a borescope to check for piston/valve damage? Leakdown test? Either test should answer your wuestion.

Hello Amir We would like a bit more explanation, what do you mean by “ the motor will spin completely “? When you turn by hand do the cams move, chain move ?? Does it feel like a solid lock? If so how does the starter turn the engine ?

Hello Amir, Add a few ounces of oil to each cylinder then repeat compression test compression test to see if it now has some compression in at least a couple of cylinders. This issue favors fuel washed cylinders or jumped timing. If they did a recent fill up and the problem started, check the fuel quality for water or contamination. Ground tanks still have issues with water migration…

You did what?

Do the cams turn either manually or with starter? Check flywheel . It may be broken.

Asking another way to clarify: when you use starter and think it's turning engine over(rotating) , are you sure it's engaging flywheel (pinion gear coming out) or is it possible that it's sheared off and starter motor is spinning?

Apologize, reading your post again, you stated you see cams rotating.

I have had this problem before. More than likely valves are bent. Starter will spin engine fast enough to crank over but turning by hand piston will hit valve and lock up.

That seems logical upon further inspection it seems the exhaust cam is out of sync .. haven’t really heard of these engines jumping time.. I can’t seem to find a definite answer of this is an interference engine or not

If the valves touched, it needs inspection, a borescope may be useful for checking the pistons. With high miles and poor maintenance, I have experienced the cam gears slipping slightly on the cams, but usually only causes fuel trim or surge issues. Check for evidence of slipping between the cam gear and cam.

That indicates that at least one piston is hitting at least one valve or carbon buildup, the low/no compression indicates that multiple valve have been hit and damaged. Use a borescope to inspect it. This is all normal stuff, nothing very special here.

General rule, zero compression, bent valves. Chain jumped time. Probably weak tensioner or high rpms(racing it). Extreme down shifting if a manual trans. Just have the exhaust valves replaced if that's all that touched. I do my own for a fraction of head rebuild. New valve stem seals and 8 exhaust valves, around $100. Seats aren't hurt, just replace valves. For security lap them in if you want…

If it looks like a new belt on the ac , they probably removed the crank pulley instaed of stretching the belt on as required. Needs valves, and retimed, requires a kit no way around it

Low oil pressure on these motors can cause the cam to bind up allowing the gear to slip on the end of the cam. The ratchet lock typically prevents the tensioner from allowing the chain to jump.

Can’t really describe what caused it to jump but the exhaust cam is way out of sync .. intake and crank shaft timing marks are dead on

Hello Amir, I always enjoy hearing the “Paul Harvey” version of "The Rest of the Story” during the diagnostic process. Fortunately, you did not blindly tear this down just to find the engine was a boat anchor. At that point usually the customer wants the shop to give away that labor once the decision to put an engine in it is established. Just out of a guess, the cams got hot from lack of oil…

well around this time of year when profit sharing and income tax if flowing.. they really didn’t care for the explanation lol. They just want It fixed at this point