Well something broke Dont know what. Reset timing ran great then turned it off had a run on engine.......clack,clack, clack, bent valve? Very noisy help Time to upgrade? Rebuild?76 2.0

Hmmn, what did you set the timing to? At what RPM?

Clack, clack is usually in the valve train.. Diagnose it well before you give up and call me :-)
It may not be more than a loose rocker arm, etc... Get some audio of it and post it.. Do a leak down tests and compression test..

So it was dieseling (running after spark was cut?)

Zach

And that tells me it was over advanced and or hot when it was shut off..

Timing adjustments on these engines must be done precisely as 2 degrees can be good for 10HP and 50 degrees of CHT... You are literally playing with fire and it will burn your ass!

Number 4 has no compresion. The engine was hot and it did diesel when I turned off the ignition. I think it is a valve problem. Never pulled an engine but now it is time or take it to a shop.

Sounds like you may have dropped a seat.

Do you use a CHT gauge? If so, what were your head temps?

At any rate, it is time to drop the engine. It really not all that hard, just intimidating the first time.
Zach

Let me know if you need any help.

I think I would take the valve cover off and look at the 4 cylinder rocker arms before the motor is dropped. Maybe it's just a broke or loose rocker. If the intake valve isn't opening it won't have any compression probably. If it's a valve seat it should have a lot of air coming out the intake or exhaust while cranking. You could just put a air hose in the spark plug hole using the compression checker hose and listen for where the air is coming out to see whats what. If the seat is loose it should be holding the valve lower under the rocker arm and the pushrod should be loose or out from under the arm maybe?

Put some air to it. Listen to where it's coming out. intake or exhaust could mean rebuilding the heads. air out the crank case could mean you holed a piston. Heads would be the safe bet like a dropped seat. the piston holing thing would suck. Either way you will end up pulling it.

Pulling the valve covers is very easy to do. That would be my first step. Look at the rocker arms and valve tips, see if there is anything obviously wrong with one of them.

--DD

Not really.

Valves need to be closed and sealed to the head to make compression. If the valve was stuck closed, it would make compression.

Zach

If the intake is not opening (broke rocker arm, pushrod loose, or adjuster backed off and the pushrod got loose) it is like you don't open the throttle to check compression. No air in no compression.

Ummn, if the intake valve is stuck closed there will be no compression either..
Because the chamber can't be filled to allow compression to occur..

Thanks every one. I will be pulling off the valve cover just to take a look. I think it could be a pushrod issue by the way it sounds. I will keep you posted.

I pulled the valve cover off. The second rocker from rear is loose(intake)? The valve spring is not compressed,(in proper position)?The push rod is not tight against the rocker. Could it be broken or bent? Any thoughts on how to proceed.

Is the valve stem in question at the same height as the other one when the valve is closed? ie is the seat loose and holding the valve intoward the piston a little?

Put #4 on tdc by hand if it gets tight stop. If it goes to tdc do a leakdown test or just put air pressure in it to see if it will hold a seal at the valve seats. While it's there check for the valve clearance to see if it's right if it's not maybe the adjuster backed off. Make sure the pushrod is in the center of the lifter if the adjuster backed off before you readjust the arm.

Compare the intakes and exhaust adjusters to see if they are approximately at the same position to see if the one in question has loosened up. When you put it back make sure the pushrod is centered in the lifter. It will go in a little farther when it is in the center.

Look visually at the valve spring on which the rocker is loose and see if it is sunken in more than the others next to it at tdc for that cylinder. If it is you probably dropped a seat. Maybe the valve adjuster backed out, see if the nut on the rocker is tight.

I think I know whats wrong..... The valve is stuck it never seems to move when I bump the engine. Time to pull the engine.....1st time....