Jumped Timing

My father and I are looking at a truck just outside of Savannah that the owner claims has "jumped timing"

What exactly could he mean by "jumped timing" and what is the timing system on a m37? Is it chain or gear-timed? He said when this happened it apparently "popped" yet still ran strong. Any help?


thanks,
ken

okay, after thinking it through. my only question is How hard would it be to repair it? What would I need to do/ have to repair it?

thanks,
ken

"jumped timing" means that the gear teeth or chain "skipped" past the proper setting, thus causing a "Off-timed" motor, that WOULD NOT run very strong. It could also mean bent intake/exhaust valves, depending if the motor is a "interference motor", or a "non-inteference motor", meaning that the valve train could/could not come in contact with "jumped" timing.

Most of the time a jumped cog or two would not cause valve problems even on an interference engine. Most of the problem with the interference engines was when a timing belt breaks and the valve train would stop while the pistons continued on. If it had enough timing jump to cause valve train problems then it would not run at all. I used to see the messed up valves on Escorts all the time when I was working as a mechanic.

check to see that the oil pump is installed(timed) correctly.
i would;
remove #1 spark plug and set the engine to tdc #1 compression,
verify the crankshaft timing indicator is where it's supposed to be (0 degrees),
remove the distributor cap and verify that the rotor is pointing to the plug wire tower that is supposed to be connected to #1 cylinder.(it should be slightly past #1 in the direction of distributor rotation).or that the rotor is pointing to the tower thats connected to #1 cylinder at least.
also check that the plug wires are connected in the correct firing order and that the distributor hold down clamp is tight.
examine the cap and rotor for wear or evidence of carbon tracks that could cause missfire.
check the plug wire insulation for cracks or damage.
if the parts are ok and everything lines up it should run.

if your oil pump is timed incorrectly and you skip the steps for verifying the #1 compression stroke and just use a manual for visual reference as to which lug on the distributor cap is supposed to be #1(lets say 12 o'clock) your distributor timing could be anywhere.these flatties are different than a chebby small block in that the oil pump is gear driven off the camshaft,not by the distributor drive gear like a chev.
in a smallblock,when you change the distributor,if the rotor doesnt point where you want it you just yank the dist out,put a big blade screwdriver into the oil pump drive,and rotate it until the rotor lines up where you want it once the dist is in.in a flattie you have to remove the oil pump to change the relationship between the distributor drive and the camshaft.
it's not a big deal to get right,you just have to be systematic in your approach and follow the steps.

good luck.

i am a liar. The timing chain in the girl is virgin. Fuel delivery problem.

Ran the in line (fuel pump) into a gas can sitting where the radiator was until we took it out, gave her some choke, gave her some gas, hit the starter, 4 revs, then, well, lets put it this way. If I had a microphone and tape recorder, I would have recorded the sound and gone to sleep to it. SHE LIVES!!!

This stuff should be prescribed as an anti-depressant, as its damn good! Thanks for the help guys!

(Plus our '50 8N had quit, so we put a probably 25 year-old coil in it and now she runs like a champ, double the effect!)