Timing problem 302 Ford "Help"

302 ford motor with 10 degrees of timing, ran great.. drove it to the customer's house and two hours later he gets in it to drive and it starts fine and moves it about 100 ft. to the end of his drive way and then gives it a little gas to move and it dies... won't start.. we go back over and try to start it for him and it sounds like it's out of time... put the timing light on it and you have to give it 25 deg. of time to get it to start and it runs fine like that... he took it to a shop and they put it on a scope to check the if it was elect. and they told him the timing chain has jumped a tooth and that's why you have to have to put 25 deg. in it to make it run... Question has anyone else had the timing chain on a ford motor jump a tooth and put it out time.. ??? Or could it be something else that we are over looking?? hate to tear the motor down to replace the timing chain if not needed...

Not sure of Fords but maybe sheared pin in cam gear on distributor??? This happened to me a long time ago on a SBC Like to drove me nuts. Timing kept changing.

It's been known to happen, at least on a SBF you don't have to partially drop the pan

fords can shear cam pins . if the right dowle pin is in the cam it can dead head on cam bolt washer giving to a false Tq reading on the cam bolt and then back off then shear cam dowle pin . the pin can shear in the dist as well .if it did this would drill the gear and shaft then go up to 3/16. i like the double rolled pins if you can find one Msd use.s them mc master car i think has them

The sheared dist. drive gear pin gets my vote. If the cam jumped time for some reason the engine would not run great and if it slips more, the valves might hit the pistons if you run it much trying to test it. Sheared dist. drive gear will run fine if it is still tight on the shaft... until it slips again and stops running.

Pulling the dizzy is fast an easy compared to the chain for inspection. Also, a compression test will let you know if the chain has jumped. With the cam out of time with the crank, compression will be lower. Even a vacuum gauge could help give you an indication of whats happening...

Thanks guys for the info.. the shop that did the scope work said they checked out the diet. but who knows for sure... they also said that when they pulled the dist. and looked down in the hole they could see the timing chain move as they rocked the motor and i guess that's how they thought the chain was slop enough to jump a tooth... We will try and pull a compression test next week and the owner is thinking about buying a new mallory diet.

What's the age/mileage on this 302? Some of the OEM's had a white plastic timing chain gear that became infamous for wearing down enough that it easily jumped a tooth or two.

Roger i don't the history of the motor only to say i think it was rebuilt not to long a go.. it came with the '49 ford truck the owner bought as a basket case.. most parts on it looked new but inside it's anyone's guess.. It did run strong and smooth before all this happened..

Like others have said, I'd focus on the distributor first and verify what the shop told you before I started pulling the front cover.

I went out to shop but didn't have any 302 so my question is---Can you see the chain thru the dist hole??????

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Originally Posted by jerry clayton

I went out to shop but didn't have any 302 so my question is---Can you see the chain thru the dist hole??????

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Yeah, from the right angle but not clearly. Here's a shot of a bare block.

Attachment 60742

That's what I thought, but wasn't sure-----you can roll the crank forward and back to see how much rotation you can get before it starts to move the cam---it will have to have several degrees of rotation if the chain is loose enough to have skipped a tooth====


Also, if the manifold is removed you can put a straitedge across the tops of th two lifters on #1 and when they are equal the crankshaft should be at zero (this will be on the overlap stroke) so the lifters would be at there RAISED/OPEN position--
maybe a little easier step in the trouble shooting process before undoing all the front end stuff--------

Jerry the shop the owner took it too took the dist. out and looked down in and moved the crank back and forth and said he could see it tighten up and then get slack but didn't say how much he could move it.. he thought by the amount he could move it that the chain had enough slop in it to jump... we are still up in the air about that...

At this point that's what we're thinking .... i still wanted to get some in put from all you guys, knowing someone here would know.. or at least make me feel better about which way to go.. hate wasting my time and his money if we don't have too..

I sheared a dizzy pin in. 302 once. A piece of the nylon from the timing gear got into the oil pump and locked it up. The pin gave enough resistance to move the dizzy somewhat when the crank moved, but it was pretty apparent what the problem was.

Well it all came clear today about the timing problems the 302 small block was having... after having it tested once again by a very smart guy here in town it came down to a bad coil..... not sure what went wrong with the coil but it appears that it was breaking down... The shop that did all the test and thought it was a timing chain that had skipped was wrong and they refunded all the money he spent with them to test it... Pretty nice of them it think...... something to think about next time the old motor starts running ruff... COIL...

Thanks for posting back what fixed it. That's one of those that reinforces the need to eliminate all of the simple stuff before jumping to the more complex. Funny that it "ran fine" with the timing so far advanced, but glad it's fixed for the guy. Getting the refund from the first shop is definitely a bonus, and not the norm in my experience.

Was the coil OEM or aftermarket and if aftermarket whose brand?

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Originally Posted by rspears

Thanks for posting back what fixed it. That's one of those that reinforces the need to eliminate all of the simple stuff before jumping to the more complex. Funny that it "ran fine" with the timing so far advanced, but glad it's fixed for the guy. Getting the refund from the first shop is definitely a bonus, and not the norm in my experience.

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I too was a little shocked to hear that he got all his money back, but the stepped up and did the right thing.. and yes it was worth the extra time spent checking things out but for tearing the front of the motor apart...

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Originally Posted by NTFDAY

Was the coil OEM or aftermarket and if aftermarket whose brand?

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It was a Pertronix flame thrower... and the distributor was a ignitor ll..