Have my 63 F100, with the 292. The other day was starting it and had a bad back fire. Now she will not star. Ithink that the timing chain has jumped. what do you all think?

 

This is a simple method to check for excess slop in your timing chain or gears. It is not necessary to remove any components as long as you can see the timing marks clearly. It can be done with one person, but a second person can be helpful if the distributor cannot be easily seen while turning the canskshaft from the front of the engine. This test cannot tell if a chain has jumped; it can, however, tell you if there is enough slop in the chain to have let it jumped.

Tools: Breaker Bar with socket to fit the front crankshaft bolt

1. Mark the TDC or 0 mark on the damper clearly. Ensure the rest of the timing marks can be clearly seen; clean them if necessary. You may find it useful to scrape a little chalk over them to highlight them.
2. Remove the distributor cap and place it out of the way. You must be able to see the rotor while turning the engine with the breaker bar. It usually is not necessary to remove the spark plugs, but some high compression engines may require it to get an accurate reading.
3. Turn the engine in its normal rotational direction until the TDC or 0 mark is lined up with the pointer.
4. IMPORTANT: Do NOT turn the crank backwards just to line it up. Doing so will give erroneous results. You MUST rotate the crank in ONE direction only. If you overshoot, just go around again. This is where it may be helpful to remove the plugs.
5. Once the marks are lined up and while watching the rotor, rotate the crank in the opposite direction. When the rotor begins to turn, STOP. It may help to have a helper push against the rotor's direction of rotation. They can feel it begin to move more accurately than you can see it begin to move.
6. Note the value of the timing mark the pointer is indicating. It will be BTC, because you went in reverse of normal rotation.
7. This value is the amount of slop your timing chain has in degrees of rotation. Anything less than 10 is safe, but performance begins to fall off after 5.
8. If you have anything over 25, STOP driving that motor and get the chain and gears replaced! I have seen motors run quite well, and for a long time with up to 45 degrees - but I wouldn't risk it myself.

 

I dont think you jumped your chain. Its possible but notice how it wouldnt start after backfiring. I think you blew you powervalve one good backfire will often kill a carbs powervavle. Let us know what you find.

 

stupid question, what is the best way to chech if it was the powervalve?

 

Or a qwik check, pull #1 plug & roll engine over by key, or hand, 'til piston is up top.

Timing mark on balancer should be either close to dead on or close to 180 degrees off. If mark 15 degrees or more off in either direction (as in + or -) with #1 Piston up top something is definitely wrong in engine timing system. Futher diagnosis is req'd. If mark is close and timing was correct before backfire, something else is wrong.

If you still run points & condenser I'd start there instead of thinking timing. make sure it all works & is correctly set up/ adjusted. Also make sure nobody played any tricks on you.

As for the power valve, it won't prevent an engine from starting, but it will make it run really bad, not Idle, stall out, burble, sneezs or back fire when you attempt to throtle up your engine RPMs.Anyhow, 1st off it depends what carb you have, not all have power valve. Some use metering rods & so forth.

Diagnosing a bad powervalve is best done with engine running, or else when carburetor is being rebuilt. I'd say after a major backfire tho, if you do in fact have a power valve it has a 98% chance of being wasted now.

FBp

 

Points and condenser are new, new coil and wires and plugs. It is getting fuel, and spark is good.but checked what the timing marks, they is off so it must be a jump in the chain.

 

Ok what is the best way to do the timingchain with out pulling the block out of the truck. The timing cover is also the front motor mount.

 

Block the engine in place off the floor using jackstands. But if it is timing set, you really ought to pull the oil pan so you can get all the pieces out that fell in there. so you need to pull the pan then block the engine up.
FBp

 

Time to order some parts. and a long weekend. thanks ya all

 

It could allso be a loose distribuitor bolt. If dizzy moved in block timing marks will be off, serious backfiring is quite probable too.

The only way to tell for sure is way I told you with #1 plug out & #1 Piston @ TDC.
FBp

 

Check the distributor drive gear and pin I had the pin shear on mine and the gear spun about 45' same symptoms. It's easier to pull the distrbutor than a timing chain.