Well i am not sure if this is a distributor problem or what is going on. I will do my best to explain what is going on. Truck isn't getting any spark...plugs are wet after we crank on it. Has new wires and plugs. I changed out the distributor and that didn't help at all. So, then I had someone look at the part in the cap that spins to see if it spins at all when cranking and it doesn't.....so what is going on here? Thanks for any help

oh yeah. 79 f250 with 460 engine

 

Broken timing chain.

Marty

 

Remove the distributor and check the drive gear. If the gear drive is broken check the oil pump and drive also. Otherwise it may be a worn out or broken timing chain. For additional information check with the 385 series engine forum.

 

The pins on the bottom dizzy gear have a habit of shearing off as well.

You can always pull a valve cover off and then turn the crank by hand with a breaker bar socket to see if the valves move up and down.

btw, That part is called the Distributor *rotor* and it is attached to the distributor shaft which in-turn is mesh geared to the camshaft.

 

would a timing chain break with only 17K original miles on it?

 

Probably not, but an oil pump can lock up and break the distributor drive gears.

 

good greif. My aunt had this truck for 25 years without any problems and once I get it, it spun a bearing and now this. Why type of work invovlves getting it fixed? Tearing the whole engine apart?

 

No.

You can out the distributpr easy enough to check the shear pin.

Just make a note of where the rotor was pointing when you put it back in.

and Make sure the engine doesn't get bumped while the disty is out

You can check for a broken timing chain by putting a breaker bar and socket on the crankshaft bolt and turning it "with a valve cover off" ....to see if the valves go up and own.
If they go up and down the timing chain isn't broken.

 

thanks for all the help! I had the distributor out before, and dumb me, forgot to mark where it was pointing before. When I look down into the hole, what am I looking for to be able to tell if the pins are sheared?

 

Is the gear on the end of the distributor shaft on solidly? The pin that shears is the pin that holds that gear on.

I never mark them myself because it is just too easy to put them back in if you have done a few. The engine always seems to get moved anyway...

 

At the end of the arrow there should be a clevis pin holding that gear in position.

You can try turning the gear on the shaft first but you can just take a punch and tap that pin out to see if it is in all one piece.

 

The whole shaft moves somewhat on the distributor, but the new one moves a little bit as well---nowhere near as much though. There is a spacer type thing at the under the base of the new one, while there isn't one on the old one.

 

The shaft is supposed to turn in the distributor the easier the better.

What isn't supposed to turn on the shaft .......is that Gear.


Pop the pin out that holds that gear on the shaft

 

Thanks for the help guys. But, wouldn't the new distributor work?

Sorry for all the questions....not used to older engines, more of a F.I. guy. LOL~

 

The gear on the end of the distributor shaft meshes with the gear on the camshaft in the engine.

If the engine is cranked with the starter and everything is as it should be...the rotor inside the distributor should turn when the engine cranks.

If it doesn't turn with the engine being cranked there is something wrong.

These pins are notorious for getting /being sheared off.

There is only one way to verifiy that.

Punch the pin out that holds the gear onto the shaft to see if it has been sheared off

It takes 2 minutes to do this.

Please do this and get back with the results.