Distributor seems to jump out of timing?

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Moab-MoparKid

Moab-MoparKid

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I have a friend who also has a 71 dodge dart swinger with a 360. He's been having trouble getting it timed. I told him to bring it over and I'll give it my best shot. When we drove to my shop I could tell the timing was way off the car was hard to start but when it did it was fine....until you gave it some gas and gained rpm's. The car would fall flat on its face. When we got it to the shop we put a light on it and it was off(can't remember the degree) and no matter which way we would move the distributor the car would die. Then I noticed it seems to be jumping out of the distributor gear? The end of the distributor shaft seems to have marks of it slipping? does he have a wrong length distributor? or would it be the gear inside the motor?
 
Could be a really worn intermediate shaft bushing causing poor engagement of the distributor shaft to the intermediate shaft. I have personally never seen one worn on the thrust face like that but its possible I guess.
Can you post some pics of the distributor shaft end that shows the wear?
 
I would suspect the entire distributor set up. Pull the drive gear out, examine the shaft, as you get it "up" out of the cam gear check it for play in the bushing.

Now that you have the distributor out, you can go through that. Some drive gears are pinned and subject to damage/ slipping etc.
 
If it was jumping, it would quit, not run at all. There is so little resistance in the distributor it pretty much spins freely. If its point type, then you would feel the lobe opening the points. Another case of a mechanical or vacum advance issue.
 
MoparMike1974 said:
Could be a really worn intermediate shaft bushing causing poor engagement of the distributor shaft to the intermediate shaft. I have personally never seen one worn on the thrust face like that but its possible I guess.
Can you post some pics of the distributor shaft end that shows the wear?
Click to expand...
I can probably get a pic later this week. it just seems no matter what way you turn the distributor it pulls out of position or doesn't retard or advance?
 
Good point. If it were jumping time there it would be either 180° out or correct.
Pull that distributor out and check for wear. Maybe the advance plate is floating around loose.
Another good point...some intermediate shafts have the gear pinned to it. If that pin is sheared it will appear intact until you give it a rev and it will slip. Again, never seen it happen on a SB but its a very common problem on /6 with the nylon gear.
 
MoparMike1974 said:
Good point. If it were jumping time there it would be either 180° out or correct.
Pull that distributor out and check for wear. Maybe the advance plate is floating around loose.
Another good point...some intermediate shafts have the gear pinned to it. If that pin is sheared it will appear intact until you give it a rev and it will slip. Again, never seen it happen on a SB but its a very common problem on /6 with the nylon gear.
Click to expand...
Mopar small blocks don't have a gear on the distributor shaft, just a slot in the pump drive and a corresponding tip on the distributor shaft.
The pin coming out wouldn't allow the distributor to jump time unless the shaft was jumping up so far as to slam the heck out of the contact button in the cap.

#1, check the reluctor to pickup gap .008 or so is fine.
Chk the collar and pin for up and down play and the cap for rotor button damage.
Looks ok?
Pull the reluctor rotor off and advance plate to check for the springs on the weights, and that the weights move easily and return.
All good?
Could be a bad pickup coil in the distributor or ignition box problem.

One more bit of info is that big block and small block distributors are different in rotation so they advance differently but look the same other than the pickup coil rotor position on the shaft and the direction the vacuum advance pulls.
This means if he happens to have a big block distributor in a smallblock the rotor phasing would be way the heck off but the engine may run some if the plug wires are installed in the smallblock orientation. (clockwise firing order)
 
Moab-MoparKid said:
I have a friend who also has a 71 dodge dart swinger with a 360. He's been having trouble getting it timed. I told him to bring it over and I'll give it my best shot. When we drove to my shop I could tell the timing was way off the car was hard to start but when it did it was fine....until you gave it some gas and gained rpm's. The car would fall flat on its face. When we got it to the shop we put a light on it and it was off(can't remember the degree) and no matter which way we would move the distributor the car would die. Then I noticed it seems to be jumping out of the distributor gear? The end of the distributor shaft seems to have marks of it slipping? does he have a wrong length distributor? or would it be the gear inside the motor?
Click to expand...
Put the timing lite on again and watch the strobing. Just rev it up until it starts misbehaving and watch. If the timing jumps backward and forwards or starts dropping sparks, I could be that the polarity is reversed on the pick up. The correct pick-up has one orange wire on it, and I forget the other color but it doesn't matter, as it's the orange one that matters. The plug-ins are wired for correct polarity with the orange-wired pick-up.
But if the strobing is consistent and not dropping sparks, then I would sooner look at the reluctor or rotor phasing. But first disconnect the VA and try again.
 
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Orange and black are the v8 colors. I have seen bad grounds do almost what is described on my dist machine also. The spark just jumps all over usually in one direction.
 
It is pretty easy on the machine to see it on a car not so much. Usually the clamp is loose or the distributor is painted and the clamp will not bight through to the aluminum.
 
Mopar Distributor Shaft Lengths
Mopar Distributor identification guide by measuring shaft length, measured from mounting surface to lower end of distributor shaft.

Mopar LA engine – 3.875”
Mopar B engine – 3.5″
Mopar RB engine – 4″
–
Chrysler 331/354 Hemi – 4.25″
Chrysler 392 Hemi – 4.5″
 
halifaxhops said:
Mopar Distributor Shaft Lengths
Mopar Distributor identification guide by measuring shaft length, measured from mounting surface to lower end of distributor shaft.

Mopar LA engine – 3.875”
Mopar B engine – 3.5″
Mopar RB engine – 4″
–
Chrysler 331/354 Hemi – 4.25″
Chrysler 392 Hemi – 4.5″
Click to expand...

Thanks Hops, as I was going to mention the different length shafts, but didn't know the specifics that might allow a shaft to partially seat.
Then I thought that if it was a shorter shaft it wouldn't engage at all, and if it slipped at all it wouldn't run anymore at all.
 
Sweet guys! thank a lot for all you're help. I am going to try and get together with him as soon as possible and put to use all this information. hopefully find a verdict and get him driving his dads car again.
 
Pull the number off the dist and I can look it up to se what motor it is for.
 
halifaxhops said:
Possibly a B in a LA? No idea without a #
Click to expand...
Shaft may be skipping out, falls on it's face when rpm's go up,.......................B-RB dizzys spin backwards.....the vac can would come in from the wrong side and the
mech adv plate would turn the wrong way...........I actually thought of doing this(with the correct shaft & mech adv unit) in the reverse, a SB housing on My 383 to use
the vac adv/plate system to retard the timing when i hit the NOS. Sounds very likely by symptom anyway.......................
 
Your right brain fart there. I found all the housings are the same length except the slant so any thing is possible. They did make a advance that electricly retards the timing on 70-71 b & RB pricey if you but a nos one. Think it is 5 degrees I will find a pic, was used to stop dieseling at turn off.
 
s-l500.jpg
270 on flea bay
 
halifaxhops said:
Your right brain fart there. I found all the housings are the same length except the slant so any thing is possible. They did make a advance that electricly retards the timing on 70-71 b & RB pricey if you but a nos one. Think it is 5 degrees I will find a pic, was used to stop dieseling at turn off.
Click to expand...
Would this be an electrical connector on the vacum advance pot?reason is the 400 2bbl i dropped into a 59 regent had this connector, couldnt find any literature on it at all.
 
K i see it. Looks like that.
 
Yes two different styles one has a terminal like on a oil pressure sender and the other which is shown two terminals.
 
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