Distributor drive gear

W

willobs

Senior Member
Can the Distibutor drive gear be replaced without pulling the head? I have to much play in turning rotor, what about the oversize gears anyway to tell if oversize needed? Thanks
 
you only need to remove the side cover

does the dizzy body need to be re-bushed? I would check that first. That is also easier to remedy since the side cover stays on.

There is supposed to be some lash in the gears
 
yes, it is located in the valve chamber , and is accessed by removing the valve cover. Easier with the intake and exhaust removed. Be careful if you haven't recently removed the distributor. It is prone to rust at the head, and bind up enough to resist removal. And do not pry up on the distributor body. the casting likes to break with this technique. buy the distributor puller if you have this situation.
les andrews has a procedure I would guess in his red manual.
Bob
 
It can (be replaced without pulling the head) but you have to pull the distributor. The entire thimble that holds the distributor drive gear comes out through the valve chamber opening, but you have to have room to lift the thimble/gear "up" against it's retaining spring. With the distributor in place this can't happen.

IIRC, you remove the distributor, and accessing the thimble, lift up compressing it's retaining spring. Then the bottom of the thimble/drive gear assembly "tilts out" through a sort of "clearance slot" formed in the bottom of the valve chamber - and you have it in your hand.

Installation is the reverse of removal - sort of. You place the thimble/gear, and then use long nose pliers to reach in through the distributor hole and turn the gear and play around with it until the lower tongue end of the gear meshes with the oil pump. This is easier to do by dropping the pan and placing the oil pump AFTER the drive gear. You can turn the engine too somewhat as an experiment to get the helical gears to mesh and "catch" the oil pump too.

You can tell if you've succeeded with the oil pump when everything sets back in it's original position.

Then place the distributor and time and you're good to go!

Joe K
 
How much lash is my same question ? The lash can also be in the drive shafts not just the drive gear.
 
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Patrick L. said:
Have much lash is my same question ? The lash can also be in the drive shafts not just the drive gear.
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I know one of the reasons that Bill Stipe started making cam-shafts was the developing issue of the helical thread being worn at the distributor drive gear. Bill might be able to help us by telling about his "worst case" seen - which might not help that much - but would be at least a place to start.

One can see though that backlash in this are alone is not fatal - action of the engine and timing gearing is primarily "forward" and the tendency is for the gear to always sit/wear to the same side as in "free play is taken up" - and you time the engine according to that basis and always in the forward direction.

This is a general statement. Accelerating/decelerating the engine COULD make the backlash in this area go to the other side of the wear margin - as could (even) the action of the lobes of the point cam (IIRC are more pronounced on the B cam - I may have to check this thought over at FordGarage.)

On one of the engines I tore down for inspection the prior owner had stuffed the tongues of the distributor with leather to take up free play - perhaps he had issues with performance and found the leather to improve his problem somewhat? That engine sits so I can't confirm that thought.

And wear of the timing/crankshaft gear is another ball of wax entirely since it affects not only the ignition timing - but also the valve timing. But the best part about the timing/crank gear is that the incremental wear is spread out over a larger diameter - and not so much change to start and finish of events can occur for the same degree of wear as it can with the smaller diameter camshaft/distributor drive gear?

Jest some thoughts.

Joe K
 
Thanks for all the posts. The reason I suspected to much lash was engine in 30 CCPU said to be rebuilt 7 years ago less than 10K use. I have had 3 years, truck runs 55 mph very easy no overheating, but will not idle slowly. Engine bored 125, lightened flywheel, 5.5 snyder head, original type points. will not run good when timed Ford way, Red book way also used the new type NuRex wrench. If the rotor is set at a contact point in cap you have 2 widths of the rotor tip free play!
 
willobs said:
Thanks for all the posts. The reason I suspected to much lash was engine in 30 CCPU said to be rebuilt 7 years ago less than 10K use. I have had 3 years, truck runs 55 mph very easy no overheating, but will not idle slowly. Engine bored 125, lightened flywheel, 5.5 snyder head, original type points. will not run good when timed Ford way, Red book way also used the new type NuRex wrench. If the rotor is set at a contact point in cap you have 2 widths of the rotor tip free play!
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You may be able to use a timing light and a clear distributor cap and see if there is any "waiver" of that distributor action.

Joe K
 
If you are lucky you will just need a new shaft.
 

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Tom, that's what the shaft tongue looks like the one that was stuffed with leather.

Joe K
 
Thanks everyone, never thought of the tongue on shaft wearing, had gear slop in my head. will check it when I have time
 
originally the shaft was a 2 piece so check both, the female end also wears out.
A single shaft is not as good a choice. The original 2 shaft design was not as ridgid.
I think the rotor turns smoother with the correct, 2 piece shaft.
Bob
 
Brentwood Bob said:
originally the shaft was a 2 piece so check both, the female end also wears out.
A single shaft is not as good a choice. The original 2 shaft design was not as ridgid.
I think the rotor turns smoother with the correct, 2 piece shaft.
Bob
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Why is it not a good choice ?? I have never had any problem with them, & as you said, its just one less shaft to wear out..:D
 
willobs said:
Thanks for all the posts. The reason I suspected to much lash was engine in 30 CCPU said to be rebuilt 7 years ago less than 10K use. I have had 3 years, truck runs 55 mph very easy no overheating, but will not idle slowly. Engine bored 125, lightened flywheel, 5.5 snyder head, original type points. will not run good when timed Ford way, Red book way also used the new type NuRex wrench. If the rotor is set at a contact point in cap you have 2 widths of the rotor tip free play!
Click to expand...

I doesn't hurt to check that out as it's a quick repair to replace... but I don't think that's going to cure your idle problem. I might be wrong and don't know how much your flywheel has been shaved, or rpm your idle is set too... but in my experience a lightened flywheel engine won't idle as smoothly as a stock flywheel. I think you have other issues. The rotating motion of the shafts will be fine with the engine running. They all have some backlash slop in the rotor.

Larry S.
 
Thanks for all the input. My shaft makes Tom,s look good it looks like a knife blade! have ordered a new one.
 
willobs said:
Thanks for all the input. My shaft makes Tom,s look good it looks like a knife blade! have ordered a new one.
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You mean there is one worse than the one I removed from a customer's car?
Did you also check the lower shaft?
I think this shows the importance of keeping the engine and distributor full of clean oil.
 
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