Distributor drive U-joint?

V

VT Cruzan

Junior Member
1. My 1931 Standard Coupe has a universal joint between the oil pump drive and the distributor shaft. The joint and shaft are quite worn causing close to 90 degrees of play in the rotor. (It runs remarkably well but is a challenge to set the timing!) There is a spring steel oil pump retainer instead of the normal coil spring.

I am tempted to replace it with the conventional upper and lower distributor shafts along with the coil type oil pump drive spring.

Was this an aftermarket add-on attempt to reduce wear on the distributor bushings?

2. The oil pump drive gear shows wear. Is it advisable to replace it with a .004" or .010" oversized gear? If so, how to select the correct size without pulling the camshaft?
 
As far as I know, all of the A and B engines had the same type oil pump and distributor type drive system. This would include the oil pump drive assembly, coil spring, and lower distributor drive shaft. I've not seen a set up with a universal joint included yet. It must be some aftermarket set up. maybe someone else would know more.

Using an oversize gear on the drive would depend on how much backlash there is between the cam and the driven gear. It would likely be a trial by fit of the next larger size if backlash is too much but it would have to be checked with a new or serviceable gear to tell if its the gear or the cam teeth that have more wear. I just replaced a distributor drive gear that had some pretty obvious wear on it. A new standard gear reduced the backlash to an acceptable level.
 
It could be you have the centrifugal aftermarket automatic spark advance . I would replace all with standard parts .

John in Suffolk County England .
 
Take a picture of that thing and post it. Automatic timing advance sounds like the likely culprit, but if it's worn that much, it could be a period accessory, which is rare.
 

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Bob C said:
Sounds like this is what you have. https://www.nurex.com/automatic-spark-timing-system-mechanical-advance-12176
Click to expand...

I'm with Bob C. You have a Nu-Rex (originally Phillips) centrifugal auto advancer. The "u" joint you refer to is a gyroscope that changes your advance as engine speed changes.

I have one on my Town Sedan and it works great. I set my timing at 30° full advance.

https://www.fordgarage.com/pages/nurexadvance.htm

https://www.snydersantiqueauto.com/content/Snyders/Product_PDFs/A-12176-X.pdf
 
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Thanks for the replies. It does look like what Bob C posted a photo of except the spring steel part is a different configuration. I can see, looking at the design now, that it would advance the timing by centrifugal force. It was stuck in an off-center position due to worn pins. The real issue with the excessive rotor play was was a worn down tang on the shaft above the gyroscope and the corresponding broken slot in the distributor shaft. Basically the joint was held together by rust. It's a wonder it ran at all!

I will start off with a standard oil pump drive gear and order the standard distributor drive setup.

I would have posted photos but I need to change some settings apparently to allow access to my photos.
 
The standard shaft and blades (tangs) are a little loose and act as a universal joint, allowing some small amount of lateral displacement.
 
This is a curious relic of the Model A aftermarket era. The problem with any of the rpm sensitive spark advance systems made in the Model A & B era is that a person can't adjust for load while going up hills or heavily loaded with freight (truck) or passengers (car). Here is Vince's information on the unit.
https://www.fordgarage.com/pages/phillipsspark.htm
 
rotorwrench said:
This is a curious relic of the Model A aftermarket era. The problem with any of the rpm sensitive spark advance systems made in the Model A & B era is that a person can't adjust for load while going up hills or heavily loaded with freight (truck) or passengers (car). Here is Vince's information on the unit.
https://www.fordgarage.com/pages/phillipsspark.htm
Click to expand...

The Phillips/Nu-Rex mechanism doesn't replace the manual spark control linkage. They tell you not to use it, but nothing's stopping you from zeroing it with the lever down a few notches. Then you can retard it under load. That's how I have mine calibrated.
 
alexiskai said:
The Phillips/Nu-Rex mechanism doesn't replace the manual spark control linkage. They tell you not to use it, but nothing's stopping you from zeroing it with the lever down a few notches. Then you can retard it under load. That's how I have mine calibrated.
Click to expand...

Exactly. I have mine set up so I can not advance it more that 30° but I can retard it if I need to. Most of the time I never have to touch the spark lever.
 
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It is exactly like the photo Alexiskai posted on 1/3/22. As mine was jammed, it did not affect timing advance. I used the spark lever on the steering column and the engine response was as normal. Probably been stuck for the 50 years I have owned the car.

The only reason I took it all apart was because the play in the rotor had increased dramatically, which turned out to be due to the worn tang and slot in the shafts. Interesting discussion.
 
VT Cruzan said:
It is exactly like the photo Alexiskai posted on 1/3/22. As mine was jammed, it did not affect timing advance. I used the spark lever on the steering column and the engine response was as normal. Probably been stuck for the 50 years I have owned the car.
Click to expand...

Let me know if you want to sell it as a curiosity, I'd love to take a look. :)
 
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