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Ford 351w reverse distributor problem

Ron2691

New member
I will start by saying that my motor skills are elementary level however I have read/researched this topic to gain as much knowledge as possible.
Boat has Prestolite E5JL-12100 OA distributor running on points system that I would like to change to electronic system after an electrical problem that has left me dead in the water. Options are converting over with a kit or installing a new distributor. IF I decide on new distributor, I cannot find the correct one for my application. I have read forums that say simply changing the gear is not correct because the force is change from “up force” to “down force” and will stain the gears operation. Has anyone converted this Prestolite reverse distributor to a PROPER fitting new distributor currently on the market?
 
I will start by saying that my motor skills are elementary level however I have read/researched this topic to gain as much knowledge as possible.
Boat has Prestolite E5JL-12100 OA distributor running on points system that I would like to change to electronic system after an electrical problem that has left me dead in the water. Options are converting over with a kit or installing a new distributor. IF I decide on new distributor, I cannot find the correct one for my application. I have read forums that say simply changing the gear is not correct because the force is change from “up force” to “down force” and will strain the gears operation. Has anyone converted this Prestolite reverse distributor to a PROPER fitting new distributor currently on the market?


First off..... are we discussing a REV RH Rotation 5.8L Ford engine?
If so, yes...... the helical gear cut (for both camshaft and distributor) for a REV RH Rotation engine does create an opposite and opposing force.
This means that a true REV RH Rotation ignition distributor will be equipped with the proper thrust load bearing surface.


Secondly..... the Pertronix kits use Hall Effect triggering via a small diameter plastic trigger wheel that is embedded with magnets.
Pertronix themselves have admitted to finding errors of up to 1.5 degrees in separation.
1 degree @ the distributor is 2 degrees @ the crankshaft!


Thirdly...... FYI and FWIW....... the 5.0L and 5.8L ignition distributors are not the same. The hex drives for the oil pumps are different.
Point being..... do not think that a 5.0L distributor will work for your 5.8L engine.




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Your knowledge is much appreciated!!! I believe the 351 is a 5.8 L??!!? The only RH rev distributor I have been able to find is made by DUI (M35820RRBL) however it is a bit pricey at $500.
My first step will be to remove existing Prestolite and check gear condition. If the condition is good ( boat only has 350 hours) than I will probably search for the proper conversion kit. Rick, do you have any recommendations as to a manufacturer of such a kit for my application? I was looking at Pertronix however after your response, I’m hesitant.
 
Unfortunately, the Pertronix kit is about your only option for an existing distributor.
Which ignition system is your STD LH Rotation engine equipped with?



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Suggestion:

Pull both ignition distributors.
Take them both into a shop who owns and operates one the old Sun, Allen or King distributor machines.
Take along your Marine OEM ignition advance curve graph.
Have each of them run on the machine and ask to have the curve verified and/or adjusted if need be.

They will also be able to replace the shaft bushings if need be.

They can also adjust the dwell angle.

Re-install... set BASE advance..... verify the Progressive and TA.... and go have fun.
 
FYI...... aaamarine.com lists a driven gear for the 335 series Ford 302/351W ignition distributor.

"Ford 302 351W reverse opposite rotation distributor gears .500 shafts 18-26823 18-26825"


For anyone looking here, please note that the hypoid gears are cut in an opposite fashion to accommodate the Rev RH engine's camshaft rotation.
The distributor maintains the Std LH Engine's rotation in order to drive the oil pump.
This changes the upward shaft thrust to a downward shaft thrust, causing the need for an upper thrust bearing.

In other words, we can't simply change the gear and expect the Std distributor to function correctly in a REV RH Rotation engine.


Also note that the 302 and 351 distributors are not interchangeable, due to the hex drive size.



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