Sprite Questions

J

Joe Schlosser

Member
OK, this should be the place to get a couple of answers.
First and I assume the simplest is what size is the screw that is used to hold down the base plate to the housing in a Lucas distributor (25D). 6-32 is too small and 8-32 is too big.
I know that no one uses distributors any more, I did not either but this is for a street Bugeye
Second; I rebuilt a ribcase gearbox (for street Bugeye with new 1275). When I installed the tail shaft housing it did not center on the tail shaft. almost touching on the RH side and all sorts of clearance between the shaft and housing. Nothing I did would correct this (aside from shimming the housing which was not a good idea).
I took another tail shaft housing form the spares bin and it centered on the shaft perfectly.
Question is: are the tailshaft housings specific to a main casing ??? I could have gotten them switches when doing the rebuild
Any one have any thoughts
 
Never noticed that the screw was special on the distributor, but it has been a long time since I had to fool with one. Probably Whitworth or something. Just re-tap it for SAE.

I have interchanged tailshaft housings on numerous transmissions without a problem. Can't think of anything that would cause what you are describing. The front of the housing pilots on the rear bearing, right? Why not use the housing from the parts bin and call it a day.
 
Wonder if the distributor screw is metric? a 6-32 is 3.6mm and an 8-32 is 4.18mm.
Maybe it's a 4mm x 0.8mm ?
 
Distributor clamp screw on every series A block I ever worked on were 1/4-28 x 1/2. NOTE: Clamps can get distorted and become ineffective.

If memory serves; tailhousing (and front cover) have 2 counterbores. One to pilot over the extended bearing race, and the other to clear the retaining ring on the bearing race. check for burrs or dents in these counterbores. NOTE: bearing counterbore is sized to depth for the packing washers that fit the bearing clearences. Make sure there aren't packing washers stuck in the counterbore.

Shifter rods extend out of the case into a cavity in the tailhousing. Could one of these be extended out of the case too far? (Sign of a problem with fork installation).

RJS
 
Yes - The front cover and tail housing pilot on the bearing O.D. with clearance for the retaining ring. I would have thought that someone who is having trouble with alignment of the housing might have noticed crushed shim rings but that could be a problem. You had best have the shift forks in neutral when you install the tailshaft hosing or you will be taking something apart later, either removing the housing or the side cover because you will likely be stuck in two gears at once. If they are in neutral there won't be any clearance issue with the shift rods. So no real answer unless the housing itself is bent. That is unless we aren't following your description of the problem.

As for the screw, the clamp screw and clamp mounting screw are both 1/4", but I think you might be referring to the small screws internal to the distributor itself. If so, just re-tap to something that you have or take one out of another distributor.
 
Thanks Everyone.
Regarding the distributor screws; I am talking about the internal screw that holds the Base plate to the housing. I agree with Ron that the easiest way is to re drill to 8-32 thread. BTW the screws can be had, in a kit from Minispares, with all the other internal distributor screws.
It is interesting that no one seems to knows the size of these screws

Regarding the Tail shaft cover, I am not trying to change back but was just wondering id there was a difference in the cover. Box is in the car and shifts fine.
Maybe there was a burr that I did not see, but everything else went together as it should. The housing was perfectly flush with the main casing but the alignment with the shaft was way off.
I do hate getting the remote shifter into the forks. Sometimes it just drops in with a little wiggle and sometimes it never goes
 
Joe,

All fasteners on the '59 & later Spridgets were English (fractional) except a few gas line fittings, so I'd guess the distributor screws are also fractional; 1/8, 5/32, 3/16, etc. Don't know if they included 64th sizes. Don't believe BMC ever adopted metric size or number size fasteners. Do not know where/if you can buy fractional screws. Ron B. idea of cannibalizing another distributor is easiest. These threads are often stripped out, so retapping to number size may be best option.

Boy; if tail shaft didn't align with the tail bushing/seal, I think you are going to have some problems soon. This condition will load the tail bushing and input/output shaft bearing abnormally. Was it difficult to get the drive shaft yoke to enter? Don't have any good suggestions.

RJS
 
Ron
Re the tail shaft , the alignment was such that I could not get the yoke of the driveshaft into the space. Not a case of a night fit but a case of no fit.
Using the spare housing corrected this immediately. No issue at all.
I have a full dissembled ribcase in a box(needs a lay shaft) That I was going to assemble some day and was curious about mix and match

Re the distributor , remember that this is a Lucas part not BMC. I would think that the design/casting for the DM2 distributor was pre 1950 and the 24 and 25 D distributors were early 60s. I am still guessing Whitworth.
Over the years it seems that these screws for the spare distributors have seemed to disappear. Must be a mouse in the basement that eats small machine screws.
At the moment I have what I need to make up a working unit, however I am very curious what size these screws really are. NO one (this side of the Atlantic) seems to have the answer.
 
Just incase any one is interested I have been informed that the screw for the base plate to the distributor is a 4BA.
They are a very weird screw sort of a cross between Imperial and Metric
 
Joe,

The small screws that hold the distributor base-plate to the housing are probably 6-40. Again, 6-40.

I had built a special thick distributor base-plate, and needed longer screws, which I found at a local specialty house. A rare size.

Charlie Tolman
 
Using a micrometer and pitch gauge measure the screw. Then go to Old Faithful Machinery's Handbook to find the size. Should be in there.
 
Or you can call this guy, he has built more Lucas Distributors than most of us have ever seen.

http://advanceddistributors.com/


I known Jeff Schelmmer at Advanced Distributor for a good while, he is the Lucas distributor guru, he also provides the best points sets, rotors, and other items he has this stuff made to his specs and supplies vendors all over the world with this stuff. Lots of vintage racers use Jeff's distributors.
 
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