BB truck distributor quesstion

R

Royal Ryser

Well-known member
Asking for a friend who is only slightly less computer savvy than me. He has a BB truck with a bad distributor. He got it out of the engine but it is very badly rusted.
Is the distributor for a BB truck engine the same as for a Model A car?
Where can a BB distributor be repaired or purchased?
Thanks for the help.
 
You can use an A distributor if you rig a way to manually control the spark..way better to fix the B,it has mechanical advance.
 
The Model A distributer is a very poor choice since it requires a manual advance rods/levers while the B/BB distributer has an automatic advance. Definitely not the same distributer. The best source for parts and rebuilding of the B/BB distributer is Renner's Corner, https://www.rennerscorner.com/index.html

Also keep them in mind for other Model B/BB mechanical parts.

Charlie Stephens
 

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Overcoming the timing pin issue takes a bit of initiative,so does the manual spark control,but it can be done..before doing anything disassemble the B distributor,if the advance plate is cracked or the shaft is badly galled its better to buy a rebuilt one from renner..those are good folks to do business with BTW,first class..
 
The most vulnerable part of the B distributor is the advance mechanism. Even small amounts of rust, grease, or dirt may impede the advance.
 
All that being said,the B mechanical advance distributor is a marked improvement over the A distributor,automatic spark advance provides smooth acceleration and eliminates spark knock,a leading cause of main bearing failure..on model a engine. The B had improvements to the crankshaft journal diameter and pressure lubrication to the main bearings,along with the mechanical advance distributor,all helping to end the main bearing issue with the A..later B engines also had counterbalanced crankshafts.
 
I agree,


Get the B Distributor repaired by Renner's and your friend will be back in business.


My opinion,


Chris W.
 
My Gordon Smith Compressor has a "B" engine - with the B distributor.

I have another Gordon Smith "in the works" based on an "A" engine. I should probably get a B distributor and valve gear cover to go on the "A".

Users of compressors are not usually called upon to adjust the advance to match compressor loading.

Besides there is no steering wheel/driver's seat on a compressor.

Joe K
 
The model B distributor seems to be too slow to advance. I prefer the simplicity of the model A distributor , especially if its a model A .
 
If using a Model B distributor on a Model A with a Model A timing cover, can one use the B distributor as-is or does the distributor need to be modified in any way to get the proper advance?
 
If using a Model B distributor on a Model A with a Model A timing cover, can one use the B distributor as-is or does the distributor need to be modified in any way to get the proper advance?
Click to expand...
I have examined this thought in answer to my question of the Gordon Smith interest I cite up at reply 11.

The easiest way to put a Model B distributor on a Model A would be to change out the front cover and replace it with the Model B cover.

Currently there are two covers listed on Ebay which report to be Model A covers, but are in fact the Model B cover. One can tell from where the timing pin hole appears relative to the casting boss. Not too expensive on either of these, you pay almost the same for the cover as for the shipping.

AND - if one is talented and pretends to be a machinist, one can find "aftermarket replacement covers" made by Ford which can be drilled for either the Model A or the Model B. This would be the A-6019-BR cover. There is one of these on Ebay currently which is drilled for the Model A but to which a second hole could be added for Model B. Available again for small money.

See Vince Falter at http://www.fordgarage.com/pages/timingcovers.htm for how to identify which cover is which.

The 9-1/2 degree difference between the two marks is "intrinsic" in the distributors and relates to where they start the engine in "full retard." Model B distributor starts out "later" at full retard than the Model A distributor. (Ford perhaps realizing that by the time of the Model B, car users were mostly using the electric starter rather than a hand crank) And advances with increasing speed automatically, but does not advance as much as the manually advanced Model A distributor is capable. (Ford perhaps realizing that full "super advance" is NOT where the engine is most efficiently operated.)

Vince Falter addresses the differences in timing quite nicely and the reasons why at http://www.fordgarage.com/pages/bdistributoradvance.htm

There is a Model B distributor currently on Ebay for medium money which has a damaged tang. Were I to modify a Model B distributor to work directly on a Model A I would start with this one and weld up and re-machine the damaged tang to 9-1/2 degrees difference. This WOULD be a job for a machinist - assuming he has enough of the original tang to "get a read."

Note that one CAN use a Model B distributor with the Model A cover. Starting would still occur at the "full retard" just as it does with the Model A distributor. But the problem comes with increasing speed - the Model B distributor will not match advance properly to speed and will always be "retarded" (in a timing sort of way) and not operating at the most efficient match between advance and speed.

AND - that 9-1/2 degree difference still exists in the point-plate locations at full retard. As I say, the difference is intrinsic.

I marvel at some of the research done by Vince.

Joe K
 
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