"B" Engine to my "A"

3

32fordb

Junior Member
Would appreciate advice on what I might expect if I were to install Model B engine and transmission in my 1931 rolling chassis. I'm doing a ground up restoration on '31 roadster and have opportunity to buy fresh rebuilt Model B engine with transmission bolted on.
 
You can expect a big shift pattern--I went to '39 gears to get the pattern more reasonable. You may need to use a 31 front timing cover to bolt the model A front mount to. You will need the special rear float-a-motors, or you'll have to fabricate rear mounts. You can expect more power, and especially if the B engine has a counterbalanced crank, smoother running. I also used an A head and water pump. The B head is about 4.6 to 1.
 
32fordb said:
I'm doing a ground up restoration on '31 roadster and have opportunity to buy fresh rebuilt Model B engine with transmission bolted on.
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Is it really a "Restoration" if your using a B engine, transmission, and all the other parts needed to make it work?
 
I have a B engine in my cabriolet ,the engine alone is a straight bolt in job.You have to remove the flywheel housing from the B pan.Some are spot welded on others are seam welded but either are easy to remove.If you want to keep the B transmission attached then it gets more complicated.It just depends if you want to enjoy the slightly dubious synchro gears. I would not bother, the A trans is fine and generally trouble free.Sell the B trans and put the money into the rest of the restoration.With the counter weighted crank you can have some weight turned off the flywheel.I put a BF 14.9 HP flywheel on mine which is much lighter and it runs a treat.You will also need a different top hose to marry the B waterpump to the rad top tank.The conveluntant(?) type works well.

John in glorious sunny weather England.
 
Geo. H said:
You can expect a big shift pattern--I went to '39 gears to get the pattern more reasonable. You may need to use a 31 front timing cover to bolt the model A front mount to. You will need the special rear float-a-motors, or you'll have to fabricate rear mounts. You can expect more power, and especially if the B engine has a counterbalanced crank, smoother running. I also used an A head and water pump. The B head is about 4.6 to 1.
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Geo,

Did you use the 15/29 or 16/28 gearset?

Thanks
 
Not to be nosey, but is this the B engine at Cozad, Ne. or a different one? Just curious. Rod
 
32fordb said:
Would appreciate advice on what I might expect if I were to install Model B engine and transmission in my 1931 rolling chassis. I'm doing a ground up restoration on '31 roadster and have opportunity to buy fresh rebuilt Model B engine with transmission bolted on.
Click to expand...
If you are going to use a Model A distributor on the B engine you might install a Model A front timing gear cover and save all the drama of the timing problems if you use the B cover ( B cover starts the timing at 19 BTDC (crankshaft degrees) unlike the A which is 0 Degrees.
 
I've built half a dozen of the trannys ('39' gears in a B case), Can't remember which gear sets for sure. I'm pretty sure the one in my roadster is the same ratios as the stock 32-35 gear sets. Email geohawk@q.com if you have more questions.
 
Geo. H said:
I've built half a dozen of the trannys ('39' gears in a B case), Can't remember which gear sets for sure. I'm pretty sure the one in my roadster is the same ratios as the stock 32-35 gear sets. Email geohawk@q.com if you have more questions.
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Geo,

Thanks for reply ... I am building a '39 transmission with the 16/28 gearset that has 2.80 ratio in first (vs 3.11 for A) and 1.60 (vs 1.85 for A) in second. Just wondered how that the 16/28 gearset works with the B block and 3.54s. I will find out soon.

The 32-35 gearset with spur gears in my other stock B box with 15/29 works out to 1st(3.12) 2nd(1.77).
 
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My 29 Pk Up came with a B engine. Had all the A stuff fitted to it (head dizzy, rear flywheel housing, original motor mounts,A ******. Still used the B front timing cover. Iceman
 
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