John Deere B RPM

[41106]

Could anyone tell me if the fan shaft spins at the same RPM as the crankshaft, or is it reduced? Thank you in advance!

 

[Bob]

The camshaft turns at 1/2 engine speed.

The governor is driven off of the camshaft gear and runs at engine speed.

The governor shaft gear that drives the fan shaft gear is quite a bit larger than the fan shaft gear, so the fan rotates considerably faster than the crankshaft.

If you can find the tooth count of the gear on the governor shaft that drives the fan vs. the tooth count on the fanshaft gear, that will give you the "overdrive" ratio.

 

[Bob]

Looks like it's 25 teeth driving 15 teeth, meaning the fan rotates 1.67 tomes as fast as the crankshaft.

 

[41106]

Forgive me if I misunderstood, but if I follow you correctly, the fan shaft spins at 1.67 times HALF the engine rpm?

 

[machineryman1945]

(quoted from post at 03:54:04 01/03/19) Forgive me if I misunderstood, but if I follow you correctly, the fan shaft spins at 1.67 times HALF the engine rpm?

He said the fan turn 1.67 times the engine rpm

 

[Mike M]

Is this just for curiosity or some project you want to drive off the fan ?

 

[41106]

Wanting to put an alternator on it and just wanted to make sure it turns quick enough to get it charging.

 

[Mike M]

When I worked at the alt. shop ( IIRC ) we changed the pulley on the alt. to a larger dia. one than normally found when used on a car. The delco 10 si mount up easy enough. Use the same bracket as the gen. and make a spacer to take up the difference on the lower bolt. For the upper adjusting bracket I would find one from a car that had some nice length to the slot.

 

[machineryman1945]

(quoted from post at 11:20:30 01/03/19) When I worked at the alt. shop ( IIRC ) we changed the pulley on the alt. to a larger dia. one than normally found when used on a car. The delco 10 si mount up easy enough. Use the same bracket as the gen. and make a spacer to take up the difference on the lower bolt. For the upper adjusting bracket I would find one from a car that had some nice length to the slot.

From experience the B generators may barely keep the battery charged...never had any problems with the later model Delco 12 volt generator....in changing my old B's to 12 volts the starter was 6 and would turn at a faster cranking speed.

 

[machineryman1945]

(quoted from post at 16:29:33 01/03/19)

(quoted from post at 11:20:30 01/03/19) When I worked at the alt. shop ( IIRC ) we changed the pulley on the alt. to a larger dia. one than normally found when used on a car. The delco 10 si mount up easy enough. Use the same bracket as the gen. and make a spacer to take up the difference on the lower bolt. For the upper adjusting bracket I would find one from a car that had some nice length to the slot.

From experience the B generators may barely keep the battery charged...never had any problems with the later model Delco 12 volt generator....in changing my old B's to 12 volts the starter was 6 and would turn at a faster cranking speed.

When I changed my B's over to 12 volt...I used A generators which are 12volt to satisfy the correct police....most of the time I found that the regulators were the culprits...John Deere put those on top of the generators where they would shake and also they put them about 4" from that hot exhaust. No wonder people had trouble with them. I remember and owned 420's and 430's and those regulators were behind the dash and I don't recall having many problems with them. Alternator's have a higher output but the old systems worked good if you stayed about 1/2 throttle....I never tried relocating the old deere regulators but that might have solved a lot of problems....

 

[Pappy]

I put a Delco 10SI alternator on my "A" JD and it will charge at 20 amps with the engine running about 600 RPM. No problem. It's a 3 wire set-up.

 

[buickanddeere]

(quoted from post at 00:17:08 01/03/19) The camshaft turns at 1/2 engine speed.

The governor is driven off of the camshaft gear and runs at engine speed.

.

horse feathers

 

[buickanddeere]

The 20amp Delco generator from a 20/30 series spark ignition Waterloo two cylinder has plenty of capacity .
It is true that the generators on lettered and early numbered tractors were intended for use on tractors that ran for hours at a time, only started and stopped to fill the fuel tank.

 

[Bob]

(quoted from post at 08:16:25 01/05/19)

(quoted from post at 00:17:08 01/03/19) The camshaft turns at 1/2 engine speed.

The governor is driven off of the camshaft gear and runs at engine speed.

.

horse feathers

What point are you trying to make, Mr. Buick???