John Deere B

41106

Member
Not exactly going to be a pulling tractor, but plan to do plow days and maybe a local deadweight pull. With that in mind, and also knowing that I want to run premium 93 octane pump gas or less, please let me know your thoughts. I am planning to rebuild engine now that I made up my mind what I want to do (I've bounced several ideas around for a while). My plan is just a solid rebuild.....redo head, bore block, etc...etc... I also plan to get a reground cam from Blackburns. I am not going to stroke it, but as a way of giving it a bit more power, I want to lengthen the connecting rods to raise compression. That's where my question is. What compression ratio can I shoot for that runs on 93 octane or less and doesn't cause any other troubles? Again, not going for an all out puller, just a little more stout of a B. Thank you in advance.
 

I guess we can assume the "B" is a "Late Styled" ( newer than 1947).???

If an earlier model, you have a problem with having a fast 1st gear..

For Stone Boat pulling, the low 1st gear of a GAS LS"B" will do even if stock..

For something to compare against..My one LS"B" is Bored +180", with probably 7:1 Comp ( I need the Petcocks open to start it)...and the
difference between it and my other identical but Original "B" is about 1/2 of a gear higher when working in the field...hardly noticeable most of the time..
Oh, it does "Sound" eager..
It would have not been bored if a ring had not broken and scored a cylinder in 1960...
 
I have to agree with bushogpapa...For dead weight/percentage pulling a stock late "B" does fine. Leave the stroking/rod welding etc to pullers only. You say you are going o plow days..probably even more than pulling. Do you know of anyone who has a double HP "B" or "A" with stroker crank,cut rods,cut rockers, hi comp etc , etc that has even taken it out to plow for 3 - 4 hrs? I personally would not do it. If the hp doubles, the stress loading and harmonics are at their limit especially on an already 60+ yr old tractor. Great for short stint pulling but if I were you the most I would do to the "B" is have cam ground back to factory specs. Probably the best boost you will get and no added load to internals. No fun having to open compression reliefs way under the block of a late "B" electric start just to start it for what little benefit you gain.
 

I cannot say that a GOOD re-grind on the cam with some added valve Over-Lap and Lift, a little more compression and some more RPM would would maybe bring it up to equal a good JD 520, by raising the Max HP and Torque RPM.
There is not much and on the "B", "A", 50, 60, 70, 620, 630 and G, there is NO Valve Over-lap timing from the factory..

Odd thing is that the 720 and 730 Diesels did have improved valve timing WITH valve over-lap timing...Hummmm
 
Overlap lowers the affective compression on a low rpm engine. The diesel has enough to give away a little without affecting hp. Lift helps the most on low rpm engines.
 
If its a late styled B then its plenty good for the weight classes of stone boat you should be pulling with that tractor in first gear.
Speed isn't really a factor in stone boat pulling.
So if its running fine then leave it. If not then just do a stock rebuild or maybe a 1/8" overbore at the most.
You wont gain anything measureable by pulling fast on a stone boat. Starting a stone boat out fast often ends up in just spinning tires so first gear is all you need.
 
Hey Randy, should we show him what a stock 50 will do.lol easiest best money spent, cut the rocker arms and a good dyno tune will get a xtra 5 good hp.all color puller.
 

I did say an increase in RPM would be beneficial and the improved breathing will raise the Brake HP and Torque RPM peaks.

Besides compression being raised, a JD 520 only really exceeds the LS"B" in the RPM of the HP and Torque peaks.

I use both and there is little difference ..
 


Yea, and I have heard for many years of the magical JD"B" with a power block that will run away in 4th gear with a 4 bottom plow...
Ofcourse they never materialize..

I had been telling YOU ALL about the Great Strides JDBPuller had made with his "B", but it seemed nobody would listen..NOW, there are 3 suppliers of Specialty Blocks being made and possibly every one is a direct COPY of the ones Ray has been making for years..

I have a video of him pulling ( at a Pull) a Pulling sled in the 3250LB class while in 6th Gear and he got it up to 13 mph before the sled pulled it back down..( just for "Kicks").
That was about a '49 "B"..
One Early "B" ( Unstyled) Pulls here in Plain City Ohio at the sanctioned Pull and won the last couple of years..I think he is using one of Ray's small ( 5 3/4") Blocks. 220lbs of Compression is impressive when it first rolls the engine over when starting... Sounds like the engine just Exploded..!!!
 
Seems like a lot of wiggle room here with this fairy tale:

"possibly every one is a direct copy"
"I think he is using one of Ray's"

I've seen some of Ray's very unimpressive stuff, he's certainly a legend in some folk's mind.
 
I really appreciate everyone's input. Just when I thought I had a plan, now I am uncertain about raising compression versus just doing a solid rebuild. As I decide, could someone please inform me what octane would be required to run properly IF I did build to 9:1 as mentioned? Really want to stick with pump Gas on this one. Thanks again.
 
Might as well save it , Dave, no one will believe you any more than the guys at Ithaca did before you took 1st from their regulars. I guess I thought by this guys original post that he was on kind of a budget AND planned on more plow days than pulling. Clean-up bore/rings and little more lift and factory blueprint cam, 25 degree mag cup or taylor a little quicker advance curve if distributer AND a perfect 71 carb on cold gas factory manifold with inlet die grinder matched/blended back into manifold 3". Works great on my '50 "B". Low cost , reliable...plow 40 acres with it if one wanted. have good weekend , Dave!
 
Because of the overlap built into a car cam as apposed to your tractor cam, a car can get away with 9:1 on 93 no lead. I'm going to say no more than 7:1 on your tractor especially if plowing any amount. With good bat and elect start you should need no comp releases with that. Make sure mag is set for TDC start timing (not advanced any)
 

I know and you must be one of them who spreads this Crap about a Very Honest Man...

I KNOW the "stories" and it is pretty sorry rhetoric...You just will not get off his back because he got behind when he came down with Pancreas Cancer..

I actually have trouble accepting that you fellas are actually "Human"..Sorry excuses, for Sure...
 
Ron,
You keep throwing out outrageous statements & then get bent outa' shape when someone responds. Best to just stay with the facts & tone down the exaggeration.
 
(quoted from post at 02:52:02 10/29/16) I really appreciate everyone's input. Just when I thought I had a plan, now I am uncertain about raising compression versus just doing a solid rebuild. As I decide, could someone please inform me what octane would be required to run properly IF I did build to 9:1 as mentioned? Really want to stick with pump Gas on this one. Thanks again.

Pump gas 93 octane would probably suffice.
But I'll put it this way: With stone boat pulling, you wont gain anything measurable by building up the motor. The only thing you might be able to do is pull in very heavy classes in which your now likely to break the tractor itself.
Go to a stone boat pull and watch the guys that win. Not too often are they moving the boat fast.
In stone boat, low and slow is the way to go. Complete opposite of a transfer sled.
 

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