14B/BT crank in 3B

[abosely]

I have been reading up on B series engines and seen it suggested that a 4b/14B/BT crank will fit in the 85' later 3B block.

I know most everyone knows these numbers, but I put them up here to help me keep track of the differences. Just putting one engine name 4B and not the variations since stroke & bore are the same in the 'family".

3B - 3431cc, 102 mm bore, 105 mm stroke
14B - 3661cc, 102 mm bore, 112 mm stroke
15B - 4136cc, 108 mm bore, 112 mm stroke

My thought is to use a 4B/14b/BT crank since it has 7 mm more stroke and bumps the cc up another 230 cc, can use the same pistons and not need to bore out cylinders.

From what I could gather the 15b/BT block is a little different than the 3B &b 14B. It was mentioned it was strengthened for the extra torque, but wounder if changes were made to accommodate the 6 mm larger diameter pistons?

I don't know if 5B pistons are available or not. Anyone know if the 3B block can be bored out 6 mm larger to take 5B pistons? Are 5B pistons available?

Since I'll be doing a complete rebuild on what ever engine I use, putting a 14B crank into the 3B
would be a pretty simple mod. Bumping displacement up by 230 cc and having a 7 mm longer stroke should help increase the torque a bit.

Of course this could be done to a 13B also. But for my situation the IDI and inline pump have advantages.

It will be cheaper to pick up a tired 3B needing overhauled than getting a 13B too.

Basically would be building a 4B out of a 3B I guess.

Allen

 

[Dieseler]

Even though the bore and stroke are the same I am thinking the journals are not the same spec or else this would have been done already.

 

[abosely]

Hmmmm good point, how or where can I find the crank journals size specs for the 3B & 14B?

 

[RufusTheDufus]

This post might be helpful
14B swap for 13BT ?

 

[abosely]

Thanks Rufus, every bit helps. I think this is doable, with mixing and matching the crank journal bearings and or opening the journals in the block if need be.

I'm still researching and hunting to verify it will work. It would sure be a nice upgrade to a 3B or 13B/BT if it works.

Allen

 

[RufusTheDufus]

I'd expect the pin placement in the piston to be different in the IDI vs DI piston. I was trying to find photos here that could be used to compare the two. I guess if the 3B and 13B rods are the same length then it would imply the piston pin is at the same place relative to the deck height.

 

[abosely]

I'll see if I can find the part numbers for the 3B & 13B rods & check if their the same & post it up.

Allen

 

[Dieseler]

3b and 13bt crank parts are different numbers this includes rings, pistons ,con rods and pins .and crank.
Can't say on the 14B or 15B not sure what application they are from and years of production.
Isn't the 14BT an American engine used in Chevrolet delivery vans and Bobcat backhoes.

 

[abosely]

Dieseler, there is a Cummins 4BT in the States, the 4B is the IDI version of the 14B the turbo version of the 14B is 14B-T. There's not a lot of information about them that I have found yet. I'm sure it's out there, I'll keep digging for it.

If I read it correct the 4B, 14B & 15B share the same crankshaft, PN 13411 and same rod end bearings PN 13411 but for the crankshaft journal bearings the last two digits different 3B PN 11704 4B & 15B PN 11711. Didn't write down the 14B, though I meant too.

I wouldn't trust this information yet, I'm still trying to figure this out. Those parts catalogs are a pain to decipher. The ones I've found so far list engines and parts by vehicle & years in production, but I don't know what vehicles that had these engines, so have to do a lot of searching and cross referencing to find part #s on them.

If this is correct even, I need to find out what the difference is between the crank journal bearings are. Maybe just different thicknesses and they can be mixed & matched or the 3B block journals can be opened to fit the bearings, I don't know. So I'm keeping after the answers.

If anyone has any info or a direction to search please post up.

Allen

 

[Dieseler]

Isn't the 4B and 14B a Cummins motor if so I would guess it has different specs all around than the Toyota 3B block unless they stole the design specs from Toyota.
IIR there is motors in JDM applications like the Dyna bus and others commercial applications that used a bigger B series than the 3B but I cant find that info right now.

 

[abosely]

Toyota makes/Made 4B, 14B & 14B-T engines.
They are 3660cc with the same 102mm cylinder bore as the 3B, 13B & 13B-T but with 112mm stroke (7mmlonger than 3B/13B/13B-T), that gives them 230cc more displacement.

The 4B is IDI like the 3B and the 14B & 14B-T are DI engines.

There is a 5B IDI and 15B 8 valve, 15B-F 16 valve and 15B-TF & 15B-FE 16 valve DI engines with 112mm stroke but with 108mm bore for 4104cc displacement.

The 5B & 15B series has a different block, or the block has a few changes to it compared to the 3B/13B/13B-T & 4B/14B/14B-T blocks. I think it is more of changes in the castings as opposed to a different block.

Allen

 

[abosely]

Here is link to thread that has the answer. From this info it would be it depends on what year 3B block.

Page 3 post #47 this thread: pic's of rebuilding a 13B-T

From 2 Bees,
13B & 13B-T blocks
9/84 - 4/88, mains 11701-56010, rods 13041-58010
4/88 - 3/89 mains 11701-56010, rods 13041-56040
3/89 - 12/92 mains 11701-56020, rods 13041-56040

14B block
8/88 - 12/99 mains 11701-56020, rods 13041-56040


main bearings
11701-56010, bearing width 27.6mm (1.087)
11701-56020, bearing width 26.9mm (1.059)

rod bearings
13041-58010, bearing width 30mm (1.181), has 4mm oil hole
13041-56040, bearing width 30mm (1.181), has oil slot

HTH Allen

 

[leonelcanut]

Guys, do you know if I can use a 3B bare block and use head and the rest from a 14B or 15B? Thanks!