B diesel trivia question (1 Viewer)

[roma042987]

Does a say...78 model bj40 have the same bellhousing dimensionally as a 3b? Both are cast iron, the B bell housing has a threaded hole or provision for the transmission mount underneath it. Fyi, the 78 bj40 among others, (not sure of interchange) has a three piece cross member just like the later fj's and bj's although it is positioned slightly forward under the bell housing instead of under the trans.

I'll elaborate a bit, the reason I'm trying to figure this out is because I'm going to move the crossmember back to accommodate an h55. I have a spare 3b block laying here, the B bell housing, and an h42 trans I can use to dummy fit it all together. I would rather not pull the 3b h55 drivetrain from my donor bj60 just yet for mocking things up. It'll be a few weeks or months before this frame is ready for the drive train and I don't have the spare room for it to be sitting around in the interim.

 

[OTBT]

The short answer is Yes !
My stock '78 BJ40 came with a 2977cc B engine, and will soon have an '81 3B engine. The bell housing from the B matches exactly with that of the 3B.

 

[roma042987]

The short answer is Yes !
My stock '78 BJ40 came with a 2977cc B engine, and will soon have an '81 3B engine. The bell housing from the B matches exactly with that of the 3B.

I'm leaning toward this as well but, that doesn't necessarily mean it's the same dimensionally....alas, I highly doubt they are different.

I'm well aware that the engines B vs 3b have the same mounting as well as the 4 bolt pickup points between a 4speed and 5 speed. My concern was perhaps the length could be different, although thinking about it more that certainly wouldn't be the case since the same trans fits either pilot bearing. I suppose that's really the only dimension that matters....perhaps I answered my own question and was just over thinking it.

 

[alberta mac]

I'm thinking of some other things incase your not. Emergency brake on the drive shaft, it may match up or you may have the option of a rear e brake set up which means another axle and making sure the gear ratio is the same.