1984 3406b ???

Yesterday I found (and purchased,) a 3406B Cat about 1985-'86 vintage according to the seller. He bought it out of a running driving Autocar dump truck with intentions of using the engine on an industrial application. But research into his project determined that the motor wasn't going to work out well due to bell housing issues, etc., so he placed it for sale.

It's a 7FB59727 serial number on the block (tag is long gone.) I'm going to research it more, but he had his Cat man do it already and found it to be legit in terms of HP and application. Has a Jake on it already...a PLUS .

Plan is to "freshen it up" by rolling bearings into it first thing before anything. I am still hallucinating about whether or not to just close my eyes and order 6 holes for it and do it all right while it's out and on the floor...but as said before, "if it ain't broke, don't fix it..." I have to make that decision yet.

If I do decide to do all 6 holes, then of course the head gets sent out to be checked, counterbores get checked, determinations on whether or not to have to cut them and clean them up...it goes on and on and on as we all know. My $3,000.00 engine can soon become a money pit, but there's always the "right way-wrong way" approach to things too. It's a tough decision, one that the checkbook will always determine which direction to head in.

Still, I'd do a new clutch, resurface flywheel, rear and front main seals at the very least while on the floor.

Anybody here ever do a swap out from a 3406A to a B, that can tell me if they simply bolt right in place motor mount and bell housing wise? I have to assume they do, but we know what happens when we ASSume...lol.

The compressor doesn't have the drive gear on it to accept my Vickers pump I have to convert to power steering on my A Model KW either, (Grrrrr,) have to order that from the Cat store I guess. But all in all, I think this is a good decision. I get roughly 4.6 MPG with the existing 3406A at best. If I gain a mile to the gallon which is highly likely, that equates to a lot of money saved in one year, almost enough to justify the entire project.

Needs a turbo (I don't like the play in the shaft,) so there's a few bucks well spent. I think I'll be tickled with this B after running this A engine up and down the highways and byways the past month or so. I had a 400 B in an '86 Western Star I had new...it did a "fine job."..

 

My guess is you'll need to move transmission forward and lengthen the driveshaft because there's no retarder on the B and I would guess your A has one?

 

Nice score! I assume that's a good price for a complete engine? I know you can't get a newer style engine for under $7k so with that's a smokin price or them mechanical motors have no demand? Either way looks like a win.

 

mechanical motors seam to be on a comeback with all the GOV control going on looking at a 87 b model now myself

 

Sure looks like a 350 or a 310hp to me

 

No, no retarder on my A. Should bolt in place.

 

What makes you say that wore out.... how can you tell just by the pics? Or did you look up that serial number and get that info? If so, where would I find the same info? Just curious, as I've spent a little time over the weekend trying to find information online about the engine's ratings by the number on the block, but I guess I don't really know the right place to go to look it up. I was gonna have to wait till Tuesday morning before I could call my Cat man and start figuring out what I am buying.

I really, really need to know what this thing is BEFORE Wednesday the 31st, on which day I'm obligated to go pick the motor up and pay him in full. I'd LOVE to have that knowledge before I make the final commitment, in case there's something fishy or left out of the story by the seller....

Any way I could get confirmation where you think it's a 310/350 HP wore out? Then I can call my Cat guru and see if I can use that motor without doing a whole bunch of work and spending to get 400 hp+ out of it. I could have sworn years ago (1988) a guy had a new Western Star 10 wheel dump truck with a 310 hp 3406B, and in order to turn it up it was gonna take a bunch of modifications, but that was so long ago I could be all wet in saying that. I thought he said it would take different injectors and some other stuff to do it. I'd rather pass on this one and invest in a full 400B instead if I have to go crazy making all sorts of changes.

 

I say it's a 310 or 350 because of the turbo. A number off the turbo tag would really point us in the right direction. It just looks small to me. Also the pipe from turbo to the intake has a good size gap around where it fits. The 400's used a bigger pipe that barely fit in that block (for lack of a better word).
It's really dark around the pump area but that looks like an 84 pump. I can't really tell. The first b model pumps had a different look. I can't remember the casting number. The later b's used a 7W-3906. On the pump being older I have seen the older style really run well, it just caught my eye because the motor is supposed to be an 86. Many think all b's were big HP. I have seen a 7FB in a cabover shacker with air to air that was 285 hp.

 

I looked at pics again. It has the right timing advance cover to be 85 to 86. But I still can't see the pump.

 

Even better. My A has the retarder. I'd delete it but I'm too lazy/cheap to replace the driveshaft lol.