4bt front sump

[RGT]

Hi, looking for info on using a Cummins 4BT in a 1980 GMC 30 series 4 wheel drive chassis. I have picked up some great info looking through the threads and links, but I have not seen any info regarding the front sump, maybe on the 4 wheel drive it won't be an issue, but in my '86 1 ton 2 wheel drive(my original conversion idea) the front crossmember would not allow a front sump. Can the pan be reversed, possibly with a new pickup tube? I am also interested in hooking up to the auto transmision in the truck(turbo 400?) that is coupled to the v8 in it now. The engine I have found is out of an old bakery truck, I believe it has the rotary pump rated at 105 hp set up with clutch and 4 speed and all its accessories, this was a non aftercooled installation, the guy also has a parts engine, complete with accessories and aftercooler plumbing, that threw a rod. Should I stay away from the rotory pump engine? Do newer 4 BT engines have glow plugs?

any input would be great, I know if I wait too long the engine will be sold... ... .



Thanks in advance

Roger

 

[w-cummins]

You will need a new pan and a new pickup tube too. Cummins sells them both and when I priced them for a 6bta swap they were really happy to quote me about $200 each for them! You will also have to re-gear your front and rear axles, problem is you likely have a dana super 44 or dana 60 front, and a GM 14 bolt rear. The matching ratios of that combo are not real hot in the lower (3:XX) range i. e. they match at 4:11, 3:73, and I think that's it!! You will want some thing like a 3:08 or so with the turbo 400 transmission. I would look for an overdrive trans for the swap!



William... .

 

[RGT]

Thanks for the sump input. I was wondering about the gearing, it is the 4. 11 set with gm rear/dana front, the rear is blown though. What would a good replacement a dana 70/80, I had sort of assumed I would do the correct geared rear and worry about matching the front later... . I did not know the gm rear was ratio limited, at least as far as matching the front. What are overdrive versions of that transmission ?, do thay need electronic controls... ? what about mounting up to the auto? the engine I saw was complete with 4 spd manual, I think it had the rotary pump, should I keep looking and get one with an inline pump and auto already bolted to it?



Thanks

Roger

 

[tk064]

On some of the 4b's the oil pan is reversable, but I don't know which is which. In regards to gearing, with a 4X4 tire size can very greatly. 4. 10's are fine with 36-38 inch tires.

 

[T. Baker]

The inline pump is preferable. I do not think you can switch pumps so what you get you have to stick with. It is easier to make more power with the inline pump.

 

[w-cummins]

Originally posted by tk064

On some of the 4b's the oil pan is reversable, but I don't know which is which. In regards to gearing, with a 4X4 tire size can very greatly. 4. 10's are fine with 36-38 inch tires.

Well with the 4:10 and 38" tires your running 2420RPM @65 Mph

and that's allmost right at the gov speed if the motor you would hate it... Btw I never did ask why you would want to run a 4 in a full size truck anyway the 6 will fit just fine!



William.....

 

[Crash_AF]

I've never seen a 4BT with a front sump... all that I've seen are rear sump. I don't know about the feasibility of reversing the pan, I'd think the pickup tube would be the limiting factor there.



I also haven't seen a 4BT with an inline pump. I've only seen the rotary pumps.



Later,

Joe

 

[Brian R]

What is the bell housing pattern for these 4BT's?

 

[Crash_AF]

You can get them with either SAE or General Motors flywheel covers (where the bellhousing mounts) or you can swap for the Dodge flywheel cover.



Basically, the flywheel cover unbolts from the back of the block and you can change it out to any of the available patterns.



Later,

Joe

 

[RGT]

I like to have a lot of room in an engine compartment as I do all my own work. I also like the Idea of getting great mileage. And mostly I like an engine that works hard, I hate idling around with a big engine. When I Hotroded I always built and ran small v8's. Did I mention that I am really cheap, it's much cheaper to buy an old backery truck than it is to buy a Dodge Ram to yank a motor out of.

 

[w-cummins]

Originally posted by rtrudeau

I like to have a lot of room in an engine compartment as I do all my own work. I also like the Idea of getting great mileage. And mostly I like an engine that works hard, I hate idling around with a big engine. When I Hotroded I always built and ran small v8's. Did I mention that I am really cheap, it's much cheaper to buy an old backery truck than it is to buy a Dodge Ram to yank a motor out of.

Yeah but cheap=stock ( BTW no conversion is cheap by the time it's done. It's looking like I'm going to have about $7500 in my ISB chevy by the time it's all done) and @ about 110hp @ the flywheel on the 4bt, in a full size 4X4 with a turbo 400 ( expect it to eat abbout 20-30HP of that 110hp ) you will have a DOG!! I have seen 6bta motors selling for around 2k for some thing usable (Remember that soon the bad part of the Dodge/Cummins will rot away and the Cummins will be selling cheap! ;-)



William Cummins... .

 

[philb4]

Gov speed

The gov speed should be 3200 and 29" tires and 373 rear give you 75mph top speed. www.jeeptech.com go to gear&tire to work out the ratios on the spread sheet. I run a 4bt in a 1 ton 105hp getting 120hp at rear wheels. You won't lay rubber but I get 28mpg which makes up for that. My engine has 200,000 and no problems other than the alt bracket broke. The turbo 400 will work ok,but allow for some torque converter slippage when working out top gear.

 

[Brian R]

Thanks for the flywheel cover info. That is great to know.



I disagree that conversions are always expensive. I think they are if you farm out a lot of the work or always have to buy new parts. When I put my Mustang 5. 0 EFI motor in my 1983 Mitsubishi pickup I did the whole thing for less than $1500. I bought a rolled Mustang for $1200, used its R&P steering, modified the Mustang headers, bought some brand new Flowmasters, Modified the Mustang exhaust, brazed together Mitsu and Ford AC lines, made my own drive line, etc. I later added a disc brake Dana 44 from an Isuzu Rodeo which I bought for $120. If you buy all your stuff from a dealer or mail order "the best stuff" and pay people to do the work you'll be into the the thing pretty deep. With some creativity, hard headed determination and lack of enough sense to listen to every one who tells you to "do it right the first time" you can get by quite cheaply. Incidentally, I drove that truck to work for six years total, three with the setup mentioned and three more with a couple of older Ford 302's I had put in.

 

[RGT]

I appreciate all the input, at this point it looks like I will probably go with the 4 bt in my 2wd 86 1 ton GMC, it currently has 4:10's and it plows snow o. k. when I put enough weight in it, maybe I can put a locker with some taller gears. This set up with the 292, 6 gets 11. 5 miles/gallon without any load, 28 mpg sounds heavenly. I know the early Dodges, with Cummins, are finally coming down to affordable prices, and I actually like the way they look, but I am so comfortable driving in the GMC... ...

 

[w-cummins]

Re: Gov speed

Originally posted by philb4

The gov speed should be 3200 and 29" tires and 373 rear give you 75mph top speed. www.jeeptech.com go to gear&tire to work out the ratios on the spread sheet. I run a 4bt in a 1 ton 105hp getting 120hp at rear wheels. You won't lay rubber but I get 28mpg which makes up for that. My engine has 200,000 and no problems other than the alt bracket broke. The turbo 400 will work ok,but allow for some torque converter slippage when working out top gear.

I guess I assumed that the normal gov speed on a 4bt would be 2500 I didn't know that they ran up to 3200 stock. That would give them more breathing room with the 4:11's still for max fuel econ. you want to run it at peak torque at cruise not max rpm... .



Wow a 120 rwhp out put from a stock 105 fwhp motor you sure got a strong running 105!! is yours a turbo 400 too??



28 mpg is a good figure is yours a 4X4 or 2 wheel drive? is it in a chevy 1 ton truck??



William... .

 

[w-cummins]

Originally posted by Brian R

Thanks for the flywheel cover info. That is great to know.



I disagree that conversions are always expensive. I think they are if you farm out a lot of the work or always have to buy new parts. When I put my Mustang 5. 0 EFI motor in my 1983 Mitsubishi pickup I did the whole thing for less than $1500.

Ok I admit that "ALL" was not a good choice for conversion costs. I suppose I could have done a "farmer john" conversion on my truck ya know the type, a 1949 international binder frame and 59 dodge convertible rear, the radiator off the ole massy Ferguson tractor, the tires off the John Deer riding mower a whole bunch of old sprockets welded to the cracks in the frame and to reinforce the ole brackets welded every place made from the old bed frame metal... ... oh ya mean that wasn't the "Farm out" you had in mind Some times you have to buy new parts too ya know and Diesel parts VS most gas engine parts are in a whole different league. The first 6bta I rebuilt ten years ago I paid $128 for EACH piston from Cummins the gasket set was $250!! you can buy a whole recon sbc for $650 or buy new pistons from JC Whitneeey and some sand paper and fix up your own "Rebuild" for even less BTW I didn't mean to single your post out for my retort, sorry... .



OK I also admit that I did spend some of the $7500 on stuff that really wasn't required for the conversion to simply run. like the edge comp box and the DDII injectors, the Autometer gauges and the Mallory fuel pump and all that shinny aeroquip hose and the purdy blue & red ends... . come to think about it, I will have more than the $7. 5k in it outch:-( I should have just purchased a Dodge truck with one in it..... humm ... . Nah...



William... .

 

[philb4]

Info

Sorry I don't get to this page every day, I run a std toploader gm trans,1 ton dually, 2 wheel drive and 3. 73 rear the lowest in a dana 70 I could get. As I understand most 4bt out there are goverened to 3200 as they were installed in P-vans and used 4. 10 rears thus they could pull the load but would not speed (damn delivery drivers). Most common use Frito-lay, high volume low weight. The engine is slated for 16,000 gross vehicle max but I have run it at 26,000 several times. The only complaint is a slow turbo spoolup when the temp is above 80 ( I'm at 5000') but I have a 3. 8 eaton supercharger that I may replace the turbo for better low end boost. The engine needs 5psi to start working.

 

[Brian R]

To W-Cummins,



What would be the fun in that? I don't want to see myself coming and going on the freeway and it sounds like you don't either. When I see a guy driving something tuly custom I think "that guy is cool because he is a determined thinker who made it work" When I see someoned in a 2001 Powerstroke Super Duty with every aftermarket part available I wonder "Is that guy cool just because he earns a bunch more money than I do?"