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hey, sorry if this is in the wrong thread....
im swapping a 4bg1t motor from an isuzu generator into a tj and was wondering if anyone had any info or experience with it...
pretty uncommon swap from what i hear.
i know there are adapter kits from an SAE 3 flywheel housing, which from what i can tell is what the 4bg1t comes with, to the AX15 transmission. but that doesnt solve the flywheel issue.
i understand that i may have to get an adapter made, does anyone have any imput on how best to measure the distance between flywheels so that i can get one made?
i havent yet pulled both flywheels and housing apart, the jeep 4.0L and the isuzu, so there may be issues with imput shaft spline count...? ill know later this week..
am i going about this the wrong way?

cheers for any imput.
-J
 

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Pretty sure a 4BG1T will turn an AX15 inside out. I'd go for a heavier transmission.
 

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Dougal,
The information I found on the 4BG1T is 107 HP and 284 lbs/ft. Does that sound right? The AX15 will probably last a while if the 4BBG1T stays stock and if the AX15 isn't shock loaded.

If it's a "true SAE 3", Phoenix Castings makes an adapter set to small block Chrysler/Dodge bolt pattern. With their set of adapters and a bellhousing from a 3.9L V6 AX15 equipped Dodge Dakota, the Isuzu and the Jeep AX15 will bolt together. Use the 12" clutch/pressure plate/ and flywheel from a 5.2L Dodge Dakota. If the AX15 doesn't hold up, an NV4500 and bellhousing from a gas 5.9L V8 Dodge ram will bolt up to the same set of adapters. Note use the 5.2L flywheel because the 5.9L flywheel has a cast-in counterweight due to 5.9L being externally balanced. I used similar Phoenix Castings adapters and 3.9L V6 bell housing to bolt an AX15 to QSB3.3T with an SAE 4 flywheel housing and SAE 10 flywheel.
 

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Dougal,
The information I found on the 4BG1T is 107 HP and 284 lbs/ft. Does that sound right? The AX15 will probably last a while if the 4BBG1T stays stock and if the AX15 isn't shock loaded.

If it's a "true SAE 3", Phoenix Castings makes an adapter set to small block Chrysler/Dodge bolt pattern. With their set of adapters and a bellhousing from a 3.9L V6 AX15 equipped Dodge Dakota, the Isuzu and the Jeep AX15 will bolt together. Use the 12" clutch/pressure plate/ and flywheel from a 5.2L Dodge Dakota. If the AX15 doesn't hold up, an NV4500 and bellhousing from a gas 5.9L V8 Dodge ram will bolt up to the same set of adapters. Note use the 5.2L flywheel because the 5.9L flywheel has a cast-in counterweight due to 5.9L being externally balanced. I used similar Phoenix Castings adapters and 3.9L V6 bell housing to bolt an AX15 to QSB3.3T with an SAE 4 flywheel housing and SAE 10 flywheel.
Big 4 cylinders are far harder on gearboxes because they have two big torque pulses per revolution. It also occurs at lower rpm which gives the flywheel more time to accelerate and decellerate between pulses. A petrol (gasser) 6 or 8 is far kinder on gearboxes at the same torque compared to a diesel like this.

Also, keeping it stock wouldn't be any fun. With more boost and a few turns of the fuel screw you can double those numbers.

I've posted up some relatively modern gearboxes in the transmission section recently which won't have the headaches that a NV4500 can bring. But they do cost more.
 

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Yeah Dougal, marine versions of that engine were rated as high as 197 HP so it has a lot of potential. Also, like a Cummins it's not a feather weight. Dry weight is listed as 849 lbs. That near 100 lbs heavier than a Cummins 4bt. Probably would need a front axle upgrade in a Jeep.
 

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Be best to get a proper trans. up front rather than going through process again when Aisin fails.

Ed in CO.
 

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My uncle has an adapter for the ax15 he planned on using for his 4bd. I’ll see what all he’s got if you want. He’s in Wisconsin right now, so it may take a bit.
 

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I've posted up some relatively modern gearboxes in the transmission section recently which won't have the headaches that a NV4500 can bring. But they do cost more.
I haven't had any problems with the NV4500 behind my 12 valve.
 
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