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Crankshaft Flange Spacer/Adapter

JMRobins

Well-known member
Joined
May 21, 2020
Member Number
1032
Messages
48
Loc
Colorado Springs, CO
I need to design a crankshaft flange spacer to adapt a BMW M57 engine's flange to a Jeep 4.0 crankshaft flange. The problem is, my little brain can't comprehend how thick I need to make it.

The 4.0's flange to engine block measures .570", the 4.0's dust shield is .086", and the total thickness of the transmission adapter plate is .787" (20mm).

The dust shield on the M57 engine and the 4.0 won't be used. I need to keep both the M57's flexplate and the 4.0's flywheel so the spacer will go in between them.

My measurements were done with a Harbor Freight caliper, so if anyone has better measurements, please let me know.

Any help would be greatly appreciated.
 
JMRobins said:
I need to design a crankshaft flange spacer to adapt a BMW M57 engine's flange to a Jeep 4.0 crankshaft flange. The problem is, my little brain can't comprehend how thick I need to make it.

The 4.0's flange to engine block measures .570", the 4.0's dust shield is .086", and the total thickness of the transmission adapter plate is .787" (20mm).

The dust shield on the M57 engine and the 4.0 won't be used. I need to keep both the M57's flexplate and the 4.0's flywheel so the spacer will go in between them.

My measurements were done with a Harbor Freight caliper, so if anyone has better measurements, please let me know.

Any help would be greatly appreciated.
Click to expand...
Will need pictures and details of the m57 engine swap first :flipoff2:. What you using to run the engine? Who is doing the engine computer reprogramming?

I so want to swap a m57 into my c10.
 
We would need to know the crank flange to bellhousing flange dimension on both the jeep and bmw to figure out the proper spacer thickness. But honestly it can probably be anything as long as it’s close if you’re using an auto trans a little off on the torque converter depth should hurt too much. Even a manual if the length is off .125 either way it should be fine.
 
You have to take the adapter thickness and converter plunge in the pump into account too.

Basically you need a lot more measurements than this.

You say you are keeping both flexplates. How do you intent to bolt the converter? Won't the BMW flexplate be in the way?
 
Bebop said:
You have to take the adapter thickness and converter plunge in the pump into account too.

Basically you need a lot more measurements than this.

You say you are keeping both flexplates. How do you intent to bolt the converter? Won't the BMW flexplate be in the way?
Click to expand...
He is putting a spacer inbetween the engine and tranny so hopefully there is enough room to fit everything.
 
ThePanzerFuhrer said:
Will need pictures and details of the m57 engine swap first :flipoff2:. What you using to run the engine? Who is doing the engine computer reprogramming?

I so want to swap a m57 into my c10.
Click to expand...
Kassel Performance programmed the original 335d computer to work standalone. The guy's not easy to work with, in my opinion, but he's the only person I know of who claims he can program it for standalone. A few of us have used him, but I don't think any of us have actually started an engine on his DDE programming yet.

I have nothing worth showing yet, but I'll post up when the time comes. Right now I'm just collecting parts to reseal the engine and do a whole new timing setup. The prices for parts are ridiculous, but I don't want to stick an engine in the XJ until it's freshened up.
 
JMRobins said:
Kassel Performance programmed the original 335d computer to work standalone. The guy's not easy to work with, in my opinion, but he's the only person I know of who claims he can program it for standalone. A few of us have used him, but I don't think any of us have actually started an engine on his DDE programming yet.

I have nothing worth showing yet, but I'll post up when the time comes. Right now I'm just collecting parts to reseal the engine and do a whole new timing setup. The prices for parts are ridiculous, but I don't want to stick an engine in the XJ until it's freshened up.
Click to expand...
The m57 uses chains you feel like it needs to get replaced?
 
Bebop said:
You have to take the adapter thickness and converter plunge in the pump into account too.

Basically you need a lot more measurements than this.

You say you are keeping both flexplates. How do you intent to bolt the converter? Won't the BMW flexplate be in the way?
Click to expand...
Manual AX15 set up. The BMW clutch is tiny so I'd like to keep the Jeeps 10.5'' clutch. This also allows me to get a tach signal because I can keep the Jeep's CPS. The BMW flex plate needs to stay so I can use the starter. I also want this to be pretty heavy to soften the power stroke of the diesel. I hear it'll make the manual trans super loud without a dual mass flywheel, but I'd prefer not to use one due to cost, complexity, and the small size of the BMW one.
 
ThePanzerFuhrer said:
We would need to know the crank flange to bellhousing flange dimension on both the jeep and bmw to figure out the proper spacer thickness. But honestly it can probably be anything as long as it’s close if you’re using an auto trans a little off on the torque converter depth should hurt too much. Even a manual if the length is off .125 either way it should be fine.
Click to expand...
I'll get the info off the BMW.

Thanks for the help.
 
Ohhhhhhhhh

So you're using the flywheels not the flexplates. Gotcha.

Super easy to do so. Make the spacer the depth you want, it doesn't matter. What matters is the depth of your engine/trans adapter.

Measure the offset from the jeep block to the jeep flexplate and make the engine/trans adapter match that.
 
Bebop said:
Ohhhhhhhhh

So you're using the flywheels not the flexplates. Gotcha.

Super easy to do so. Make the spacer the depth you want, it doesn't matter. What matters is the depth of your engine/trans adapter.

Measure the offset from the jeep block to the jeep flexplate and make the engine/trans adapter match that.
Click to expand...
Yeah if he measures the crank flange to bell housing flange off both engines we should be able to get the dimension with no issue.
 
ThePanzerFuhrer said:
Yeah if he measures the crank flange to bell housing flange off both engines we should be able to get the dimension with no issue.
Click to expand...
The engine is on a stand, so it was a little hard to get a decent measurement. The best I can do is about .875" from BMW flange to the bellhousing flange. The dust shield is about .05" thick, and won't be used.

Thanks again for the help guys!
 
JMRobins said:
The engine is on a stand, so it was a little hard to get a decent measurement. The best I can do is about .875" from BMW flange to the bellhousing flange. The dust shield is about .05" thick, and won't be used.

Thanks again for the help guys!
Click to expand...
You need very solid numbers. Can't wing this. Take your time.

You need to measure the jeep block to flywheel mating surface.
 
ThePanzerFuhrer said:
You get the tuner to remover the immobilizer also?

You gonna tear a harness apart to get this to work?
Click to expand...
Kassel deleted the immobilizer, deleted the swirl flaps, deleted the DPF and deleted the EGR crap in the software. I also paid for a decent performance tune, but I'm waiting until it's running before I put that tune on. I want to see how she drives with stock power first. I'm not looking to race the XJ, I just want to be able to comfortably drive the thing over all the Colorado passes without bouncing between 2nd and 3rd gear like my JK. The XJ is stock right now, but will be on 1 tons soon(ish).

I have the factory 335d harness. The engine harness is super easy and almost stand alone by itself. The body harness is huge but I only need a few wires from it so I'm gonna cut that harness up.
 
Last edited:
Bebop said:
You need very solid numbers. Can't wing this. Take your time.

You need to measure the jeep block to flywheel mating surface.
Click to expand...
The Jeep crank flange to bellhousing mating surface is .570" without the shield. The shield is .086" thick, but won't be used. I'm assuming the spacer will have to accommodate the thicknesses of the two dust shields that won't be used.
 
JMRobins said:
Kassel deleted the immobilizer, deleted the swirl flaps, deleted the DPF and deleted the EGR crap in the software. I also paid for a decent performance tune, but I'm waiting until it's running before I put that tune on. I want to see how she drives with stock power first. I'm not looking to race the XJ, I just want to be able to comfortably drive the thing over all the Colorado passes without bouncing between 2nd and 3rd gear like my JK. The XJ is stock right now, but will be on 1 tons soon(ish).

I have the factory 335d harness. The engine harness is super easy and almost stand alone by itself. The body harness is huge but I only need a few wires from it so I'm gonna cut that harness up.
Click to expand...
You ever drive the 335d? I have the 105hp tune on mine and it rips pretty good. I would love to have this engine in a pickup. Almost 375hp and 610ftlbs of torque. Take lots of pictures for me!!!! I get a bigger or dual cp3 kit and can get those numbers up to 405 and 690.

You buy a crashed car?
 
ThePanzerFuhrer said:
You ever drive the 335d? I have the 105hp tune on mine and it rips pretty good. I would love to have this engine in a pickup. Almost 375hp and 610ftlbs of torque. Take lots of pictures for me!!!! I get a bigger or dual cp3 kit and can get those numbers up to 405 and 690.

You buy a crashed car?
Click to expand...
It was a salvaged title car, but was fixed nicely. I picked it up in California and drove it home. I was real tempted to keep it, but it wouldn't pass smog here in the Springs without a lot of money put into it.

378101462_781808903695054_3119966171080990306_n.jpg
 
The BMW flexplate thickness is .401".

So I have:

.875-.570+.787-.401= .691"

I'll double check all these measurements and make sure they're as accurate as possible.

Does anyone happen to have the bolt spacing on the crankshaft for the Jeep 4.0 block?
 
1695146335095.png


Black is BMW engine block
Blue is BMW flywheel
Red is Jeep flywheel to BMW flywheel adapter
Green is Jeep flywheel
Orange is Jeep block to flywheel dimension (.570" + .086")
Yellow is the BMW block to jeep bell housing adapter.

Unknowns are Red and Yellow. You have to set one to make up the other.
 
Bebop said:
1695146335095.png


Black is BMW engine block
Blue is BMW flywheel
Red is Jeep flywheel to BMW flywheel adapter
Green is Jeep flywheel
Orange is Jeep block to flywheel dimension (.570" + .086")
Yellow is the BMW block to jeep bell housing adapter.

Unknowns are Red and Yellow. You have to set one to make up the other.
Click to expand...
Blue is .401''
Red is what I'm trying to figure out
Orange is .570+.086
Yellow is .787 (20mm)

Thanks for your help!
 
My calculations were assuming the crank flange was recessed in the engine block, not a protrusion from the bellhousing flange.

Yellow dimension is .787 the thickness of the adapter plate .
 
Do a little addition and tadaaaaaa

You may even have to machine the BMW flywheel to be able to bolt the red adapter to it.
 
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