8.3 liter cummins block compatability

[98G]

Is the block for our M939a2 trucks the same as used in a 325 HP 8.3 in a motorhome from the late 90's?

Yes, I searched. Yes, I called Cummins. Yes, I called several parts places to ask for numbers. No answers forthcoming.

Old bad block motor number is 45383673. New block part number is 3971411. New block serial number is 3968602.


I've got a guy with a bad 8.3 liter block in his motorhome. He says the entire engine is just rebuilt with all good components and assembly errors ruined the block. He wants to use everything off his motor to build one of my NOS bare blocks.

Before we go shipping big heavy things accross the country, I want to be sure that this is viable...

I strongly suspect that there are not huge differences between blocks.*

Thanks.

 

[HHhuntitall]

3921666
3921848
3923292
3926144
*3929524
3928963
3928964
3802559
3934906
3968620
3968732

The bad engine number you give has the above cylinder block numbers listed as parts available or superseded..... I can tell you the new block part number is for a 6CT8.3.... The older engine is listed as a 6C8.3.... Older than your good block. Your good block number does appear in an engine option package BP9897.... very close to the BP9898 options for the old bad engine. But I can't cross-reference the two older blocks to each other anywhere on the Cummins database. I can cross them on other websites, where the 3971411 (your block) does cross for the 3968732 (last superseded number above for the part numbers for the bad engine). It says they are both double thermostat 8.3C engines in marine uses. That indicates they will cross.

Most likely, they'll work fine, but you have to check the bolt mounting holes for accessories and engine mounts. I'd measure them carefully, front, back, and both sides, and if they measure out, it "should" fit.

 

[mwilson]

I am on the road so of no help. I don't know what you can see but look for any parts topics to go with the super cessions. Dont want any surprises from a design change in the progression..

 

[HHhuntitall]

I am on the road so of no help. I don't know what you can see but look for any parts topics to go with the super cessions. Dont want any surprises from a design change in the progression..

Right, well, I have nothing available on mine.... Only the part numbers listed above come up when clicking on the cylinder block part number for the Bad engine.....

 

[mwilson]

I got them to come together.........I'll see if I can print this in a legible fashion....

Motorhome Engine....

 

[mwilson]

New Block....

 

[mwilson]

There was a block change which requires different liners. I wonder if they put the wrong liners in the motor home engine?? Someone better check so that it does not happen again......Just sayin'.....

 

[mwilson]

Shadrach!!!!!!

Shad, check my work here buddy!!! You have a few more tools at your disposal!!!

Mike.