motor position

[nam vet]

A few months ago I posted a question about my B that was converted from a gas motor to a 673. The diesel motor and trans seemed too long for the frame and the radiator support,radiator surround,and hood were modified longer to fit. My original question was,is the gas frame shorter than the diesel? After many months of measuring other B models I went out and bought a B parts truck that had a diesel. After many hours of trial and error I figured out that when the gas/diesel swap was made they used the trans mounts and frame mounts from the original gas motor.The diesel mounts,even though they look ALMOST the same, are different. After the swap, the motor and trans sit in the correct position. Here's my question,standing in front of the truck with the radiator out, the motor seems to lean to the left. Not a lot but noticible. Is this correct or should it sitting upright? Thanks

[mattb73lt]

So your saying it's leaning to the passenger side? A short nose B67 had the engine tilted to the passenger side by, I think, 14 degrees. This was done to provide clearance for the driver's feet, steering box, etc. If you have a standard cab the engine should be vertical. The frame should be pre-drilled or gas or diesel engine mounts and as you stated, they are different. I've done this swap to a B42 and have a 237 in mine. If the previous owner did the swap it could be possible they used a B67 engine. To tilt the engine Mack drilled the bolt pattern offset on the engine bell housing to get the tilt needed for that application. Pictures of what you have would be helpful to determine what's going on and to more clearly see your issue?

[doubleclutchinweasel]

GREAT insight, Matt!!!

[nam vet]

Hey Matt,you seem pretty knowledgeable about these old Macks. Here's a few more questions. The engine in the truck I am trying to put back together is an Endt,the engine in my donor truck is a End. You mentioned in your first reply that the B67 had offset bellhousing bolts, but did they use the same endt/end engine series. just that it was tilted? Other than it not being correct do you see any problems with running the tilted engine in my b61? Lastly the replacement Endt engine in my b61 is painted gold{under all the grease} is that any indication of what year the motor might be? Thanks again

[70mackMB]

The motor in my MB leans toward the curb to make room for the shift tower.    .....Hippy

[JoeH]

EN=Engine

D=Diesel

T=Turbo

675=237hp variant

676=283-287hp variant.

A gasser example would've been an EN707 or something along those lines whereas you probably have an ENDT675. A turbo charge diesel, 237hp.  A naturally aspirated diesel (no turbo) would be END6xx (probably 672, but not positive.) I believe they're all 672 cubic inch engines, but to differentiate the newer variants they just changed the last numerical digit.

[mattb73lt]

The basic engine is the same. The bell housing is the difference. The tilt shouldn't effect anything as it was designed to be that way. As long as there's no interference with the firewall or other areas, I can't see any issues. To get it vertical, the best way to do that would be to swap the engine bell housing. The B67 series had the fire wall cut out and a removable "doghouse" inside the cab for access to the rear of the engine, as the cab was moved forward on the frame and the front sheet metal was shortened. As for the color, earlier engines were a blue-grey tint, similar to a Detroit Diesel. I believe the Maxidyne was the engine that started the gold paint, from 237 HP and up.

[steve s.]

I had a B61 with the engine tilted to the ditch side. It was not the original engine . I have no idea why someone did that, but it was a pain in the neck to work on at times. In order to pull the back cylinder head, I had to drill a hole in the firewall to remove the last push rod. Trying to use a torque wrench at that odd angle from underneath was awkward to say the least. The engine must have come originally in an MB or some other cab over, as the engine number is on the back of the block, under the cylinder head. 

I took the engine out, changed the flywheel housing and water pump housing, and put it in a different B61 standing straight up. I like it much better this way.