ENDT 673 ENDT 676

[fatboyben]

Hello i could use some information if any of you would help me ??   I have a C600 with a transplanted endt673  With a ape6bb injection pump starts and run smooth but is tired and smokes  I happened across a 1979 endtb 676 long block rebuilt from a company that no longer runs Macks  OK the questions when i sit the engines side by side they look the same  How different are they can i use the injection pump from the 673 on the 676 i remember back in trade school this was a good model pump any help would be great thank you 

[j hancock]

Sort of thinking it might not be able to supply enough fuel to take advantage of the 676.  Settings are different between a thermodyne and a maxidyne.

[terry]

Not totally sure, but I think the injector lines have different fittings between the two systems.    terry

[mowerman]

your problem could be just a timing adjustment or a bad injector ,,,sometimes valve adjustment....as far as i remember...a 676 will work...but not positive.i know it will bolt on...good luck...bob

[39 Baby Mack]

I would think it would work.

I'm not sure how different the compression ratios are of the two engines.

Cubic inches they're identical 4-7/8" × 6" =672 C.I.

The injection lines might even work, either way I 'd change them to the hi-rise lines (back 4 between the valve covers instead of between the heads).

Biggest problem right off the top my head would be the injection pump drive. 673s and early 675s had a ball bearing style pump drive housing. Later 675s through the E6 production had an aluminum pump drive housing with a bigger shaft and no bearings.

Your pump probably has a tang drive on it.

The shafts on the 676s I'm pretty sure we're made for the celeron drive coupling. They did make a shaft with wide tangs to fit into this drive housing.

You're pump is an APE6BB 90...... which means it has 9mm plungers in it so it has the smaller tangs on it.

There was a special coupling that went between the drive in the motor and the drive on the pump (2 wide slots and 2 narrow slots) for this application.

I don't how available these parts are today?

 

There were a couple of different oil pump ratios also. Depending on how old the ENDT673 is. It might have piston coolers and it may not.

There was direct driven (15 teeth on oil pump and 15 teeth on air compressor/ oil pump drive gear) and over driven (13 teeth on oil pump and 17 teeth on on air compressor/oil pump drive gear)

 

Ron

 

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