Mack ENDT 673 engine series differences?

[seyser]

I have been researching the ENDT673 engine and still have a handful questions.

ENDT 673A 205hp No piston coolers?

ENDT 673B 211hp Piston coolers

ENDT 673C 250hp Piston coolers

Does the above info look correct?

What respective years would each of the engines been available? Did Mack stamp the series (A,B,C or just B,C) in the castings along with the other numbers? Anyone have any pictures of theirs?

My truck is a 1964 with the original engine, It reads ENDT673-xxxx on the front, Can I assume my engine is the "A" series 205hp?

Jeremy

[Superdog]

There was a 225 hp version too,but it may have been just a derated ENDT673C.

[theakerstwo]

The ENDT 673B was the 225 HP I don't know what A is.

[Superdog]

The ENDT 673B was the 225 HP I don't know what A is.

Thanks Glenn. I never knew what they were officially called,all I knew was the h.p..When I was building my 1st B model,the local dealer had purchased 4 or 5 old Garrett Freight MB611 tractors to part out,and the owner told me they were 225 hp. I almost got one of the engines,but they were mounted at a slant and would have had to change some stuff to make it work in the B. I ended up finding a parts B with a good engine.

[Maddog13407]

the first turbo 673's were END673T's . they were the 205 hp version. no piston coolers. as a result they experienced alot of problems. the later 673 turbos were ENDT673B and ENDT673C's. i think these were the 225 and 250 versions and i think both had piston coolers. after all these years tho its hard to tell what it what as many engines have been built up with whatever parts were around.

[theakerstwo]

The B and C engine was complete different engine than the 673.Different block and heads.The 673 used 18 head bolts were the ENDT used 20 head bolts

[39 Baby Mack]

The ENDT'S turbo engines came both ways 18 and 20 stud heads.

The first blocks had 18 stud heads with 9/16" studs. Next blocks came with 18 stud heads but the two corner studs were 3/4". Last blocks had 20 stud heads (double corner studs) 5/8" studs. There were even special washers made that looked like an inverted top hat so if you had to replace a head on an older 18 stud motor you could use a later 18 stud head with the 3/4" holes in it.

Ron

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[theakerstwo]

I don't remember it that way but could be wrong but do remember the 711 using the 3/4 corner studs and then later the 20 bolt so I guess maybe the 673 had the 20 bolts also.Its been long time ago.

[39 Baby Mack]

Glenn, do you remember the early blocks with four bolt mains at 4 and 7?

Ron

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[theakerstwo]

I probably have seen them but have forgot so much the last ten years and it ant from drugs.I remember the old block that did not have full flow lub system and I started in 65 and at that time they was still when the engine was out of the frame drilling thru the oil filter mounting pad on the block and pushing a sleeve down thru there.It would drirect the flow up to the mount pad cutting off the flow from the pump to the galley and forcing it to the filter and then back down into the galley.There was a oil galley made of cast that came up from bottom of the block to the deck of the engine for the two oil holes for the rockers and some times they would crack and lose oil pressure to the rockers.There was a fix for it I remember and it was a small tube that was pressed down thru the oil hole from the top when head was off.We did turbo a lot of 673 engine in the mid sixtys.The smoke screw was taken out of the governor and the scrovance was removed and a direct drive was installed.Two rounds of rack and a pyrometer.Some of those turbos were water cooled.

[39 Baby Mack]

I probably have seen them but have forgot so much the last ten years and it ant from drugs.I remember the old block that did not have full flow lub system and I started in 65 and at that time they was still when the engine was out of the frame drilling thru the oil filter mounting pad on the block and pushing a sleeve down thru there.It would drirect the flow up to the mount pad cutting off the flow from the pump to the galley and forcing it to the filter and then back down into the galley.There was a oil galley made of cast that came up from bottom of the block to the deck of the engine for the two oil holes for the rockers and some times they would crack and lose oil pressure to the rockers.There was a fix for it I remember and it was a small tube that was pressed down thru the oil hole from the top when head was off.We did turbo a lot of 673 engine in the mid sixtys.The smoke screw was taken out of the governor and the scrovance was removed and a direct drive was installed.Two rounds of rack and a pyrometer.Some of those turbos were water cooled.

The first turbos we had were in those 3 H-613's we had, they had the water cooled schwitzers.

Ron

I probably have seen them but have forgot so much the last ten years and it ant from drugs.I remember the old block that did not have full flow lub system and I started in 65 and at that time they was still when the engine was out of the frame drilling thru the oil filter mounting pad on the block and pushing a sleeve down thru there.It would drirect the flow up to the mount pad cutting off the flow from the pump to the galley and forcing it to the filter and then back down into the galley.There was a oil galley made of cast that came up from bottom of the block to the deck of the engine for the two oil holes for the rockers and some times they would crack and lose oil pressure to the rockers.There was a fix for it I remember and it was a small tube that was pressed down thru the oil hole from the top when head was off.We did turbo a lot of 673 engine in the mid sixtys.The smoke screw was taken out of the governor and the scrovance was removed and a direct drive was installed.Two rounds of rack and a pyrometer.Some of those turbos were water cooled.

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[57 bcr]

Thank you Glenn and Ron. That's good stuff right there. Al

[theakerstwo]

And Ron I forgot that when we installed turbos on 673 engine we also pulled the air compressor and installed a spacer with a oil line fitting in it to connect the turbo oil drain.