Bigdogtrucker Posted April 27, 2020 Share Posted April 27, 2020 Engine in my "68 R611T is stamped T673. Anyone know the exact details on these? Quote Link to comment Share on other sites More sharing options...
Popular Post j hancock Posted April 28, 2020 Popular Post Share Posted April 28, 2020 Mack Thermodyne Turbo 673 225 HP with 650 Torque. 2 1 Quote JimIt doesn't cost anything to pay attention. Link to comment Share on other sites More sharing options...
Brian L Blaylock Posted April 28, 2020 Share Posted April 28, 2020 Shouldn’t it have END stamped before the T? Quote Link to comment Share on other sites More sharing options...
j hancock Posted April 28, 2020 Share Posted April 28, 2020 7 hours ago, Brian L Blaylock said: Shouldn’t it have END stamped before the T? I would think so but the guy stamping that shift could have been bored or feeling lazy or ??? Quote JimIt doesn't cost anything to pay attention. Link to comment Share on other sites More sharing options...
Bigdogtrucker Posted April 28, 2020 Author Share Posted April 28, 2020 2 hours ago, j hancock said: I would think so but the guy stamping that shift could have been bored or feeling lazy or ??? No, this isn't the only one. I don't believe they're very common but there was a"T673". Quote Link to comment Share on other sites More sharing options...
davehummell Posted April 29, 2020 Share Posted April 29, 2020 I got an odd one in my truck etz673 came out of a mack fire truck 2100 rpm 260 hp. plate says made in 1980 Quote Link to comment Share on other sites More sharing options...
j hancock Posted April 29, 2020 Share Posted April 29, 2020 ETZ673 E = Mack Diesel Engine T = Turbocharged Z = Max 10 grams per bhp-hr emissions level Quote JimIt doesn't cost anything to pay attention. Link to comment Share on other sites More sharing options...
davehummell Posted April 29, 2020 Share Posted April 29, 2020 Thank you for the info. Why is it still listed as a 673 when the 675s and 676s were out all ready? Would it have something to do with the torque rise of the engine? Quote Link to comment Share on other sites More sharing options...
j hancock Posted April 29, 2020 Share Posted April 29, 2020 Mack used various prefixes, suffixes and numbers to identify their engines. It does seem that the 673 designation is for a Thermodyne type engine and a narrow power band. The 675 Maxidyne (later also with the 676) introduced in 1966 was the high torque rise engine with its wide power band. Quote JimIt doesn't cost anything to pay attention. Link to comment Share on other sites More sharing options...
JoeH Posted May 4, 2020 Share Posted May 4, 2020 I do believe they're all 673 cu inch engines. Even the 675/676. Quote Link to comment Share on other sites More sharing options...
theakerstwo Posted May 4, 2020 Share Posted May 4, 2020 672 Quote glenn akers Link to comment Share on other sites More sharing options...
Maddog13407 Posted May 4, 2020 Share Posted May 4, 2020 I got an even weirder one in my 66 R600.... timing cover is stamped endtb675 but the rivetted tag on the block says ETAZ673T. engine came out a 1980 R612LST originally... Quote Link to comment Share on other sites More sharing options...
j hancock Posted May 9, 2020 Share Posted May 9, 2020 On 5/4/2020 at 5:42 PM, Maddog13407 said: ETAZ673T. engine came out a 1980 R612LST originally... Hmmmm..... At least the ETAZ and 612 are a match! Quote JimIt doesn't cost anything to pay attention. Link to comment Share on other sites More sharing options...
Mudman089 Posted May 26, 2020 Share Posted May 26, 2020 Bigdogtrucker has a '68 R611T. I have a '69 R611 ST. Just wondering what the S stands for on my Mack. Thanks. BP. Quote Link to comment Share on other sites More sharing options...
terry Posted May 26, 2020 Share Posted May 26, 2020 5 hours ago, Mudman089 said: Bigdogtrucker has a '68 R611T. I have a '69 R611 ST. Just wondering what the S stands for on my Mack. Thanks. BP. I believe the S is six wheel and the T is tractor. terry 1 Quote Link to comment Share on other sites More sharing options...
Mudman089 Posted May 26, 2020 Share Posted May 26, 2020 Thanks. Quote Link to comment Share on other sites More sharing options...
Popular Post doubleclutchinweasel Posted May 29, 2020 Popular Post Share Posted May 29, 2020 I love how the number nomenclature comes up in threads every now and then! The old Mack stuff had an elegance to the numbering system that everybody could use as a pattern. Even individual part numbers had a system. Then, Volvo came along and assigned random numbers to the parts, and royally screwed that up! Anyway, it is cool to see that folks are still learning how to read the number codes on the engines, transmissions, and model numbers. Makes me feel like I'm not such a "newbie" anymore! I remember going through all those same exercises when I was piddling with my old R611ST. Yes, sometimes the "END" was omitted from the engine marking (ENDT-673 for instance), because ALL the diesel engines at that time started with "END" (ENgine - Diesel). The ENDT-673 was a turbo (T) version of the "673-series" engine. That would have been the venerable "Thermodyne" engine. I know they were available in at least a 250-horse version. The END-673 would have been the normally-aspirated (non-turbo) version of the same engine. And, yes, it was 672 cubic inches. The "672" series was an older engine. The "673" was used to denote the "new" engine. Another very common version would have been the ENDT-675...the much beloved 237-horse Maxidyne (still 672 cu-in). Remember, the model number on the truck actually hinted at the powertrain configuration (R611 = ENDT-673 Thermodyne), (R685 = ENDT-675 Maxidyne). There were also similar numbering "clues" on the transmissions. Lots of folks don't remember that a "0" on the end of the trans model number denoted overdrive. Like, TRQ-7220. This was a TRansmission - Quadruplex. I believe the 722 indicated the torque rating or the particular gear rations used...or something. The "0" indicated that it was "overdrive in 5th"...making it an 18-speed rather that a 20-speed. I used to have a list of all those trans model numbers and what they meant. I need to see if I can find that... The attached pic shows a little of that. Again, elegant. Sorry for the rant! I guess I just miss being a part of the conversation!!! 4 Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment Share on other sites More sharing options...
rklahs Posted May 30, 2020 Share Posted May 30, 2020 i HAVE A 1978 RL685LS endt675 MACK i GUESS A Maxidyne? 1 Quote Link to comment Share on other sites More sharing options...
terry Posted May 30, 2020 Share Posted May 30, 2020 8 hours ago, rklahs said: i HAVE A 1978 RL685LS endt675 MACK i GUESS A Maxidyne? 675 is a 237 maxidyne. terry Quote Link to comment Share on other sites More sharing options...
Freightrain Posted May 30, 2020 Share Posted May 30, 2020 19 hours ago, doubleclutchinweasel said: I love how the number nomenclature comes up in threads every now and then! The old Mack stuff had an elegance to the numbering system that everybody could use as a pattern. Even individual part numbers had a system. Then, Volvo came along and assigned random numbers to the parts, and royally screwed that up! Anyway, it is cool to see that folks are still learning how to read the number codes on the engines, transmissions, and model numbers. Makes me feel like I'm not such a "newbie" anymore! I remember going through all those same exercises when I was piddling with my old R611ST. Yes, sometimes the "END" was omitted from the engine marking (ENDT-673 for instance), because ALL the diesel engines at that time started with "END" (ENgine - Diesel). The ENDT-673 was a turbo (T) version of the "673-series" engine. That would have been the venerable "Thermodyne" engine. I know they were available in at least a 250-horse version. The END-673 would have been the normally-aspirated (non-turbo) version of the same engine. And, yes, it was 672 cubic inches. The "672" series was an older engine. The "673" was used to denote the "new" engine. Another very common version would have been the ENDT-675...the much beloved 237-horse Maxidyne (still 672 cu-in). Remember, the model number on the truck actually hinted at the powertrain configuration (R611 = ENDT-673 Thermodyne), (R685 = ENDT-675 Maxidyne). There were also similar numbering "clues" on the transmissions. Lots of folks don't remember that a "0" on the end of the trans model number denoted overdrive. Like, TRQ-7220. This was a TRansmission - Quadruplex. I believe the 722 indicated the torque rating or the particular gear rations used...or something. The "0" indicated that it was "overdrive in 5th"...making it an 18-speed rather that a 20-speed. I used to have a list of all those trans model numbers and what they meant. I need to see if I can find that... The attached pic shows a little of that. Again, elegant. Sorry for the rant! I guess I just miss being a part of the conversation!!! I printed out the spec sheets from here many years ago. It lists the transmission code and gearing. Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment Share on other sites More sharing options...
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