Popular Post fjh Posted July 14 Popular Post Share Posted July 14 27 minutes ago, Joey Mack said: I was taught the same thing. Mack would only cut the journal that needed cutting. To this day i look at all the counter weights, and bearing numbers.. i dont assume. And Mack bearing kits are not always packed in the correct order. I was blessed to have a cranky old Man take me under his wing... Earl Harnden was his name. Maine Mack, 299 Warren ave. ,Portland M.E. I had to post his name.. He went home a couple years ago.. RIP 🙏to him Joey ! Bless some of these guys we worked under ! Grumpy or not For their knowledge! Best we can do is pass it on here! What goes around comes around! Grumpy is sometimes a good way to learn shit ! Sometimes there’s a reason! The biggest takeaway is PAY Attention ! None of this is written in books! 2 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579105 Share on other sites More sharing options...
Joey Mack Posted July 15 Share Posted July 15 Amen.. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579106 Share on other sites More sharing options...
BOBWhite Posted July 15 Share Posted July 15 On 7/12/2025 at 12:34 PM, Geoff Weeks said: The tip turbine and Low Flow cooling were both attempts to better charge cooling without have to re design the front of the truck for enough room for an CAC cooling radiator (Air to air). once trucks were being redesigned anyway, the reasons for the tip turbine and low flow systems went away. Having the charge cooler in front of the radiator give the best cooling, and what has become the std today. At the time, Mack tip turbine was revolutionary, both Cat and Cummins were still using water cooled aftercoolers, and low thermostat temps, to walk the fine line between good block temp and enough cooling for the charge air. After Macks success, Cummins used the low flow system to run the "super cooled" multi-pass radiator coolant through the aftercooler, before sending it the engine. Cat never did and opted for the cooler in front of the radiator, which meant that their engines above 400 hp could not be fitted to many trucks. Cat engines below 400 hp still had the old water cooled aftercooler. I didn't know that about the Cummins low flow engines. I know that they were mostly hated around here in tractors, they seemed to go through fan belts frequently and you'd have to keep the radiators sterile to keep them cool. The weird oil thermostats they put on Cummins later weren't much liked either 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579115 Share on other sites More sharing options...
steve s. Posted July 15 Share Posted July 15 (edited) 13 hours ago, Freightrain said: Not sure of year. Only thing I have is serial on motor. EtAZ673C 7S8762. If that means anything. I E- Mack diesel engine. T- trubocharged. A-single stage aftercooler. Z-maximum 10 grams per bhp/hr emissions level. Certified in California 1975-1976. 673- approximate engine displacement. C- variation of the basic engine unit, or(obsolete) emissions standard. Your engine was rated at 295 HP and governed at 1800 rpm. If there was a B in the engine number it would indicate a Dynatard engine brake. Edited July 15 by steve s. more info 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579123 Share on other sites More sharing options...
Freightrain Posted July 15 Author Share Posted July 15 Thanks Steve. What I need to know is the serial number after the Etaz673c, does that correlate with anything? 7S8762 ?? Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579124 Share on other sites More sharing options...
steve s. Posted July 15 Share Posted July 15 8 minutes ago, Freightrain said: What I need to know is the serial number after the Etaz673c, does that correlate with anything? 7S8762 ?? Sorry Larry, I don't have any information on your serial number. The Mack Museum could probably tell you more. Quote Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579126 Share on other sites More sharing options...
mowerman Posted Tuesday at 01:52 PM Share Posted Tuesday at 01:52 PM That’s very interesting I thought 285 and 300 plus were 676???? Quote Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579138 Share on other sites More sharing options...
Freightrain Posted Tuesday at 03:04 PM Author Share Posted Tuesday at 03:04 PM I think the 285/300 were 676(maxidyne). The 300+ isn't the same. 1 Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579143 Share on other sites More sharing options...
mowerman Posted Tuesday at 03:08 PM Share Posted Tuesday at 03:08 PM it seems like its the same size as my block,,bob Quote Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579145 Share on other sites More sharing options...
terry Posted Tuesday at 03:10 PM Share Posted Tuesday at 03:10 PM 1 hour ago, mowerman said: That’s very interesting I thought 285 and 300 plus were 676???? The 237 was a 675, and the 285 was 676, not sure on the 300+ terry 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579146 Share on other sites More sharing options...
fjh Posted Tuesday at 03:37 PM Share Posted Tuesday at 03:37 PM 24 minutes ago, terry said: The 237 was a 675, and the 285 was 676, not sure on the 300+ terry Me thinks just different fueling! Comes down to gearing again Need gears for the 300 plus!285 not so much! 2 Quote Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579147 Share on other sites More sharing options...
Freightrain Posted Tuesday at 04:27 PM Author Share Posted Tuesday at 04:27 PM 49 minutes ago, fjh said: Me thinks just different fueling! Comes down to gearing again Need gears for the 300 plus!285 not so much! Yup, from what I have read. Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579151 Share on other sites More sharing options...
Freightrain Posted Tuesday at 04:29 PM Author Share Posted Tuesday at 04:29 PM 1 hour ago, mowerman said: it seems like its the same size as my block,,bob It is, just fuel and timing is different. The "673" denotes a Thermodyne(multi gear trans) and the 675/676 was Maxidyne(5spd). Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579152 Share on other sites More sharing options...
mrsmackpaul Posted Tuesday at 05:39 PM Share Posted Tuesday at 05:39 PM 1 hour ago, fjh said: Me thinks just different fueling! Comes down to gearing again Need gears for the 300 plus!285 not so much! Im fairly certain 285 Maxidyne is a air to air intercooled tip turbine job A 300 Maxidyne is series air to air, so water cooling and tip turbine intercooled job A little more fuel and a more efficient intercooling and 300 Maxidyne was produced after 285 In the Thermodyne it was the same and 320 went to 350 hp We never had the range of motors, transmissions and backends etc that was available in the U.S. So I have never heard of a 315 or a 295 hp motor Even gear boxes 5, 6, 10 and 12 speed None of the other numbers you blokes mention Paul 2 Quote Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579159 Share on other sites More sharing options...
mrsmackpaul Posted Tuesday at 05:42 PM Share Posted Tuesday at 05:42 PM And even before the Maxitorque box was around, pretty much everything had a quad box and very occasional duplex I have never seen or heard of triplex or simplex (think that was the name of Mack 5 speed) in Australia Paul 2 Quote Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579160 Share on other sites More sharing options...
mowerman Posted Tuesday at 05:58 PM Share Posted Tuesday at 05:58 PM duplex and triplex,,were very common here Quote Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579161 Share on other sites More sharing options...
fjh Posted Tuesday at 06:00 PM Share Posted Tuesday at 06:00 PM 19 minutes ago, mrsmackpaul said: And even before the Maxitorque box was around, pretty much everything had a quad box and very occasional duplex I have never seen or heard of triplex or simplex (think that was the name of Mack 5 speed) in Australia Paul Odviously things are done differently down under! Paul! Couldn’t get 650 v8 here ever I would like to have seen one! With a vmac pump! Very interesting! We were able to at one point order the cam and turbo here through the Mack system we did two trucks up with the Aus turbo and cam with the pump jacked up they pulled like know body’s business! 2 Quote Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579162 Share on other sites More sharing options...
mrsmackpaul Posted Tuesday at 06:50 PM Share Posted Tuesday at 06:50 PM And yet our close neighbors in NewZealand had a bigger range of Macks as some were Australian based and some fully imported from the U.S. RHD Seems to be no rhyme nor reason to how it all went Anyways, back the build Oh I think 675 was the biggest power output of the E9 offered in Australia Paul 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579166 Share on other sites More sharing options...
Freightrain Posted Thursday at 06:01 PM Author Share Posted Thursday at 06:01 PM I remember a video from way back showing a big power KW getting out run by a Mack up a hill in Australia . The KW driver was like WTH! I tried searching for it but never find it. Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579305 Share on other sites More sharing options...
Freightrain Posted 15 hours ago Author Share Posted 15 hours ago What is the common way to get the balancer off the front of crank? No holes to use for puller. Get a real big one and grab around the outside? I don't remember what I did to the 237 when I removed it and swapped my 673? Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579500 Share on other sites More sharing options...
Joey Mack Posted 15 hours ago Share Posted 15 hours ago Well. I just did one last month.. i sprayed it with pen oil, heated the flange with a torch, and used a dead blow to knock the balancer. It took 30+ minutes, and it was on a spare engine that was outside for years.. very rusty. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579501 Share on other sites More sharing options...
other dog Posted 13 hours ago Share Posted 13 hours ago Here's my 1 cent opinion- I've driven most transmissions that have been mentioned here, and my favorite is the 18 speed. However, you seldom if ever even need to split the gears in the low side, so I think your first choice of a 13 speed and 3.55 rears would be the cat's ass. I'm pretty sure you'd love it, and there's probably more of them around than there are 18's so they're probably a bit cheaper too. Now, as far as tip turbines, charge air coolers, dynatards, fire rings, etc. I have no clue. None. 1 Quote Producer of poorly photo-chopped pictures since 1999. Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579504 Share on other sites More sharing options...
fjh Posted 12 hours ago Share Posted 12 hours ago 2 hours ago, Joey Mack said: Well. I just did one last month.. i sprayed it with pen oil, heated the flange with a torch, and used a dead blow to knock the balancer. It took 30+ minutes, and it was on a spare engine that was outside for years.. very rusty. Yup they can be nasty! Quote Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579510 Share on other sites More sharing options...
terry Posted 10 hours ago Share Posted 10 hours ago 4 hours ago, Freightrain said: What is the common way to get the balancer off the front of crank? No holes to use for puller. Get a real big one and grab around the outside? I don't remember what I did to the 237 when I removed it and swapped my 673? The balancer is separate from the crank hub if i remember right? terry 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579514 Share on other sites More sharing options...
Freightrain Posted 2 hours ago Author Share Posted 2 hours ago Thanks guys. Kinda figured I just knocked it off or I would have a tool from the last time. I'll get to spraying it with oil now. Terry, yes, it bolts to a flange that slips onto crank. I remember warming it up in the oven to get it to slip on easily. I'm considering removing the inj. pump so I can regasket the side covers. How bad is it to get it back correctly? Timed? Etc? Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/75768-300-rebuild/page/4/#findComment-579520 Share on other sites More sharing options...
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