Popular Post chuckholes Posted December 3 Popular Post Share Posted December 3 Had been sitting 24 years in one spot. Ran when parked lol Any pointers on trying to start it? It’s a 1981. Are they 24 volt negative ground? 5 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/ Share on other sites More sharing options...
Brocky Posted December 3 Share Posted December 3 Where are you located?? That looks like a GA plate on it????? First try to roll the engine over with a bar on the front pulley bolt. If free, start from there. Quote Brocky Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563123 Share on other sites More sharing options...
chuckholes Posted December 3 Author Share Posted December 3 1 minute ago, Brocky said: Where are you located?? That looks like a GA plate on it????? First try to roll the engine over with a bar on the front pulley bolt. If free, start from there. I’m in Warner Robins Ga. Found the truck in Bullock County Ga Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563124 Share on other sites More sharing options...
mowerman Posted December 3 Share Posted December 3 make sure you remove all the injectors and shoot a bunch of mystery oil into the cylinders and let it sit a week or so before you try to turn it over also remove inlet turbo oil line and shoot oil into turbo bearing,,,and make sure the turbo spins free nice going bud,,,,,bob 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563126 Share on other sites More sharing options...
Brocky Posted December 3 Share Posted December 3 2 minutes ago, chuckholes said: I’m in Warner Robins Ga. Found the truck in Bullock County Ga Please add it to you profile.. Being a F-712 what engine does it have in it??? If it is a 2 stroke Detroit you have to make sure the rack is free or it will run away!!!! 1 Quote Brocky Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563127 Share on other sites More sharing options...
chuckholes Posted December 3 Author Share Posted December 3 6 minutes ago, Brocky said: Please add it to you profile.. Being a F-712 what engine does it have in it??? If it is a 2 stroke Detroit you have to make sure the rack is free or it will run away!!!! Believe it’s a Mack motor with a 5speed. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563128 Share on other sites More sharing options...
tjc transport Posted December 3 Share Posted December 3 if it is an 81, it should ne negative ground. as for 12 or 24 volt, you would have to look at the alternator and starter to be sure. or it could throw a monkey wrench in the plans and be 12 volt electrical and 24 volt starter. 1 Quote when you are up to your armpits in alligators, it is hard to remember you only came in to drain the swamp.. Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563132 Share on other sites More sharing options...
chuckholes Posted December 3 Author Share Posted December 3 Odd thing is it currently has 4 22.5 inch wheels and 2 20 inch wheels . One side or the rear duals is mismatched. Front has one 22.5 and one 20 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563133 Share on other sites More sharing options...
Brocky Posted December 3 Share Posted December 3 (edited) 2 hours ago, chuckholes said: Believe it’s a Mack motor with a 5speed. I do NOT know all of Mack's numbering system, BUT in the R models a 600 series had a Mack engine and the 700 series had outside vendors engines.. The 22.5 is the tubeless version of the 10-20 tube type tire. Size wise they are interchangeable. Just start looking for decent 22.5 rims and tires and you will be in good shape. Depending on what you are going to use it for, as a hobby truck you can get away with what you have is they are not too far worn or out of date.. Edited December 3 by Brocky Quote Brocky Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563136 Share on other sites More sharing options...
BOBWhite Posted December 3 Share Posted December 3 Glad you got it out of there! A few more years with those pine needles and there would have been nothing left of that truck. Your brake and throttle pedal might be stuck so I would spray some stuff on those asap. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563138 Share on other sites More sharing options...
chuckholes Posted December 3 Author Share Posted December 3 30 minutes ago, BOBWhite said: Glad you got it out of there! A few more years with those pine needles and there would have been nothing left of that truck. Your brake and throttle pedal might be stuck so I would spray some stuff on those asap. The cab is fairly decent. Are you familiar with the truck? Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563140 Share on other sites More sharing options...
terry Posted December 3 Share Posted December 3 4 hours ago, Brocky said: I do NOT know all of Mack's numbering system, BUT in the R models a 600 series had a Mack engine and the 700 series had outside vendors engines.. The 22.5 is the tubeless version of the 10-20 tube type tire. Size wise they are interchangeable. Just start looking for decent 22.5 rims and tires and you will be in good shape. Depending on what you are going to use it for, as a hobby truck you can get away with what you have is they are not too far worn or out of date.. The R700 series had the longer hood for cat or cummins engines, but i also seen them with mack six cylinder, and mack V8 engines. Terry 2 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563142 Share on other sites More sharing options...
cruiseliner64 Posted December 3 Share Posted December 3 Thats a beautiful truck.best of luck with it.keep us posted as you get things done. Paul 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563150 Share on other sites More sharing options...
BOBWhite Posted December 3 Share Posted December 3 11 hours ago, chuckholes said: The cab is fairly decent. Are you familiar with the truck? No not this perticular truck. I'm just remembering all that was wrong with our Mh cabover after sitting a few years outside. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563168 Share on other sites More sharing options...
Mark T Posted December 4 Share Posted December 4 We're gonna need a picture from behind the cab looking forward ( in under the cab ) put this engine mystery to rest 😏 2 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563211 Share on other sites More sharing options...
chuckholes Posted December 5 Author Share Posted December 5 On 12/3/2024 at 7:14 PM, Mark T said: We're gonna need a picture from behind the cab looking forward ( in under the cab ) put this engine mystery to rest 😏 Here is a picture Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563290 Share on other sites More sharing options...
chuckholes Posted December 5 Author Share Posted December 5 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563291 Share on other sites More sharing options...
Joey Mack Posted December 5 Share Posted December 5 E-6 2 valve?? 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563292 Share on other sites More sharing options...
Mark T Posted December 5 Share Posted December 5 300. Coolpower Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563294 Share on other sites More sharing options...
chuckholes Posted December 5 Author Share Posted December 5 45 minutes ago, Mark T said: 300. Coolpower How can you tell? Is there a data plate on the engine anywhere? Is the 300 cool power considered a Maxindyne? thanks for the info. Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563296 Share on other sites More sharing options...
Mark T Posted December 5 Share Posted December 5 I see two ducts on the air cleaner. One is for the turbo and the other is for a tip fan. There's nothing on the shifter ( like a range valve ) . In my opinion it would suggest it's a 300 Maxidyne. 300 Plus or 350 would be an Econodyne with a transmission with more speeds than 5. That's my guess from what I see in the picture (s) . 2 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563300 Share on other sites More sharing options...
cruiseliner64 Posted December 5 Share Posted December 5 (edited) 7 hours ago, Joey Mack said: E-6 2 valve?? Looks much the same as the EM 6-300 in our Cruiseliner.The shape of the valve covers,the exhaust manifold and a few other details all look the same....its a Mack motor me thinks.... Paul Edited December 5 by cruiseliner64 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563301 Share on other sites More sharing options...
BOBWhite Posted December 5 Share Posted December 5 (edited) Another thing to check before starting is try to take what's left of the exhaust pipe so you can spin the turbo with your hands. Make sure it spins freely and clean out any critter crap that may have gotten in there, look over the intake good and make sure nothing got in there too. As stated previously take off the turbo oil feel line, oil it up, and you should be good to go. Edited December 5 by BOBWhite 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563302 Share on other sites More sharing options...
Freightrain Posted December 5 Share Posted December 5 Surely no Driptroit! 😆 Once you get the cab tipped you can look at the front of the accy drive( below right of water pump) and it will be stamped 676???? Not sure what the proper designation for 300? I would pull the side cover off the injection pump and as you roll motor over watch for all 6 pumps are moving up/down. They may be stuck. They look like valve springs and easy to see if they are moving. Might take a few taps to get them unstuck. My 237 had a few hang up from sitting a long time. 1 Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563303 Share on other sites More sharing options...
mechohaulic Posted December 5 Share Posted December 5 tip turbine answers my question from the first two pictures as to why the over sized intake pipe. as stated may times pictures worth thousand words. thanks .good respirator , open both doors ; take top cover off in cab ;; air hose the liven sh-t out of it. spray the brake / fuel pedals. while everything soaking in penetrating oil =tip the cab for engine compartment cleaning. you know there will be rodent homes in the turbo with that open exhaust. it's a diamond in the rough. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563304 Share on other sites More sharing options...
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