Devious10 Posted October 20, 2012 Share Posted October 20, 2012 What all do i need to convert to a 12 volt electrical system? keep in mind Electrical is not my strong suit ,I can do it but i hate it. Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/27909-b61-to-12-volts/ Share on other sites More sharing options...
Vladislav Posted October 20, 2012 Share Posted October 20, 2012 At least you need 12V starter.Vlad Quote Никогда не бывает слишком много грузовиков! leversole 11.2012 Link to comment https://www.bigmacktrucks.com/topic/27909-b61-to-12-volts/#findComment-142438 Share on other sites More sharing options...
theakerstwo Posted October 20, 2012 Share Posted October 20, 2012 Starter and a primary relay plus find out if its pos or neg ground and wire that way. Remenber when you go from 24 to 12 you need more amps or bigger cables. No less than 00 in size and a pair of them per set of batteys.And after i think that you have a button for start so no primary relay will be needed.If its got a alter make sure you have your ducks lined up before you start the flashing of reverse polarty to the alter.glenn Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/27909-b61-to-12-volts/#findComment-142440 Share on other sites More sharing options...
Devious10 Posted October 20, 2012 Author Share Posted October 20, 2012 Thanks glenn, so starter and cables then? thats it??? Quote Link to comment https://www.bigmacktrucks.com/topic/27909-b61-to-12-volts/#findComment-142446 Share on other sites More sharing options...
theakerstwo Posted October 20, 2012 Share Posted October 20, 2012 Yes because all of the acc are running on 12 volts any way. It starts on 24 but is charging the batterys with 12 volts.When you change starters make sure the starter drive has same count of teeth on the drive. glenn Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/27909-b61-to-12-volts/#findComment-142450 Share on other sites More sharing options...
Devious10 Posted October 20, 2012 Author Share Posted October 20, 2012 thanks again! this is going to be easier than i thought!!!! Quote Link to comment https://www.bigmacktrucks.com/topic/27909-b61-to-12-volts/#findComment-142453 Share on other sites More sharing options...
Dennis Posted November 3, 2012 Share Posted November 3, 2012 I changed mine over to 12 volt. Like BMT said, you just need a 12 volt starter and good heavy cables, 2(0) or bigger. My truck already had big cables, but they were old and stiff, so I replaced with new. I also changed the the ignitiion switch to one with a start position on it and used a starter relay (ford type) on the firewall. But the old starter button will work okay. Quote Link to comment https://www.bigmacktrucks.com/topic/27909-b61-to-12-volts/#findComment-144261 Share on other sites More sharing options...
Mike Posted November 3, 2012 Share Posted November 3, 2012 A DELCO M39 is a good 12 volt starter to consider, because has double reduction for a faster spin over on that big motor and still use 950 CCA Group 31 batteries. The Part # if you are interested is Part# 8300017 Best Regardsmike Quote Link to comment https://www.bigmacktrucks.com/topic/27909-b61-to-12-volts/#findComment-144265 Share on other sites More sharing options...
thomastractorsvc Posted November 18, 2012 Share Posted November 18, 2012 not trying to highjack but I am in need of some starter info too, the guy I bought my truck from had put a 12 volt starter on it but he said he had some problems and it ended up being the starter gear and he said he changed it, when I got the truck it would catch and then kick out or just spin like it needed to be shimed. I took it loose and seen it was not pulled up tight so I fixed the bolts and it caught about 95% of the time the fist time. I then started the restoration and pulled the tanks, on Thursday I put working fuel tank on and primed the engine up and it would catch and kick right back out or bind up, I pulled the starter and checked it on the bench and it spun fine but the nose bushing is cracked so thats it appears the armature may be bent. The starter looks like it had the mounting adapter made so I amsure that it was someting that was out togeather and not purchused.Instead of jacking around with this one I have will the AC Delco starter mount up and what about the starter gear drive match in the fly wheel, I have a B61T with END engine. Also what is the number of teeth for the starter gear? Thanks for responses. Quote Robert"I reject your reality and substitute my own." Link to comment https://www.bigmacktrucks.com/topic/27909-b61-to-12-volts/#findComment-146625 Share on other sites More sharing options...
39 Baby Mack Posted November 19, 2012 Share Posted November 19, 2012 The starter pinion should have 11 teeth on it.Ron Quote Link to comment https://www.bigmacktrucks.com/topic/27909-b61-to-12-volts/#findComment-146871 Share on other sites More sharing options...
Mike Posted November 19, 2012 Share Posted November 19, 2012 Just like 39BabyMack said, it should have 11 pinion gear teeth. Here is a photo of my old starter and new.mike Quote Link to comment https://www.bigmacktrucks.com/topic/27909-b61-to-12-volts/#findComment-146880 Share on other sites More sharing options...
Freightrain Posted November 21, 2012 Share Posted November 21, 2012 When I converted mine over, I installed a Ford starter solenoid under the passenger seat and tied it into the original starter button on the dash. The Ford solenoid fired the starter solenoid. Works perfect, no unneeded changes to the wiring to get it to work. Since the original series/parallel switch was right there and the starter button was connected to it, it was a no brainer. Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/27909-b61-to-12-volts/#findComment-147276 Share on other sites More sharing options...
thomastractorsvc Posted November 30, 2012 Share Posted November 30, 2012 Hey all, I been jacking around with the starter got it ID as a MT42, it had abad bushing and I think the solinoid needs replaced as it is cracked and I think that is part of the reason for the kick out. Got the 5 dollar bushing installed bench tested and it worked fine, installed and started acting finunny and spinning, started dragging, put the booster charger on and still dragging obviously need more power, so I went and redid all the connections still did not work right would spin, kickin then out again,when I was at the starter shop they thought it was fine except for the nose cone bushing.Is the MT42 the right starter or is part of the problem is it is the wrong dimensiosn to engage properly??? I found the MT39 on line and locally but if all I need is asolinoid that would be aheck of alot cheaper, I just want to get the truck started so I can finish putting it back together.SPECIFICATION:VOLTS: 12ROTATION: CWDEGREES: 52°NUMBER OF TEETH: 11MODEL TYPE: DELCO 42MTAPPLICATION: Medium & Heavy Duty Trucks & Industrial Equipment 1986-98. Quote Robert"I reject your reality and substitute my own." Link to comment https://www.bigmacktrucks.com/topic/27909-b61-to-12-volts/#findComment-148718 Share on other sites More sharing options...
Maddog13407 Posted November 30, 2012 Share Posted November 30, 2012 i put a 42MT starter on my B613 with a 711 and its worked fine for 4 years now. i had to take the back loose with the allen screws and index it different so the solonoid on top cleaned everything but it works find. my truck has the later bellhousin like a 237 with the starter on top on the driver side which is a real pain in the ass ina B model. had to screw around to get the starter to cleaner the throttle linkage and the hoses for the big 750 lubrifiner and the steering column. if you have the older bellhousin with the starter underneith it shouldnt be a problem. the 42 mt will work but you might have to index it differently. most people are using the 39mt i believe. Quote Link to comment https://www.bigmacktrucks.com/topic/27909-b61-to-12-volts/#findComment-148721 Share on other sites More sharing options...
thomastractorsvc Posted November 30, 2012 Share Posted November 30, 2012 mine is on the passenger side lower, when I took it off originally I turned it one postion so I could get at the the bolt between the oil pan and starter because it was difficult to get to. I took a harbor freight air file and a dremel to the banged up flywheel teeth and that seemed to help some with the engagement. is there suppose to be any shims??? Quote Robert"I reject your reality and substitute my own." Link to comment https://www.bigmacktrucks.com/topic/27909-b61-to-12-volts/#findComment-148723 Share on other sites More sharing options...
Maddog13407 Posted December 1, 2012 Share Posted December 1, 2012 you think that bolt is hard to get in by the oil pan?? you should try the one on the backside of the starter when the starter is on the top.and all the hoses. have to tape the damn bolt in the socket with a long extenstion behind the starter and have to go and buy the special 12 point bolts from Mack to ge them in there. thats definatelt a 2-3 beer to cool off after bolt 1 Quote Link to comment https://www.bigmacktrucks.com/topic/27909-b61-to-12-volts/#findComment-148848 Share on other sites More sharing options...
Dennis Posted December 1, 2012 Share Posted December 1, 2012 Replacing those 5/8' bolts with 12 point heads is the way to go You don't have to go to Mack to buy them. Any well stocked bolt or fastener company should have them. Then you can use a 5/8" gearwrench to tighten them up. Makes life a lot easier. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/27909-b61-to-12-volts/#findComment-148853 Share on other sites More sharing options...
Maddog13407 Posted December 1, 2012 Share Posted December 1, 2012 i agree. just got mine from Mack cause i was there. they are about impossible to tighten or loosen when they are the old 6 point. Quote Link to comment https://www.bigmacktrucks.com/topic/27909-b61-to-12-volts/#findComment-148883 Share on other sites More sharing options...
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