T-Mack1 Posted April 4 Author Share Posted April 4 On 4/3/2025 at 8:17 PM, Geoff Weeks said: Post your solution to the selenium unit when you get to that point. Will do. I have been talking with my buddy who is most likely a genius that never went to college. Machinist, Top 50 GM mechanic at one time, and Electronic GURU. I had him look at all the options including using the more modern Leece Neville rectifiers (one Pos one Neg. ). His opinion, since the selenium rectifier has significant resistance forward, one of those 3-phase rectifier modules would be a big improvement. He said get one that is rate higher than the alternator output. 120A at a minimum, for our 100A ALT. Also said get the lowest voltage one you can get. So, after he looked at the spec's of one I found, we got a 800v 160A bridge rectifier module. I just have to build a heat sink for it. Again, working with him on size for it. He said that we should see slightly higher charging AMP's and at a slightly lower RPM. EDIT: the bolts on the module are M6-100 which is nearly equivalent to the 1/4-28 bolts used on the Selenium rectifier. Quote Link to comment https://www.bigmacktrucks.com/topic/75276-former-boston-fd-b85f-1211-project-mack-brothers/page/2/#findComment-572804 Share on other sites More sharing options...
mowerman Posted April 4 Share Posted April 4 Excellent thanks for sharing. Nice going bud…. Bob 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75276-former-boston-fd-b85f-1211-project-mack-brothers/page/2/#findComment-572809 Share on other sites More sharing options...
Jack Mack Posted Monday at 03:35 PM Share Posted Monday at 03:35 PM Been awhile since Mack brothers posted, Tom is exploring Ireland with his wife and enjoying retirement, me I still have a bit to go yet and resent him everyday he forgets that others have jobs. Original fuel tank has been repaired and lined , all painted , frame and brackets painted , I assume the retired guy will get it in by end of this week. Me? I have been working on taking off hydraulic system and stabilizers added by Boston FD, everything including tank leaked, truck undersides covered in thick oil, but engine and transmission are very clean and mostly oil free other then PTO pump which will be coming off. Federal siren ,Tom went over works and ready to mount , have correct Mack truck spotlights on windshield frame, sourced correct Mack Unity windshield alternating red lights , engine is getting detailed bit by bit . Still looking to check out a sister truck with original fenders yet to start working on restoring rear end to original and looking for wheels and tires as we want to move away from 11x20 split rims and go radials. All in all Tom and I are having great time and enjoy working on the truck!….Jack 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75276-former-boston-fd-b85f-1211-project-mack-brothers/page/2/#findComment-576841 Share on other sites More sharing options...
mowerman Posted Monday at 04:42 PM Share Posted Monday at 04:42 PM holy cow you been busy,,,,got more done in a few months than most of us have in many years,,,,,mine is also caked up underneath like yours ,,,started pulling steering box couple weeks ago then hear come more chores and then extreme heat here lol....so box is still in there,,,,great progress bud,,,hopefully your bolt pattern is the same on your wheels...1100.22.5s are everywhere rims and tires,,,just take your pick and go for the best deal,,best of luck,,,,and yes i would love to be touring ireland,,,bob 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75276-former-boston-fd-b85f-1211-project-mack-brothers/page/2/#findComment-576849 Share on other sites More sharing options...
mowerman Posted Monday at 04:45 PM Share Posted Monday at 04:45 PM your lucky to be in your area,,,,tons of parts compaired to reno lol.bob 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75276-former-boston-fd-b85f-1211-project-mack-brothers/page/2/#findComment-576851 Share on other sites More sharing options...
mowerman Posted Tuesday at 10:39 PM Share Posted Tuesday at 10:39 PM was just wondering whats wrong with your front fenders,they look perfect,,,you mentioned running down some other ones on a parts truck?????? Quote Link to comment https://www.bigmacktrucks.com/topic/75276-former-boston-fd-b85f-1211-project-mack-brothers/page/2/#findComment-576949 Share on other sites More sharing options...
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