Just kinda as weird story I thought I would share. Little back story ,bare with me 1942 Merc flathead in my 39 Ford Picup. Last year while driving with my wife (never happens) on the hi-way the center bolt that holds my generator snapped .Fan and genset fell into radiator ......loud noise ,bing bang boom , made it off the hiway ......Open the hood and Im like ok ,, get the wife to pry up the gen .Ill tighten the bolts ,oh shit ,the bolt is sitting on the backside of the fan hub ,,, never saw anything like it . Towed home, ,switched out the intake manifold.back on the road .....8 months later Today ...smelled a little antifreeze after a trip up town . Open the hood ,mmmmm , fan belt is a little loose,gen belt is fine . I Drive to my brothers house because I need two hands .loosend the two 5/8 fan bolts ,then the Big 7/8 generator bolt . Tighten fan ,,, tighten generator ,,,SNAP , ,AGAIN , I did not over tighten ! IM thinking WTF. I ordered another bolt going to fix /drill an tap the original intake and do the swich back. Im thinking 2 things , cheap crappy bolt .(they look original)...or my pullies are a smidge out of line ,causing undo pressure / fatigue. They look good to the eye .Two bolts in less than a year ????
can you get some pics of how it looks when it's all assembled? Usually problems like this are due to the bracket design allowing side loads on the bolt, instead of using the bolt just for tension (clamping load). We can imagine what it looks like, but we would probably be wrong. Maybe it's a factory setup...but maybe not...we can only guess
Bolt has fatigue cracking. Somehow your bolt is getting cyclic (bending) loading. The solution is to keep the bolt from being subjected to those stresses. Maybe your brackets are sllowing flex? An overall picture of the setup would help. Sent from dumb operator on a smart phone
do you have the big square washer ford used on there too? seems odd, thats a big bolt, 9 1/6 if i remember, should take a lot to break it. the wide belts grab pretty good, no need for hyper belt tension with a generator, over tighten the bolt?
Like has been already said a picture of when it is all assembled would help to find a solution for this problem.
Thanks for the replies . Truck is at my brothers. Sittng in the driveway I'll post a photo or two of the setup when im back there .. All factory with the exception of an aluminum fan hub.I joke at the car show that ,thats what makes it a HotRod ! I just wanted to tighten the Fan belt ,,,,,Im glad it happend in his drivway . Square washer is there, and looks a little worn. I Ordered a new bolt and washer from Mike at Third Generation, be here Tuesday .Got till then to get the original intake fixed . Might try to weld a nut to it and back it out .I,ve never done it .
My guess is you are making the belt too tight. As things expand and contract with heat cycles it is breaking the bolt.
Usually the factory bolts hold up better than anything new. One of the 3 OG bolts on my SBC is a stock alternator mounting bolt. Look for something out of line once you start putting it back together.
Looking at the paint scraped off the front of that manifold, it may show the fan hub is not sitting down in the groove. Looks like one side is down in the groove but the other is up on the shoulder. That would cock the bracket and cause the bolt to bend. Maybe your "hot rod" hub is not the correct fit for that intake. You might need to upgrade to a "hot rod" intake to match.
Tig weld ? Personally , I would stand it on end, pour some Gibbs lubricant on it. Drill a hole and tap a slightly oversized Allen key into it ( think poor mans easi out ) before going at it with the welder, especially if it is a first attempt . But that’s just me and you certainly did not ask for my opinion.
Well, just more questions. How long were you running the motor after putting on the hot rod hub compared to how long it took the second bolt to break? Did the second bolt break in the same place as the first one did? I'm not worried about the time to break in days, but how many hours do you think you have on the motor before it broke? Were both bolts sourced from the same place? New bolts or used? Seems like you'd have to put serious misalignment or over-tightening to break what, as rustyvalleys says, is a seriously sized bolt. On the other hamd, Ford never spend a penny they didn't have to so maybe a flathead guru could explain why you would need such a heavy duty bolt? I'd certainly be checking that bolt a lot more frequently until you figure it out.
i agree with alchemy, it looks like the generator may not have been seated between the shoulders on the mount surface. that would do it, but a sideways load on the bolt. better check that the genny fits in there properly
I've done the "weld a nut to the broken stud" thing several times. Works most of the time. I use a bigger nut than the stud so you can get a good weld. Most recently was on Model A exhaust manifolds where the intake bolts to them for heat transfer. 5/16 bolts that always are broke or twist off when removing. Not 100% were successful and sometimes used a lot of nuts but then was able to drill and tap anyway. Hope this helps, Dave
From the rust marks it looks like it might have been cracked for awhile before it let go. Does the second one look anything like that? No significant experience with the weld a nut method so will will forego judgement on that for now. I have had good luck with penetrating oil soaking overnight, or longer when time allowed, followed by heating the bolt red hot and allowing everything to fully cool, then center punching and drilling with a left handed bit as big and deep as possible, sometimes the bit will spin it out. If not follow up with an easy out but don't hammer it in tight enough to expand the bolt into a more binding situation. That fails use a small chisel to break the remains apart towards the drilled hole. Everything gets mucked up it's time for a threaded insert of choice. Ed
SUCCESS ! ! My little brother weaseled a battery drill in between. Had to cut the bits down . Got in an easy out ,little heating of the busted bolt. Just like the Ol Man said it would be ,,, "Duck-soup". I will get the NEW nut and square nut in the mail tomorrow,,put everything back and take some measurements.
I want to thank everybody for their in-sight and knowledge. It makes one know, they "can-do" ,,,,even if they wonder about it .my friggin brother was pretty dead on on his blind drill job ! Im thinking a straight edge off the bottom pully, and true everything off that. Its probably the Aluminum fan pully ,its the only Non-stock item in the set up
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