GM alternator on a Flattie

I am building a 8BA flathead and bought one of those special brackets and pulley from Speedway to adapt a GM alternator to the thing. Got new water pumps with the 3" offset, put the original manifold on with the new bracket and the alternator. No matter how I look at this thing, the alt pulley is about 3/4 " too far out to line up with the pump pulleys. I am using the original sized 5/8 belt too. Any ideers whats going on here?

The guy at Speedway thought there must be different manifolds in that year. I tried both the original one and one from a 46 flathead and they both come out the same. The mounting surface for the alt bracket is even with the mounting surface of the front cover.

Any help would be appreciated

 

Alternators belong on new cars....Generators belong on old cars with old motors. Put a generator on it. Problem solved.

 

YEP!

 

There are several different styles of GM alternaters as well, picture of your application would help.

 

The commonly used 1970's one is available with a 2 sheave pulley--that might give you a proper line up.

 

You ever get this solved? I'm trying to find out what bracket to use on my 52 F-1. Several folks on here talking about this same thing, but nobody has posted the solution. Well, except for the one that says he found a bracket at rod n somethings for this engine, but now the web site does not come up.

Thanks
M Joiner

 

I always make my own. and generators are ugly
show us a picture

 

I'm as much a traditionalist as anyone, but some of the above posts make me wonder. Why not suggest that he pop a small block Chevy in and get rid of that old flathead? Problem solved!!
Bruce Lancaster has offered the best solution....maybe the right one.

 

Double pulley will push things forward or out. From what I've been told, the alt. has too be shaved down so that the pulley will move inward. I can't find anyone who knows why, but Speedway Motors and the Hot Rod Co. both state this on their site.

M Joiner

 

I don't know. i have an o/t 300 ford 6cyl. and the alternator set-up looks like ASS. i'll use it til i can find something better, but the alt just looks wrong to me. i'm on a tight budget though, i've seen some of the "gen/alt" conversions" and i just don't trust them for a car that'll be a "reacher" i wanna drive my car 1000 miles with-out a problem. if i do have a problem, i wanna get parts at the local NAPA, not be hung-up by some "fancy-dan" conversion. i think i may just go with a generator and avoid all the drama.

 

If you plan on running 1000 miles without problems I would stick to the plan of using an alternator. I've had my flattie on long trips up to 4000 miles and it sure is nice to know I can readily get parts for it in case I break down. Plus the engine will run stronger and cooler and be more efficent.The last time my alt went I was able to get one at Advance Auto parts. Took less than an hour to get back on the road. That would'nt have been so easy with a generator. Look up some of the members here who use Flathead as their handle and pm them directly. Not everyone is on the hamb everyday. Most of those guys are really sharp and like to help out. Good luck.You could also talk to flathead Jack directly. You can find his number on his website.Good guy with lots of knowledge and quality parts.

 

used the Speedway bracket and pulley it all worked out but the bracket should be on so raised part is to front , the alt. case will need mods. the mount will have to be narrowed to 1 7/16 " the spacer for the ear shortened to what works may have to machine off the back of the pulley can't remember. should use a smaller dia. pulley so engine can idle under 700, go to a rebuilder and get a new flat cooling fan plastic and metal alt will cool better because of fan wash. used this for 5000+ miles no issues

 

The post is from 2005. I would guess he figured it out.

 

If I'm not correct ..... Powermaster makes a generator looking alternator ..... try the best of both worlds.

PACO

 

Had a Powermaster looks neat but didn't last made 5 miles waqs able to return it but looked inside first , it is to restricted for air flow to cool so it overheats air is suposed to come in the back and out the front but reaf bearing mount prevents that . GM alt may not looka as pretty but sure lasts

 

Had a couple of PM's about brackets. There are two guys on Epay, search FordFlathead Alternator. I have no connection with either one. Shamless self promotion, if you have a low amps needed I have the brackets for the 45 Amp Denso type mini alternator.

 

This is in response to a PM from 52Flat in regarding the alignment of an alternator using a slingshot bracket on 8BA engines. In this case he has a 52 truck which uses the wide belt truck pulleys and is similar to other pre 49 hot rod applications where an 8BA block is used.

Presently sling shot alternator brackets made fit 32-48 engines without any issues but using the bracket inconjunction with 8BA engines has an alignment issue.

I have tried to quickly research and respond to this issue and believe that some of it can be traced to the differences in case casting mounts for the GM alternators. Using a fresh off the shelf bracket on an 8RT truck engine the bracket does pose a 3/16" misalignment problem as evidenced in the picture however this can be quickly addressed by simply modifying the case boss on the alternator to bring the registration of the pulley and the belt back into alignment. Without driving the guys at the auto parts store nuts trying to compare GM one wire units its just easier to face off the back side of the casing mount to the corresponding thickness and shorten the opposite side shim and you are good to go.

 

Exactly! Your guessing because he never followed up with the solution.

 

Dick Spadaro,
Sorry to beat a dead horse but help me understand the yard stick. And is that the fan? Not sure what your doing there in the pics. I bought a bracket (Certified Auto Electric) and put it in with Gm alt.& 5/8's wide belt pulley and it is off 1/8 to 3/16's. I got those numbers measuring the old set up before and after removal and then also measuring the new set up and subtracting. I am interested to know how you got your numbers. Thanks for looking into the problem.

M Joiner

 

Only thing worse than an alternator on a Flattie is a fake generator (PowerGen). Stay true to HOT rod tradition and install a real generator. They work just fine.

 

Attn 52 Flat:

This picture shows the misalignment due to different alternator cases, just like you questioned. The answer is how to correct the alignment. The yard stick is aligned with the face of the water pump pulley and shows that in some cases depending on the case design of the alternator, you could be off 3/16 of an inch for alignment. It is an easy adjustment to simply remove the corresponding material off the alternator case mount to bring the fan pulleys back into alignment.

Yes that is a cut down fan for a display to show how every thing works with a bolt on fan pulley.

 

oh crap! i have a stock 52 truck engine. well, I,m glad this came up again, i,m goin to go an check mine out

 

Thought thats what you were doing. I tried this on my truck with a steel framing square and while it shows there is misalignment it was really small. I held the straight edge against the front surface of the water pump pulley and it lined up almost dead even with the inside edge of the new alt. pulley. I knew I had a larger offset than that because of my previous comparisons of the old and new system with a steel ruler. Then I noticed that the water pump pulley is not flat on the front surface and is thicker than the new flat front alt pulley. So, to align the belt surface on the two, I need to move my alt. pulley back a distance equal to the thickness of the front lip of the water pump pulley. This will be different with each individual unless they have the same parts, but I just wanted to put out a word of caution for anybody that might do the straight edge test. Unless the pulleys are identical you have to take the difference in to consideration.

M Joiner

 

I am all for the alternator but get the one that looks like a generator .
As for the GM on a Ford , that is just plain wrong ! I have seen them on Flatheads before and they look like shit !
Just a thought !

RetroJim

 

Make sure you have the right year alternator y bracket. They have early flathead and late flathead brackets.

 

After you sent me the personal message I saw more activity on this thread so I thought I would update everyone and show a few pictures.

Yes I did solve the problem. I took the route of using a standard single wire GM alternator cuz it fit between the radiator hoses and in front of the front carb. I also did not want to modify the alternator so I could buy any standard GM alternator if I had a problem. I have the wide pulleys on the crank so I bought stock wide pulley water pumps for a truck with the horizontal engine mount tabs. Then I bought the wide alternator pulley and slingshot alternator mount from Speedway

When I mounted everything up, I put the belt on and I could see by just eyeballing it that the alternator was too far forward. I just shimmed the left side back far enough to make everything right and then I cut off the top part of the right side of the bracket so the alternator could be lowered into place and fastened. Now the right side just jogs back about 3/8" and I just have to weld it in place.

Look at the pics I attached, this should help

-Dave

 

Nice to see someone else trying something besides cutting the alt. case. My bracket is from Certified Auto Electric and it is only 1/8 inch off. I was thinking if I could get a machine shop to make a 1/8 flat bottom hole around the mount hole on one side of the bracket, then the alt. boss would fit back into it. Don't know if they have a tool for that or not. Btw, my stock set up ended up measuring 3 3/8 inches from intake to center pulley and the alt in the new bracket is 3 1/2.

Thanks,
M Joiner

 

Yes they have a tool for that. It is called an end mill and they come in the basic size diameters like 1/4", 5/16", 3/8" etc. a machinist could do what you are talking about pretty easy I would think.

-26

 

Thats right. Its an end mill. I just went by the shop and it cost $90 an hour. The guy was sure the whole process would take at least an hour. Does this thing fit in a drill press? I wonder how much just the bit cost.