'57 Generator Mounting bracket

[Richard M.]

Re: '57 Generator Mounting bracket

Dan, I know this is a old thread but I don't think you ever got replies to all of your questions, other than Joe's reply regarding the spacer.....I embedded them into your quote for reading ease.

According to the parts book the Passenger Car 1956 p/s Generator 1102041 and the 57 Corvette Generator 1120043 take the same end plates and armature. So all the dimensions have to be the same . But the parts book shows the 56/57 Corvette 3728514 U bracket to be 1 11/16 high and 6 a 7/64 long . The 56 passenger car Generator shows 1 11/16 high and 6 5/8 long .

Dan, Many of the bracket changes had to do with hood clearance on the early Corvettes. I think the designers had different design specs due to this. Passenger cars had plenty of room under their hoods.

This also brings up the issue of the endplate differences on the Corvette differences on the 1112043 generators. The early tach drive generators had slightly different end plate(s) height. This brought the mounted generator downward to help clear the hood. One can use a Passenger car generator on a Corvette as there is actually plenty of room under the hood. I think the designers also took engine torque into consideration as to why their end plates were a shorter height. Just a assumption on my part though.

Attached below is a pdf image of the endplate differences. Also, if a Passenger car had Power Steering, the same long armature was used to drive the end mounted pump. More details of that in my document attached in Post#2.

Also included is a pdf of a document regarding brackets, pulleys, spacers, generators and overall alignment.

If the armature and end plates are the same how can the O.L. be different . Could the parts book be wrong and Noland Adams be right. The measurement that Noland Adams shows for the distance from the end of the U bracket to the centerline of the mount hole is 1.26 the passenger car U bracket measures 1 inch . Did they move the Generator forward because of the water pump being spaced out by the Motor Mount .

I don't know about Pass cars, but it's possible the generators were mounted with additional spacers at their U-Brackets.

The parts book shows a Harmonic balancer spacer 3734984 and Corvette Central shows A Harmonic balancer spacer .Are these spacers used to space out the balancer so it will line up with the water pump.

Absolutely correct. All 1956 to 1962 Corvettes required the use of the harmonic balancer spacer to move the balancer forward the same thickness as the forward engine bracket. Outlined in detail in the 2nd document attached.

[David L.]

Re: '57 Generator Mounting bracket

David, Great photos and reference info.

I've never seen nuts like that. I'd think they may be a form of lock nut, whereas a compound jaw press is used to squeeze the ID a few thousandths. Interesting.

Rich

Rich,

The nuts seems to be the locking type as you only can twist them on about 3/4 of the way. After that a wrench is required. I did try a standard 5/16"-24 nut on one of the bolts and I could twist it on all the way. I do think the reason that the nuts have the notch on each of the 6 sides of the hex is to indicate that they are lock nuts.

BTW, I do not think that my 6.1" long bracket stamped "0" is GM # 3728514 because the measured height is only 1 1/2". The 3728514 bracket height is 1 11/16". GM sure made it interesting as some of the brackets are stamped with a part number and some are not.

Dave

[Gary C.]

Re: '57 Generator Mounting bracket

David and Rich,

Nut resembles the Russell, Burdsall & Ward special hex lock nut part #3695966 with vertical slots. Not observed these nuts being used after 1957.

Important to remember - the Corvette only generator mount bracket ears are shorter (not as tall) than the other generator mount bracket ears. Thus when a generator is mounted to the bracket, there's not enough space to slip fingers between the bracket and generator. Whereas, there is on the other generator mount brackets.

Bracket - Generator part #3728514; length = 6.6~6.617, width = 1.12 +/- .03, ears height 1.66 +/- .03

Gary
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[David L.]

Re: '57 Generator Mounting bracket

David and Rich,

Nut resembles the Russell, Burdsall & Ward special hex lock nut part #3695966 with vertical slots. Not observed these nuts being used after 1957.

Important to remember - the Corvette only generator mount bracket ears are shorter (not as tall) than the other generator mount bracket ears. Thus when a generator is mounted to the bracket, there's not enough space to slip fingers between the bracket and generator. Whereas, there is on the other generator mount brackets.

Bracket - Generator part #3728514; length = 6.6~6.617, width = 1.12 +/- .03, ears height 1.66 +/- .03

Gary
....

Gary,

I guess that there is an error in the description of GM # 3728514 my 1957 Chevrolet Parts Catalog (Mar. 1957).

GM # 3725274 is listed for "56-57 ALL P/S" and is described as "(30 amp)(1 11/16" high X 6 5/8" O.L.). This would convert to 1.69" high X 6.625" O.L. As far as I know the "ALL" does not include the CORVETTE.

BTW, maybe my 6.1" long bracket with the stamped "0" is GM # 3836756 which is described for "55 ALL (12 volt), 56-57 ALL (exc. P/S, PASS. 8 cyl.) ................(for 25 amp. generator - 6 1/8 O.L.)".

Dave

[Gary C.]

Re: '57 Generator Mounting bracket

Dave,

Measured a '57 generator bracket that I marked years ago as from a parted out '57 Corvette. Length = 6.5675 and ear height = 1.649

Gary
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[Dan P.]

Re: '57 Generator Mounting bracket

the difference is not in the length or height . The difference is the mount is moved forward on a Corvette to compensate for the water pump being moved ahead by the motor mount. Remember there is a spacer behind the balance as well.The 1956 Passenger car power steering generator is the same as the Corvette.