Engine V-Belts

[Roger S.]

According to the GM Specification Package for my 1973 the v-belts are to be 0.375" (3/8")in width at the top. Is this correct? Most of the belts from the auto parts store have widths greater than 3/8", most appear to be 13/32 and/or 15/32". Also, according to the IDBI belt interchange book the GM parts listed in the 73 AIM are not all 3/8" in width. Who/what should be believed for v-belt specifications?
For my 1973 L-82 w/AC & TM400, I am trying to get a v-belt for my alternator that does rub on the power steering pump.
Roger

[Joe L.]

Re: Engine V-Belts

Roger-----

The original V-belts for many early Corvettes were mostly of the 3/8" width, although some of the belts for certain applications were other "oddball" widths. The original power steering pump drive belt for your 1973 L-82 with AC was a 3/8" belt of 36-1/4" length. The original GM part number was GM #326083. For non-AC cars, the belt was GM #9433740, which was a 15/32" (one of the oddballs) wide belt of 44" length.

GM #326083 has been discontinued for quite a few years and no supercessive part number is available through the GM parts system. GM #9433740 is replaced by GM #9433741 which is still available.

Also, you might try to obtain belts from an aftermarket source that meets the above specs. Getting the 1/4" increment belts may prove difficult. However, a 3/8" belt of 36" or 36-1/2" may be available. Also, most 3/8" belts have been the with-AC power steering belt application. GM specifies 7/16" width belts for virtually all early Corvette applications which originally used 3/8".

Another option is to obtain a reproduction belt which should be just like the original. Sources like Quanta Products should have it.

[Harmon C.]

Re: Engine V-Belts

To stop the rubbing on the PS pump a shorter belt usually helps. You may need to remove the alternator the first time to get it on. Also check that the holes in the bracket are not egg shaped,or pulleys out of line.

[Roger S.]

Re: Engine V-Belts

I have had the lower alternator bracket bushed to remove the "egged" out hole. I also had the lower hole in the alternator bushed to removed its "egged"out hole. Once these two items were repaired the pulley alignment is correct, but the belt still hit the PS pump. I did notice that a 3/8" belt about 1/2" shorter just barely touched the PS pump, not as bad as before. I just want to made certain that using a 3/8" belt would not be a problem. I am looking at using an industrial belt with a 3V width designation instead of the typical automotive belt.
Roger

[Duke W.]

Re: Engine V-Belts

In many cases service belts are not the original numbers and 3/8" original belts are often serviced with 7/16" belts. Aftermarket suppliers seem to key off the service numbers rather than the originally installed numbers, so errors can be universal throughout the replacement industry. On one car I destroyed two radiator hoses before I figured out that the service belt was NOT correct, and certainly not "engineered" for the application. It was a longer 7/16" belt. The original was shorter and 3/8". I was able to find an aftermarket exact match from the measured length of the original. ALL the parts books - GM and aftermarket suppliers had the wrong belt that abraded the lower radiator hose.

The best bet is to cross reference the original numbers from the AIM, measure a known original belt or pull the dimensions from the MVMA specs and see if you can find the exact size in the aftermarket.

Duke

[Harmon C.]

Re: Engine V-Belts

The 3/8 belts should work. Could the length of the power steering belt be putting it in a postion that is causing the rubbing?