dharris45

my 66 L79 is no air & no power steering. It uses the double row crank pulley and water pump pulley. One of the grooves is for the captive belt. The original GM part number is 3837810. The belt is also used on some of the big block cars as the captive belt.

Quanta make the correct reproduction belts, but there are two that reference the GM partg number 3837810. One is listed as Long and the other Short. I believe the lengths are 34.8" and 34.4".

My question is now do I determine which will fit my car? Since the belt goes between the water pump pulley and crank pulley there is not adjustment, so it must be tough to get on, and must be correct length.

When I got the car it had all the wrong pulleys and I am now replacing with correct pulleys and belts.

Thanks,

Don

Bluestripe67

Don,
I have never had this issue, but walking the belt on would be one process. Maybe you could leave the water pump pulley bolted, remove all but one bolt (loosen it) from the bottom pulley then pivot the pulley, slip the belt on, use a drift through one bolt hole to bring the pulley back in alignment and put the last two bolts in. JohnZ may know the actual process from the factory is different. Dennis

mhanley

Don,

I just did mine on my 67 L79 and I bought both belts, the long one is to big and the shorter belt worked perfectly. It wasn't to bad to put on just takes a little time. Put the bolts in the pulley's but don't tighten down.

Mike

wmf62

i put one bolt in the water pump pulley and tip the pulley to slip it on, then straighten the pulley to tighten it.
Bill

JohnZ

Reproduction belts today aren't the same width as they were in '66, which is why they offer two captive belts; order both, use the one that fits, and send the other one back.

You won't be able to "walk the belt on" - either remove the fan clutch and water pump pulley to install it, or remove the crank pulley to install it. Photo below shows a '66 L-79 with no A/C or P/S on the line at St. Louis, and you can see the captive belt installed (the alternator went on later).

dharris45

Did you also use the short belt?

wmf62

i cut an old belt to see what fit and then measured the length and went to the local parts store and got that length and one a size longer and one a size shorter and went from there, then took the unused ones back.

you can use a piece of rope or string, but you will probably have to try more sizes.
Bill

mhanley

I have an extra Quanta GM 3837810 long belt, I'll take $25 shipped to you.

Mike