retrodude

I recently converted my 69 big block to a serpentine system. I have a custom power steering bracket that wouldn't allow me to use the recommended belt. Needless to say I've measured and purchased about 10 belts trying to get the exact length I need since they don't seem to stretch very well. I had one that was just a hair off so I thought I would bake it in the oven make it warm and possibly stretch it one quarter of an inch. That actually shrunk it an inch.
I took one of the belts that was an inch too long and baked it in the oven for 10 minutes which shrunk it to the exact perfect size.
Has anyone on here done this because I'm trying to figure out if the belt will just stretch back out again. I haven't had much time to drive it since it was cold.
Thanks for stopping and reading.

hugie82

Never heard of that but let us know if it holds up! I'm sure many of us have gotten the wrong belt or needed to make one fit in an emergency but why doesn't the belts shrink from engine heat. What temp were you using to shrink it?

Bloodzone

I'm guessing that it would not only stretch back out but also weaken the belt and it may even end up longer. Still can't hurt to try. Good luck.

I worked in printing and we would do this to rubber printing plates if one was outta spec. They would return to original size if allowed to cool before mounting.

retrodude

I cooked a 6-rib Goodyear "Gatorback" Serpentine belt on a pan for 10 min at 300 degrees. It took an inch off it.

Richard454

Ummm- that doesn't sound like a good idea....

IIRC- when I did my serp set up- you just take number of ribs then "PK" and the length in MM...and they make them in 5MM increments

5 ribs and 785 MM length = 5PK785 then do a google search and you'll find one!!!

My custom set up turned out to be the same size as a Subaru...got several for $5ea

My HTD belt for my Dry sump oil pump was a little more challenging- but there were several guys that had "custom" lengths and IIRC the belts were right at $20/ea.

Wee

We used to shrink and grow our kart racing tires to get stagger correct....Never thought about doing this with a fan belt....? I guess they close as far as construction goes....?

Brian

mikem350

If your serp system has a spring loaded tensioner..no problem!

But I would not worry anyway, see if it works as is!!!

Kacyc3

Are you sure you have the belt routed correctly, that can make the difference in belt length.

SH-60B

It shrank because the heat cured the rubber further. It's probably harder now and more prone to cracking. Shorter service life. I've seen this on vacuum pumps at work. Those belts get pretty hot and will generally only last a week. I couldn't believe how hard the rubber was when they let go. Keep an eye on the belt, I'm very curious to hear how it performs.

mikep3

Boy, it would be nice to see a picture of belt drive.

CMTECH

May be a good idea to contact the manufacturer of your system..I'm sure they have run into this problem in the past and can help..Cheaper than buying the local parts store, LOL