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Author Topic:   how to stretch a water pump belt
posted February 05, 2004 02:57 PM
sbc 358. I'm running a belt from the crank up
around my water pump pully. local parts stores
sells a belt 33 inches and 33.5 inches.

I'm not running an alternator. I do
use a power steering pump and run a belt from crank to ps pump - that belt fits fine.

33 inch belt is too tight; 33.5 inch belt is too loose. I need a 33.25 inch belt. How do I stretch my 33 inch belt another quater inch? or should i just run a single belt around water pump, cransk and ps pump - that seems kind of risky to me.

Ego Racing
posted February 05, 2004 03:21 PM
What pullies are you using? This may be a dumb question but you are unbolting the crank pulley?

posted February 05, 2004 03:31 PM
Try loosening the water pump bolts alittle that may help.

posted February 05, 2004 04:00 PM
depending on how much work you want to do you can take the water pump off and elongate the holes vertically then wehn you put it back together you have some room to move the pump up and down to adjust the belt tension before you tighen the pump down.

posted February 05, 2004 04:17 PM
I'm using 25 percent reducition water pump & crank billett aluminum pulleys from Day motorsports.

To put the belt on, I leave the crank pulley
on. I remove the water pump pulley, put the
belt in the crank and water pump groove and
attach the water pump pulley to the water pump. Once I get water pump pulley bolted back on, the belt is really tight.

[This message has been edited by avila (edited February 05, 2004).]

posted February 05, 2004 06:14 PM
this is one more good advantage of having the engine wired with a ford solinion you could just leave the pullies on get the belt on as good as you can then bump the starter a couple times and there you go good tight belt that isn't gonna slip been doing it that way for a long time and never lost a belt

[This message has been edited by racer17j (edited February 05, 2004).]

posted February 05, 2004 06:37 PM
It may be easier to keep the pulley bolted to the water pump and just loosen the pump from the block. You may try a wider 33.5" belt as well.

posted February 05, 2004 09:01 PM
Do what Racer17j said, I've always done it that way with no problems.

posted February 06, 2004 06:41 AM
Why dont you call day and get them to send you the right belt,or get the part number from them and you should be able to find a parts store to match it.The belt you get with the pullys are real tight when you first put them on but it dont take long for them to stretch, I change mine every 6 races or so.If you already have the belt that came with the set you will have to spin it on.You wont be able to put it on by taking the water pump pulle y off, its to tight.

[This message has been edited by waltonjr1 (edited February 06, 2004).]

posted February 06, 2004 07:10 AM
i agree with walton.walking the belt on is alot easier than loosening pulleys.also call where you bought the pulleys and get a belt to fit.if they dont have one they can probably tell you who does.

posted February 06, 2004 07:26 AM
We use Dayco belts on the car with deep groove pulleys. They have a bunch of 1/4" increment belts. No parts stores have the weird sizes, but they were able to get them for us.

Just watch how tight the belt is. My partner swore "Oh it has to be tight... It won't hurt anything...That belt won't hurt the motor". Well.. the first motor just burnt the top of #1 main and bottom of #2-#5. The second one nearly overlapped #1 and got the others so hot the caps for #2-#4 are loose and the bolt needs align honed to be used again. The crank was standard and had to be cut .020" under 'cause of the wear on #1.

Just some advice... the belt really will hurt the mains if it's too tight. My car has a serpentine on it now. When I tore the motor down, there wasn't any damage to the bearings at all. No signs of being pulled in any direction.

posted February 06, 2004 08:25 AM
not to mention it can be hard on the water pump as well. I would try to find a belt that fit better or try any one or combination of the above methods of adjustment. Different pulley combos, belt widths, movign the water pump etc.

I guess if you wanted to try putting an old pulley on the wall, slip the belt over it then slip another loose pulley on the belt and hang 50# or so from it it might stretch. I have never done this nor have i heard of it being done..but you never know it might work.

posted February 06, 2004 09:26 AM
I did call the place where I got the
setup and they said that was the only belt
that they have. They said it should work - it's way too tight. I think I will search
a little harder to find the right size belt.
thanks for all the replies.

posted February 06, 2004 09:38 AM
Try switching to a different brand of belts. If you're using Gates, find a place that has Dayco, etc. Sometimes you'll find a little difference between them.

Agree with Raz tho, I bought a KRC serpentine setup this winter, and it looks like a hot setup....

Ego Racing
posted February 06, 2004 11:14 AM
I agree with cmiller51 different MFG's have different tollerances. Going to a wider 33.5 belt would caude it to ride higher in the pulley and be slightly tighter, As a narrower 33 would ride lower and it would be slightly looser.

posted February 06, 2004 04:57 PM
You could also try another water pump.....or take a round file to the inside of the water pump would be surprized how little you have to file to get room. Then when you bolt the water pump back on you can move it up or down as needed...i had to do this to 2 diff water pumps to get my kse belt tight!

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