Belt Tensioning issues

[Al1exx]

Hello again everyone.

I've managed to finish the install of my JRSC over the last couple of days and I've decided to fit the belt just now since the car won't be moving for a while (giving me time to get my electrics sorted out)

Only thing is, I'm having problems with the belt tension. The manual says 90 ft lbs of tension in the belt, so I tried setting my torque wrench to 40 lbs to start off with and began tightening everything up. Well, 5 minutes in and I've got very little travel in the adjuster bolt left, a horribly tight feeling belt and virtually no resistance on the torque wrench!

Am I tensioning this correctly? Or can I use another method? I remember a method relating to a simple 'you should just be able to twist the belt 90 degrees at it's longest stretch with a lot of effort' for alternator belts - will this work as a start off point?

Thanks for any pointers you can give me.
[img]smile.gif[/img]
Alex

[promotion]

thats not how you tension the belt. You dont torque the tensioner to 90 Ft/lbs, the belt has to have 90 ft/lbs tension on it. The only way to acurately tension the belt is to tighten the belt with a belt tension gauge atached to the belt.

[CROM]

Yeah, that is not how you tension a belt...and that tensioner for the upper belts is made of weak metal, so I'm suprised you have not broken the head off the bolt yet.

Please step away from the car, take a deep breath and do the following:

-Install belts
-Tighten tensioners(upper and lower, finish one at a time please) down until resistance is felt
-Use a long flat head screw driver and push against the belts
-You should be able to deflect the belt about 1/2 inch pushing medium hard.

Basically this is a guessing game and you need to use your best judgment on how tight the belt is.

[Al1exx]

Crap, I knew I was doing something wrong. I undid all the excessive tension before I left the car last night & didn't run it so putting it back to 'loose' mode has hopefully ensured no damage done.
I'll re-tension the belt as you described & take it from there - adjusting a wee bit at a time if needed.
Thanks guys [img]biggrin.gif[/img]
This is a great, no nonsense board. I have a feeling that, had I posted this question elsewhere, I'd have been laughed off the web.

[cosworth]

you're not kidding [img]graemlins/shhh.gif[/img]

[Al1exx]

you're not kidding

<font size="2" face="Verdana, Helvetica, sans-serif">[img]biggrin.gif[/img] yeah, despite fitting turbo's, radiators, wiring looms, interiors n' stuff to various cars over the last few years this is the first time I've ever had to change a belt!! [img]confused.gif[/img] I had a feeling I was doing something stupid.

I've now got the belt on and the car ticking over nicely. I can't drive it yet as I've no fuel / ignition management but that's on it's way & at least everything is working as it should and I have no odd leaks (so far).

It's running exactly as it did before (smooth, correct tickover, warming up correctly etc etc) except for the nice noise [img]smile.gif[/img] . Hopefully I'll be able to actually drive the thing soon!

Alex

Alex