Keeping the fan belt on??

[benlawrence]

Im sure you guys have covered this a zillion times over the years, but as the title, we are struggling to keep belts on at the track, we have spent a good amount of time making sure the alignment is spot on between top and bottom pulleys, with an original diameter aftermarket bottom pulley and v belt both engines say farewell to their belts pretty much every run. To the point that i dont bother running one now. So this year weve gone for a power pulley to reduce the fan speed, but this hasnt cured the belt being thrown on my friends car (ive not run mine yet), in fact hes now throwing it more with the smaller bottom pulley. We both agreed that the serpentine belt system is not an option as our back to back tests on the dyno resulted in losses of over 20bhp running that system.

Would any of you loungers be able to steer us in the right direction with a belt setup that will stay in place to 8k rpm?  Im fed up of chasing and retrieving them like a gun dog  

[Peter]

what helped for me was to give the belt some slack,
so it slips a bit easier, and use a good generator pulley too!
my belt lies kind of deep in the top pulley, so it cant be thrown off easily..
a power pulley helped in my friends bus, it ate belts like crazy
I saw the belt sometimes 'rolled over' due to the generator pulley edges, they didnt have the same slope,
after changing to an original top pulley the belt hasnt come off anymore...

[modnrod]

Use a 9 or 9.5 section belt instead of 10 to drop the belt into the pulleys.
Make it a bit looser than normal to give it plenty of slip, not bite and throw.
Make a curved belt "flapper-stopper" (uhmmm, that's a technical term right there  ) to follow the belt on the left, no preload.

[Bruce]

Change the brand of the belts you are using.  They fly off when they stretch.  A stronger belt won't stretch as much.

[glenn]

Gates belts don't flip.

[Iryanu]

This was belt number 3...

Changed the top pulley for a flat-4 one and not the cheap Chinese chrome plated nasty with cover and all is well again. No belt problems since.

I would always throw or snap the belt at the same junction too. It's a renowned testing road, I measured it out and it's just about a quarter mile before you need to brake for the roundabout. 

[Erlend / bug66]

Gates belts don't flip.

Mine did all the time, before I changed to a narrower belt. And slack.

[leec]

Anyone got a link to the narrower/gates belt?
Lee

[glenn]

Gates 7355 XL

[Fiatdude]

I like a little slack and this top pulley -- its a video, so click it to see the slack

[Paul H]

We both agreed that the serpentine belt system is not an option as our back to back tests on the dyno resulted in losses of over 20bhp running that system.

Would any of you loungers be able to steer us in the right direction with a belt setup that will stay in place to 8k rpm?  Im fed up of chasing and retrieving them like a gun dog  

The last high RPM motor I tested with a V belt and full size pulley took 22hp If you insist on running full size pulley with V belt I suggest you buy belts in bulk or get a gun dog collar and some Pedigree Chum. Have a look at many of the "exploded fan" threads for some free 20/20 hindsight

[dannyboy]

i run a serpentine system on my old race motor it never shit itself up to 8k, but the best bit i found was the ease of removing/replacing at the start/finsih of a run. an alan key is all you need to take it off and replace it in seconds  the same belt has been on it for 3 seasons of racing and i only started removing it on the last season i used that motor

[BeetleBug]

I just don't get it guys. Unless you are in desperately need of electricity (big nitrous system etc) why on earth are you willing to loose 15-25 HP? Remove it before you go racing and install it after a race. Or at least mount a power pulley when racing. Above a certain rpm (not as high as you might think) the fan stalls anyway.

If you race you race. No more, no less!

[TyeDyeBug]

X2!!  It's not worth the headache  LOL

[dannyboy]

I just don't get it guys. Unless you are in desperately need of electricity (big nitrous system etc) why on earth are you willing to loose 15-25 HP? Remove it before you go racing and install it after a race. Or at least mount a power pulley when racing. Above a certain rpm (not as high as you might think) the fan stalls anyway.

If you race you race. No more, no less!

i totally agree when on the track whats the point of going a bit slower just to say you ran slower but had your belt on???
but then its the same as running 11somthing na and not fitting gas and running 10 something 

[speed7]

Hi ,
I take off the belt at the beginning of a race weekend and put it back on before leaving for home.
In the meantime I use a replacement belt I made in a material that is used for transportation belts.
It's 10mm in diameter , round (and green) and can be soldered together using a normal soldering tool.

It allows revs up to approx 3500 rpm and can be mounted and taken of by hand without loosening
the alternator pulley ( of which the thread will be damaged after a number of WE of you do ...)

That way running back and waiting allows you to cool the engine and charge the battery.

Greetz
Marc