Stripping Blower Belts

Hi All,

I have been having trouble stripping blower belts on an alky FC at 125% OD. The car will only get max 4 seconds and all the teeth are gone. It is a PSI D, with a duel RCD Idler, 8 mm belts pt no GT 8M 1600 84P82 USA. Has Anyone had a similar Issue?

Cheers

 

Two idler's, is one pushing belt in and one pushing belt out? if so get rid of the one pushing in, the belt should not be bent in ( idler pushing on the outside of belt) .

 

They both push out, we are using a RCD duel idler system that has a small idler on the other side to normal (the normally straight side) it is a small idler, the belt general has no teeth left on it..

 

no teeth

Could be to much timing

 

In my experience belts break because;
1-there too tight
2-too much ignition timing
3-too lean
4-intake valve springs are too weak

Maybe there isn't enough teeth engaged in the little pulley?



I'm curious why people make dual idlers when it seems one idler will do the job?

 

I wondered that myself and so far we havent ran 2 but there is a good video on YouTube showing some slow motion shots of a belt with and without dual idlers. The belt really does a dance even on the power side and the 2nd idler does smooth it down some. Search blower belts and you should be able to find it.

 

I thought it would strip them if too loose?

 

The belt may dance around but is that hurting anything? First answer is yes, but at the end of the day I am not so sure. about a million passes have been made with one pulley. 2 idlers reduce the contact area on the top pulley but the belt teeth are prolly leaving from too much timing or lean.

 

had the exact same problem years back..it would strip all the cogs out I tried everthing under the sun even went and got all new parts from rcd and it didnt help finally I went to a 13.9 1543 75 belt and all problems gone..and yes to loose will strip the belt to tight will break it..Dave

 

if you ran in sydney on the weekend i seen that belt.........kinda looked like it had delaminated , it looked like it spun the whole centre out....have you sent a pic to gates belts........just looked to clean t have stripped the teeth.faulty belt???,,......just my opinion .........let us know if you find anything

 

Yes I agree, I was in the mindframe of breaking belts not specifically taking off the teeth.

 

I hurt my PSI D & put another one on for next quali, I knew it was fresh (tighter clearances) 125%, 8mil belt, striped all the teeth off buy 1000ft. Put new belt on 1st round & it did it again by half track. The motor was on song with no changes between runs.

My question is anyone moved up to 11mil belts to solve this problem?

How does the 11mil belt cope with 125% overdrive (32t pulley)?

 

Stripping teeth

If you ask a belt engineer (as opposed to a racer ) they will tell you stripped teeth are from a loose belt or a radically overloaded belt (assuming basic crap like alignment,pulley condition etc are ok). It is common knowledge that these belts can take it when the conditions are good so that only leaves one issue.

 

I would check a few things first, I don't know a single alky racer running 11mm as 8mm works just fine.

1. Ignition - send it to Leahy
2. Valve spring pressure
3. Make sure something isn't out of line from crank to snout - manifold bent etc..
4. Most run their belts tight as a banjo string....we were breaking them when we first started because they were too loose.
5. Check the pulleys for any burrs and check the bearing in the idler
6. Make sure all bolts and set screws are tight - we had a loose bottom crank bolt and it was making our life hell with belts.
7. Ram head into wall....repeat....

Hope this helps

Brandon Booher
NHRA TAD #323

 

Print this off and post it on the wall in your shop and trailer:
http://www.geocities.com/beyond_stretched/circle.htm

 

Stay with the 8mm and run the belt as tight as a guitar string.

We ran the 13.9 stuff back when we are allowed to run 125% and we had to replace the belt every run. It would melt the centers out of them.

.

 

Thanks For all the help Guys.

Have checked all the above things, been happening with two motors, belt batches magnetos pulleys etc etc. Only thing is the same is the Blower. Am going to put spare on and 11mm stuff to try an fix it for the next round.

Thanks Again

 

I run the 11mm and would not even try a 8, Looks like you have to run the 8 a lot tighter to keep it on the pulley compared to 11

 

Just a thought, with two idlers pushing outwards there is less belt wrapped around the blower pulley so there will be more pressure on fewer teeth or fewer teeth are doing all the work,
what do you think ?

 

could it be possible that there is a bad batch of belts, i know of two cars here in australia, both blown alcohol f/c with between 100 and 125 over on d psi, having the same problem, thay put on a new belt and around 1000 ft the belt has no teeth left, the backing on the belt looks like new but all the teeth are gone, one guy is using rcd dual idler and the other is using rcd single idler, both cars have been running for a while with no problems then all of a sudden have struck this.