Cog Belt Questions..............

[RICH JELINEK]

I just got my new F-2 set-up out to the track a few times and I'm having some belt problems. At first I was throwing belts, but now I seem to have things aligned better and the belt is staying on, BUT I can't make it past the 1/8 mile mark without stripping all of the cog teeth off of the belt!!! I'm running a 50 mm cog set-up, a Gates Powergrip GT2 # 14408MGT50, and 70/36 cogs.

I made two passes ( actually only half passes ) the other night and stripped two brand new belts clean.

Am I possibly overtightening the belt, causing it to tear itself apart???

Is the rubber belt just not strong enough and I need to switch to a Polychain ( kevlar ) belt??

This is my first cog set-up, up until now I've had serp. belts, so any help/info would be greatly appeciated.

THANKS ALOT,
RICH

[John91coupe]

Only thing i know of that will strip cog teeth the way you mentioned is a big leak in the plumbing or in the bypass valve. I had this happen to me on a previous setup with cogs on the dyno. Hose popped off the plumbing and immediately stripped all the teeth off. Happened twice.

Check all of your connections to make sure they are completely on and not coming off once you start to build boost. Also check to make sure the bypass valve is working properly and adjusted correctly. You might want to check any rubber elbows that you might have because they sometimes split on the seams and it is hard to see the split when there is no pressure to open them up.

Also, cogs do not need near the tension of a serpentine belt. Just make sure it is snug but not under lots of tension.

[RICH JELINEK]

I'm always keeping an eye on all of my tubing/connections, and they are all fine. I'm running the big red Procharger bypass valve and have it adjusted properly also.

I also posted this question on the NMRA forums and a few of the Drag Radial and SSO guys seem to think I might have just been over- tightening the belt, which you also mentioned. I'm going to do some testing in a few nights and run the belt a little looser to see how that works. Once I can figure out these belt issues this hotrod ought to really fly!!!

THANKS AGAIN FOR THE REPLY,

RICH

[RICH JELINEK]

I made three full hits the other night with the same belt and it still looks great!!! I fabricated a new brace which helped tremendously as far as keeping the belt aligned.

SPECIAL THANKS to LARRY at ASSC RACING for all the help and advice with figuring out a few other things.

THANKS to JIM SUMMERS at PROCHARGER for hooking me up with what I needed to get the car ALL THE WAY down the track.

See ya out there,
RICH

[1dirtyz]

good to hear you got it figured out.
now i have a question after reading this so pardon my ignorance, but why would having a leak in the plumbing cuse the teeth to rip off? i can see having the bov not oppening ( or not flowing enough) when the throttle body closes causing a surge that shocks the blower but i can't see why a leak would hurt anything.

[badfoursixgt]

Been there, done that... Chances are you DID NOT fix the problem. The rubber belts just don't hold up. It's not the bypass valve's fault, it's the blower's. The "F" series blowers have so much momentum with the 5:1 step up that the belt cannot slow the blower when the throttle slams shut or the engine coughs. I spaced the main bracket out an extra 1/8 inch and used a 72mm wide Kevlar belt. The belts are virtually indestructable when all is aligned properly. The crank pulley will also need spaced, but I am running a crank trigger and distributor so I didn't have that problem...

[1dirtyz]

if that is the case, would bigger crank and blower pulleys help out with the load dispertion ( more surface area touching the belt to help with dissepating the load)??

[badfoursixgt]

Well to acheive more surface area you are going to end up with much larger pulleys to notice a difference. Then you will more than likely run into clearance issues. But most of all we are VERY limited on belt lengths. If you can find a combo that works chances are the belt is going to be hard to come by. The kevlar WILL NOT strip, as the teeth are much harder. The kevlar belts, unfortunately are not produced in 50mm widths though. I suggest running them though in whatever width you can get to fit. They are much more durable. The belt I run is the exact width of the pulley, and requires some minor clearancing and spacing of the brackets...

[MichaelFreedman]

Give Procharger a call and order the 88 tooth crank pulley. This is a necessity with the F2 if you are spinning it at all. We went from the 66 tooth to the 88 tooth and stopped throwing belts completely.

Mike Freedman

[badfoursixgt]

88 tooth is WAAAAY too big for my car...lol It would it the tensioner, crank trigger, and no telling what else. Besides the huge kevlar belt is holding up fine...

[badfoursixgt]

Besides, the belts strip on the blower pulley, because of the momentum. The step up ratio is too much for a soft (rubber) belt. And when the engine RPM's drop the belt can't slow the blower down fast enough. Larger crank and blower pulleys may help but clearance issues are huge on a car like mine.