Pulley/Belt Problems

[DLM06]

We have had a problem with throwing belts and belts twisting (but staying on the pulley) on a 415 open motor and are looking for a bullet-proof pulley/belt system.

We've been using normal high quality v-belts and pulleys, turning the motor in the 8-8300 range. The power steering pump is run off both pulleys with a second belt from crank to water pump. We have checked and rechecked alignment, tension, replaced pulleys, water pumps etc. The most recent problem was the inside belt (crank to water pump only) twisting on the pulleys.

What type belts and pulleys do the pros use?
Thanks for the help.

[fast_crew]

DAYCO belts, once the belt twists it's JUNK. Are you running a reduction crank pulley? Deep grove pulleys? Excessive crankshaft endplay maybe, causing misalignment when crank moves back and furth?? just some thoughts...

[DLM06]

The pulleys are deep groove. Bad choice? I hadn't thought of the crank end play. The motor is at the builders now so I guess I'll find out on that.

Is anyone using a serpentine belt or cog type belt system? What is the most common setup?

[fast_crew]

You want the deep grove pulleys, besure to run a belt that sits down in below the top of the grooves. Is the crank pulley a smaller one (reduction) This helps slow the belt and the accessory speeds down. The only other issue that I can think of maybe dirt or rocks dislodging the belts. I have seen some use the serpentine systems no issues that I have heard of. Nascrap uses serp.

[stock car driver]

serpentine, its a no brainer.

[Egoracing]

Either the belts are to long and the wrong width and at RPM they are flapping as the get deeper into the pulley and get loose, you have some serious alignment issues, You are running a CHEAP set of pulleys and they are not true in circumference, OR you are running cheap parts store belts.
Buy good belts that sit into the grooves, check the run out with a dial indicator and base.
I have seen someone B*&$%ing about there belt and pulleys but they were putting the pulleys on the water pump and crank then putting the belts on with pry bars and the starter.

[dirty white boy]

be sure belts ant bottoming out in the pulleys, make them twist up bad,..so will over tightening belt!!

[DLM06]

Thanks for the responses. Pretty sure we have good parts but we'll recheck them.

[parrot69777]

We had that happen once....many years ago....but we were using factory pullies with Gates belts. We were told it happened because the belts we were using had the cogs on the inside. We switched to Dayco belts with the cogs on the outside and never had a problem afterwards.

When we went to aftermarket pullies we went back to Gates belts and never have had an issue.

I will agree though...if you run cheap pullies....they don't make two alike.

[Darkstar15]

Go to Jones Racing Products they are pricy, but high quality.

John

[sj valley dave]

How do you put on the belts if they are just crank and water pump. We have always used the pry and starter method. Crude, I know, but never have lost belts...8200-8400 rpm..

[Lizardracing]

A lot of guys forget to get the right width belt. If the bottom of the V hits the bottom of the pulley groove the belt will feel tight but the sides of the "V" won't get the friction they need to keep em from flipping over or flapping so bad they jump the groove. A proper sized belt will measure about a 1/6 wider then the grooves widest point. When installed the belt should sit flush to slightly above the pulley groove. It should at no point ever touch the bottom of the groove.

Serpentine Belts provide more surface area on the accessory to reduce slipping.

[1Blacksheep]

The old GM 32Deg 4 blade is especially hard on belts that are anything short of a perfect fit for the pulley's with O stretch allowed. That Badboy will stress test any cheap belt for ya !!!

[Milford Motorsports]

The two belts are trying to turn the water pump pulley at different speeds,one may be setting deeper in a pulley than the other.Try running one belt from crank to PS pump and one from crank to water pump.You will not see any more twisted or jumping belts.Belts for industrial multi belt setups are always purchased in matched sets,all belts are same length,otherwise they will eat each other up always.

[Egoracing]

How do you put on the belts if they are just crank and water pump. We have always used the pry and starter method. Crude, I know, but never have lost belts...8200-8400 rpm..

You should put the belt on after bolting one pulley in place and then separate the two pulleys and bolt the other pulley on. It has always been easier for me to bolt the water pump pulley on, put the crank to WP belt on, set the crank pulley on the belt then use a piece of wood to separate them then bolt the crank pulley in place.