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throwing belts, high rpm.

YZEATER

YZEATER

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got a problem with my new engine, well, not the engine, but a accessory problem. it keeps throwing the v-belts off.

the trucks thread: http://coloradok5.com/forums/showthread.php?t=220787

built 383.

since i installed the engine it's been throwing the belts, so last week i put on an electric water pump and fan. when it would throw the belts i had to quit cause the engine got hot quick, no water flowing or air moving.

so yesterday it threw the belts again, but at least i could still hammer thru the mud and finish. just was a bit hard to steer with no pwer steering.

the setup i have is 1 belt around the crank to the power steering pump, and one belt around the crank to the alternator. i have stock brackets for the p steering pump and March alternator brackets. pulley alignment is almost perfect, don't think it could get any closer.

ideas? deep groove pulleys? thinner belts? change to a 2 belt serpentnine setup.
 
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Need a pic of the front of the engine with the alternator and P/S pump on showing how the belts are arranged. I'm thinking since you said you installed an electric water pump and the alternator belt now goes from crank to alternator the throw (distance between the pulleys) is too great and the belt startys to whip and then comes off and take the P/S belt also.
 
Were the belts new when you put the motor in?

I once had a similar problem with the SBC in my Impala. The alt belt squealed, so I replaced it. The new belt kept getting thrown... alignment was great and tension was always fine, but it still would throw at high rpm.

I then put the old belt back on (after rubbing a bar of soap on it) and it quit getting thrown. It's still fine to this day, it must have simply been a bad belt.
 
it's a little dirty yet. i think the alternator got closer if anything.

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http://i130.photobucket.com/albums/p276/YZEATER/85 chevy 1-ton/100_2566.jpg
 
USSkoval said:
Were the belts new when you put the motor in?

I once had a similar problem with the SBC in my Impala. The alt belt squealed, so I replaced it. The new belt kept getting thrown... alignment was great and tension was always fine, but it still would throw at high rpm.

I then put the old belt back on (after rubbing a bar of soap on it) and it quit getting thrown. It's still fine to this day, it must have simply been a bad belt.
Click to expand...

the alternator has a turnbuckle to adjust tension, so it can get as tight as you want it. and it also has the shortest belt possible i could get on it.


brand new belts for this weekend, after the electric water pump. thru them both once, then re installed, thru them again, then the power steering got all ripped up, left it off, and put the alt back on and ran it.
 
I had a similar problem with my power steering belt. I bought a new cheap autozone belt and threw it within an hour. It twisted all up I tightened it as much as I could but threw it two more times. I ended up just cutting it and then putting the old belt back on.
 
YZEATER said:
the alternator has a turnbuckle to adjust tension, so it can get as tight as you want it. and it also has the shortest belt possible i could get on it.


brand new belts for this weekend, after the electric water pump. thru them both once, then re installed, thru them again, then the power steering got all ripped up, left it off, and put the alt back on and ran it.
Click to expand...

The PS belt must have been the problem. It would have thrown, then caused the alt belt to throw. You could try switching to a dual groove PS pulley and running two belts. It could take care of it... or make a bigger knot when it throws:doah:
 
Get a smaller crank pulley its rather large, or a bigger alt pulley if you are turning 5900 rpm that alt is spinning like 11800 which is really fast especially cuz you really don't need it for mud racing

Find a two groove power steering and run that and ditch the alternator belt and get a good battery charger :D
 
Looks like you got a problem with the main pulley.

Compare the wear marks on the alt with the marks in the picture of the main.
You have a nice smooth even mark on the alt, with interruptions on the main.

Where you don't see a mark, the belt is not touching for some reason.
Probably bent.

It does not look like it is from the pictures, but be sure the belt is not bottoming out in either pulley. V-belts depend on the constriction of the sides pulling down into the grooves for friction. I don't see any wear marks on the bottom of the grooves, or belts, but I have often seen folks accidentally get too thin a belt and they slip.

At high speeds, a slight "bump" in a pulley will cause a belt to throw. When the system is running slowly, the belt rises up on the bump and tracks back down. But all things have inertia. When the belt gets thrown up on the bump fast, it can keep right on going up and off.

Check out where that interrupted mark is and see what is keeping the belt from touching there, and I think you will find the problem.

J.
 
hmm, all that mud on there might help finding the problem. i'll check it out tomorrow to see if it's bent or pinched.

i do have a double pulley for the p-steering, but then i just might be ruining 3 belts at a time.

i usually make about 4 passes or so and i don't want to have to charge it between runs with no alternator. i don't know if one battery would last for running full msd ignition, electric fan and water pump.

i have taken the truck off the road, no more insurance, ect, so more mods are coming for it.
 
wasted wages said:
I agree...smaller crank pulley...slower belt speeds...
Click to expand...
Yep, x3
You are not cruising this thing down the freeway.
You are turning higher RPMs than most of us here. (Except for me)
Pulleys make a big difference helping to keep the belts on.
 
i found a 25% underdrive crank pulley on summit. i can also get a 5" dia alt. pulley. all for v-belts.

i don't see any serp. crank pulleys that will take 2 belts.

could do this- http://www.summitracing.com/parts/ASP-541100/?rtype=10

serp for the alt and v belt on the power steering, and underdrive.



oooo, i'm still running hydroboost brakes. anyone know how much more drag that creates then vacuum brakes.
 
I'd be concerned with running the batt down in between runs with a giant 5 inch alt pulley. That's just a guess though, I have no experience with one.
 
I had belt issues on my nova, I put the basic serp belt that just goes around the water pump, crank pulley and alternator on and that part was fixed, but something with the PS bracket was off so I cut the PS belt. Stupid thing was that the car drove way better with no steering assist... figures
 
Small crank pulley.....bigger alt and P/S pulleys..

I only had to ruin 1 blower belt to figure this out.....:D
 
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