Astrodokk

I decided to start a new thread on this subject in case someone else has this same problem now or later.
I drag race my car and anything over 5000 rpm, I've thrown the v belts. I understand that proper alignment is a prime factor in retaining them in the grooves, so I've been working on this.
-old chrome water pump pulley wobbled, so replaced with same type from Summit...still wobbles.
-just bought a new machined aluminum pulley and installed on pump...still wobbles and rocks on pump flange when not bolted.
-will buy new pump and hope that solves the problem. I also bought spacer shims to bring the pulley forward to match the crank pulley grooves.
-I'm finding that the idler pulley will be hard to use with this set up, as the adjustment arm hits the pump pulley.
But if nothing wobbles, and I align ALL the pulleys correctly, I'm hoping my belts will stay on at drag races. I was told by a parts guy who threw belts alot that he now has no problems when he switched to 17's versus 13 or 15 size belts.
We'll see. I'll keep updating this thread.

AZDoug

Dayco Top Cog works for me on long spans and misalignment. To 7000+ RPM. Bad water pump is not a good thing.

Doug

jim lockwood

Chevrolet solved this problem over 50 years ago. Besides obviously proper pulley alignment, the key to not throwing belts is to run deep groove pulleys. On my vintage racer, I run a bone-stock Corvette pulley system and, in several thousand road racing miles (many at the Thunderhill track you are soon to experience), I've never thrown or twisted a belt.

Deep groove pulleys. Ask for them by name. Accept no substitutes.

Jim

AZDoug

Yes. you can see in my Jpeg that those are deep groove ~1965 L79 pulleys, except the deep groove Ford tractor alternator (Delco) pulley.

Doug

jim lockwood

Blasphemy.....

Can you even say F*rd on this forum without the thread getting locked?

AZDoug

Only if I use the correct acronym translation of F*ckin' Old Rebuild Dodge will it get locked.

Doug

Astrodokk

Mechron came over with his "puller" and we pulled the pump flange forward about 1/4". Now the machined aluminum water pump pulley aligns PERFECTLY with the crank pulley AND idler pulley! This misalignment was what was throwing my belts!
But now, due to the thickness of the aluminum pulley (vs stamped metal), there is no "nose shaft" sticking through it for the clutch fan to get aligned with! It sits flush with the outer side of the pulley.
I'm hoping that the 4 studs I'll be buying Monday (currently using bolts) will align the clutch accurately so that there is no imbalance.
Or, I'll have to just get the expensive OEM stock or deep groove stamped metal pulleys to be able to have some of the nose sticking through the pulley for the clutch. But I'm not trusting the stamped metal pulleys so much anymore. The newer one I bought from Summit wobbled so badly!
One more thing...the old water pump pulley was larger than the crank pulley, so it was underdriven and that is good. The new ones Summit sent me are reversed...top pulley is smaller than crank one. Not happy!!!

Kensmith

Carlos, my machined pulleys were the same size (crank and water pump) both I believe are 6 1/2" diameter.

midyearvette

i would be leery of a clutch fan with no center support bwdfdik??

Astrodokk

I am leery as well, that's why I'm thinking of going back with the OEM style stamped pulleys. I wonder if they make water pumps with extra long shafts for after market applications.
Ken, I should have asked about the diameters. I just assumed that they would be the same. I'm tempted to return the chromed water pump AND crank pulleys and go with oem stamped deep grooved...not as pretty but who cares! I'll be able to center the clutch fan AND retain belts. That aluminum one you showed me sure is purdy, but since I don't have an electric fan like you do, it doesn't work with my app so far.

Kensmith

Yep, the deep groove would be better for you. I have never thrown a belt but I also have not taken my stroker over 5500-6000 RPM.

Astrodokk

Well, I was so disgusted with the quality of the new crank and pump pulleys, that I took them off and reinstalled the older ones, which now make the pump underdriven as I like it. It also seems to me now, that since we lined up the pulleys correctly, they don't seem to wobble as much. Since I just finished this close to midnight, I didn't start the car out of courtesy for my neighbors. Tomorrow will tell if they wobble less.
It's too bad that I can't use the aluminum pulley with the clutch fan.
I'm going to race in this configuration, and if I don't throw a belt, then it was alignment all along. If I do throw one again, then it's deep grooves for me. I don't mind them being unpolished metal, as long as they're functional.
Off to bed now. I don't know why I have all this energy all of a sudden. Maybe it's anticipation of Thunderhill! I had fun today.

KC66

Just a thought. You do have the right pulleys that go with the right pump? If original you should have a short waterpump and crank pully should be flush on the damper. Just a thought. KC

midyearvette

i went through the same bs as you several years ago as i am a chrome or polished billett nut....after several tries on my bb with ps, i just had the STOCK pulleys chromed and i was done with it....maybe if you had an elec, fan it would be different but the factory hp pulleys do the job just fine and that's what counts.....jmo.....

MikeM

If your water pump pulley was off 1/4" and you fixed it, I believe you've found/fixed your problem.

I never had any problem throwing belts with the stock shallow groove pass car type pulleys at 7000 and a little above but I do recognize Chevrolet changed to deep groove for a good reason.

If a belt has run for very long on mis-aligned pullies and has been thrown off a few times, it may never stay on as they'll get a twist in them. You may have to buy a new belt.

Astrodokk

Anytime I throw a belt, I replace with a new one. Originally I was using Gates or Goodyear Gatorbacks. Now I replace with the less expensive store brands from Kragen or Autozone. Usually the belt breaks, but there have been a couple that just twist, and those I reuse at normal driving speed until I can get a new one on.
Mike, I'm counting on the now correct pulley alignment being all I need to fix this, so that I won't have to buy deep groovers.
There are different varaitions of pulleys that can be used, and I prefer the larger alternator, larger pump (short water pump) and smaller crank pulleys (yes it is flush) for drag racing. Being underdriven gives me a slight advantage...I need all I can get.
I didn't think about chroming the stock deep groove pulleys. That may be an option if needed, but someone told me I may have a little too much bling in the compartment anyway (tastfully done though), so I may not mind toning it down some.
Thanks for all the help!