C-2 Belt issues at high rpm
I have a '65 327/365 with the dual pulley 1) water pump and 2) alternator. Finally, got car back on road for testing and did a red line blast. Car threw both belts and they got chewed up a bit. I re-installed and continued road testing, with some near red line bursts. When I returned home I noticed that both belts had inverted themselves on the pulleys (narrow side out). I tend to go tight on installation, will this cause belt being thrown or is that strictly an alignment issue? Are the belts inverting now because they are damaged? Any and all feedback appreciated.
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Re: C-2 Belt issues at high rpm
Philip,
Are these the cloth Quanta belts? I had a P/S belt on my 67 that kept inverting and after taking it off and re-installing turned 180* it seems to have stopped.
The pulleys seem to be fine so I don't know why this happened except to say it's the way the belt is cut.
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Re: C-2 Belt issues at high rpm
used "WRAPPED" belts not "CUT" belts if you want to prevent this. check the local parts store for "agriculture" belts as they are a wrapped belt. look at your deck on your riding mower and you will see "belt guards" by the pulleys to keep the belts on the pulleys when they are not under tension and you can duplicate something like those next to the alternator/generator pulley because that is where the belts "climb" off of the pulley first.Comment
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Re: C-2 Belt issues at high rpm
Philip,
I overheated a 365 and had to tear it down for the same problem years ago.
I found that my alt fan was not the right one and it would flex forward at red line and take the belt off.
It would then flex back when the centrifugal force was gone.
I saw the rubber marks on the fan.
It seemed impossible for the fan to flex forward enough to do that but it did.
I did a test on it before I tore it down and took a V file and cut a groove on the fan blades then welded a welding rod around the fan to keep it from flexing due to high RPM's.
That was it.
I remember throwing a blade off a generator when I was racing a 59 biscayne with a later 409 in it. That one put a dent in my fender well.
Just another place to look.
DOMComment
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Re: C-2 Belt issues at high rpm
Thanks guys. Belts are Quanta. Restoring car per NCRS JG. I will try reversing 180 degrees. I will also check the fan blades for belt marks.Comment
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Re: C-2 Belt issues at high rpm
Don't know if this will help or not but if the 'V' on the belts does not match the groove of the pulleys they will have a habit of flipping over. Some suppliers will sell you something that's close but you want it to be exact under those extreme conditions. I've been down this road before. Good luck.
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Re: C-2 Belt issues at high rpm
Phillip,
I was working on my vette today in the shop and pulled out the overnight remedy to the problem that cost me a new engine.
It worked till I was able to buy the right one, the welding rod kept the fan in place.
As you can see the weight on the fan blades is in the back which gets pretty heavy when you rev.
Here is a picture of the pulley I modified.
DOMComment
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Re: C-2 Belt issues at high rpm
Thanks guys! Now the dilemma. Go with what looks right (NCRS) or go with what works right. Dom, then the alt fan for the L76 is different than low HP engines?
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Re: C-2 Belt issues at high rpm
You also want to be sure the pulleys line up. Twin belt SHP/FI pumps had the pulley flange pressed on to a different dimension.
If you install a standard "single belt" pump the pulleys won't line up properly, which is a recipe for throwing belts.
DukeComment
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Re: C-2 Belt issues at high rpm
Phillip,
I'm sure it is , the pulley would be bigger to slow down the alt speed and the fan might have a plate behind it to keep the fan blades from swinging out and taking the belt off.
You will find out here because the guys that are running the high RPM 327's will respond.
DOMComment
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Re: C-2 Belt issues at high rpm
In correcting Flight judging deductions, I bought and installed Quanta's belts on my '65 L76 A/C Coupe. The first time I took the engine over 4 grand, the Quanta A/C belt came off and was chewed up. Luckily for me, I heard it over the thundering side exhaust when it happened, slowed, and pulled off the road. The remains of the Quanta belt had to be pried out of the fan shaft, etc. Also, luckily for me, no other damage was done.
When I asked my restoration shop about this, the owner told me that the Quanta belts should only be used for NCRS Flight judging, not for (solid lifter) high rpm blasts. So, I put the old (incorrect-NTFP) belts back on and save my new Quanta belts for the next NCRS meet. -ClarkComment
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