[RandyB]

We've done all the aligning there is to do, but every time he comes out the hole and tachs it to 6000 and above it slings. No problem what so ever with my 396 set up and I've got a stock pulley set up. He did install a deep groove moroso alternator pulley with a little bit of help. The only other difference that he seems to think is the size of the torque convertors. 3500 stall so it tachs up pretty quick. I guess this could be a issue.

[RickD]

Three things come to mind:

- Pulley alignment
- Belt length
- Belt tightness

If the pulley's are aligned and the belt adjusted, then use the shortest belt you can. While I don't launch like you describe ( street car ), I regularly do 6500 shifts and have never lost a belt. This is with a standard depth pulley, using a short belt. I put a metal straightedge across the pulleys and shimmed to get as good an alignment as I could.


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Rick Dorion
69 RS Conv,355,M20,4.10's and I don't worry about stone chips ( yet ).

[HOTRODSRJ]

Try a differing style of v belt. I have seen some with expansion issues at high RPMS and some manufacturers of belts are better than others on this. Make sure that the V specification is the right one for your pulleys....yes there are choices on this! A deep groved pulley that has a shallow groved V belt will expand at high RPMs and get sideways with a little misalignment and voila....walkoff happens. Goodyear stuff comes to mind for quality belts. If it walks then, the alignment is still off.

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STEVE JACK
ConceptOne Pulleys and Brackets

[DjD]

You mention the alt pully, what about the others? Also try a Gaterback pully I believe from Gates. I have std pullies and swapped out all the belts for new ones (don't recall the brand) and started throwing belts. They were twisting in the pully and distorting. Put the old belts back on and no problems!! Replaced the belts again with Gatorbacks and haven't thrown a belt yet.

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...Dennis
"The '69, the '96 & the club"

[Joekool1234567]

Ive seen brackets actually bend or flex do to improper mounting or missing bracket supports.

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70 Camaro 307cid(350soon) /350th ex. dark purple (dark blue soon) in. black
74 Trans Am 400cid/th400 ex. red in. red power windows

[JohnZ]

Assuming your pulleys are properly aligned and are the correct deep-groove type, try Dayco "Top Cog" belts - I've used them for years, and have never thrown one, even in abusive applications.

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JohnZ
CRG
'69 Z28 Fathom Green

[RandyB]

Using GoodYear belts now with the vented ribs. But these are not the deep groove style. That's where he's headed though. Thanks for the comments gang.

[vettefab]

hello
On your problem of slinging belt at high rpm one thing you might want to check is that the belts are of the right width. Belts come in 13/32 , 15/32 , 17/32 if you install the 17/32 belt on a 15/32 pulley it will ride to high in the groove and when it stretchs under high rpm it will jump out of the pulley. On most pulleys the belt sit 1/8 inch down in the pulley. Good Luck.

[vettefab]

hello
On your problem of slinging belt at high rpm one thing you might want to check is that the belts are of the right width. Belts come in 13/32 , 15/32 , 17/32 if you install the 17/32 belt on a 15/32 pulley it will ride to high in the groove and when it stretchs under high rpm it will jump out of the pulley. On most pulleys the belt sit 1/8 inch down in the pulley. Good Luck.