Hi, I have a Home made (302) put together back in the 70 & still together & doesn't smoke or use oil 283 -punched out 327 heads AnyO Way I can't kept a belt on it when you hit about 6rpm the belt just comes off . .What to do?
. Thanks LarryMc
are ya running a 3/8's belt or a 7/16 ??? if yer running a 7/16, try dropping down to a 3/8 which will ride lower in the pulley grooves... or a different set of pulleys may be needed... before ya do anything though, check very carefully the pulley alignment... at High RPM's it's much more critical for really good pulley alignment... if the alt pulley is off by only a little, it'll cause the belt to jump at high RPM's
You don't mention what this engine is in but if it's in an old car with the alternator or generator up on the drivers side of the engine it is real hard to keep a belt on. When we were stuck with the old style short water pump set ups the belt was so long and unsupported to reach the alternator or generator it would stretch and get to flopping and come off. If this is your situation I'd try deep groove aftermarket pulleys and underdrive as well. RM
I agree with the alignment suggestion. You need to make sure all the pulleys are aligned straight and with the proper offset to each other. Also make sure you are not running cheap belts. I have found that Gates or GM belts will stay on at high rpms while cheaper belts tend to take flight at high revs. I have had to address this problem on lots of cars over the years. I can appreciate the deep groove pulleys but I have never had to purchase one to cure this problem. 90% of the time, it is a misalignment problem.
I am having the same problem on my 74 SB . I am moving the alt around to try different things. Luckily I can make spacers and things like that at work. Have been checking the alignment with straight edge but ain't helped me yet.
I was wondering if any one had ever converted to the serpentine set up like the new ones and if it is any better or not.
I converted a camaro over to serpentine and it worked flawlessly.Also you can check to see if you have both brackets on the alternater aligned.I had a bottom bracket that was not completly lined up and it would throw belts at high RPM.You could barely see it by eye.
Did you get your parts from a donor or did you buy anything. I changed alternators last nite because this one looks like it has a better pulley and its polished. It came off of my other 74. I noticed my crank pulley looks like it runs out of center a little. It don't wobble it just looks as if it rise and fall to it. I hope to try it out this week end but I hate bad results because after you peel a new belt they don't look so good.
In the shooting the bull department ,I have thought of taking a piece of 3/8 stock and milling or grindind the angle on it to match the belt. Then laying it in the pulley to help line them up ro just check it out. Possible putting a little bend on it to catch more of the pulley. Thoughts anyone??