Hi all, Need some ideas here. Got truck running great, but now that other things are quiet can hear a fanbelt squeal at 2200 rpm and higher. Replacement engine is a 1978 292, water pump shows up as 65 to 74 for a 292, alternator is a new 10si with the pulley from what I think was an old 10si when I got the truck. Belt upon delivery unreadable junk. Now on 2nd replacement belt using a dayco topcog 15370 11a0940. I've checked pulley alignment and they're darn close if not dead on, adjusted to less than 1/8" flex from pump to alternator span. Fan belt does not ride to bottom of pulley grooves as they are really deep and narrow. Suggestions????
Ray Charles could "see" the misalignment of that alternator pulley. It's putting the belt in a constant bind and wearing out the sides. Investigate/repair the reason the alternator housing is cocked clockwise several degrees in the picture. Jerry
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I’m not so sure your brackets are correct. Explore some other options to beef it up and get proper alignment.ðŸ›
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Can't tell from the picture, but check condition of the pulleys, all of them. Although they look generally V shaped they need straight true flat sides in the V. If they're worn the belt won't grip and either sequels or eats belts in short order, or both.
Agree with Jerry. I saw that right away unless "optical conclusion". The alternator pulley is not planar with the fan pulley. Use a straight edge/level/plumb bob to align. Your eyeball method is cockeyed. Look at your picture and see how that long alternator bracket is not parallel to the fan pulley. Also the alt seems tilted upwards. Brackets are too weak and bent?
I little more looking and you're right the alternator was lined up front to back but rotated slightly due to a mismatch between bracket, alternator sleeve and bolt diameters. Tweaked it a bit but may need to take all parts to the bench and find bolts and sleeves to match everything properly. The bracket on the engine is quite heavy duty, 3/16" steel, but the spacing on it is about 50% too wide for the alternator, thus needing spacers to fit in as well. Anyone got better ideas than what I'm thinking? Thanks all!
If your thinking is to get it aligned properly no matter what it takes, then you are thinking correctly. Never heard of someone describing a fit with percentage. The is no quantitative spatial value for those trying to visualize and help.
You are good to go with 3/16 bracket at bottom. It does all the mechanical holding and alignment. The long bar is just for tension adjustment but you can see it tell tales the misalignment.
I doubt there's an easier way than full removal of alternator and bracket. The percentage i was describing is the bracket allows for about a 3 inch long sleeve on the alternator, yet all the 10si' I've looked at and have are only about 2inch .
The Parallel/Planer alignment is automatic due to a rigid bracket and a rigid alternator case. The front to back alignment is by location of bracket on motor and spacers. You have a problem with the "automatic" part. Better figure out why before worrying about spacing front to back.
Agreed. 1/8 sounds really tight. Don't chase your squeak by tightening the belt, you will damage the water pump bearings/bushings and other components.
292's seem to be just slightly odd for most of the accessory attachments unless you have all the original parts. I can't remember exactly how I got there but I had a similar problem on mine. I had to put a 2 groove pulley on the alternator and use the outermost groove and I had to make a special adapter to move the alternator about a 1/2" or so; I believe I had to move it toward the radiator. I also had to flatten out the slotted tensioning bracket that goes on the top of the alternator. I've learned that if you want a 292 and you want power steering, AC, etc you better be good at improvising. I'm still working on how to put an AC compressor on mine. Good luck.
By the way, if you need to make an adapter out of angle iron like I did you need to keep the pivot axis in the same place as it was before. I rotated the original bracket 90 degrees but kept the pivot in the same place.
Last edited by jfnar; 07/02/20188:48 PM.
'64 swb stepside (gone) '57 1 ton '53 phone truck '59 swb '46 1 1/2 ton '68 swb gmc
