I have the Camaro belt tensioner and an added 76MM ribbed idler pulley above the A/C compressor. I have tried 79" and 79.5" belts. I have never been able to get this system to be noise free. Makes noises I would describe as chirping There is a flanged smooth idler pulley below the alternator that is original to the engine. I thought I would replace this pulley just to eliminate it as a possible cause. However when I search for idler pulleys for this engine they are all non-flanged. What do other have on their 4.9's?
------------------ formerly known as sanderson 1984 Quad 4 1886 SE 2.8L 1988 4.9L Cadillac 1988 3800 Supercharged
fieroguru
MAR 04, 03:24 PM
If the belt is chirping, it means the pulleys are not properly aligned and parallel.
sanderson231
MAR 04, 03:44 PM
quote
Originally posted by fieroguru:
If the belt is chirping, it means the pulleys are not properly aligned and parallel.
I have checked multiple times with a straight edge. The alignment looks OK by that method. I'm not sure how else to check it.
I did improve the chirping by machining a custom, mild press fit stud for the idler above the A/C compressor. Despite having the idler between two washers with a through bolt it could wiggle a bit on the bolt. And I think that allowed the belt to walk back and forth on the smooth tensioner pulley. That pulley would get glazed with rubber. The bearings on that same idler have a smidge of play in them. I am going to replace the tensioner pulley and both idler pulleys.
------------------ formerly known as sanderson 1984 Quad 4 1886 SE 2.8L 1988 4.9L Cadillac 1988 3800 Supercharged
cyrus88
MAR 04, 07:16 PM
Is the belt you are using a Dayco Poly Rib? Those belts develop squeaks very quickly.
[This message has been edited by cyrus88 (edited 03-04-2023).]
sanderson231
MAR 04, 08:19 PM
quote
Originally posted by cyrus88:
Is the belt you are using a Dayco Poly Rib? Those belts develop squeaks very quickly.
I think it is a Gates belt but not sure. even with a new belt I get chirping ------------------ formerly known as sanderson 1984 Quad 4 1886 SE 2.8L 1988 4.9L Cadillac 1988 3800 Supercharged
[This message has been edited by sanderson231 (edited 03-04-2023).]
lou_dias
MAR 19, 03:44 PM
My new 3.4 pulley gave me a week of silence before the squeaking returned...
