Superformance Cobra MK III Roadster SPO 2650, 7,000 miles, Roush 402R, Tremec TKO 500
Can anyone recommend an alternator belt manufacturer & size for this engine? Is a 36 degree angle belt what I should be using?
My engine has developed a crankshaft/alternator/water pump belt slipping/squealing/chewing problem. It only happens when it is hot outside: 100 f OAT, and the engine is hot: 100 - 110 c
oil temp. More prevalent when I drive it hard, but will squeal at low RPMs when hot. The squealing can become almost continuous. Small bits of rubber on the underside of the hood, from the belt. I've owned this car just over a year. Other problems kept it off the road last summer, so this is the first I've driven it hard in the Texas heat.
The belt gets loose, I tighten the belt, the squealing/slipping goes away for a week or two, then returns. I tighten the belt some more, but the metal fan blades on the Delco alternator pulley (which I move outboard to tighten the belt) now dig a groove in the right front wheel well fiberglass when the engine torques to the right. My mechanic installs a shorter belt, and we repeat the squealing/chewing/tightening process, with the alternator fan blades eventually getting back to the fiberglass chewing position.
My mechanic verified that the Roush billet aluminum crankshaft and water pump pulleys are aligned with the steel Delco alternator pulley. The two Roush pulleys both have a dark deposit of belt rubber near the top of the groove. The Delco alternator pulley shows no belt rubber deposit. The two longer belts we removed showed wear/glazing on the sides near the top, consistent with the rubber deposits on the aluminum pulleys. The edges of the aluminum pulleys are blunt, while the edges of the steel alternator pulley are eased. All three pulleys are smooth.
The belt that was on the pulleys when I purchased it one year ago was:
Gates XL 7380 - 38 5/8" long, 13/32" wide, 36 degrees
The shorter belt we installed last month was:
Gates XL 7375 - 38 1/8" long, 13/32" wide, 36 degrees It was so short it was very difficult to install.
We just tried a wider belt - 15/32", 36 degrees, GATES 90385 - to effectively shorten the length, but that is chewing up even faster.
Any thoughts or advice is greatly appreciated. What belt do you use for your engine?
V/R,
Carroll Payne
alternator/water pump belt chewed up & slipping at high temperatures
Threaded Mode
