Break-In Period For Belts?

[240z_is_king]

Yesterday I replaced the belts, radiator, hoses and alternator on my early 71 240z. Now, when I turn the car on I hear a loud squeal right as the car turns over. I'm thinking it could involve something like a belt rubbing, but I'm not completely sure. Does anyone have any suggestions?

[Marty Rogan]

It sounds like you might not have the belts tigh enough.

Marty

[Jeff G 78]

What brand of belt(s) did you use? I tried a store brand belt once on my race car and it kept stretching during the first practice session. I tightened it and it worked fine for a bit and then start squealing on start-up again until finally failing completely. Luckily, it all happened during practice. I now only use Gates belts.

[Oiluj]

It could be it's just not tight enough.

That said, I've had the exact same experience as Jeff using a $6 "store brand" belt. Replaced it with a $15 Gates belt and it's been trouble free.

[ajmcforester]

You can have the belts stretch a little and need more tightening, but that normally happens over months not weeks or days.

It is important to use new (recently manufactured) belts and by a good manufacture like Gates Rubber. The rubber needs proper pliability and traction in the grove, a good belt also won't stretch out as much and will have the proper amount of stretch to keep from binding or adding unnecessary strain on the parts. One of the things I notice in a good V-belt is when installed properly the belt takes the flexing when the engine winds up and down and not the bracket. With cheap belts you will see the pulleys and brackets take the load. The belt drive equipment on older cars are not mounted as rigid as modern cars mainly because serpentine belts need to stay in alinement, a little bit off and you will eat the belt. Unlike V belts, that as long it is within 1/4" you're OK (not great but OK).

Also make sure the belt is not to tight that also can jam the part making is squeal when it starts. Make sure the assessors move smoothly. The smog pumps will start to give resistance then run smooth after a bit, especially if your getting exhaust gasses or carbon buildup or it needs to be rebuilt.

[riceburner]

If the belt is slipping but seems tight enough try giving the pulleys a light sand or wire brush. It'll take the shine off the pulley surfaces and give better grip.

CRC also make a product called 'belt grip' it's kind of an adhesive spray, can be helpful as a last resort. It can be messy though.