XJR belt has come off
Discussion
I have just spoken to my mechanic who was looking at a squealy belt and a knocking noise from the belt/pulley on cold start up. This went after a minute or two when warmed up but the knocking was worrying. He tells me he started the car and the belt has come off, we can't work out why. How can this happen? Any ideas?
I`ve had a few V8Rs in lately with the same problem. Trouble is the factory idlers are fitted with low speed rated bearings,therefore have a much shorter life. Also the sprung loaded belt tensioner pulley surface, wears half round and tracks the belt back and forth making it belt squeak.We have just designed and fitted a poly V wheel for the tensioner with a belt guide either side to illiminate the problem.The static idler,does not run square either and this adds to belt squeak .This pulley also runs a substandard , smaller bearing, infact all the bearings haave a low speed rating, made worse if you upgrade the supercharger drive. The upgrade is great, but shortens the life of the tensioners and bearings.
My system is currently on test so watch this space.
My system is currently on test so watch this space.
The AA came out and refitted the alternator/PAS serpentine belt and on starting the car the knocking had gone. I drove home with no issues. The next morning the knocking was back but after it warmed up dissapeared again. The AA came out and looked at the car and noted that the sepentine belt was tracking half on and off but didn't know what the cause of the problem is. I drove the car to the garage with the AA behind me just in case the belt came off again.
I spoke to the garage today who are Jag specialists. They told me they have started the car and the belt doesn't come off. They suggested changing the tensioner but couldn't guarantee this would solve the problem.
I suggested they start the car when cold and listen for the knocking. They are going to get back to me tomorrow.
Do I ask them them to change the idler bearings or look at something else?
Any further thoughts?
I spoke to the garage today who are Jag specialists. They told me they have started the car and the belt doesn't come off. They suggested changing the tensioner but couldn't guarantee this would solve the problem.
I suggested they start the car when cold and listen for the knocking. They are going to get back to me tomorrow.
Do I ask them them to change the idler bearings or look at something else?
Any further thoughts?
Edited by S6 Devil on Wednesday 22 December 02:20
Edited by S6 Devil on Wednesday 22 December 07:51
They won`t change the bearings, my system is something I`ve developed myself because of the problems clients have had.Think about it.If the bearing wears in any of the idlers/tensioner the belt will come off. Also if the blower nose cone bearings have too much end float,the belt will come off.You need to check all the drive pulleys and your crank drive pulley. If the chains have been changed
and the bottom pulley bolt has come loose on its cone retainer because it has not been tightened to the correct torque, the same problem will occur.D`ont leave it,or the crank nose will be ruined if it is loose.
and the bottom pulley bolt has come loose on its cone retainer because it has not been tightened to the correct torque, the same problem will occur.D`ont leave it,or the crank nose will be ruined if it is loose.
Nickbattersby said:
If you give Don a call in our workshop at Sport and Classic on 01922 455 566 then he might be able to give you some advice. Mention that Nick has replied to your forum post so that he knows what it is about.
Dosn't matter if you are not in our area as we always try to help if we can.
Dosn't matter if you are not in our area as we always try to help if we can.
Thanks Nick, much appreciated. I am waiting to hear back from the garage, if they can't find the problem I will give Don a call. Cheers!
RW774 said:
Thats good, keep an eye on it though for run out,As said the bearings are not up to it
Thanks, will do. The garage I went to do a bearing upgrade but couldn't do it this time on the AA warranty. If all goes pear shaped that is the next thing that will be done.Gearbox fluid change and new stainless exhaust next though, got to have a little more noise from the V8!
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