For the life of me, I cannot find a page in the Parts Manual that has the idler pulley for my 1975 4.2L engine. Anyone have any clues? Mine is starting to make noise.

Thanks, Bill

 

Bill, I have never seen an idler pulley in a 4.2 XK engine, so I can't help.

 

You mean my 4.2L engine is the only one with this idler pulley? No one recognizes it?

 

Hello, That looks like a idler pulley for a XJS 5.3 L V-12 engine. I have never seen that on a Series 3 4.2 engine. What belt does it adjust the tension on?

Larry Louton

 

Damn! Why is nothing easy with this car? It's a Series II 4.2L engine. It provides tension on the belt that goes around the outer crank pulley, water pump and power steering pump. And it's held by two bolts to the PS pump. The middle crank pulley goes to the A/C compressor. And the inner crank pulley belt drives the alternator.

 

Do you have a old time parts store buddy that you could take the part to and maybe he could match it up?

 

Page 22.30 in the parts manual.
For power steering part number C18733

 

I wish I could see the other side of the pulley, remove the belt, Remove the spring loaded tensioner. Maybe you can remove the bolt thru the pulley bearing. Take pulley to parts store. If it's a roller bearing, Perhaps they can find just the bearing by the number on the race?

Larry Louton

 

Actually, my pulley is the I,e that is swedged (sp?) Onto the arm. Not the one with the nut. I would probably have to drill out the pulley shaft from the arm and buy a pulley with the nut from SNH Barrett. Another $65 towards making it the ""perfect" car! But at least I'm steered in the right direction now.

 

C39871 perhaps?



Cheers
DD

 

Yup! That's it! Doesn't seem to be available any where though.

 

that is a belt tensioner, not an idler pulley. Although it has a pulley.

I think you can change the ball bearing if it is worn. Alternator and Starter repair shops can do it.

 

Jose, that's a good thought. However, mine is the style of PN# C39871 where the pulley is swedged on and not bolted on. So I think, judging by both the picture and me seeing the actual part on the car that this pulley is really an assembly. Unlike PN# C18733 which is just the pulley. That's what makes me think I need to un-swedge mine, drill a hole in the arm, and go with PN# C18733. If anyone has any other thoughts, they are well appreciated. I want to minimize downtime as much as possible as she's been my daily driver now for over a year.

 

my '65 Jaguar S type uses a belt tensioner too, same principle, different design. If you cannot find a new assembly, yours can be rebuilt. If you cannot find a local rebuilder, contact White Post Restorations to get it remanned.

 

It's never easy because it's a Jaguar. Un-swedging builds character. Looks to me like the swedged one was done to save money. I would think you could drill it out and bolt up the other style. At least it's not electrical.

Jeff

 

Lost a post.

Short version. Find a bearing supply house Take the assembly to them. They might match it.
Carl