Hi all,

So I noticed my supercharger tensioner was wiggling a bit more than I expected at idle. In my attempt to diagnose the cause, I saw the lower supercharger pulley was not concentric to the main crankshaft pulley that drives the main accessory belt. The pulley is not loose, but it does wobble relative to the other main pulley behind it, suggesting misalignment.

To confirm this had nothing to do with the supercharger itself, I removed the s/c belt and ran the engine, but the lower pulley still wobbles (not under load). The upper pulley (on the supercharger itself) rotates fairly easily by hand, doesn’t make significant noise and has maybe 5 degrees of play between forward and reverse directions. So I assume the problem is indeed with the lower pulley. Incidentally the car drives completely fine without the s/c belt connected and throws no codes, just lower power.

Has anyone else has this issue? Is it easy to realign the lower pulley, or does this suggest it’s damaged? Would my service shop have R&R this part to do the timing chains/ tensioners and perhaps reinstalled it incorrectly?

Thanks for your thoughts.

All the best.

 

I don't know but I just changed my 2014 XJR to a larger lower pulley. The pulley is easy to remove I would take it off and see if it's something simple.
There is not anything special about the pulley or how it is mounted. T50 is the bolt size and they should be torqued to 48 ft-lbs. be sure and use lock-tite on the bolts.

If it is warped I have my perfect stock one that is available? Let me know.
Mine runs straight as an arrow.
There is a used one on EBay right now for $150.

I have NOT done tensioners on this engine but yes I think it does need to be removed to get the front engine cover off.
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I do believe the pulley would be removed in the process of doing the timing job. Its likely the shop did not reinstall it correctly. That said, as Clubairth1 stated, removal and reinstallation is pretty simple.

 

Thanks guys, I’ll take a look in the next couple days.

 

The lower supercharger pulley on early models XJs had a harmonic balancer (aka a rubber ring in the middle of the pulley). This is in addition to the harmonic balancer on the crank pulley. I have been told that this style supercharger pulley was not used on later models. My rubber ring was starting to come apart. Found a used Landrover one on eBay for cheap. Runs straight now.

All the best.