i had the same experience with my genIV supercharger, after installing the solid couple it sounded like a box of marbles at idle. In revs it sounded and worked fine. Replaced the needle bearings but no improvement. Rotors look fine and there is no scraping. I think is was not designed to work with a solid coupler due to the increased tolerances on the bearings, there is still play on the rotor paks after installation of the new bearings... maybe the shaft has some wear also... Iam looking for a 4.2 supercharger now

 

I wonder if the ignition timing is off and the "marbles" sound is due to pre-ignition (engine knock from too much advance) ?


Is there any difference in the sound when the engine is stone cold compared to fully warmed up ?

 

How did you get on with supercharger noise ? Mine is doing the same & mine has solid coupler & new bearings !!!

 

According to your post, I'm guessing the noise got worse when you changed out the coupler??? In my opinion, the noise usually starts from the center rotor bearings. To the best of my knowledge no one other than a professional rebuilder can replace the center bearings. I'm not brave enough to try it on my own charger. I'm sure it involves heating up the rotor pack to a predetermined temperature that is unbeknownst to me and then quickly pressing them out.

 

My worse fears !! Bugger only thing left I spose. Oil was very dark & very smelly!!
Thank you for your advice

 

When I was sorting out my rattling at idle 4.0 supercharger I tried the new pulley first to find the coupler had already been changed for a solid one. This didn't solve the rattle so not the snout bearings.

Then I tried the rear needle bearings, no better.

Eventually I purchased a low'ish mileage 4.2 charger and fitted it , with the new coupler I had originally fitted to the 4.0, and the flexible coupler that came with the 4.2 S/C. This finally sorted things and it's been perfect since.

Basically the bearings pack in the middle of the S/C on my 4.0 was ever so slightly worn. Side by side on the bench I could feel that the 4.0 action was looser and not as tight as that on the newer 4.2., it didn't spin as smoothly or for as long as the 4.2. Everything still worked perfectly but I believe this slight play between the blades bearings allows the cogs teeth to chatter when idling without a load on the S/C.

A note on the oil.. I replaced the oil in the 4.0 3 times in total during everything else. Each time it was a rather murky unpleasant grey colour. I don't know why, it could have simply been colouring from the black sealant I was using or something more sinister, but I did note that the oil out of the 4.2 I bought was a lovely honey shade which made me confident that nothing was too much amiss with new S/C.

If I was starting again on another car... I'd go straight to finding a 4.2 S/C from a reasonably low mileage car and getting it fitted. Fortunately for me I was doing all the work myself... if I'd been using a garage the labour costs would have massively outweighed the cost of buying a decent second hand S/C for about £400 and it working first time.

Grab the pulley at the end of the coupler and rock back and forth, if you have a definite movement and clonk when you change direction the chances are the center bearings are loose and only a replacement S/C will solve it. Notice how many are listed on E-bay with a 'slight backlash'. I expect most of these would rattle at idle if fitted - IMHO of course.

Best of luck!

 

Did notice a noise rocking back & forth before I fitted back to car but thought coz it spinning it was how they where & used to working with turbo charged cars nost of my life didn't think of anything else so as you side I will get a 2nd hand 4.2 Gen 5 Supercharger & remove my modified & coupler & swap over to 2nd hand one & just replace Needle roller bearings while its disassembled. I do all the work myself to & should be quicker next time !!
Your a little star. Thank you so much for your help.

 

I've got a brand new 4.0L Supercharger here so recon I will sell that & get a 2nd hand 4.2L charger. If ya know anyone who wants one.

 

Play is @the needle bearings. The front are fine. I know this because i have a second rotor pack from an old 4.0 and when I install that, one lobe is play free. Almost no clunck sound... This means that over time the shaft wears out also. I think you have to replace the needle bearings before they where out.

 

How much do you want for it 😄

 

QUOTE: "According to your post, I'm guessing the noise got worse when you changed out the coupler??? In my opinion, the noise usually starts from the center rotor bearings. To the best of my knowledge no one other than a professional rebuilder can replace the center bearings. I'm not brave enough to try it on my own charger. I'm sure it involves heating up the rotor pack to a predetermined temperature that is unbeknownst to me and then quickly pressing them out." END QUOTE

Could this rotor pack seal be causing the problems? I have a bit of 'drag on' after I shut down my car, but only intermittently at this point. If it is this bearing seal pack in the video, it looks like he has designed the rotor pack seal without the need to heat them or press them on.


This is the back rotor seal in front of the needle bearings, I believe. Do you think these would wear enough to cause problems and movement to the rotors? As he states in the video around 2:20, excessive heat damages the original rotor bearing seal packs, and that the bearing lock could be released and the seal or seals will spin, causing varying degrees of oil leakage and possibly vibration or movement/chatter in the rotors?