In the process of doing the valley hoses on my 07 SV8. I checked the supercharger and it feels like the coupling is bad. Which is the best replacement the factory torsional or a solid oil filled. If I go with the solid one what are the downsides if any ?

Thanks Duane

 

The factory coupling is designed like that for a reason and quite inexpensive. It handles the snap on/off accel motions of the engine transferring to the snout of the blower/bearings/rotors etc... A solid one will place more stress on those associated parts.

 

The stock style is fine and is theoretically easier on the bearings. However, I will say that the solid couplers are usually fine as well. I've owned a lot of cars with the Buick 3.8 and Eaton M90 and have had the stock solid couplers go well into the 200k+ mile range. My current 2004 Impala SS has 290k and original solid coupler is just fine. Never replaced bearings either, just changed oil every 50k or so and good to go. Have also had the M112 on 03-04 Cobras and most guys replace them with solid couplers without issue (including myself). Not sure if there's something different with the Jag but I doubt it, just a basic Eaton blower.

Edit - I was curious so read through a few old threads and consensus is about 50/50. Some forum users claimed to hear more noise with a solid coupler and other said no issue. In my experience with the M90 and M112 in my Cobras was that there was no extra noise and if there were its not noticeable.

 

Thank you both for your input and information. Guess I’ll have to make a decision. 🙂

 

Being that the Jag blower is a pain to remove I'd probably go with the stock coupler just in case there happens to be unwanted noise. With most other non-intercooled cars it would be an easy swap but on these Jags its a bit more involved to remove.

 

DO NOT use a solid coupler, unless you want your engine to sound like a coffee can full of rocks at idle

(I did my /07 XJR valley hoses, etc about a year ago, and replaced coupler with solid per bad advice. It sounds horrible, and has done so for 20K miles now. Not sure I want to pull the sc again to fix: its a big job)

I've posted about this; do a search for details

 

Thank you Hisport, the kit I purchased had the oil and solid coupling. After more checking the rattling I was getting was because I was wiggling the super charger pulley to hard. When I hold the rotors there is very little play before it gets to the torsion spring. So I plan on just changing the oil and calling it good.

I am still waiting on hoses and then it can all be put back together. The rear heater hoses were slightly leaking also. I will have replaced all of the hoses except 1.

 

Duane,
Sounds like my experience - a zillion hoses!
I replaced all three water pumps also. Check your AT cooler line flex sections for seepage - easy to replace while you're in there. And, check that your SC coolant hasn't turned to jelly.

My spring-loaded coupler had a slight crack in the plastic body. So, suggest replacing yours. They're cheap (~ $60).

The spring coupler acts as a torsional damper.

 

I changed my coupling whilst I had the S/c out and Man do I regret it, it now rattles so bad I,m thinking of doing it all again just to quiet it down!!!
So, my take on this:
DO NOT GO SOLID!!!
DO NOT GO SOLID!!!
DO NOT GO SOLID!!!
DO NOT GO SOLID!!!
DO NOT GO SOLID!!!

Nuff written??:

 

I replaced my supercharger due to noisy rear bearings and tight timeframe. When looking at replacing the coupling on the old supercharger, I initially bought a solid coupler, but after reading the comments on this forum, I bought the torsional one. The coupling on the new (used) supercharger was good. The supercharger looked like a very low mileage unit, much better than mine with 200K Km on it.
The torsion couplelr works in both directions but the spring on the acceleration side is weaker and with more angular deflection than the one for the overrun. The torsional couplers are known to cause problems in the 5.0 engines, but their supercharger coupler is run dry, not in an oil bath like ours.

The coolant for the supercharger intercoolers is not separate, but connected to the main coolant system and is circulated by the electric pump. The only check necessary is to remove the screw plug at the top beside the right intercooler and check the level with the ignition on.

Pete M