Volumex rotor gear torque settings. Help please

[squiglyzigly]

Can anyone help me with the torque settings for the two 30mm nuts that secure the gears to the rotors in a standard VX unit. The last one I rebuilt was some 15-20 years ago and I cant remember what the torque value is or where I have put the information.
I remember the belt drive pulley is 88 ft/lbs but not the main gear syncronising nuts.

(my 1st post on the forum so I hope its in the right place).

[rossocorsa]

interesting question unfortunately I don't know the answer, I'm curious as to how you are setting the rotors back in phase? I don't think Fiat published this info as I suspect they expected dealers to send the unit back to Abarth for overhaul, if I find time though I'll check my info tomorrow.

[rossocorsa]

It just says send back to abarth for overhaul, you'd probably be best to ask Guy Croft, it might be in his book I suppose(??)

[squiglyzigly]

Setting the rotors back in phase is not as difficult as some might make out. I made a jig some years back which I seem to have mis-placed for the moment. I'll make another if I can't find it. It's simply a 10mm piece of ally plate with 'T' shaped cutout machined to the width of the rotors. Then you drop rotors assembled with the end case (containing the bearings, gears etc) into the plate and torque away. If necessary you position some feeler gauges strategically between a rotor and the plate too get the desired minor positional adjustment if it's not spot on. You have to then drop the assembled rotor gear assembly into the case and build up with the greased end bearing assembly and check the rotor to rotor clearance finally once inside the main body.  If it's not perfect, then disassemble and repeat. It's no biggie and worth the effort if you like to put your own stamp on the job.

[75coupe]

I know it was a while ago now, but did you manage to find the torque settings for the 30 mm blower nuts?

Cheers Ian

[squiglyzigly]

Couldn’t find a definitive document but I believe Guy Croft torques them to 150 ft/lbs.

[squiglyzigly]

Decided it was time to make a new jig to phase my spare supercharger rotors.
Here a few pics from today’s playtime in the garsge.

[squiglyzigly]

After marking and cutting out the pattern with a combination of angle grinder, drill and a file I ended up with this jig firmly bolted to the workbench, which in turn was firmly bolted to the wall

[squiglyzigly]

Dropped in and bolted down the rotor/front bearing and gears assembly ready for torquing up.

[squiglyzigly]

Ready for tightening up with all threads, washers, gears and nuts dry.

[squiglyzigly]

Then assembled the charger and checked rotor phasing with a spin by hand and conformed with feeler gauges. Found clearance even all round at 5 thou.

[rossocorsa]

Well done! I wasn't brave enough to do this. Did you find any issues at the front end? I always felt that the rear bearings etc were the most susceptible

[squiglyzigly]

Front end bearings were fine but the lower rear bearing had some radial play. I believe the lower bearing wear was caused by a failing seal. This was obvious as the grease in the lower bearing darkened every couple of hundred miles, whilst the top stayed clean and as a result the upper bearing had no noticeable play. When stripped it was evident the lower seal had lost its hug around the shaft. Changed both rear bearings and seals using brass cage ntn bearings.

[rossocorsa]

pretty much what i thought I'm probably relatively safe leaving the front bearings etc alone