Hi,

This issue is starting to drive me nuts as I can't seem to get it resolved!!

My N1000 failed a while back due to a bearing or seal failure by something passing through the charger. Anyway I got it rebuilt (in New Zealand) (re balanced, machined, new bearings and new seals.. full details below) and when it came back to me i noticed that oil was on the top of the bonnet.. My Bosch blow off valve points straight up at my bonnet so that's where it was coming from. There was also some residue in front of the impeller.

I sent it off to supercharger rebuilds so I could get the job done properly and they noted there was still an original oil seal in there so they changed it. I was happy and when I got it back I put it all back together and the same thing seems to be happening!!! I'm hoping its still the residual oil from the previous failure in my intercooler and pipework but I think i'm clutching straws.

Before the failure there was no oil at all! My only conclusion is:

- The first machine work has permanently damaged something
- Excessive pressure (but why now??)

Any help would be totally appreciated - thanks.

First rebuild sheet:

Paxton Novi 1000 Supercharger

Strip supercharger to fit kit of new seals and bearings as supplied only. Upon stripping find some washers and nuts used are incorrect – not correct spacer for pulley, compressor wheel touching housing and wont turn.

Compressor wheel damaged as well as compressor housing – wheel has made heavy contact with the housing and has continued to be run with failed bearing and seal.
relay to customer of extended work required. Also advise customer upon opening up of supplied parcel of parts that the carbon output seal carbon portion is broken from insufficient protection in parcel – customer orders new.

Whilst awaiting new seal continue to prepare al parts.Wheel required deburring, machining, balancing, polishing and resetting of clearances.

Housing required setting up and remachining of contour section as well as removing small portion of back side and recess to reinstate clearances to compressor wheel.

Remove bearings from shafts, remove seal from housing, thoroughly clean all components ready for reassembly.

Clean oil supply squirter, press all new bearings onto shafts aligning the high speed bearings and do dummy assembly and check bearing shims and wave washers for correct clearance.

Disassemble new seal when arrives , pressing of outer seal case into housing, reassembling and disassemblying of the seal to obtain a 0.050” preload. Making alterations to obtain – finally set at 0.051”.

Final assembly of unit, fit main case and compressor wheel into aligning fixture, double check nut washer for correct alignment and press wheel onto shaft.Fit up locating washer and nut and reassembly of unit and bracket replacing washers and nuts where necessary.

Machining of new pulley spacer. Vacuum and pressure test gear case – pressure test snail and confirm no
leakage into gear case. All ok

 

Having rebuilt these superchargers, I found that where the seal attaches around the shaft, behind the impeller, that there is usually a little amount of wear to the shaft that prevents the seal from making a 100% perfect seal (even with a brand new seal). Under vacuum, (or getting pressurized from crank case pressure) the seal weeps and lets in a little bit of oil that gets aerated and either pools at the bottom of the compressor housing, (you can look inside the compressor housing on the output side) inside the charge pipes or on the blow-off valve outlet. The only way to fully prevent this is to replace the shaft, or maybe weld new material onto it and then shave it down to the original diameter.

 

Damn.. not what I was hoping for, several people have said a small amount can be the norm though, it's still annoying.

I'm getting a compression check done today anyway.

I've got the hose from the valve cover going to a catch can rather than the inlet - would this make a difference?

Also if I take the dipstick out I can feel air pulsing out, is this normal?

 

If I remember correctly,
There are sleeves used when the shaft is warn to the point of leaking.

 

http://www.928motorsports.com/parts/...ebuild_kit.php

This guy has some seals that are supposed to compensate for minor shaft wear.

 

I had these guys rebuild my NV1000 several years ago and it leaked when I got it back.

 

i think supercharger rebuilds use high quality seals too.

I've not managed to get a leak down test done yet but there's a chance the bearings that failed could have damaged something.

I've put the hose from my catch can back to the inlet (from the rocker cover) to see if the vacuum will help but i doubt it.

 

Having a bit of oil coming through isn't the end of the world. Running a catch can will help you from ingesting additional blow-by from the motor (via suction) but will not have an affect on oil leaking from the oil seals on the blower. Every motor I have ever worked on has some air pulsing from the dipstick when its been removed, but some have more than others.

I've read about these in other applications, but hadn't seen that done with these blowers.

I've used those seals for a blower I rebuilt on my personal car and while it decreased oil ingestion, it did not stop it completely. I had rear on their website that some blowers have worn shafts and there is no real way to prevent it from leaking. Since I posted this, I cannot find that on their website now.

I too had oil leakage after getting their kit.

Good luck!