Supercharger blades

[Lordgaz]

As ongoing strip down progresses (re other posts) Supercharger has been removed. Inspection of the blades, there appears some light scoring / scratches (lord knows what’s been through there).. anything to be concerned about? All moves freely.

[Lordgaz]

Scraping on the outside edge of the blade, indicative of needle bearing replacement required?

[J44EAG]

Yes, that chipping and scoring is perhaps the worst I have seen. Most chargers will have some marking but not as much as you have shown here.

The needle bearings with special grease together with the correct grade of lubrication oil can be sourced from Lawson smith at Powerhouse Automotive. Lawson advised on my charger strip, modify and rebuild. Front snout case bearings are also worth changing if sounding worn. Lawson also sells an up-rated coupling but be warned. They are noisy at idle speed...he will also tell you that!

If the big main bearings are worn, then I`m afraid those are NOT replaceable. They are swaged into the rotor lobe case and cannot be removed. Lawson has tried to find a way of bearing extraction but told me it was just not possible. The only economical way around the issue would be to buy a new charger or ask Eurojag if they have a decent used one. Their prices are reasonable and the parts come with a short warranty.

I`d suggest you send Lawson a few images of your rotor damage and ask for his advice. Mention my name to him. It may open a door for you.

Mike

[Lordgaz]

Thank you! I’ll drop a message out to Lawson tomorrow.

[Lordgaz]

Thanks Mike - Contacted Lawson, who said not to worry too much about the coating on the blades - My supercharger seems to have ingested something in the past which is long gone - Based on the images, he thinks the centre bearing is ok - Swapping the other bearings though seeing as it is off the vehicle now (+ the coupler)

[J44EAG]

Knocked about rotor lobes will obviously leak pressure when compared to lobes in A1 condition. A loss of performance can be expected dependent on the degree of damage sustained. Unless you were using the charger under racing conditions, you are unlikely to notice the fall off in performance unless you had another car alongside with which to compare performance, one against the other.

Most chargers that I`ve seen have suffered a degree of chipping, scraping or coating degradation. By how much is probably governed by the amount of solid particulate held in crank case breather gasses. I`d perhaps suggest an engine which runs in clean oil consistently is less likely to sustain lobe damage than an engine which consistently operates with dirty and old, carbonated oil. Carbon solids are very abrasive even in minute particulate form. Remember that these lobes can spin up to 1,600mph within the charger case and tolerances are originally near gas tight. Any small abrasive particle is likely to do destructive damage and the higher the mileage of the charger, the greater the visible damage will be.

Mike