Supercharger died, need to rebuild

SuperV8 · Post by **SuperV8** » Fri Oct 19, 2012 11:49 am

Whist drag racing last weekend my Procharger C1 supercharger had a screaming death! Half way down the track started making a horrible screaming noise so I turned the engine off and coasted to the fire truck. Took the supercharger belt off and luckily the engine ran fine.
When home I took the outlet hose off the supercharger and to my horror it was lined with aluminium dust

I took the hose off the plenum inlet and it all looked clean so I'm hoping the intercooler acted as a large air filter?? Engine seems ok anyway.
But now to the supercharger, dismantled it to find the compressor rodgered, the volute look remarkably un touched with just a slight roughness.

I split the case to fine the compressor bearing had failed with lots bits of it's cage strewn about the gearbox.

Small inner bearing - missing its cage!

So I need to re-build this. I have it all apart, bearing should be straight forward, need to have a think about the compressor high speed bearings. The compressor side had a small bearing within a large one, is this to lower their effective required speed limit?

What i'm stuck on is the compressor. My compressor had a 70mm inducer and a 108mm exducer. There was also a higher flow version of my supercharger called the C2 which has an 80mm inducer and a 108mm exducer. I can't buy the standard compressor wheel. There is an aftermarket one available in the states but it is over $300 and the company has not yet returned my email!
Then I though about turbo compressors... I have found an 80mm x 108mm garratt GT4708 compressor. Do you think it would be possible to re-profile my volute to match this compresser?
Do they have standard shaft diameters? My shaft is 0.5" dia
I don't know how the height compares?
Can anyone recomend any turbo suppliers/re manufactures to contact? or anyone who sales other compressor wheels?

Tom.

kiwicar · Post by **kiwicar** » Fri Oct 19, 2012 12:14 pm

Hi
I always assumed the compressor side of one of these was just the comprssor of a big ish Turbo, all you had to do for spares was find the truck the original turbo came off and order parts that way. I take it then that the impeller is a special and the housing is machined to match? seems a lot of effort!
Best regards
Mike

mgbv8 · Post by **mgbv8** » Fri Oct 19, 2012 7:22 pm

Have you tried emailing the pro charger support team?

ian.stewart · Post by **ian.stewart** » Fri Oct 19, 2012 10:18 pm

I think I would be replacing all the bearings, for the cost of another compressor bearings would be cheap insurance, Intercooler would be bin fodder if it was mine, I wiped out a very expensive engine years ago by not changing a oil cooler after a minor bearing failure, and reused the cooler cos it looked clean,
Have you tried UK blowers??

stevieturbo · Post by **stevieturbo** » Sat Oct 20, 2012 5:07 pm

There are a couple of places in the US that make replacement parts. As to quality, no idea.

Superchargerrebuilds and 928 Motorsports

http://superchargerrebuilds.com/

http://www.superchargerupgrades.com/

I'd think you should be able to get bearings locally, although buying a kit might just be as handy.

Is it worth rebuilding or trying to source a used unit ? good question.

mgbv8 · Post by **mgbv8** » Sat Oct 20, 2012 8:08 pm

When you get the bearings out, give us the details. I work for a bearing suppplier. We may have what you need??

stevieturbo · Post by **stevieturbo** » Sat Oct 20, 2012 9:00 pm

The bearings in that unit will be pretty basic stuff.

Now if you you can find a pair of 7203 angular contact equivalent that is happy to turn 70,000rpm and readily available at sensible prices...I'd be interested.

They list them in catalogues, they even give them part numbers, except in the real world they are few and far between lol

SuperV8 · Post by **SuperV8** » Mon Oct 22, 2012 6:52 pm

Right then my bearings are:
Input pulley bearings; ID OD Thk
1x Koyo 6305 C3 Japan 25 62 16.9
1x Koyo 6203 C3 Japan 17 40 11.9
Output compressor bearings;
1x Koyo 6009 C3 Japan 45 75 15.9
1x THRUST NHBB USA ME-1203 DL 17 (this is one one which failed) 17 (approx because it is misshaped after failing!) 39.9 od and 12 thk
1x FAFNIR OIS LOT 3220 THRUST USA 7202W 15 35 10.9
Oil slinger
2x Koyo 6000 C3 Japan 10 26 7.9

The Koyo bearings are all standard (i think) and should be easy to get equivilent. The tricky ones will be the output high speed ones, although maybe the standard bearings weren't high speed enough? On the compressor wheel side there is a bearing within a bearing, would this help reduce the speeds each bearing sees? so you can use two lower rated bearings? The large outer one is very stiff so maybe the reason the compressor failed was the smaller inner bearing was forced to go over its speed limit.

I've emailed supercharger rebuilds in the states but no response so going to have to find my own bits.

Does anyone know if there is a standard size for turbo compressor wheel ID shaft sizes?

Thanks for your comments/help,
Tom

stevieturbo · Post by **stevieturbo** » Mon Oct 22, 2012 7:02 pm

There is no standard on any parts. Other than bearings really.

Post a picture of the high speed bearings. Mine are 7203 angular contacts and the same dimensions you posted. The high speeds will all be high precision bearings
Athough some of the lesser Vortech units appeared to use bog standard bearings at that location.

Ive basically come to the conclusion that a lot of them simply overspin the bearings and they work just fine.

NSK do list a 7203C which is rated at around 65k, but when I priced them locally they were around £200 a pair !

I have a brand new pair of Nachi 7203's here, although I never used them They only rate their precision range to about 38k. I dont recall the ones I have costing that much though !

http://www.vxb.com/page/bearings/PROD/Kit10891

SuperV8 · Post by **SuperV8** » Mon Oct 22, 2012 9:08 pm

Layout of compressor pulleys & shaft including alu spacer which holds the smaller bearing within the larger bearing.

Large bearing Koyo 6009 C3 45x75x15.9 small bearing which was destroyed THRUST NHBB USA ME-1203 DL 17 approx ID x35x12

FAFNIR OIS LOT 3220 THRUST USA 7202W 15x35x10.9

The one you have mentioned is for the input which would only see about 20000 rpm were as the compressor bearings would see 80000

Tom.

stevieturbo · Post by **stevieturbo** » Mon Oct 22, 2012 9:55 pm

What pulley combo do you have ? Are you spinning the unit anywhere near those speeds ?
Looking at the specs, the max 80k would mean a 17k low speed shaft. That should be well within the range of most bearings.

The fact the bearings state thrust on them mean they will be angular contact bearings.

It is weird joining 2 bearings together like that, but as you say, it probably is to reduce the overall speed of the bearings. Not a bad idea really, although quite bulky.
Normally angular contact bearings will have wave washers to apply pre-load to them though

Does the high speed set have 2 bearings either side of the gear ? Or is that only done on one side ?

Might find some info here

http://www.superchargerhelp.com/forumdi ... 8-C-Series

But until you can source an impeller, the bearings really dont matter.

Ive emailed that supercharger guy before and he was always prompt with replies.
Never bought anything off him though

Another seller, dont think they do those sort of parts though

http://www.superchargersonline.com/inde ... &cPath=512

SuperV8 · Post by **SuperV8** » Mon Oct 22, 2012 10:21 pm

The double bearing is only next to the compressor wheel side. On the end of the shaft is a single bearing.

Yes I have geared the pulleys it to run it at it's max listed speed 80k.

Looking at them yes I think the two smaller high speed ones which say thrust are indeed angular contact types, were as the the larger one is a deep v type. There is a wavey spring washer for the larger input deep v washer but not for the high speed ones, maybe there should be?

I agree unless I can fine a compressor the bearings are pointless!

I have found a Garratt GT4708 has a copressor wheel with a 108mm exducer compressor and a 80mm inducer which I think my volute could be re-profiled, but don't know about the shaft diameter? or the height?

Tom.

stevieturbo · Post by **stevieturbo** » Mon Oct 22, 2012 10:30 pm

It is possible a turbo unit might do..

A friend had some Caterpillar turbos off a generator, they are huge Garrett items
He was going to throw them out...or may already have done.
Their compressor wheels might not be far off that.

No idea on shaft diameter or height though, or profile. There really is an infinite number of variables there, as well as are the blades strong enough to withstand the mechanical drive of a supercharger. With a turbo the unit just floats and wouldnt have any shock loadings on it from the drive.

Will check tomorrow to see of he still has any of the turbos.

Eliot · Post by **Eliot** » Tue Oct 23, 2012 2:43 pm

Not seen it mentioned - but aren't the teeth/splines on that shaft stuffed as well?

SuperV8 · Post by **SuperV8** » Tue Oct 23, 2012 10:12 pm

Not seen it mentioned - but aren't the teeth/splines on that shaft stuffed as well?

Have had a very detailed look at both the gears and I think they are fine, the photo makes it look worst than it is. When it happened I though maybe the gears are screwed but it aphears to be 'just' the bearings and compressor wheel.

Tom.