TheSamba.com :: View topic - Shorrock C75BV on a Ghia Cabriolet in Australia

Thu Feb 02, 2023 3:18 am

I usually spend my time on the Ghia forum but that has to change now that I've acquired a Shorrock for my '66 Karmann. This had been a long time coming with many dead ends and diversions but finally a complete set up became available out of the UK. John Moxon helped to get this into my hands and it arrived in Australia during the pandemic. More delays ensued because I'm working in New Zealand and access wasn't possible with closed borders.

Since it was removed from a running 1300 beetle in the UK it is quite possible for it to go right on the car, but it looks a little bit aged and could do with a freshen up. It was also damaged in transit and for that some repairs are due.

First up is to show what I have and then to go about doing a full refurbishment of it and its appendages.

My ’66 is built with a 12 volt system. Originally a 6 volt car It was reasonable to convert to the higher voltage during a full full restoration. So to make the Shorrock work it needed a new 12 volt fuel pump. John organised that to come with the shipment and the old pump he managed to sell to someone who needed it.

There were two carburettors provided. One was right off the previous install and the other is a spare. we have a CD 150 Stromberg and a CD 150 Zenith,

There is an Air filter elbow

And a period Air filter which won’t be used. Instead I propose to plumb the existing oil bath filter by extending the existing tube and revising the provided filter tube so it points vertically. I prefer an oil bath over a filter. Fewer consumables.

I have to get a spare set of belts. These look like a Mintex CUPT374 and a Rootes 9926586. I've looked for those but can't seem to find them. If anyone knows better, do let me know what they are so I can order a set.

I have 2x manifold ends with blow off valves for 1300/1500
and the original rubber manifold couplings.

The blow off valves were seized and I spent a little time with them trying to unbind them. I removed them from the manifold ends

Then I sat them in the vice to try loosen them with some force. I used the handle of a small wooden hammer to push down on the internal piston.

But they wouldn't move until I put a small amount of machine oil on them and that loosened them right up.

I wiped them up and set them aside. Maybe some of you know if that is good enough or if more work is required to get them to spec. I suppose a pressure test of some kind to validate that they open at the right pressure would be something to do.

So here are the broken bits. Poorly packed in transit would be the root cause of that.
The VW stand is broken in one corner. This isn't a difficult TIG repair. There are lots of talented TIG welders out there.

More concerning is the cast iron pulleys both of which are chipped. I have the chipped piece from the larger pulley

The chipped piece is missing from the smaller pulley. I'd like to learn if there are replacements out there. Otherwise I'll have to find someone who can rebuild them.

There are also some studs that got bent in the move. I removed those without difficulty

I also removed the name plate off the unit. I cleaned it up and set it aside. I was amused that the Specification number was stamped upside down. Perfect for life in the southern hemisphere!

And finally a comprehensive series of photos of the blower itself

I have sat it on the bench with an electric drill to rotate it and it spins freely and provides quite a bit of suction at the input and blow at the output. Possibly I only need to do a cosmetic refurbishment but that's not really going to satisfy me. It will look odd going on a motor that was totally stopped down rebuilt and looks like new.

I plan to strip it down and have the outer case water blasted to give it a fresh out-of-the-casting look. All the studs, nuts and washers will be replaced. The same will go with the manifolds and the CD150s.

This will take a while since I'm hoping back and forth across the Tasman but I'm sure it won't take as long as the car to restore.

So stay tuned for the likely infrequent updates.

Cheers for now!

Nicholas

Thu Feb 02, 2023 7:25 am

:popcorn:
Gonna be cool!

Fri Feb 03, 2023 4:13 am

Wrapped to see one down under.

Sat Feb 04, 2023 5:43 am

It's going to be a fascinating watch.

I love my Shorrock and have had great service from it over the last 12 years. To say the VW 90 degree version is "rare" is a misuse of the word. I'm pretty confident in saying my Shorrock is the only one running on a Karmann Ghia in the world today...it will be great to have another one with which to compare notes.

The Shorrock back in the day was considered to be the "Rolls Royce" of small superchargers. If you follow Nick's restoration of the supercharger you'll begin to understand why "Rolls Royce" never challenged them over the use of the term in their advertising.

Sat Feb 04, 2023 1:19 pm

Man, this is a really cool build. Gonna be very interesting to see it in action.

I would be inclined to use that period air filter, just maybe look into a paper element for it?

Fri Feb 10, 2023 4:20 am

For those of you unfamiliar with the VW model, it was offered by EMPI for a short time in their 1967 catalog...

The collaboration between Shorrock and EMPI wasn't a great success as very few superchargers were sold. That's not to say the Shorrock Kit for the VW was no good...far from it. Shorrock, as we have seen had the reputation as the "Rolls Royce" of superchargers; far and away the best engineered of all the small superchargers. Unfortunately they were just too expensive to crack the volume VW market of which Judson held a stranglehold. In 1967 the basic EMPI Shorrock Kit sold for $395...at the same time you could buy the Judson Kit for $144.

Tue Jun 20, 2023 3:46 pm

I’ve found a guy here in Australia who can copy the broken pulleys in cast iron. The VW crank pulley would be the most rare. Would there be interest if I commissioned a few more? Not sure on the price yet but expect about $150.
Nicholas

Tue Aug 15, 2023 2:47 am

Nice!!! Can’t wait to see it running

Wed Feb 21, 2024 12:05 am

The cast iron has been milled and we have a new pulley to replace the broken one.
I was out with my estimate for the price. But how do you measure the price of unobtainium when you absolutely need to have it.
Nicholas

Wed Feb 21, 2024 12:49 am

How far out was your estimate?

Did you have much response for a batch of pulleys?

Wed Feb 21, 2024 1:20 am

I recently bought this and i intend to fit it to my old speed oval at a later date although it will take a lot of work to adapt it to my okrasa 30hp motor. I`m missing the supercharger mount but seen as i`m fitting it to an earlier motor i will have to fabricate my own mount anyway.

Wed Feb 21, 2024 1:32 am

I saw your post regarding your acquisition.

If it's anything like your Judson it'll be impressive to watch it come together

Thu Feb 22, 2024 10:32 am

Fishynos72 wrote: How far out was your estimate?

Did you have much response for a batch of pulleys?

$150 vs $500 for both pulleys

No interest.

Nicholas

Thu Feb 22, 2024 12:27 pm

sputnick60 wrote: Fishynos72 wrote: How far out was your estimate?

Did you have much response for a batch of pulleys?

$150 vs $500 for both pulleys

No interest.

Nicholas

Ouch

Mon Mar 11, 2024 3:28 am

More Photos of them both. I'm happy with the outcome.

Nicholas

Mon Mar 11, 2024 4:54 am

vwhelmot wrote:
I recently bought this and i intend to fit it to my old speed oval at a later date although it will take a lot of work to adapt it to my okrasa 30hp motor. I`m missing the supercharger mount but seen as i`m fitting it to an earlier motor i will have to fabricate my own mount anyway.

I marked up a photo for you showing the mounting holes on the C75B that mate to the VW stand.

Circled in red are the mounting points. One is a stud fastened with a washer and nut and the other is a countersunk slotted screw fastening to the C75B body. Only these two support the C75B. Circled in green are bolts with through holes on the face of the stand and there is no support provided at these points. I'm guessing there would be interference with the belt if a washer and nut were sitting under there.

On the other face ( towards the front of the car) are a couple of straps that probably help with the twisting moment. These use a couple of studs and you can see them in the earlier photos. As yet I haven't had a chance to work out how those go.

Nicholas

Thu Sep 12, 2024 4:53 am

I carried the Supercharger in my luggage over to Auckland so I'm able to make progress with cleaning it up along with its ancillary parts.

The C75BV being an English affair is definitely not metric. I've been working for years deliberately avoiding the old imperial measures but now I'm going to have to learn. It gets tricky with both Australia and New Zealand having long been metricated and finding a bolts supplier carrying Whitworth hardware is a small challenge. I found one but even then they sent the wrong sizes. I was stuck for a while till I found the oil inlet is held in with the same thread size as is used to split the sections of the supercharger. So I could make a start.

This screw is tightened to split the front plate.

Taking care to not strip the aluminium and make sure the plate comes of squarely.

Inside the rotor and vanes look oily but clean enough. No damage is apparent.

I spotted one screw is missing. It would have fallen out into some previous owners intake manifold. Hopefully it never made it into the cylinder head.

Counting up the punch marks this unit has been worked on at least twice since it was built. I'm lucky third

Nicholas

Fri Oct 04, 2024 2:46 am

The VW specific stand has been repaired by one of the guys at work who is an aerospace grade welder. It came up quite well.

Overall view

The repaired corner before drilling

After drilling and counter sinking the hole I test fitted it on the face cover. It seems to line up ok.

Drilling this was easy, holding the work in place on the drill press was challenging. Before starting I did a bit of research on the question if this hole needs to be counter sunk. Nearly all the photos of I uncovered on the web show a countersunk screw. Only in the EMPI catalog of '66 does it appear with a bolt. I guess the tight clearance for the belt was discovered after the first few prototypes.

Anyhow, on this project we have fixed everything that was broken in transit. From here we are moving forwards.

Nicholas

Sat Oct 12, 2024 2:07 am

I have a question concerning the oil metering fixture.
Which side of the pin should the spring be situated? I think it is shown below in the correct sequence. I will need to clean off the corrosion from the pin, or put in a new one if I can find a replacement

I've found a new bit of damage or at least the cause of it. The bearing on the outer face appears to be around the wrong way so the shoulders touch the spinning plate and jams the bearing. This causes the bearing to spin in the aluminium mount inside the face plate and the bearing can't do its job properly. I'll have to extract it and work out a fix.

This is the view inside showing the blades in the trunnions and the lock nut that's secured with a split pin. Before I venture down in there I have to make a mandrel to slide the vane mounts on. Only after that can I lift them out and inspect the bearing at the other side. The trunnions will need to be replaced. I understand replacements are not difficult to engineer and the modern day material of choice is PEEK plastic (Poly ether ether ketone) which is supplied as rods. Convenient to machine in shape and to slit.

Nicholas

Fri Nov 08, 2024 5:04 am

I noticed these parts for a shorrock supercharger a guy makes and remembered this thread. So I figured I'd add it to this thread in case someone was unaware of its' existence.

https://www.ebay.com/sch/i.html?_from=R40&_trk...p;_sacat=0