John Moxon |
Fri Nov 08, 2024 7:56 am |
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thomas. wrote: 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
You might be lucky to see if they can supply a Shorrock Mandrel Nick. |
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[email protected] |
Fri Nov 08, 2024 5:36 pm |
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sputnick60 wrote: 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
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
I know this has nothing to do with this fourm but it got me thinking about these blow off valves on these shorrock supercharger...how would these perform... if one were to use them on a corvair turbo would I have to use the 2 shorrock blow off valves or only 1 for a 36hp corvair turbo setup ???? I've never seen anyone use these blowoff valves for a vintage turbo setup .... |
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thomas. |
Wed Nov 13, 2024 2:43 am |
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On a draw thru. with the carb. before the supecharger it is my understanding that a pop off valve is not needed. I've installed various superchargers on draw thru set ups on 40hp & dual port & never used one. You could eliminate it if not worried about originality. |
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macdweal |
Sat Nov 23, 2024 6:24 am |
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I think the pop off valve is for preventing the compressor going airborne in case of a backfire. |
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sputnick60 |
Wed Dec 04, 2024 4:04 am |
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macdweal wrote: I think the pop off valve is for preventing the compressor going airborne in case of a backfire.
Yes, that's what I've read too. To protect the vanes from damage. A backfire must have a lot of energy behind it I suppose.
Nicholas |
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wagen19 |
Sat Feb 01, 2025 1:30 am |
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sputnick60 wrote: macdweal wrote: I think the pop off valve is for preventing the compressor going airborne in case of a backfire.
Yes, that's what I've read too. To protect the vanes from damage. A backfire must have a lot of energy behind it I suppose.
Nicholas
Good luck to all compressor junkies!
It´s a interesting field to "play" and combine with old VW technique.
Humourus thinking, remembering W.O. Bentley about the Birkin-Paget-project, the 4 1/2 l Bentley Blower.
On the positive side, while racing, more than one "fastest lap" was not achieved.
„to supercharge a Bentley engine was to pervert its design and corrupt its performance“
https://de.wikipedia.org/wiki/Bentley_4_%C2%BD_Lit...%E2%80%9C) |
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John Moxon |
Sat Feb 01, 2025 3:09 am |
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Ahhh they were coarse Roots blowers.
These Shorrock Superchargers sip fuel like a Vicar at a summer tea party. :lol: |
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wagen19 |
Wed Feb 05, 2025 6:17 am |
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John Moxon wrote: Ahhh they were coarse Roots blowers.
These Shorrock Superchargers sip fuel like a Vicar at a summer tea party. :lol:
Thinking about the inner lubrication of all mechanical parts of the Shorrock Superchargers.
On paper and on pics here, I could not see a kind of oil or grease reservoir, or a lubrication system, as at the Judson for ex.
Is there a hidden or separate system for sipping oil to the mechanic, I still have have not been able to see?
OK, it´s written, the lubrication system is connected to engine, that seems to be the tiny hoses in upper pic.
What about total oil consumption of engine + blower?
What about the smell of exhaust fumes? Similar as old style 2 stroke engines like the german Trabant cars emitted? (or clouds of burnt "Rizinus", castor oil?)
Is it known, measured, how much, or how many hp the compressor needs to be driven under full throttle at engine rpm 2000, 2500, 3000, 3500, 4000 or more? |
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John Moxon |
Wed Feb 05, 2025 8:38 am |
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wagen19 wrote: John Moxon wrote: Ahhh they were coarse Roots blowers.
These Shorrock Superchargers sip fuel like a Vicar at a summer tea party. :lol:
Thinking about the inner lubrication of all mechanical parts of the Shorrock Superchargers.
On paper and on pics here, I could not see a kind of oil or grease reservoir, or a lubrication system, as at the Judson for ex.
Is there a hidden or separate system for sipping oil to the mechanic, I still have have not been able to see?
OK, it´s written, the lubrication system is connected to engine, that seems to be the tiny hoses in upper pic.
What about total oil consumption of engine + blower?
Oil consumption is small...it only needs a little to feed the main bearings. The Shorrock vanes get what they need from the mix with fuel but the Shorrock runs a lot cooler than the Judson as the vanes are not in contact with the casing. You see in the picture the oil feed is simply from an adapter fitted to the Oil Pressure outlet under the distributor to the back of the supercharger. You can adjust the flow of oil with a metered pin if you need.
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wagen19 |
Wed Feb 05, 2025 1:06 pm |
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John Moxon wrote: wagen19 wrote: John Moxon wrote: Ahhh they were coarse Roots blowers.
These Shorrock Superchargers sip fuel like a Vicar at a summer tea party. :lol:
Thinking about the inner lubrication of all mechanical parts of the Shorrock Superchargers.
On paper and on pics here, I could not see a kind of oil or grease reservoir, or a lubrication system, as at the Judson for ex.
Is there a hidden or separate system for sipping oil to the mechanic, I still have have not been able to see?
OK, it´s written, the lubrication system is connected to engine, that seems to be the tiny hoses in upper pic.
What about total oil consumption of engine + blower?
Oil consumption is small...it only needs a little to feed the main bearings. The Shorrock vanes get what they need from the mix with fuel but the Shorrock runs a lot cooler than the Judson as the vanes are not in contact with the casing. You see in the picture the oil feed is simply from an adapter fitted to the Oil Pressure outlet under the distributor to the back of the supercharger. You can adjust the flow of oil with a metered pin if you need.
Thank you for your pics and answer.
"Small" oil consumption is very relative, I guess and what about fuel?
Correct me please, I think, the blower is allways engaged, or is there a bypass and a kind of electric clutch, similar as on air condition? (A kick down switch and so on could also make sense, I think.) Sorry about my stupid questions, but with these superchargers I´ve no experience. What about high revs, when shifting next gear, while sporting? What displacement and cam does your engine have? Trans? |
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John Moxon |
Wed Feb 05, 2025 1:37 pm |
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wagen19 wrote:
Thank you for your pics and answer.
"Small" oil consumption is very relative, I guess and what about fuel?
Correct me please, I think, the blower is allways engaged, or is there a bypass and a kind of electric clutch, similar as on air condition? (A kick down switch and so on could also make sense, I think.) Sorry about my stupid questions, but with these superchargers I´ve no experience. What about high revs, when shifting next gear, while sporting? What displacement and cam does your engine have? Trans?
These are low pressure superchargers. All the supercharger kits supplied by Judson, MAG, Pepco, Shorrock were intended for everyday use and to be fitted to you car at the weekend so you could drive your car to work on Monday.
They were configured to utilise your stock engine without the need to open the case. As kits their success was based on replacing as few parts as possible. This won't change your VW into a racecar.
Shorrock Supercharger Road Test
https://www.thesamba.com/vw/forum/album_page.php?pic_id=489935
https://www.thesamba.com/vw/forum/album_page.php?pic_id=489936
...then there's the question of where you're going to find a Shorrock Supercharger Kit?? |
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wagen19 |
Wed Feb 05, 2025 3:00 pm |
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John Moxon wrote: wagen19 wrote:
Thank you for your pics and answer.
"Small" oil consumption is very relative, I guess and what about fuel?
Correct me please, I think, the blower is allways engaged, or is there a bypass and a kind of electric clutch, similar as on air condition? (A kick down switch and so on could also make sense, I think.) Sorry about my stupid questions, but with these superchargers I´ve no experience. What about high revs, when shifting next gear, while sporting? What displacement and cam does your engine have? Trans?
These are low pressure superchargers. All the supercharger kits supplied by Judson, MAG, Pepco, Shorrock were intended for everyday use and to be fitted to you car at the weekend so you could drive your car to work on Monday.
They were configured to utilise your stock engine without the need to open the case. As kits their success was based on replacing as few parts as possible. This won't change your VW into a racecar.
Shorrock Supercharger Road Test
https://www.thesamba.com/vw/forum/album_page.php?pic_id=489935
https://www.thesamba.com/vw/forum/album_page.php?pic_id=489936
...then there's the question of where you're going to find a Shorrock Supercharger Kit??
Dear John,
thank you very much for your answer.
My understanding is, the car feels smooth, has allways more torque, more peak, is never nervous. That all sounds very good.
Can the feeling be described, similar to a 1600 "B engine with a bit higher top rev? Around 50 to 55 hp?
Of course, a 1600 B-engine is technical totally boring, compared with a Shorrock blower.
My 50 hp bugs I had, nipped around 9 to 12 l per 100 km, my 34 hp bugs take 7 to 10 l. My 30 hp ovals in summer go 450 to 500 km before switching to reserve. On long distance trips I come around 520 km before reserve is needed. Cold weather: after around 400 km reserve is needed. The low compression 49 split, 25 hp with old 26 VFI mostly wants more fuel, so around 8 to 9 l.
So far, thanks again. |
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