Bought an oval project a few years ago and it came with a recon. engine ,gearbox and a judson.I thought the judson was brand new as every thing else was new(Pulleys,Oiler etc.)But when running was noisy but pretty much same as others i have heard.Decided to pull it apart and found out it was well, stuffed see photo.
1956 judson supercharged oval
1975 kombi camper
1976 kombi panel van
The vanes must have worn away quite a lot, to get that sort of wear on the rotor. Maybe had the wrong [or no] oil, also.
Is that a crack between the slots? If so, the rotor's rooted.....sounds like that place in NZ.
I'd rather wear a Beetle out by racing it than by polishing it!
the slots are mean't to be 3/16" wide but are well passed that.It has also been machined oversize so it is time for a new rotor.
The body is badly grooved but should hone up ok.
New rotors are available but are $700 plus postage and vanes $100. So i think first will try to make one.The vanes being oversize ,i should be able to mill these down to the right size.
I have ordered a billet of aluminium 90mm in dia.and 200mm long.
Have honed the body and has come out ok.
1956 judson supercharged oval
1975 kombi camper
1976 kombi panel van
HappyDaze wrote:The vanes must have worn away quite a lot, to get that sort of wear on the rotor. Maybe had the wrong [or no] oil, also.
Is that a crack between the slots? If so, the rotor's rooted.....sounds like that place in NZ.
The vanes aren't worn that bad.The original rotors are quite soft,as they are a cast alloy.The rotor is not cracked but is rooted as you said.
1956 judson supercharged oval
1975 kombi camper
1976 kombi panel van
Steve
I can not see any cracks in the rotor I have had Judsons since the early 90s in both cars
My rotors are similar in wear and have just add new vanes to make them work
Greg can you see cracks ???
new parts available from the guy in Ney York George F i can look his details up if you want
Looks like you have things under control, Steve. What grade of aluminium are you using? See if you can get a 'radius' in the bottom of the slots, when milling them.
I'd rather wear a Beetle out by racing it than by polishing it!
HappyDaze wrote:Looks like you have things under control, Steve. What grade of aluminium are you using? See if you can get a 'radius' in the bottom of the slots, when milling them.
Have forgotten grade ,i went to a aluminium suppler and told him what i was going and the said this is the best grade for machining(it is not 6061 i think it was 5 something)But will be a lot better than original.
1956 judson supercharged oval
1975 kombi camper
1976 kombi panel van
Honestly i wouldnt worry about that one Mine are similar in wear and still work Good
I have purchased a few items from George F in Ney York hes really good and easy to work with for the parts you need
What about remachining the slots and putting in spacers or thicker rotors. ??
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matberry wrote:What about remachining the slots and putting in spacers or thicker rotors. ??
The slots have already been machined oversize with thicker vanes.
1956 judson supercharged oval
1975 kombi camper
1976 kombi panel van
vw54 wrote:Honestly i wouldnt worry about that one Mine are similar in wear and still work Good
I have purchased a few items from George F in Ney York hes really good and easy to work with for the parts you need
I have also purchased parts from george.
It was working ok as you stated but iam very fussy .(It costs me a lot of money at times but it is the way i am)So i will be machining a new one or trying to.If i mess it up i will have to buy one from george.
1956 judson supercharged oval
1975 kombi camper
1976 kombi panel van
tried to press the shaft out of rotor but it would not move.My mates 20 ton press was starting to bend.I think i will make a new shaft as this one has a few battle scars.
1956 judson supercharged oval
1975 kombi camper
1976 kombi panel van
Its NOT meant to be removed the steel shaft has tangs on it to stop the alloy section from mooving
its cast as one piece when being made
Please ask questions before you do any more damage
vw54 wrote:Its NOT meant to be removed the steel shaft has tangs on it to stop the alloy section from mooving
its cast as one piece when being made
Please ask questions before you do any more damage
What questions do i ask? Iam going to make a new rotor and shaft because mine is worn out. Tell me how please?
1956 judson supercharged oval
1975 kombi camper
1976 kombi panel van
Reckon you are on the right track, Steve. How will you 'key' the al. rotor to the shaft? Please show us your progress...... It will be interesting to see the results.
I'd rather wear a Beetle out by racing it than by polishing it!
yes well the hard bit will be keeping the shaft n rotor together
It would be good if you could get a lump of alloy cast onto the old shaft and machine up a new rotor
Interest to know if the OD of the old rotor has varied or still concentric ( so just the slot has worn )
May be easier to mill the slot wider and obtain thicker bakelite material for the new vanes
Ive been fiddling with these since 1984 or so
Dave i am sure you have been fiddling with it since before 1984,
Mitchell
23 windows ...8 too many!
As there is very little load on the rotor,a good shrink fit should be ok.I will freeze new shaft i have made and heat rotor to as hot as i can.Then when shaft and rotor heat up should all hang together.Iam limited by my measuring equipment (have only digital calipers and my old calipers from apprenticeship) Will start for about a .005" interference fit ,which is a lot and
slowly machine shaft until it fits.Will keep you informed
1956 judson supercharged oval
1975 kombi camper
1976 kombi panel van
vw54 wrote:yes well the hard bit will be keeping the shaft n rotor together
It would be good if you could get a lump of alloy cast onto the old shaft and machine up a new rotor
Interest to know if the OD of the old rotor has varied or still concentric ( so just the slot has worn )
May be easier to mill the slot wider and obtain thicker bakelite material for the new vanes
Ive been fiddling with these since 1984 or so
The rotor has already been machined for wider vanes.I think i have already stated that.
1956 judson supercharged oval
1975 kombi camper
1976 kombi panel van
Hi Steve, it was nice to meet you at Warwick, will have to catch up and chat again soon.
Any pics of the new rotor and shaft??
Are you going to cut the new vein slots after pressing the shaft in?
Aaron
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Steve
I take it you have seen this
http://www.vwjudsonregister.org.uk/Thanks vw54 yes have read it inside out,
1956 judson supercharged oval
1975 kombi camper
1976 kombi panel van
20bkombi wrote:Hi Steve, it was nice to meet you at Warwick, will have to catch up and chat again soon.
Any pics of the new rotor and shaft??
Are you going to cut the new vein slots after pressing the shaft in?
Aaron
Hi Aaron ,I enjoyed our chat at Warwick and it was nice to meet you.
Iam about to put up the pictures of the shaft,and hope to fit the rotor to the shaft and then machine the rotor.
Steve
1956 judson supercharged oval
1975 kombi camper
1976 kombi panel van
Steve, I assume you have in mind some form of 'keying' of the shaft & rotor? Perhaps you could also bore the rotor under-size, to provide an interference fit. Leave the shaft in the freezer for a while, and heat the rotor in the oven [200c?] before pressing together. There are people around [Dangerous?] who could help with precise dimensions, etc.
I'd rather wear a Beetle out by racing it than by polishing it!
I have made up the shaft the same specs as the sample,the thread i screw cut (last one i did was about 40 yrs ago) and fits nut like a glove.Next to bore the Rotor i made up two boring bars from 12mm and 16mm s /s i had at hand .I want them to be rigid as possible as it is a long hole.
1956 judson supercharged oval
1975 kombi camper
1976 kombi panel van
HappyDaze wrote:Steve, I assume you have in mind some form of 'keying' of the shaft & rotor? Perhaps you could also bore the rotor under-size, to provide an interference fit. Leave the shaft in the freezer for a while, and heat the rotor in the oven [200c?] before pressing together. There are people around [Dangerous?] who could help with precise dimensions, etc.
Hi Greg,Thanks for the input,yes i will be going for a interference fit.Heat the rotor in the oven,shaft in the freezer and then heat the rotor with mapp gas to get it hotter and then if it does not fit ,remove .001" of shaft until it will fit.This may seem long winded but i have only a digatal caliper which isn't that accurate when talking .0005" Will let you know how it goes.
1956 judson supercharged oval
1975 kombi camper
1976 kombi panel van
I tried a test cut in the old rotor to make sure it would work out ok.You can see the amount of wear .Also on the judson registry read about the case history ( i do not know how to do a link, i only learn't how to upload photo's last week).It states that the vane should be a neat fit in the slot,or air will bypass the vane and you lose effeciency .Commonsense pretty much.They will work in this state sort off,and be fine for a drive around the block but i like to know that i can drive from bris. to melb.Also in the resto of the oval the engine was rebuild to new specs. as was gearbox ,the whole car actually (it won 3 trophies at action day) So i want the supercharger to be the same.
Well onto the machining of the rotor first up was to bore a hole slightly undersize of the shaft.
1956 judson supercharged oval
1975 kombi camper
1976 kombi panel van
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Good luck with your project.
What is going to prevent the rotor from sliding/moving on the shaft when the finished product is in the Judson and actually working on the road? Just the interference fit?
Is it worth pinning the rotor to the shaft, so it cannot move in any direction?
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2003 Passat
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1975 Passat TS
1973 L bug
farkengruven wrote:Good luck with your project.
What is going to prevent the rotor from sliding/moving on the shaft when the finished product is in the Judson and actually working on the road? Just the interference fit?
Is it worth pinning the rotor to the shaft, so it cannot move in any direction?
I am hoping the interference fit will be enough,if done right.There is not much of a load put on it.It is only 36hp remember,but if anyone has ideas how to pin it to the shaft let me know.Thanks for the support
1956 judson supercharged oval
1975 kombi camper
1976 kombi panel van
