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MG MGA - Judson to fit 18V motor?

Hi Guys
The restoration continues......
I have recently reconditioned a Judson and a 18V MGB motor and hoped the combination would fit into the my MGA. Has anyone performed this operation? Any advice on the pitfalls and the tecnicalities would be appreciated.
It is a stock standard 18V motor.
Thanks, Dave
David Godwin

I did something similar by fitting a 948 Sprite Judson to a 1275 midget. I had to overdrive the supercharger for it to work on the larger displacement. If you've never had a Judson, be prepared for more heat, noise, loss of driveability, and marginal performance. IMO, it's more of a novelty item now. Not to be a wet blanket, but I was quite dissatisfied with mine. I did a fair amount of research and experimentation with various vane materials, including Delrin and Phenolics. The design is the main flaw and that's not easy to overcome. The direct vane-to-housing contact is the main problem. I would carry extra plugs and oil for the oiler. Extra belts wouldn't hurt.
Kemper

I agree the Judson is nice for shows but not a serious performance mod.

Yes, it will fit on an MGB engine in an MGA - I had one exactly that way, which is why I can say with some authority that I agree with Kemper!
Bill Spohn

I have an 18v motor with a Judson Supercharger on it. I still have it on. It works great once it is tuned in right. I do carry extra plugs because of oil fouling from the supercharger. I find I get a lot more tork on the bottom end and do not have to shift down in gears to stop the engine from lugging. It also has a lot of passing power. It does make a little more noise than a stock motor. The main problem I had was getting the oiler to drop once every 6 seconds. Here in the states, George Folchi has all the parts to rebuild these units. The other person to contact might be Carl Heildelman. He is listed in the archives. He has tested both Judson and the newer Moss units. Carl has written many articles on these units. He was very helpful in getting the unit to run right. You might want to also look into a Knock Sensor to prevent pre- detination. Hope this helps.

Jeff

61 MGA Judson Supercharger
JEFF BECKER

I can't believe what I am reading here....

"loss of driveability, and marginal performance", "not a serious performance mod".

I can only wonder what was wrong with these setups.

A well set-up Judson transforms the MGA. It has more torque, more acceleration, and is a BLAST to drive. Everyone (and that's now a lot of people as I am quite generous handing over the key) that has ever driven mine LOVES it compared to their own MGA. It's faster than a Twin Cam too (we have done the comparison). Dave drove it this time last year too when he visited CH, so he could compare directly to his own well travelled MGA.

Mine is on a 1622 040 overbore, with lightened flywheel and B clutch and early B head, but now otherwise standard. It does make more noise, but that's mainly because the stuffing in the Falcon SS exhaust has (again) blown out. The units are very noisy when first installed, but bed down as the vanes wear in.

Vane wear does seem to be an issue - after many miles on mine in the last year, the vanes appear about half worn, but I did have an oiler problem that went unnoticed for a full tank of gas. I do not have a problem with plug oiling, but find getting MMO very hard. Husqvuarna chainsaw oil is said to be perfect too.

George Folchi will be the best one to say if the unit will go on a 1800 engine well- my suspicion is that the extra cc over the 1650-ish that I effectively have is not going to be an issue.

Heat - depends on the state of the cooling system. I have a clean and no-sludge system, and in winter, the car will not get above 50C without blocking off 3/4 of the rad. In summer (it's 32C here today) it sits at 75C on the road and 85C in traffic. The SC therefore seems to make the car run cooler (cut to scene of overheating victims rushing to install SC).

Do check on compression ratio, and if in doubt fit the J&S knock sensor to your electronic ignition to control pre-detonation. Stay clear of dodgy fuel - I have to run mine on 98 gas, as it doesn't like 95 at all.
dominic clancy

As you may imagine, I agree more with Dominic and Jeff. I run a Judson supercharged MGA at 10psi and it is a real hoot. I dynoed it for a story in Grassroots Motorsports years ago--added approx 25 HP at the wheels. I've talked to several people on the phone/e-mail with 1800s and it can work well as long as you keep your RPMs below 5500.

Judson's can't be spun fast enough to work on 1275 A-series motors. They were designed for 948s and you've got to spin them faster than they should be for a 1275.

However, I also agree with some of the comments about drivability, novelty factor, etc.. While it's possible to set up a Judson to work well, it's a lot easier to set up a Moss blower to work well. So I'd say if you're serious about performance, go Moss. If you're serious about nostalgia, go Judson.

--Carl

p.s. Someone will chime in about a Hi-Flow sooner or later--good choice too but I have no direct experience
Carl Heideman

Looks like the "KING" Carl has said it all. It was nice metting you at MG2006.

Jeff 61 MGA Judson Supercharged ZZZOOOOOOOOOOMMMMMMMM
JEFF BECKER

Hi Again
A few issues have been raised
* Nostalgia or Performance - Answer, Nostalgia.
* Drivability - I drove Dominic's MGA Judson when it was newly installed and not set up right, and it was a pleasure to drive - again, from a nostalgia point of view. I have a full blown historic racer MGA to excite me with performance!
Very few people seem to own Judsons for MGAs and even fewer have them set up correctly - theres the challenge!!!
Jeff, what did you do to the crank pully (Harmonic Balancer) to take the dual belt?
What did you do about aligning up all the pulleys?
Do you run an alternator?
Do I need a dual water pump pulley?
Good to hear from you again, Dominic. Are you coming to work in Australia and swell the ranks of MGA nuts?
Dave
David Godwin

I too ran a Judson on an MGA with wonderful results. The head was cleaned up a bit for increased flow, and the stiffer valve speings installed for more revs. and the car just flew. I had made up a new set of vanes from some very high density polyethylene material and they lasted. Ran the charger for about 80M of the cars 130M miles, removing it when I sold the car to pass it on to a new enthusiasts.
We also had made up a slightly larger pully for the charger front. I forget what the size was but I got the boost up to over 7 pounds at about 4000 rpm..yes I had a gauge on the dash.
Biggest problem I had with the whole installation was a tendency to blow the paper gasket at the intake manifold to charger joint..finally had to have both surfaces trued up to prevent this.
I wish I could find one now to put on my MGA engined ZB Magnette. I just don't think the new Moss one can be made to fit in the existing space.

Zoom Zoom!!!
Wayne Hardy

Dave,
Here is what I did. I had to use the original pulley to be able to fit the new pulley to run the supercharger. The dog nut that holds the pulley on was modified (lengthen) to fit instead of using a bolt I also had to make a new timing mark to be able to time the engine as the 1800 is different from the 1600. My Judson is running a serpitine belt vs dual belts. The advantange is I can remove the belt without having trouble with the steering rack. The Judson and the pulleys line up so there is no problem. I did add an alternator and it lines up without any problems.You will not need a dual water pump pulley. I also have the Judson Guage in the dash. (Have a spare dash) I run about 4 pounds of boost. I know I can have a smaller pulley at the Sopercharger to raise the boost, but I want some boost but not all out as to avoid a blown head gasket. Hope this helps.

Jeff
JEFF BECKER

If anyone else wants to Judson their 'A, one was listed on eBay this morning. Not mine, but I did contact the seller to tell him it was a Judson, not a Jensen, supercharger!

Derek Nicholson

Dave

I had a new pulley made up with three grooves, the standard one for the A and two extra for the Judson. The centre is deeply recessed so that I can still use the standard dognut (makes setting the valves a LOT easier),

I moved the steering rack 1'' forward, as even with the standard Judson pulley it was rubbing the rack under hard braking. There's enough space to have no probs with belt replacement. Tracking needs to be reset after this.

I have also had to lower the rad by 1/2" to clear the bonnet on the front corners.

You may or may not have to remove the cuff for the carb air hose. On mine it had to go, but on others I have seen it still in place. I will reinstall again with less engine side protrusion in the winter.

Before you start the first time, rotate the fan manually to check that it doesn't hit the tensioner pulley - many fans run out of true and there is NO rear side clearance here!
dominic clancy

Dominic, Do you have a picture of your pulley? How did you set your steering rack 1" forward. What did you do and did you have any problems. What was the cost for the pulley. Thanks Jeff
JEFF BECKER

Jeff

I'll send a photo of the pulley when I pull and replace the still-under- guarantee rad (when the darned thing turns up - www.west-classic.ch gets no more business from me as I've been waiting 8 weeks for the thing). The pulley cost 100.- which is about $65 US (a friend turned it up for me from aluminium stock using an original A one plus the Judson bit, plus an original dognut for models, so this was really beer money).

To move the rack forward 1" I made up two steel bars to fit underneath and inside the standard mounting bracket for the rack. (about 3/4" * 1" hard steel, 4" long).
I drilled these to match holes in the standard mounting ears on the rack.
I then drilled one hole in the chassis rack mounting points midway between the original ones. I used this to hold the bar in position and then welded the bar in place to the rack mount at the front edge. I had to make a notch in the bar to clear the tack weld that is on the underside of the mount to hold the original bolt head from turning).
I had to re-tighten everything after 50 odd miles, and will check again when I do the rad (there's no room for a hand any more in there with all the belts).

To drop the rad, I just drilled new holes in the rad bulkead.
dominic clancy

Dominic, please could you also send me the details of the cam pully? A friend has a water pump pully for me. Then I should be set to fit everything up.Dave
David Godwin

Dave,

With help from Dominic and others on the Supercharging list, I put a "George Folchi Special" on my Mk II. At the same time, I switched to a Moss alloy head.

The installation was not a challenge. George's kits come with everything needed. My unit has a copper gasket for the intake ports, which made for a good seal, but a bit of a balancing act to get everythign seated. As Dominic pointed out, the only tricky part was fiddling with radiator, fan, and pulley clearences.

In my case, I needed to install spacer bars behind the radiator to move it forward 3/8 inches. With George's pulley I had sufficient clearance from the steering rack. I found the radiator fan was mounted backwards, and had to adjust the fan blades a bit. I used a Dremmel tool to cut out a notch from the carb air hose cuff to make room for the tensioner pulley. It has enough lateral play to be "self adusting".

With George's kit, the water pump pulley and belt are not changed. The dual belts for the Judson run on a "bolt on" pulley that fits on top of the crankshaft pulley. An ugly situation though, I will have to remove the radiator if I need to replace the belts.

Since the belts do not run the water pump or alternator, the issues with alternator vs generator are the same as for any other car.

To be honest, one of things I like the best about my Judson setup is the Holley carb - what a dream after fiddling with SUs ! Idle and mixture screws only, no spring tension on the choke. When you set the choke it stays there !

Takes a bit longer to start up with the longer airway path, and you need to let it idle a bit longer to be sure the Marvel Mystery Oil is flowing, but after that, as Dave Becker put it ...

ZOOOOMMM !

It's the most fun and interesting addition to my car to date.

Go for it !

-Chuck
Chuck Mosher

Chuck,
I think my first name is Jeff (My taxes are paid so I do not have to change it yet). Where did you get a copper gasket for the intake. I know copper gaskets are used on the head or a Payen gasket are used. Thanks for the information
JEFF BECKER

This thread was discussed between 18/07/2006 and 22/07/2006

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