Alloy wheels for Javelin/Jupiter, possibly others

[Jack]

Righty then. Just got off the phone with Compomotive, very very helpful chaps.

Now as it happens, they have a set of blanks in the workshop, and are happy to put a Jowett PCD on the wheel instead of the Saab one - apprently this isn't a significant additional cost for them, so initial estimate is still £850 for 5 wheels.

They have asked me to get a standard steel wheel and hub to them so that they can measure things and establish whether the offset, PCD, and other measurements are compatible, and if so will provide a price for us - possibly including a discount for Jowett Car Club members.

I will hopefully be able to get the parts to them in the next week or so, as I have family local to them that can drop off and collect the parts.

Please shout if you are interested in these wheels - they will be on file for Compomotive once we have got the precise measurements, however they are manufactured in batches so there may be a significant lead time if they haven't got a batch of blank castings completed at the time of your order.

Note, these are 15" wheels, which will mean the car sits a little lower than normal. I doubt this will be a problem for Javelins, which to me look like they could do with being slightly lower to the ground anyway, I should be able to get at least one set sorted so that we can fit to a Javelin and a Jupiter to show other members how they look and get measurements of ground clearance. I know Keith has run 15" wheels on a Jupiter in the past, and may be able to offer an insight into whether this is practical for day to day driving.

Jack.

[Robin Fairservice]

If you can find alloy wheels,then can you please look for higher ratio crown wheel and pinions as the exisitng ratios are too low now for highway work. At 60 mph the rpm are 4000, and at the Javelin's top speed the rpm is 6000 which seems too high for a 60 year old engine with a suspect crankshaft. With 15" wheels the rpm are going to be even higher.

[Jack]

If you can find alloy wheels,then can you please look for higher ratio crown wheel and pinions as the exisitng ratios are too low now for highway work. At 60 mph the rpm are 4000, and at the Javelin's top speed the rpm is 6000 which seems too high for a 60 year old engine with a suspect crankshaft. With 15" wheels the rpm are going to be even higher.

Hi Robin,

For this project that won't be an issue, we've got 100 bhp to pull things along, and will be fine at higher speed on lower rpm. Of course we'll be doing some work on making sure it is up to the job, but by the sounds of things the engine revs are the limit as opposed to the parts further down the chain.

I will, however, quite happily do some research, crown and pinions are commonplace on older cheap cars now, so finding some and having a play shouldn't be too hard. I may need some input from some who are a bit more experienced in these things, if given a brief and dimensions to work with I am fairly handy at finding things that fit or work from other cars.

Jack.

[Robin Fairservice]

The Mk 1 Jaguar's rear axle had the same track as a Javelin. There was a range of ratios for 2.4 Auto's, 2.4 Manuals, 3.4 Autos and 3.4 Manual's. I am told thatyou cannot simply switch the crown wheel and pinions, but if you can weld, then the Jowett mountings could be substituted. You would also get stronger half shafts if they are an issue. The Jags also had 15" wheels.

[Alastair Gregg]

I can confirm the CWP cannot be substituted. It was a Jowett Special. I have checked Jag, Morgan and Triumph.

[Leo Bolter]

Here's a couple of images of Carl's Javelin on 15 inch steel wheels. As you can see it looks good and still has a authentic appearance.

TOPIC

[Forumadmin]

The planet wheels from a Morgan can, as I took the last few from the Morgan stores after the 1982 Marathon.

[Srenner]

I had a 4.1 CWP (ring & pinion over here!) from a Morgan installed in a Jupiter axle. They are easily interchanged.

[Jack]

So we seem to have solved the C&P problem potentially, albeit those parts may be hard to find as well, it is possible.

Does anyone have any input on possible disc brake conversions? If it is a simple Morris Taper then surely there are other cars that used a similar size and went to discs at some point? Perhaps this is a potential new topic, it is certainly getting away from the wheel discussion and might help with searches in future if we split the brakes thing out.

Jack.

[Alastair Gregg]

Interesting conflict here.

Which model Morgan did you get it from Scott,

We had a Morgan agent (Richard Thorne who took his Jupiter round the le mans Classic) look into using Morgan CWP from the Salisbury axle used by Morgan. He said it couldn't be done. Hence my confirmation. Now this was only a couple of months ago.

Very interested to hear a bit more from Scott as I really want a 4.1 or maybe a 3.9:1 in my Jupiter.

When the JOAC had a batch made they almost without exception moaned un-acceptably after several setting sessions.

[Moises Jr.]

OK, my father's javelin have a ring adaptor to WV beetle.

[Srenner]

Okay, I have to correct an error on my part. I wrote "Morris" taper when I should have written "Morse" taper.
This is a standardized system of the machine trade to ensure uniformity, just like screw threads.

The point I was trying to make was the rear axle shaft taper is a common one to many cars, not specific to Jowett. The front stub axle has flats for the bearings, so any change in hub design requires selecting bearing ID/OD dimensions to fit the Jowett part to a different hub.

Sorry for the confusion! I posted this on the Disc brake thread as well.

[Srenner]

Morgans before 1962 had 3HA difs in them, so the whole center section is the same.
Scott

[Alastair Gregg]

Will get him to check this out but when I went into it everyone said the bearings were different od's and to make one fit a Jowett axle would be"an engineering job" Thanks for the lead

[Jack]

Will get him to check this out but when I went into it everyone said the bearings were different od's and to make one fit a Jowett axle would be"an engineering job" Thanks for the lead

In my experience that means it will cost about £200-£500. More than £500 and it is officially "a bit of a nightmare" and more than £1000 is about 3 minutes of sucking air through their teeth and poking at things while avoiding eye contact. That is The Moon Engineering Price Scale. We also have The Moon Engineering Tightness Scale ranging from "just swing on it a bit" to "swing on it a bit with a 3 foot bar" to "get everyone in the shop to hang off that scaffolding pole while I hit it with a hammer". This was what everyone used to use before torque wrenches were invented, and many branches of Kwik Fit across the country still use this system

Jack.

*Disclaimer* None of the above is actually true. Before anyone goes into an engineering shop and asks where it will be on Moon's Engineering Price Scale