Josephine rebuild

[Keith Clements]

Yes the dwell is pretty much standard starting point for most distributors. The programmable unit I have can alter dwell over the rev range which is necessary to get the best power in the spark. With points you have no such control as it is dependent on the strength of the spring.
In bad cases you get points bounce and very bad misfiring at high revs.

[Keith Clements]

A couple of hundred miles over the weekend seems to have cured the oil on the plug. Why is it that after 50 days without rain Richard arranges a hog roast and I have to put the hood up?

Some tweaking of the mixture in the hotel car park in Coventry to make it richer improved idle and misfiring. I will check with the colourtune later.
Speedo cable decided to fail and some overheating to be investigated but it has been hot.

Josephine had a lot of attention at the Car show in Rickmansworth yesterday

[CyrilWhite]

Thanks , tweeking done , much better there was a slight leak on the union joint on the carb ,new points etc
Will get plugs out after Sundays run to check colour

[Keith Clements]

Took Josephine to the Javelin windscreen rubber replacement technical day to continue her shakedown before the European tour.




Great to have a rattle free Jupiter at last although there is some propshaft vibration still to sort out. Slight overheating which on return today I found was because the electric fan had its leads around the wrong way. Also on the way back 5 miles from home she stuttered to a halt. I investigated by taking off the petrol pipe to prove it was the pump, so called the RAc breakdown service as I was not carrying the spare I normally do. Whilst waiting for the van to come I found a wire had broken off inside the pump so started to repair it when the van arrived. Managed to get some petrol through but the reliability I was not happy with and did not want to take the car on a section of motorway without a hard shoulder. So I called the pickup truck which took JoJo back top her garage. The unreliability may have been caused by another fault which was that the CB input terminal was rubbing on the Dizzie base plate. The base plate when it wears does rock upwards, but also I think in this case the capacitor wire was holding the CB terminal up . It was the wrong CB terminal for the dizzie concerned. Problem was fixed with a bit of silicone holding the CB terminal up. I suspect that I introduced this second fault when investigating the problem when checking the CB gap.
So just need to do a permanent repair to the petrol pump.

[Keith Clements]

Since Peter wanted a new distributor I sent a couple old ones off to the Distributor Doctor as he did not have any DM2s. I asked if a modern petrol and lightly tuned engine needed a different advance curve so he supplied them duly modded.
I tested them in the Crypton analyser and on the car. They are not much different to the ones with which I raced and that I had modded myself. I tested 4 other old Javelin dizzies and all had the same problem of too much advance from 0 to 500rpm. There should be no advance up to 500 rpm but the old ones were between 5 and 10 degrees. Also the old ones suffered from wear so that the max advance was too great.
What this means in practice is that doing static timing on the contact breaker causes the timing to be out by a large amount.

[Forumadmin]

Josephine performed well carrying Scott and me on our tour of Europe.
In particular the distributor performed well carrying us up those mountain passes and topping 150 kph on the motorway.
But I am just reflecting on what Scott and I did just before setting off.
We changed the gearbox which had been jumping out of third and the rebuilt one we fitted jumped out of top. Probably adjustment, so will see if I can reproduce the issue on the little humps we call hills in Britain.
But to fill some time because of our early return following Chris and Sharon up through France, poor Scott was sent to the Gulag to have a look at the assortment of gearboxes we disassembled at the Resto show.
We also tried to think what might have caused Chris's Jav issue of the gearbox seemingly braking itself in second when torque was applied. No joy there but we did find a lot of conundrums when sorting through my collection of gearbox bits.
We consulted the parts books and tech notes and this thread showing different types of lock plunger 50129 on 1st/2nd synchro ring. But then found at least three sorts of sliding dog 50033. There is the Meadows with recessed faces and electric pencil part numbers. There is the recessed Jowett and the flat faced Jowett which was a different height, 45.81 mm rather than 42.66. What is the reason for the different height and lack of recess and does it matter which type of box they are fitted into?



Also confusing were the two recesses on some mainshafts which seemed to serve no purpose. These pics are taken showing the two holes opposite each other but in different positions along the shaft. What is the purpose of these recesses?


The box we were re-assembling had been rebuilt by JCS and had a meadows 3rd/4th synchro which I swapped for a Jowett one as it was a Jowett box and all other gears were Jowett. The synchro showed signs of overheating. Can Meadows gears be successfully fitted into a Jowett box?
Another box we dismantled with the intention of clarifying the synchro ball arrangement only added to our confusion. We then noticed that some 1st/2nd sliding dogs had no holes drilled right through, others one and others two. So what goes in those straight through holes? In the Meadows there is a plunger and spring, but others had a cylindrical plunger some with two rounded ends and some with one flat end. This box had an extreme amount of travel on the 1st / 2nd assembly. My worry there is that an over enthusiastic engagement of first would pop all the synchro balls out. This box also had the wrong washer fitted in the input shaft causing this severe wear.

[IanHingston]

Keith
I see Josephine is/was running an alternator which I also intend to install on my Jupiter.
How do you now drive your rev counter? Have you replaced the mechanical original innards with a modern electrical one and drive it by running a wire from the alternator? That's what I hope to do.

FYI I've managed to source a small stepping motor to replace the cable from my gearbox to the speedometer seeing as now with an overdrive unit fitted I can't use the original cable. It's American and takes electrical pulses from the driveshaft - or wheel - which drives the stepping motor. The motor then drives a mechanical cable which drives the speedo. Bonus is that it is fully adjustable so can cater for changes in when sizes easily - e.g. 16" to 15".

I'm ages away from rewiring the car - it still has no body or motor assembled - but I'm getting everything sorted out now as I will be retiring next year and am looking forward to spending a lot of time on my Jupiter.

Kind Regards

Ian Hingston
NZ Jowett Car Club

[Forumadmin]

http://www.accuspark.co.uk/dynamator.htm
C39 either pos or neg earth with tacho.
gearbox from JCC spares.
There are pictures of it in the thread or Gallery, I hope.

[Keith Clements]

The Dynamator gives more output than the dynamo it replaces, especially at lower revs.
The rear bracket spacer may need changing.

[Keith Clements]

Two sources Powerspark or Accuspark.

Type 2 Dynamator (negative earth + tacho drive) also available in positive earth
https://simonbbc.com/stealth-dynamator- ... ith-tacho/

https://simonbbc.com/stealth-dynamator- ... ith-tacho/

I got the standard rev-counter gearbox from JOAC spares to fit OK.
It drives the rev-counter OK in the SA and performed well on Swiss rally.

Note you do need to do wiring modifications and I fitted a 50A fuse along with other extensive wiring mods for other components.
See this post.
Schematic here.

[Keith Clements]

I have just found the receipts from the first (of many) of Josephine's engine rebuilds that I have done.

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The Jowett Jupiter was the first car that I owned and cost me the vast sum ( considering I was a student) of £70.
It was spotted in the Exchange and Mart that I was reading in the University bar, so I asked my friends what it was. 'A space framed sports car' said an AC Ace owning friend! So off we went and bought it. The bearings failed driving it away so the seller agreed to pay for half the cost of the repair.

It was my only transport until the gearbox locked solid on the A6 in 1971. I was living in a flat at the time and the landlady did not take kindly to me repairing the gearbox in it. So a girl offered her dad's shed as a workshop. That girl was Jenny who later married me, or perhaps it was Josephine?

During this rebuild I went back to my parent's home in Devon in the 3/4 race MGA, that I had bought as a replacement. I retrieved some parts from a stock of parts that filled my Dad's garage. These were from a dozen Jowetts that I had previously collected from a barn of a mechanic who worked in the Jowett agents in Barnstaple.

In 1974 Jenny applied for car club membership. Ian Dearie, the then club Chairman, who was visiting his mother in the next street, persuaded me to become Membership Secretary, perhaps because of my computer knowledge. I have been on the Executive Committee ever since.

Josephine was then used to go to all the Car Club rallies and even towed a Campervan to some. Daughter, Amy, was carried initially behind in a carry cot from 1979 and then with a full harness seat belt between us on the bench seat. In 1988 Josephine started racing and rallying and over 30 years went to 27 countries. So much competition required frequent engine rebuilds and development, but not much was done to the body until 2017 when a repair after a small fire developed into a full rebuild as a birthday present to such a trusty vehicle.

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[Keith Clements]

Since I have previously removed the original midship bearing and its support, I have now made a front support for the overdrive and fitted this afternoon. This compliments the two side supports and the rear support. This hopefully will reduce strain on layrub and provide more stability.

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[Keith Clements]

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After over 3000 miles going to Italy, various local car shows, the Yorkshire Pudding Run , Curborough and Suffolk bit of a service.

The crud on the plugs was cleaned off in my grit blasting plug cleaner. Compression was 5 psi down on number 4 but the others were all at 140 psi. Endoscope not used to check.

Screw that had had dropped off inside rev counter and a sticking needle in the speedo were fixed.

[Forumadmin]

You will see earlier in this topic mention of fitting the Dynamator.
Well it failed on the way back from (or perhaps at) Curborough. I did not notice until back in the garage at home but had thought something was wrong as there was some misfiring as the battery was nearly flat. Luckily some fault finding and swapping with another unit proved it had failed.
Examination on the bench showed poor manufacture as a wire had not been joined properly and had been flung out to short out.

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This I repaired to get a circuit through the rotor. But further testing showed a failed regulator.

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A search on the Internet found what I hoped would be a replacement regulator as it looked the same and was 14v. It was duly ordered and fitted today. Bench testing using a battery , a bulb to feed the rotor coil, a meter and an electric drill showed that the light went out when charging at 14 v. So refitted in the car as this one had the tacho drive.

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Something to be said for sticking with a dynamo but this unit is so much lighter and gives twice the power so can drive the electric fan. At least it took Josephine to Italy and back, just did not like the revs I was doing at the sprint.

[Keith Clements]

After a couple of short trips after an extended hibernation, the Jup was going fairly well but there was the occasional pop back through the carb and a tapping sound.
So a quick check was thought necessary. One of the tappets needed a little adjustment, but not large. Then a compression check .
3 4 and 2 were Ok but 0 on no 1. I could not believe it.
But sure was zero. Endoscope showed a stuck out valve.
Then a bent push rod. The valve would not come back.
So head off to reveal a valve seat had come out. The worst scenario as I now do not trust any of the others.

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