Josephine rebuild

[Srenner]

RE: drums rubbing on the backing plates. I had the same issue on 758 after some years of racing and tons of side loads. I discovered that the bolts securing the backing plate to the axle had begun to stretch and some were visibly distorted. All were replaced with SAE grade 8 bolts and the problem ended.

[Keith Clements]

This week was mainly spent sorting Amy's mini and going to a great evening with Derek Bell who gave an interesting and hilarious account of incidents in his illustrious career as a racing driver. His soon to be published book will contain a lot more.


But I also wanted to design and build a cooling system test rig as although soap bubbles can provide an indication they do not do a quantitative test.
So I needed a schrader valve which I sourced from a cylinder compression tester, a gauge from a car test kit, a T piece and various adaptors. I made one adaptor from a UNF bolt that I drilled out on the lathe. This plugged into the pressure release valve of the compression test pipe.



From the bottom right the feed from the compressor goes to the air gun that can blow into the air tool adaptor that fits into the schrader valve through the pipe to the release button and then to the T piece.

Getting the system to hold pressure is a challenge. I really need some rubber bungs for the pipes. The sticky tape and rubber mat with a jubilee clip is not always successful.

One thing it did show up was the need for a new pressure cap as the one I had leaked. Luckily the one on Amy's SC is the same which is a MORRIS MINOR 1000 4LB/PSI RADIATOR CAP GRC103 AC13. This is not the standard one.

[Keith Clements]

Last couple of days has been spent first fitting one new carb , then the other. The first made a considerable difference to the idle consistency and the second made it perfect. The carbs needed the inlet pipe cutting off with a new olive and nut to fit the elbow joint. There are three very similar threads that 'nearly fit' but only one that does properly, so some time was spent trying to find the correct ones and a pair of olives.

The petrol shut of valves also needed wiring in.

The throttle arms also needed changing. Only a little adjustment was necessary on the throttle stops and the linkage sliding joint to obtain good balance with the carb flow meter. Thanks Drummond for bringing them to the Harrogate rally.

Bit of a knock on the cam shaft thrust peg which did not want to adjust out.

Video of tick over.

Then onto prop balancing. There is a vibration at 35 mph in top which I think does not change rev position when the overdrive kicks in, so suggesting the imbalance is in the front prop. There is also an imbalance in the 65mph range which does change with overdrive kick in. Note it is difficult to make decisions because the road speed is governed by the engine speed as the wheels are not in contact with the ground.

So now trying to see if my vibration meter is better at judging vibration than my left foot on the floor!
Prop balancing video

[Keith Clements]

Amy came and acted as throttle person whilst I measured the vibration and moved the Jubilee clips around. Glad to say the meter concurred with Amy's foot in measuring vibration amplitude. Also the resonance was visible like a vibrating string.

Hopefully now within limits and ready for road test.

The major issue was that the layrub bolts were in the wrong way around. The bolt head should be on the layrub and the washer and nut on the yoke.

[Keith Clements]

After knocking another couple of things off the 'To Do' list, including the bonnet catch height, I put the tools together and went for a drive (visiting the farm to collect milk and eggs on the way back).
Disappointingly the vibration between 20 and 50 mph is still as bad and is torque related, so goes away when the clutch is depressed. It is also before the overdrive as switching it out raises the front prop revs which decreases the vibration.
So could it be the layshaft in the gearbox or is it the O/D or is it new O/D fixing. Well the 'easy' way to see is replace the O/D and prop with the original rear prop. I used to do it in the race paddock in under an hour so with lift, transmission jack and the new quick release fixing should be able to do it in half the time. But it is a Jowett and did I lend that prop to Bill Lock?

Also noticed that the rear offside tyre has touched the top of the new inner wing at some stage. (Probably on full bounce coming up the lane. But also the front offside wheel almost touches the bonnet on full lock and when just sitting normally, so on full bounce would do serious damage. I will check suspension height , perhaps the torsion bars have settled, but even so this should not happen. I suspect the spacer shims on the hub need to come out. The widened rally wheels had an inset so I will check them on there first.

Also the clutch switch and brake switches need some adjustment as they currently have a mind of their own. I am pleased with my secondary flashing brake lights as they do keep cars behind at a safe distance.

[Keith Clements]

Overdrive came out in 25 minutes to reveal the problem. The output flange behind the midship bearing was loose. The split pin was in but the nut had not been sufficiently tightened so the flange was loose on the taper. I had given my spare to Bill Lock as a pattern so will have to wait until it is returned as the keyways will need a lot of work to repair.

[Keith Clements]

Pulled off the bearing housing from the prop. Set up the prop on the milling machine which required much measurement and adjustment to get straight, level and with a registration point for making two keyways 180 degrees apart.
I then cut a new keyway the whole length of the taper rather than the original Woodruff key shape. First with a 4mm end mill then a 3/16 end mill. The key fits well but I need to wait until my new stock of square keys come so as to accurately align the other keyway.

The keyway in the flange cleaned up reasonably well. Although i would prefer to get two new keyways cut in it, I do not have the broaching equipment to do this. I am investigating what is required. Could the milling machine be used to set up the work and then use the up and down movement of the mill head to do the sliding broach action?

[Chris Spencer]

Keith - Pretty sure that you will have this in mind but just to remind you that when I rebuilt the bodywork - the chassis was less it's engine & gearbox - and therefore light on the front - the wheel clearance was checked but the rebuild was undertaken with the chassis on your solid rim rally wheels and not on the Jupiter wheels - are they of the same tyre diameter ?

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[Keith Clements]

Next on the list to check. The pictures shown are of the nearside and it is the offside that is the problem.

The engine being out obviously would affect chassis height but the tyre should not touch even at full bounce. We should have relaxed torsion bars completely to check this.

The chassis height on the nearside is 5 3/8 inches and on the offside 6 inches whereas the height from floor of the top of the wheel arch is 25 inches on nearside and 24.25 on offside. So there is some twist down on the offside . There is also 2.5 inch from outside of wheel arch to tyre on nearside and 1.25 on offside, so some twist towards nearside.
I will have a play and measure from the wheel drums and chassis to wheel arch apex. It maybe these tyres are too high profile, so I will also see what the difference is to standard.

[Keith Clements]

The rally wheels are half inch taller and the tread is 1.5 inches wider (5.5 rather than 4).

So I refitted them and the clearance was about the same.
The rally wheel on the offside at full lock with no load in the car.

The standard wheel on the nearside with 10mm spacer at full lock.

I then took off the 10mm of spacer and refitted the standard wheels. The clearance was now better but not enough to be clear at full bounce.

[Keith Clements]

20180618_191333.jpg

I used 5mm keys rather than the 4.76mm original as they took up the wear giving a tight fit and gave .25mm more depth to the key.
Now the assembly is very tight. So back in tomorrow.

[Keith Clements]

The refurbished front propshaft was installed and the original rear prop put in to replace the overdrive and shortened rear prop.


This is the modified midship bearing housing. There is a cut out to allow inserting of bolts (necessary when O/D flange is used) where the grease nipple was (no longer needed as sealed for life bearing) and metalastic bushes to give greater stiffness to support.


I also adjusted the ride height to 21cm from the round part of the chassis between the bolt that holds the rear trunnion of front suspension arm and the start of the bed angle (not the bed angle apex). This required all the adjustment in the torsion bar adjuster. This considerably reduced the likelihood of the front wheel hitting the wheel arch. I also talked to Chris about the differences with the SC and misalignment. I think the centre of the oil filler cap should line up with the centre strut of the front grill, that the U shaped bonnet locactor support on the bonnet should align on the inside with the upright of the locator bracket on the chassis, the hub cap is 1.5 cm in vertically from the outside of the wheel arch, and that when suspension height is correct the top of the tyre is level with the wheel arch. It would be interesting to see how many Jupiters are like this!



This exercise started really with the rad touching the bonnet cruciform which was cured by reducing the height of the rubber support on the rad. But I also noticed the drive belt was touching the grill which has been solved by aligning the bonnet. This moved the bonnet 15mm towards the offside. The grill is still too close to the oil filler and this I think can only be cured by moving the bonnet forward on the hinges. There should be about 15mm clearance. As Chris said 'should have had engine in when aligning the bonnet'.


I also adjusted the gear shift as Amy complained it was difficult to engage. This exposed another issue where my complex use of the rear fog light as a flashing brake light and reversing light caused flashing with just the ignition switched on. Diagnosis showed a sticking reversing switch, so some WD40 fixed that.

A quick test on the lift seemed to be OK so then out for a drive on a sweltering day. A visit to a friend rebuilding a bike and a trip to the wine bar concluded a successful day.

Today will put the O/D back in.

[Keith Clements]

As well as that fixed a small leak on exhaust and a broken mounting. Also adjusted handbrake and cleaned around clutch switch so that it bedded more positively..
I checked overdrive mounting alignment on installation so will do a road test after watching the England Rugby match.

[David Kemp]

Do you know what vehicle the overdrive unit came out of?

[Keith Clements]

Not personally, and it has been in the Jup for 25 years. Various O/D units can be made to fit. OD spares in Rugby, who made the adaptors for this unit, can now offer a more compact unit that would probably fit in place of the front propshaft and not foul the seat mechanism.

I took the car out to the pub yesterday with Amy and it still has some vibration (but less than before), so more investigation required. I suspect the midship suspension is too stiff or that there is a slight misalignment of the prop/OD flange. Ideally the midship bearing should be replaced with a U/J as the prop is supported now by the O/D.