Techtips from old jowettnet

[Keith Clements]

This section currently links to the first of some technical articles learnt from 15 years of motorsport and 30 years of family use with Jowetts.

There will also be articles from readers, so please send them in.

Every pair of rear main bearings I have ever removed from a Jowett engine have broken up with the bearing material breaking away in chunks from the backing material. So on my racing engines the rear main white metal two layer is replaced with a three layer bearing with separate thrusts in the centre web. Next post shows a method used for fitting main bearings.

This is from the late Harry Brierley in an old Jowetteer and tells you how to identify a Javelin.

qa-javmods.pdf

(193.87 KiB) Downloaded 34 times

This from George Green in a 1963 Jowetteer answers various questions plus a register of cars in New Zealand.

qa-g-green.pdf

(148.09 KiB) Downloaded 26 times

This is the pdf of the Javelin Tuning Notes.

JAVELIN-TUNING.pdf

(349.76 KiB) Downloaded 21 times

A section on Rear axle overhaul from the 1950 Maintenance Manual.

jav-maint-50.pdf

(650.27 KiB) Downloaded 27 times

See subsequent post on a way of fitting an overdrive to a Jup.

See subsequent post on a few pictures on the modifications performed on my Jowetts.

Plus some tips for fitting electronic ignition 1,2,3, adjusting the electric petrol pump and the tool, converting to an alternator or changing polarity

lumenition1.pdf

(251.75 KiB) Downloaded 20 times

lumenition3.pdf

(158.81 KiB) Downloaded 19 times

lumenition2.pdf

(216.84 KiB) Downloaded 21 times

PetrolPumptool.pdf

(18.86 KiB) Downloaded 25 times

Here are the tools that you should have in a Jup but in a pizza tin (that fits in the spare wheel rather than a tool roll, courtesy of Craig Ainge.

[Keith Clements]

The end float was checked on the rear bearing and set to .0003 inch by grinding the surface of both thrust flanges with coarse paste on some glass. The end float is measured with a feeler gauge between the shell thrust face and the crank flywheel flange. If it is not 3 thou the shaft might seize when hot as the aluminium bearing housing expands. After a trial fit with torqued up bolts and some turning of the shaft some high spots were noted and ground down again. Turn the shaft by fitting the starter dog. Note do not exceed 80lbs feet torque as the dog may break. After 3 attempts I was happy. Note all traces of paste were washed off as the soft white metal tends to absorb them. There are many bearings that have oversize thrusts (10thou) so check end float. Obviously oversize bearings will not fit in a standard shaft but they can be ground down. An oversize shaft will have a bit too much end float with standard bearings.

In the absence of 30 thou oversize main shells I cut the flanges off some rears to make these.

I check the shaft turns when the bolts are torqued up, slowly tighten them in turn evenly to see which bearing is binding, as usually it binds with a reground shaft and new bearings. Then turn the shaft about 10 revolutions and remove it for examination. you can usually see a shiny bit where the bearing is grabbing. Often the interference is on the width of the bearing caused by the filet radius to the web. A smooth file will rectify the situation. when everything is turning nicely clean all the oil off. Note the oil seal wear ring on this shaft that needs to be avoided by offsetting the new seal.

This shows the use of Plastigauge to measure the main bearing clearance. The clearance is about .00035 Inch. the wire of plastic is squeezed flat when you torque up the crankcase bolts. The width of resultant smear is then measured. Note the shaft and bearing must be free of oil and must not be turned.

[Keith Clements]

This page shows one way to fit an overdrive to a Jup.

The cross-member between the battery boxes needs to be cut and some supports welded onto the chassis. Some additional 'fitting' to allow speedo drive to enter battery box and cutting of the floor and shaping of the floor support is needed. The centre support rubbers were changed to suspension metalastics welded into the holes where the rubbers should go. A prop shaft from a Reliant Robin was used. It needs grinding away since the angle of travel is great since it is so short. The setup survived Marathons across the Sahara even at full yump though I did fit a restraining rope to prevent full bounce travel. The adapters and reconditioning of the OD unit were done by OD Spares, Coventry +44-1203 543686.

[Keith Clements]

Jupiter accelerator pedal.

Dear Keith,
>
> Thanks for the greetings, please have a happy 2001 yourself. You may know
> already from Ed Nankivell and John Blaze that I own E2/SA/882R, the sole
> surviving Jupiter I believe in Asia. I've owned her for the last 30 years.
> I'm in urgent need of two sketches:
>
> (1) The toggle hood catch securing the centre of the front lip of the hood
> onto the top edge of the windscreen.
>
> (2) A line drawing of the inner workings of the Jupiter accelerator pedal.
>
> These two items have been long modified and I wish to revert back to
> original. If posting, Edmund and John have my postal address.
>
> Sincerely,
>
> Asoka Wijesurendra

Keith's reply....

Sorry it has taken so long but I have only just been given a pedal to look at.

Attached are some very sketchy drawings I did this evening. Hope they are of some help. I did technical drawing at school, but you would never guess!

I will take some pictures and add these soon.

Note Bill Lock has pedal bits in his spares list on his web site.

[Keith Clements]

Javelin Steering Column Adjustment

From Geoff McAuley

Hi Keith,

Thought your TechTip page looked a bit bare, so here's one to kick it into life (not that this will be of the slightest interest to anyone!). The Javelin steering column & box assembly is cleverly designed to allow for adjustment to compensate for wear. But it's a blighter to do, particularly adding or removing the triangular brass shims, which has to be done standing on your head with your legs flailing in the air!. The maintenance manual tells you how to do the adjustments, but few people know that it's a lot easier to do the task if you've got the engine out. Simply remove the steering wheel and the steering box fixing bolts. Pull the box and column out through the engine bay, and then do all the adjustments on the workbench. Afterwards, slot the entire assembly back up through the scuttle, & Bob's your Uncle. Thankfully the process only needs doing about once every 50 years - so it's hardly a chore!

[Keith Clements]

These are some of the modifications performed on Keith's Jowetts.

Pictures of a mod to the oil filter housing gasket available from JCC Australia.

The necessary wiring changes are shown in the two diagrams for alternator and dynamo. Some rallies insist that dynamos are used.

Halogen tail/stop 12v 35/15w at least twice as bright at the rear from Andrew Brock, Classic & Vintage Bulbs +44 2082990299. He also does the rear Number plate, festoon indicator and front side bulbs in halogen to make them more reliable and brighter. Be seen , do not be hit!

The following were done on the Javelin mainly by Ben Shaw, the only previous owner.

I think this marble wheel is non-standard.

The Kenlowe electric fan and thermostat control

The alternator bypass to the regulator

The brake fluid level switch, vacuum assist brakes and indicator, hazard and trafficator electric relays.

The jack, pump, wheel brace and rubber plug for the jacking point on a Javelin. Not a mod but somebody asked for pictures.

From Huntley Perry. The correct Jupiter tools and jack.

correctjack.jpg (10.86 KiB) Viewed 1540 times

correcttools.jpg (11.95 KiB) Viewed 1540 times

This is the pair of castings glued into the pump and timing cover and then bolted together to replace that rubber pipe that bends under the tension of the dynamo.

And now for ones on the Jup........

This is the towbar that was fitted to the Jup .

This is the sump guard fitted with wooden spacers to absorb the shock and protect the chassis. Worked when we yumped onto a boulder kindly placed by some Bedouin kids.

The aly rad with fan. Note the bottle to collect any boiling fluid. Never does now, but was useful in the past. Also note the gearbox oil filler pipe. Saves a minute or two in a rally.

Here is the oil cooler fitted on the front bulkhead. Lots of air and keeps clean and well protected. The big black cables are for the battery cut out necessary for racing.

The Delorto carbs fitted on to slightly moved studs. The Javelin has an adaptor plate that fits onto original holes. Note the 65A Alternator for those Winter rallies. The Piper filters cost a fortune and were covered with vacuum cleaner bags in the desert.

The dash with Halda Trip and Speedpilot. Also note the twin temp gauges measuring both head temperatures. Two rev counters. The one on the column is so I can see it when racing as you cannot hear the engine even at 5500rpm. I guess the small steering wheel, map reading lamp, Velcro for pencils and stop watch, bucket and fire extinguisher count as mods. Horn push is in cigarette lighter hole so that is accessible by navvy, useful on Italian bends. Switch panel below oil gauge on the right for overdrive, rally lamps, washer and heater rheostat. Yes I know the heater has been removed for the desert!

Fuse Use Amps max
1 horn push, stop light 3.5
2 ignition, petrol pump,gauge 4
3 heater,washer, wiper,overdrive 6.5
4 gauges, fanthermo,overdrive latch 4
5 horn, reading and hand lamps 12
6 clock, indicators 4
7 radiator fan 8
8 panel and side lights 5
9 headlamp 16
10 spotlamp 16
11 diplamp 16
12 foglamp, rear fog 8
glove lamp relays 2


RELAYS
overdrive
rad fan
dip
fog
spot
head
horn
Driving lamp combinations

Lamps- spot, head, dip.

Switches- new double pole, old wiper and heater.

s h d hd/sf w h
- 1 - normal head h - -
- - 1 dipswitch h - -
1 - - country head s 1 -
- - 1 dipswitch s 1 -
1 1 - rally head h - 1
- - 1 dipswitch h - 1
1 1 1 max head h 1 1
- - 1 dipswitch h 1 1
max also acts as contingency for headlamp failure

Note knobs on switches are moved from original positions

Centre panel configuration
Indicator Switch
Dip (marked W) Spot (marked H)
Ignition L Indicator L
Rear Fog (marked F) Panel
Horn is in cig lighter


Right Panel Configuration
HD/SF, Overdrive ,Heater, WashWipe
All components have separate earth feed back to central earth point. They do not use chassis.

Other electrical mods.
SC wire Tracer

SC schematic

SC schematic updated

SC wiring with relays

[Keith Clements]

When preparing the wheels for the Sahara I took some dimensions.



Wheel-------- Middle of Tyre--- Drum face-- Offset
Javelin/Jup standard -6.5 ------ 10 ----------3.5
Modified Saab-90---------7.5------------11.2 ---------3.7
Widened Javelin--------8.2 -------------11.5 -------------3.3
Modified Suzuki jeep --8 --------------13 --------------5
Note that spacers are used to bring contact patch in line with king pin and overcome offset. The adjustment can accommodate different profile tyres. Longer stronger Rover studs are used. The main thing to watch when fitting wide rims is fouling the upper suspension link (particularly on metal suspension) and cutting into the front wheel arch on full bounce and full lock on the Javelin.

[Keith Clements]

These images reveal what could be a cooling system breakthrough for the Javelin and Jupiter, as discovered by the ever-inventive and highly observant Pat Lockyer. Two new pictures from Pat .

front cover restriction mod.jpg (13.95 KiB) Viewed 1536 times

The image above shows that the water passages - as manifolded by the front timing cover - have a 3:1 constriction for the right side with respect to the left side.

The top and bottom images on the right show Pat's modification, which early tests seem to show a successful reduction in engine running temperature.

cover0.jpg (13.34 KiB) Viewed 1536 times

cover1.jpg (19.02 KiB) Viewed 1536 times

cover2.jpg (16.32 KiB) Viewed 1536 times

[Keith Clements]

This whole process started when I read an interesting article by Pat Lockyer some time ago. He discovered that there was a restriction on the driver’s side of the timing case cover caused by the distributor shaft running through the water jacket. So I decided to measure the temperatures on each side of the engine with some temperature probes. Thanks to Bill Ebzery we managed to get our hands on such a device but with no running engine of our own to test it on we waited for an event at our place so that we had the two vital ingredients. The first was Bill Ebzery to run the device and secondly the most important was Sue with her Jupiter so we had a car to test. Firstly we had to rig up the car with the temperature probes as shown by the pictures at the end of this article.

We then started the car and waited a while for it to warm up a little. The following results were taken with the car in neutral and revved between 2000 to 3000rpm. The ambient air temp was also measured at a lovely 23oc. One interesting note was that while the water pump temperature measured 65oc the cars temperature gauge read a much higher temperature which fluctuated between 75oc and 81oc. Looks like Bill has another job to do when he gets home.





Time

Interval between readings (mins)6---------8----------10----------12-------------14

Passenger timing case-------------42--------46----------48---------49-------------51

Driver’s timing case----------------56--------65-----------65--------66------------68

Driver’s water transfer------------58---------69----------71--------73------------76

Passenger water transfer---------55----------62----------63---------63----------64

Water pump outlet------------------60----------70---------64-----------65---------65





From the chart above we can see that there is a substantial temperature problem on the driver’s side of the car which is the side with the restriction, at the worst there is a 19oc difference between the two sides of the engine. We must now ask ourselves several questions. Does this affect the car’s running? How do we go about fixing the problem? Is it worth fixing the problem? These cars have run for 50 years and the majority have survived intact. Although I can’t answer all the questions above I do have a theory about how it affect the cars running. For an example let’s assume you run absolutely no coolant in your engine, when the gauge on the dashboard reads 90oc you think that’s ok I’m not boiling yet, however while the passengers side of the car may be around 90oc the drivers side is 19oc higher at 109oc and has turned into steam which is not very good for cooling.

Granted nowadays with the addition of coolant and the 4 PSI of system pressure the cars won’t boil till around 120oc however the problem is just delayed not cured. Also who knows what other affects the temperature difference may have on the engine? Hopefully this article has given you a little more insight into our beloved Jowetts. Whether you’re young or old its interesting learning about what makes our unique little cars tick. Finally, thanks to Bill Ebzery for the use of the equipment used in this experiment and his expertise in running it and Sue for being kind enough to lend us her baby to be poked and prodded.

See pictures below of the measuring points

By David Hood

. Pat Lockyer's modification can be found in previous post

[Keith Clements]

These are some specifications of distributors and equivalents that assist in setting up worn ones.

Whether the curves should be changed for modern petrol, driving conditions and modifications to the engine is open to discussion!

Anyone want to do an extensive trial on a dynamometer?

My take on this table is the max advance is 10 degrees (or 20 at the crankshaft) at 1300rpm.

This agrees with my dyno. reading of 21degrees. The extra degree is probably because it was running on 4 star rather than the pool petrol of the 50's.



Service number* Model* rot'n* RPM 1* Advance1 ±1°* RPM 2* Advance2 ±1°* RPM 3* Advance3 ±1°* no advance below* years* make* models*
40317A DM2P4 CCW 1300 10 650 4.5 500 2 250 1953-54 Jowett Javelin and Jupiter

40318B DVXH4A 1954 Jowett Jupiter racing model

40571A DM2P4 CCW 1300 10 650 4.5 500 2 250 Jen's xmg258

40795A 25D4 CCW 1200 10 600 6 350 1 225 1961-74 Morgan, Triumph Morgan Plus 4, Triumph TR4A recommended alternative to 40ll5H and 40317A for jowett

40548A DM2P4 CCW 1300 10 650 4.5 350 0.5 250

40735 DM2P4 CCW 1200 10 600 6 350 1 225

[Keith Clements]

The Javelin chart is available here in Pdf format.

[Keith Clements]

The following pictures were taken during the repair of the gear shift column that broke in Norway.

The outer shaft broke across the slot. Note the arm has been turned off to be used on Javelin shaft.

A contributing cause may have been the fatigue of 52 years of abuse on rallies and family motoring. The worn helix caused by corroded balls through ingestion of water perhaps on one of the winter rallies may have added to the stresses. A new inner and outer shaft were needed made up from the bottom of a spare Javelin column, since a Jup one was not available and Javelin ones are different lengths. Note the wire retainer on the ball bearing housing. I dispensed with this on reassembly by using Loctite.

The above shows the floppy broken column at the top before disassembly. Note rubber bush versus aluminium offset one.

Disassembling a column is by no means easy when you follow the manual and everything is covered in grease (see below); and rebuilding it to the correct orientation even harder. First you need to understand all the components and secondly you need to measure all the angles and lengths before cutting the shafts. Accurate angular alignment is essential. I was going to use part of the broken shaft as a sleeve to join the outer shaft together; but John Blanckley found a longer bit from stock to fit. We had to turn and drill a sleeve for the inner shaft.

Top gear.

Neutral

Third gear.

Reverse

You also need to modify the arms.

Note the Jup arm was turned off from the broken shaft on a lathe and then welded to the Javelin shaft that had its arm ground off. Quite a major job, since the parts are case hardened. It may have been easier to cut the arm off and weld on as I did with the other arm.

Note the aluminium bush with offset to move gear knob away from dashboard. This replaces the rubber bush. Make sure a washer is large enough on the bolt to the chassis to stop this bush moving.

It is possible to reassemble in the wrong orientation. There may be marks on the parts which should assist but the best thing to do is mark them yourselves.

Finding the small clevis pin in the reverse stop pin is not easy. I used a BA socket to act as a support while drifting the pin out with a punch. Note down the orientation of the reverse stop. This helps in reassembly.

The split pin in the shaft that holds the slider block. Mark position of aluminium housing relative to outer shaft.

Remove circlip (which is not that easy) and then spring and guide may pop out so cover with cloth! Mine did not and I had to grind a slot to get a lever under it. See? Then remove circlip at top of inner shaft. Three balls are inside helix, do not loose them when removing . Mark position of boss/arm relative to inner shaft. There are three possibilities, only one is correct. Check the grooves are smooth. Try cleaning everything and putting the balls back to test ease of movement. I did not leave it like it on final assembly; but thought that an extra ball in each groove might improve loading and movement.

Removing the wire circlip or perhaps a grub screw means you can turn the castellated retainer. There are two bearing cups and about 18 balls to fall out. On reassembly, I used Loctite rather than screw or clip. I also tightened to give smooth movement without grab and little play.

If you want instructions on removing the column and more detail, try JowettTalk.

[Keith Clements]

The original tyres fitted were crossplies.525-16 were fitted to the Javelin and 550-16 to the Jup. Standard loading recommends tyre pressure of 26psi all round on Javelin and 24 on the Jup. Here is the relevant page from http://www.vintagetyres.com/vintageindex.htm

Size -------Type --------------OverallDiameter SectionWidth Max Speedmph Max Load White Wall Width (mm) Tread
500/525-16 Dunlop C18 678 144 95 381 -
500/525-16 Firestone WW 673 134 - 300 57
500/525-16 Firestone 673 134 - 300 -
500/525-16 Avon Tourist 628 124 75 401 -
550-16 Dunlop D2/103 TL 695 155 95 406 -
550-16 Avon Tourist 691 150 75 450 -
550-16 Firestone WW 695 154 - 375 63
550-16 Firestone 695 154 - 375 -