Jupiter restorations.

[Forumadmin]

Having driven long distances in a Jupiter and Javelin in Australia I do not see a problem, provided the car is well prepared. Speak to all the Australian club members who do cover such distances. Jowetts are more susceptible than some cars to overheating in Aus summer temperatures so fitting an aluminium rad is a good idea. See articles on JowettTalk on the subject.
I have often thought we should award medals to Jowett owners who cover large distances in the year in a Jowett. Most owners manage only a few hundred miles per year.
Back to the issue of the crankshaft, it is revs which kills them and bad balancing increases that risk. Engineers in the 1940's did not really understand the forces involved in crankshaft design. Metallurgy too was not that far advanced or steels were not available. It was not until the 1960's that Laystall cracked the problem. So we need to be more sympathetic with the 1940 technology in a Jowett compared to that in the Fords, Holdens and Mitsubishis of a later era. But there is even more enjoyment as a result.

[dougie]

Brian Holmes has done over 80K miles in his Jupiter and it has managed it well. Barry Houston also as have other Australian members.
Brian has a Ford Sierra gearbox and Barry has an overdrive while Neil Hood has replaced the diff to give a better cruising rev range.
The 4.56 ration diff at 100kph means that the engine is doing in the region of 4200 rpm. As my Jupiter has been lightened by not fitting the bumper bars,quater windows and wind up windows etc I choose to trailer my car to distant events. For example the next national rally is around 1500 klm away from me. I usually carry some parts and tools including axle stands and garage jack in my towing Land Rover and act as support for the Jowetts that are being driven. In over 35 years I have yet been needed. Only small repairs have been required. Brian has driven his Jupiter to every rally since he restored his Jupiter and that it twice to Western Australia. Barry did the WA trip once I think. That is a round trip of about 7800 Klm. Australia is a big place.
David,if you choose to drive your car to the rallys you won't be traveling alone, so will have support!

[David Kemp]

Thank you, I intend to drive my Jupiter! I can't see the point of having a Jupiter & keeping it locked in a shed.
I have wanted one since I was in primary school 50 odd years ago, & intend to get as much enjoyment out of it before I am too incapacitated to drive.

[Andrew Henshall]

Hi David,

While crankshaft failures on engines built with square-sided cranks definitely occur, I've not heard of any failures on engines using Laystall cranks, and so my strong recommendation is that you purchase a Laystall crank, and build an engine based on the well-documented guidelines provided by JCCA club member Mike Allfrey using modified crankshaft bearings.

If possible you should find a Series III crankcase, but if you can't find one, then you must modify a Series II crankcase to have the upgraded oilway drillings, latest oil pump & pickup, etc, etc.

Following this specification will result in a engine that is capable of being used regularly for long distances on Australian roads. Melbourne to Toowoomba QLD and back for a JCCA National Rally over less than a week is exactly what I am talking about = 3500km. Interstate trips for JCCA events in Jupiters, Javelins, & Bradfords are the norm in our club, and all involve way over 1000km journeys.

Some of our Jupiters still have standard specification powertrain/gearbox/differential, but some have sensible modifications including Laycock de Normanville overdrives, 5-speed transmissions, or much taller axle ratios: eg Ford Falcon 4.10 ratio instead of Jupiter 4.556 ratio. All are designed to reduce the engine rpm at 100km/hr by at least 10% (axle ratio change) or preferably 20% (overdrive).

Our engines built to the latest club recommendations using the right parts in good condition (crankcase, crankshaft, oil pump, etc) are very reliable, provided they are serviced regularly. Nothing new there!

Note: according to a gear ratio table I have, a Javelin is doing 4000 rpm in top gear at 100 km/hr on standard sized tyres, while a Jupiter is doing 3650 rpm at 100 km/hr on standard size tyres, both cars with standard drivelines.

Would I personally do over 800km in a Jupiter in a day; no, I would want to take more time and enjoy the experience. People will want to talk to you every time you stop, and so planned 10 minutes stops become 20 minutes! I regularly do 800 - 1000km trips in my modern car by myself, but that's with air-conditioning, cruise control, sat nav, quality stereo, low road noise, low vibration levels. About 4 years ago I did 1200km in a day in an old Nissan Patrol towing a tandem trailer, and then turned around and drove back the next day, but that was with two drivers. We arrived home feeling quite OK, but I slept well that night! What distance would I drive a Jupiter per day: 600km.

Cheers, Andrew

[David Kemp]

Do you know what Ford Falcon diff people use? Is it the whole diff or just the CWP?
I have seen people swap early British Ford CWP out of early Escort/Anglia/Prefects, but would have thought Falcon too large.

[Andrew Henshall]

I know that Mike Allfrey used the Borg Warner 75 Series axle from a Ford XY Falcon ute! Unfortunately, there is no way that a Falcon's 4.10 ratio CWP will fit into the Jupiter's Salisbury 3HA-001-16 axle assembly. He took the tubes (complete with suspension mounts, etc) out of the Salisbury centre housing and welded them into the Falcon centre housing being very careful to get the pinion nose angle correct. Another critical element was making sure that the tube lengths were correct so that the larger Falcon centre housing fitted into the space under the Jupiter and that the prop shaft didn't hit the battery box on one side. Of course you need to match the Jupiter splines in the BW diff centre which come in both 25 & 28 splines.

Ed Wolf's standard bodied Jupiter also has a 4.10 ratio diff.

Note, these probably won't be the 4.11 ratio CWPs out of the later (stronger & bigger) 78 series BW axles, although it appears that they might be able to be shimmed to work.

Neil Hood used a different approach: he converted the Jupiter axle to a 3.73:1 ratio by fitting a complete early model Volvo diff and re fitting the original Jupiter half-shafts etc. The Volvo and Jupiter diffs were both made by Salisbury, and the Jupiter gear carrier cover was able to be re-fitted. This 3.73 ratio reduces the engine revs at 100 km/hr by 22%.

I've heard of a Javelin fitted with a 3.23 ratio diff; which is so tall that it must make the Javelin a bit of a slug in top, but gives it a very high top speed when travelling down hill with a strong tailwind!

Cheers,

Andrew

[David Kemp]

photos of the best motor I have. It is a E0PC , from the web it appears the crankcase is not that desirable as it has no oil groves for the main bearings or webbing to increase strength.
The oil pump is a short body 1 3/8th so not that desirable either.
Can anyone give an opinion on the crank,. Does the numbers on it mean anything?
From what I can work out I have nothing to jump for joy about except it is not a PA motor

[David Kemp]

Also spigot bush fell out of the end of the crank, & fly wheel was easy to remove. I thought a puller would have been needed for the flywheel.

[Srenner]

Hey David:

Here's my POV: Upgrades are generally an improvement and a stiffer block is a good idea, but the modified modern bearings work just fine with early blocks. Also, I have driven my E0 block in my Javelin quite a bit without any signs of disaster due to the lack of the extra bracing. That block was even use for a season of racing some 20 years ago. It also hauled three of us and a bunch of gear up the mountains on a 6k mile tour. The cases are unlikely to fracture on their own; freezing and flying bits of broken rods/cranks are usually the culprits. Given the thrust is on the rear, the stiffeners add some security, but make sure your crank end play is set properly. Stiffer is better, but may not be the focal point.

All the gears in all the oil pumps are the same size; the later taller pump lowers the unit into the sump. What you want is FLOW, which means the biggest diameter pick-up and delivery tubes as the later pumps have. Also, your E0 block would need to have the oil transfer holes from the front to the top in the 1/3 case enlarged to later spec. Not hard to do at home with some drill bits.

The crank is a slightly different issue. The additional meat and rounded shape, as well as the later, better understanding of metallurgy and heat treating make the oval web a much better choice. Abuse and bad prep/assembly can kill anything though.

Flywheel is located by the small boss, not held in place, so pops of fairly easily. The bush falling out is a bad sign, as it should be a very firm press fit. Yours had to be stuck to the input shaft and spinning inside the crank. Easy to see on the outside of the old bush. You need to inspect the inside bore of the crank if you re-use it.

Have fun!

[David Kemp]

Scott have you ever thought of fitting a non Jowett crank, eg a VW ? As the largest VW stroke I can find is 84mm,it would need to be a stroker crank. Subaru do a 90mm , but I think a 5 bearing crank.
Has any club thought of making oval cranks?
The NZ club made cranks for Bradfords, has there been any thought to a jupiter crank.
To fit a VW crank & keep the same capacity , a bore of 75mm would be needed, has anyone taken one out that far?

[David Kemp]

Lewis engineering have rebuilt Jowett engines, their site mentions using Ford cam profile.
Also they use JP pistons which I were once told are twice the price of Ford Fiesta pistons.
Has anyone done an mileage on a Lewis build? If so are they good or bad? Is the Ford profile good in daily driving?

[David Morris]

Hi,

The crankshaft looks like what we call a 'black-sided'. This was the last version used in production of Javelins and Jupiters. Post production, Jowett's offered the oval web version as replacements. However, not all oval web versions are the same. There were some early versions that reputably wore quickly and yes, they can break! The later ones have the word 'Laystall' stamped on them with the word in an oval. These are the ones to look out for.

There are quite a number of used oval web cranks floating about in the UK, so it might be worth asking around? However, your 'black-sided' one will probably run for years. Without access to a lab for non-destructive crack analysis, can I suggest a simple workshop test? Suspend the crank vertically on a stout piece of wire so she is hanging free. Give her a tap with a hammer...she sound sound sweet like a bell. If the result is dull...she is probably suffering from a crack somewhere.

One or two observations about your crank...the oil way holes haven't been 'releaved' after the previous grinding. This is important. Also, the rear seal journal looks scored where the seal runs just inboard of the flywheel bolts. This wear can be taken out completely by fitting a 'Speedy Sleeve'. These are readily available in the UK and provide about 0.025" increase in diameter here, which also improves the seal effectiveness.

If you have the crank reground, make sure the workshop you use understands about providing a new radius on the ends of the journals and increasing the length of the rear journal for the new rear bearing that has the thrust bearings. JCS didn't understand this and we had to reject shafts reground from them.

Improving the Series 1&2 crankcases by increasing the size of the internal oil ways is an excellent idea. Have a work with John Airey about this, he is the wizard!

Hope this helps,
All the best,

David

[Srenner]

David:

I've never looked at swapping cranks as the work involved is massive. Everything has a "center" and I have always thought the easy answer is to make a billet crank rather than modify an existing one.

Here in the US, oval webs are rare and almost have to be pried from the owner's cold, dead hands. I have often thought of expediting the process with certain owners.

I would check with NZ Spares as they likely have some oval web cranks, although all would already be some undersize on the journals.

All the cranks I have done get nitrited just to be on the safe side. I know others do not do this and have had good results.

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[David Morris]

Hi Srenner,

Yes, nitriding the crank is an excellent process. I seem to recollect it penetrates around 0.025" into the steel, so it depends how deep any regrind is before you reach untreated steel. I believe all the Laystall oval web crankshafts were originally nitrided, so a 0.010" regrind might be ok, but anything deeper should have the nitriding repeated on the reground shaft.

I am sure JCS can supply s/h oval web shafts, either already reground or ready for local regrinding, if needed? Most Javelin/Jupiter owners in the UK have one or two stashed away, just in case.

All the best,

David