Crank cases

[David Kemp]

Trolling the net there was mention of new jowett crank cases being made. Is this correct?

[Keith Clements]

David,
Putting a link of what you trawled would help in answering.
About 8 years ago some crankcases were cast. Unfortunately the machining of them did not go well so they needed a lot of work to make serviceable.
My guess is that a dozen were made and half are now being used. Can anyone can confirm numbers?
Some of us are working on improving the exercise to make another batch. So if you would like to be a part of this and assist financially (or technically) then please step forward.
I have talked with a company who make racing engine blocks. They laser scan a sample, feed into computer aided design program, 3D print a mold and cast from the mold. The cost seems comparable to the method previously used but would deliver better than the original.
We have some of the Jowett racing team who are interested but it needs more support from you out there to make this a reality. My estimate is that we need at least a dozen deposits of around £1000.

[AmilcarJohn]

Very interesting to hear about this project. What would the £1000 deposit cover? - pattern making and casting? Presumably not machining too?

[Keith Clements]

There is no firm plan to go ahead so think of the 'deposit' being an expression of significant interest. So say we had five deposits then we could go to each company involved with some confidence on the number we need to produce. We would then be able to get some idea of the final price since most steps are dependent on quantity of the run. I see no point in going ahead with the scan, CAD and pattern production without getting quotes for casting and machining. The quoted price might not actually be the final price and we might hope to get the final product cheaper. But there is always the probability that it might be more as prices are volatile at the moment.
If we had five deposits we might decide on a production run of say 10 with the five who gave their deposit getting the final product for a lot less than subsequent buyers.
For now the question is ' Would you be prepared to put forward £1000 deposit with the understanding some or all of it would be returnable should a completed block not be forthcoming, but also that the final cost would be more than the deposit?' The deposit (less some expenses) would be returned should the estimated final cost be higher than £2000 per block and the participant did not wish to proceed. Note these numbers are currently just guesses just to give an idea of how we might proceed. Things might well change for the better if JCS get involved with some capital or if early adopters show interest.
There has to be a share of the risk between those wanting the items and those organising their production and some trust between all parties.
If we get some answers of yes to the question then we can start conversations with suppliers and then ask for deposits prior to engaging them.

[Chris Spencer]

Firstly - Have you established that there is a current requirement ? - I was at JCS on Monday and currently they are meeting the demand for good usable crankcases - Obviously that will change in time but its several years away yet.

[Keith Clements]

There is not a committed demand for new crankcases which is why we are having this discussion. JCS and others may be able to find serviceable crankcases. Many crankcases have been successfully welded, even if not originally serviceable. BUT, have those crankcases been crack and leak tested and then line bored and had surfaces refaced? Experience of those who have performed the checks suggests that a large percentage will have flaws. The commercial cost of perfoming such checks and the risk of other issues developing on old crankcases needs to be taken into account.
I reckon a properly refurbished crankcase may well stretch to a well over a grand. With rebuild cost perhaps in the thousands as well, the risk of wasting this on a faulty crankcase is worth considering. That is even without any breakdown cost in service or worse in a race season.
I think there is a strong argument for investigating production and improving the design to produce a much more reliable crankcase.

Other improvements in such areas as piston, liner and con rod as well as carburation, valve gear and head gas flow mean that a reliable engine producing twice as much power as the original is feasible. Whilst this may not be desired by everyone it would mean that Javelins and Jupiters would be seen more on the roads and in competition. Such a package could be put together but once again there would need to be an initial demand to get an affordable price for the package.

[Chris Spencer]

Whilst I appreciate that an engine with twice the power is very desirable for race purposes its pretty pointless in the prospective of every other user / owner - what's the point of harnessing a such an increase in power to a vehicle that has brakes, steering, suspension & drivetrain that were designed in excess of 70 years ago to handle 60 BHP - Its been proven on many occasions that even a 25 % power increase brings nothing but disaster to all other component's that weren't designed or built to accept such power increases

[Keith Clements]

Bear in mind that the power increase will also improve efficiency, so better for the planet. Engine design has improved considerably since the Jowett engine was designed and much of this technology would be incorporated. There are also benefits in reliability so that Jowett owners would feel more confident in taking on journeys greater than 20 miles. The increase in bhp also has safety benefits as it helps in getting up hills and keeping up with motorway traffic with less strain on the engine.
The brakes on a Javelin are quite adequate and with radial tyres there should be no problem with steering or stopping, albeit with due consideration for the lack of disc brakes, anti-lock braking systems and radar detection used by the artifical intelligence of driver's aids.
Perhaps the 70 year old gearbox could also do with new parts, but that solution is already available.
The alternative is using a non-Jowett design which quite a few owners have done or fitting an electric unit.
The spectrum of Jowett owners is wide so such an offering will appeal to some of them and the uprated engine is not just for competition use.

[PJGD]

I am in full agreement with you Keith that with any replacement crankcases there is no point in slavishly copying all the known faults with the original (even the Series 3) crankcase design; the opportunity should be taken to correct some of the problems - the main one being the lack of rigidity of the bottom wall that anchors the head studs. But there are several others such as the head stud that goes through the water port, the sump retaining studs that break through into the crank case allowing oil to escape down the threads, the milled down head stud that transfers oil up to the rocker shaft (there has to be a better way); the list goes on. . .

[Tony Fearn]

Now this is a paradigm shift for me as a pre-war chap commenting on such an important issue on which the more technical people in the various Jowett clubs across the world should be able to have their say.

We should definitely widen the debate before finalising requirements for such an expensive project, if that's what JCS agrees is needed sometime in the future.

Not everyone with a valid in-put will see what we post here. Suggestions as how to proceed in up-dating, or as Keith has said - "investigating and improving the design" needs a wide audience, which should be allowed to add their 'half-pennyworth' to the discussion.

Philip (aka PJDG) has already itemised several suggestions which in his estimation are needed to improve rigidity and sort out weaknesses in several types of studs. I couldn't comment on this.

But crucially he adds - 'the list goes on'...

No doubt Philip has a good idea of what other improvements he thinks are necessary, as do Keith and his racing friends, and others who post on JowettTalk, but together, these chaps may only think of 35% (my maybe way-out estimation) of the improvements needed. There will be many other U.K. and world-wide Jowett members, some with advanced engineering, or maybe practical knowledge, who can add to the debate, whose input may or may not be applicable, but their suggestions need to be heard.

Finally, Chris makes a number of succinct points as to whether we actually need to go down this road, and if so, whether we may just need modified and up-dated 'standard' engine casings for the Javelins and Jupiters of the future, which many of you cherish. His allusion to the rest of the 70 year old parts on the cars to my mind is rather pertinent.

Tony.

[Chris Spencer]

Don't get me wrong I don't mind the going quick bit - especially the Jowett race teams which I support in any way that I can - I don't mind modifications
being suggested or made that would improve the engine quality / lifespan etc - But its wrong to assume that every Jowett owner that wants to build a fresh engine possibly with new crankcases should they become available with a huge increase in power output - maybe one or two owners do but the majority don't - They are quite happy with a car that was built to travel at a design speed of its era to do exactly that - If they want to go quicker then there are plenty of modern vehicles that are designed & built for that very function in safety.

[PJGD]

Don't loose sight of the fact that a new replacement crankcase, whatever features it may have, will have no effect whatsoever on engine power output. In other words, just by itself, there is no connection between a new crankcase and a speedier car. However, just by itself, a new crankcase is highly likely to result in a more reliable and dependable engine which is what most Jowett owners want and would pay good money for.

For those who want more power and thus a speedier car along with reliability then a new crankcase will be a key building block. The power increase will come from other features such as lighter reciprocating components, a gas-flowed cylinder head, a scientifically revised valve train, and an electronically mapped ignition system.

[Keith Clements]

The Wills ring engine I am working on has wider liners than standard. Thus giving a larger capacity. Internal bore 79 mm external bore 84 mm.
Just a thought!

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[PJGD]

Increasing the bore diameter as Keith has done is one example of what could be done with a new crankcase casting. In Keith's case, the Ø79 mm bore results in a swept volume of 1,765 cc [1.765 Litre] displacement as against 1,486 cc for the base engine.

Another aspect is that when Gerald Palmer designed the Javelin engine, the road tax in the UK was based on an antiquated RAC formula which favored long stroke engines, i.e. the longer the stroke, the lower the road tax, which appealed to those who were striving to afford a car. Hence the bore-to-stroke ratio chosen by Palmer was 0.8 [72.5 / 90 = 0.8]. Shortly after the Javelin was introduced the RAC road tax scheme was scrapped and any new engines were designed with larger bore size and shorter stroke allowing the engine to rev more freely and develop more power. There is no doubt that had the RAC formula been abolished prior to the Javelin engine design being frozen, Palmer would have chosen a shorter stroke/larger bore combination. Thus Keith's Ø79 mm bore size results in a bore-to-stroke ratio of 0.877 which is moving in the right direction.