Hi
In an article about Bill Scriven in the 1972B A7CA grey magazine, it says that in late 1936 Bill chose a Ruby saloon as his new car - the type 'with the full body around the window frames'. It then says that he 'had the engine tuned to perfection' and that it could do 60mph and return 60mpg. (Later, when the same car was fitted with a Grasshopper supercharged engine it would do over 80 mph - and was something of a handful at that speed as it spent most of its time in the air!!) However, my question is - how to get 60mph and 60mpg from a standard engine? I can imagine 50mph and 50mpg might be achievable, given that my car is capable of over 40mph and 40mpg - but 60 and 60? Anyone else get close?
Colin

Location: North Cheshire

In the sixties my Mk 1 Ruby did 60 mpg, but never 60 mph! Yes, 60 to the gallon,
but that was the sixties!

Location: Wales

Colin - In the past I found that tuning for more speed caused a considerable suffering to fuel economy and I recall being surprised at Scriven's comments. One of the Rubys I had (it was a Mk. 2) did show 60 mph on the speedo occasionally - and no, it wasn't going downhill! - but because it had an earlier roller-type speedo (not the correct needle type), I was always in doubt as to it's accuracy. I didn't tempt 60 too often as I agree with the old adage that your motor runs at it's very best just before it blows up! I'm sure there will be other claims or denials to follow. Cheers, Bill in Oz

Location: Euroa, Australia

Our Ruby would do 60 on the flat when fitted with the tuned engine, which is now in the Ulsteroid. I don't know the exact spec, but do know it has big valves and a high lift cam. The big big problem in hilly Devon was that whilst it flew on the flat, it was a total pain up hill. 2nd-3rd, 2nd....3rd, 2nd.........3rd....

Fuel economy, no idea, but you don't owt for nowt!

I can see you getting 60 mph but doubtfully in a heavy ruby 60 mpg no matter what you do.
Its taken 70-80 years development to achieve both.

Thinking about the times I have used the Ruby for a week at a time, I used just about the same amount of fuel as I would in my modern. So an average over a week of mainly short journeys, of high 30's MPG.

Harry Hales at SWA7C regularly achieves 60 miles/hour, and on club runs finds 60mpg no problem. On the runs he rarely runs at 60miles/hour, as no one can keep up with him. 1 1/8 SU, bunch of bananas manifold, and his own take on valve and camshaft tuning.

Location: s.wales

John - the name Harry Hales I haven't heard mentioned for years. Can't recall whether it was the '77 Isle of Man Rally, or the '92 Eurotour, or on another rally, but did meet him and his fiery Ruby. Would you please pass on my regards? Thanks & Cheers, Bill in Oz

Location: Euroa, Australia

60mph is quite achievable with Ruby engine and gearing in my experience, 60mpg would be the challenge! The most I have regularly achieved is around 48mpg.

Was the Ruby in question running on the fuel fumes/vapour system I wonder? Exponents of this claim mind boggling mpg.

Running a modern car with a computer shows that the fuel consumption as you are running along is affected by acceleration, speed, wind direction and slope and varies over a wide range. The key, I suppose, is whether a Seven can return 60mpg over a testable journey?

My modern car has done an average of exactly 40mpg over the last year. When running at a steady 50mph it shows an mpg of 64, but this tails off quickly as speed is increased - square law wind resistance. A lot of fuel is used up with each cold start, worse in the winter, and this - along with time spent in slow traffic and in queues - reduces the overall figure to the 40mpg seen.

My Ruby, which does almost all short runs, does not return even 40mpg overall. However, on longer runs, the fuel gauge seems to stay still and the consumption betters 40mpg, but I don't know by how much - it seems difficult to measure accurately. So when we are talking about achieving 60mpg, I presume it must over a mileage great enough for it to be checked - as there is no way to measure the instantaneous mpg of a running car? For example, the average might be obtained from a couple of long runs - perhaps made in the warmth of summer (or December this year) - with careful checking of the fuel used - to give the best number achievable from that car? I have not done this, so do not really know what the car can do.
It is interesting to hear that 60 60 is achievable - and how the mpg figure can be obtained... (though I plan to leave my engine in its standard form.)
Colin

Location: North Cheshire

Our 1938 Pearl has a mildly tuned engine; large inlet valves, ported block, skimmed late head, Bonewell cam and followers, Nippy manifold and Nippy-like carburettor. It will pull 55-60mph on the flat (according to satnav) and on the Yorkshire Experience returned 40mpg+ over 1000 miles of motorways and Yorkshire's hills. It's also fun to drive and makes it less vulnerable to modern's miscalculations. I'm currently trying a Super Accessories c/r gearbox but third is too high. I have a Nippy ratioed box ready to fit, which should make better use of the increased power. Happy to share my experiences if anyone's interested.

Location: Beautiful North Hampshire

About three years ago on the way to an event at Brooklands Race Course, I was followed by a chap in a 'modern' who told me 'I cruising along at 65mph on the M25' as he was by chance following me to the event. My Mk2 Ruby (ADY 95) has just done over 100,000 from new but the engine has had several rebuilds. However, I don't think I've ever got 60mpg although, especially under the conditions modern cars including Volkswagen test their cars, I have little doubt such a figure is achievable. To finish that particular day off the car went up 'Test Hill' with two of us in it, which if anyone is familiar with, is really steep but I have to admit it was a bit of a struggle. James

Location: Ferring West Sussex

Is the modern fuel - with its different constituents and higher octane - holding down the mpg these days? If the slower burn from the higher octane rating means that the fuel is incompletely burnt (particularly in a standard engine) then perhaps we are extracting less than was achieved in the 1930s from the fuel?

It sounds like 60mph is within reach with mild tuning... I wonder what BHP this corresponds to? Much more than the nominal 17 BHP from the 3-bearing crank engine? (In theory the air resistance is 40% higher at 60mph than 50.)
Colin

Location: North Cheshire

Mine will do 56 mph and 40 mpg.
It's a Mk 1 Ruby, so lighter than the Mk 2, but with a Mk 2 cylinder head which adds 3 bhp, I believe. So, a bit of a hot rod.
(Incidentally, whenever I post here I have to re-register. I don't know if that's a common problem.)

Location: Stoke Poges

I've never had to re-register since I joined the forum around 10 years ago !

Jeff.

Location: Almost but not quite, the far North East of England

It may be connected with the frequency with which you post.

Location: Stoke Poges

The average of 40 mpg in my modern car was obtained the old fashioned way by recording fuel bought and mileage over the last year - I wanted to see what it was really doing - I expected better than this - it is a 1.4 petrol Golf automatic! Typically, the computer gives an average of about 42mpg for a journey, but less on very short runs and a bit more on the few long runs I do. So it seems about right.

Driving style can make a big difference to fuel consumption - gentle acceleration and changing up early, as per taxi drivers round here, no doubt helps - but it is hardly fun.

Obviously a Ruby won't do 60mph and 60 mpg at the same time - but how is 60 mpg achieved at all? At what speed is the optimum mpg obtained? About 30-35mph?
Colin

Location: North Cheshire

The secret to good mpg is always coast downhill! Brakes?, what brakes?!!
Less traffic on the roads in the sixties.

Location: Wales

My Ruby is doing about 38 mpg at the moment, but it is settling down after many, many years of inactivity, I hope that this will improve, but there are a lot of hills around here and the engine is using a lot of revs to climb up, I have an HC head to fit, so hoping to improve on the performance & mpg!

From my experience with my "modern", (1965 Rover P6), when I had my first example (1971 car) in the 1980's, running on nice 4-star leaded fuel, around town I would get 25mpg and, on long runs, I could get 37 mpg, now, around town it is more like 22 mpg and the best I have had on a run is 32 mpg - I seem to recall that on the introduction of unleaded fuel that mpg would increase by about 10%, which fits my figures for the Rover, so for the Ruby, perhaps it would have got about 42 mpg on full fat petrol!

Location: Saltdean, Brighton

I refer to an earlier thread on this board re. Fuel Consumption:

http://pub25.bravenet.com/forum/static/show.php?usernum=2099944454&frmid=5&msgid=924577&cmd=show

I have never achieved anything like 40 mpg, except for one memorable run from North Norfolk to Trowbridge, where we had a North Easterly gale on our tail in a SWB saloon and did 250 miles on the 5 gallon tank!

On a cold engine, a Seven struggles to do 20 mpg but this usually rises dramatically as the engine warms up. On modern fuels, an average mileage of 35 - 37 is what I usually measure, although my Chummy is currently turning in less than that (last measure was 33.5 on a run). No, I don't have a lead right foot but I do measure my fuel consumption (from tank top to tank top divided by the mileage driven) fairly accurately. My car is driven briskly and I try not to be a nuisance on the road, so cruise at 45 - 50mph, 50+ downhill.

35 - 37 mpg is my average over many different A7's (three Chummies, two Ruby Mk2's, RP Box, AH tourer, RM Box)over forty years.

BTW, my Big 7 Forlight is considerably worse as far as fuel consumption goes with 160 miles on 5 gals being the last recorded consumption. (32 mpg)

Location: North Wiltshire

Tim - now that we're getting away from Rubys, I looked up the other day the results of a Victorian Light Car Club Economy Test held in May 1926. A '24 Sports I own (determined to get it back on the road before end 2016) came only 2nd in the Members' Class with 78 mpg. Lest anyone thinks it was tuned to be gutless, this allegedly 50 mph Seven (claimed as such by the Factory) recorded a 58 mph lap at Aspendale circuit and a 63.2 mph lap at the Melbourne Motordrome, both in 1925. At the RACV Speed Tests at Laverton it won Class A Flying Mile at 66 mph in 1927. It (always unblown) also came second in class to Waite's blown Seven in the 1928 Australian Grand Prix. I'm sure I've seen better economy results with especially-detuned Chummys - does anyone know of top efforts? Hopefully they don't include the free-wheeling downhill efforts that I know occurred. Cheers, Bill in Oz

Location: Euroa

I must be a 'leadfoot' - don't think I have bettered 35 mpg in the Chummy or Sports (a bit tricky to calculate with litres and kilometres, but l per k doesn't mean a thing to me).

Maybe because these two have SU carburettors I push a bit too hard for economy.

I haven't checked the Saloon fuel consumption with standard light shaft and bronze updraught Zenith, but with the heavier body I don't expect much better.

Tony.

Location: Victoria, Australia.

In the mid 1920s the Austin agents ran a Seven chummy two occupants “non stop” Auckland to Wellington return 1000 miles and claimed 50 mpg. Roads would have been almost all unsealed with many miles in 2nd. May have coasted down grades. A similar 680 mile escapade in the SI but over even more arduous route, including river fords etc averaged 45 mpg.

The Brooklands publications repeat a 1938 Light Car account from a Seven owner who in 8 years had covered 80,000 miles over 5 second hand Sevens, including a magneto model. Average consumption dwindled from 44.5 mpg to 35.7 for the last and latest. (Incidentally only 1 pint oil per 400 average including changes!)

Around 1950 my father maintained very diligent checks on our stock RP. On recurrent 200 mile trips on the winding and undulating roads of the time, with 2 light adults and 2 small children repeatedly recorded 50 mpg. He originally drove at 45 mph but found this too fatiguing and settled for 40 mph. (Despite the most diligent maintenance, the car has never exhibited the stability now claimed for these cars).
Curiously, with a simple silencer with few baffles, mpg reduced to about 40.

Truly flat roads are very rare but on one the same car in my use would eventually reach 50 mph indicated; the speedo much more conservative than all it was compared with so probably accurate. With later head and SU and slight cam mods, with moderate assistance from wind or grade showed 60 mph. In this state, driven hard everywhere, no experiment for greater economy, checked over tens of thousands of miles, returned 38 mpg town or main road. A Ruby is lighter but better streamlined.

Power required is more closely related to the cube of (air) speed rather than the square.

The mpg from current fuels is debatable. I recently had cause to cover 1,000 miles of main road driving in a Jowett Javelin and this gave better than true 30 mpg, the mileage obtained 1970-1990 with such a car at the same speeds. The recent car had standard jets but raised c.r which would have assisted. No ethanol.

Someone may have access to data on the fuel relative heat values. Ethanol has a much reduced heat content and is a con.

Location: Auckland, NZ

After many years of thrashing around and breaking cranks I now rarely do more than 45 mph in my very late Opal which is standard other than a Phoenix crank and remote oil filter, standard carb. On a trip last year to the Loire it averaged over the 2000 miles 35 mpg, OK fully loaded as you would for two weeks away but I believe that some of the figures quoted are to say the least. EXAGERATED.
Whoa, happy new year

Location: Oakley ,Hants

The 48mpg consumption I attained was on a standard RN fitted with a Zenith T24. This car was my daily driver at Uni, covering around 60000 miles in 4 years.

I have never got near to matching this economy out of any other Seven and attribute it almost entirely to the type of carb.

I am sure that my RP was more economical before I fitted the late Ruby head and an SU carburettor. However it didn't go nearly as well! I guess with everything there's a trade off. I reckon I average about 35mpg these days which isn't bad given the terrain round here.

Location: Gard, France 30960

Ruairidh what jets are you using. I have never got anywhere near that with my 24Ts

Location: Farnham

David,

I cannot answer that - sorry. I stopped using the car in 1996 and it is now owned by a musician in York.

It always required full choke to start, however hot the engine was, had a terrible flat spot and is without a doubt the slowest Austin I have ever owned. It chewed clutch toggles, which I put down to Glasgow traffic, but was a total workhorse.

I have 24T2 settings in my note book as follows, could not tell you mpg attained.

Choke 14mm
Main jet 75
Slow 50
Air bleed 150
Needle & seat 2.0

Location: Auckland NZ

With the 22FZb our RNs average 35 mpg and I usually reckon on filling up 3 gallons every 100 miles, I don't fill the tank to the brim about 4 1/2 gallons so that gives me 1.5 gallons up my sleeve. However on the run back from Falmouth initially I was doing 50 mph on full throttle, but after about quarter of an hour I was having to back off the throttle to keep down to 50 mph. I filled up at Exeter services and tightened up the hand throttle friction clamp and cruised up the M5 at 50 mph. After 130 miles I thought I'd better fill up at Strensham services to find I could barely get 2.5 gallons in which gives about 50 mpg at 50 mph. It was a blisteringly hot sunny day, when Sevens seem to go well