Hello all,
as some may know, I had planned my Cambridge Special to have a Sunbeam 928cc engine, a la Coventry Climax, but today I find that the gearbox won'tgo near the A78 chassis and I'm not even sure if the engine will. I think they're bigger than the 750 CC engine currently in vogue in the racing fraternity.
Not being keen to have adaptor plates made and all that jazz to fit an A7 gearbox and not keen to pay out what I recently did to rebuild a Reliant 850 engine all over again, I am thinking perhaps I'll go for the 3 bearing, unused fire pump A7 engine I acquired recently.
So, if we do (the Special is now a joint thing twixt me and my son, tell us, what is so very bad about the 3 bearing lump? There are, after all, a lot of people happily bumbling round in their Rubies, Pearls, Opals, vans, Specials, etc.

If it is a real no-no, then we will have to go the Sunbeam route.

Martin

Martin,

If you have a good 3 bearing engine I would use it. I've used a Ruby and a special with 3-bearing engines and run them both without problems. The disadvantage is that they are more inclined to break cranks and new replacements are not available.

To be honest the complication of fitting a completely different engine seems to create unneccesary work if you have an Austin engine in serviceable condition. If on the other hand it needs a professional rebuild then cost does become a factor. I must admit that the days of building a Seven on a shoestring seem to be over!

Peter.

Location: Inverness

I agree with Peters comments, I broke a crank in my 3 bearing engine but was lucky that it did no other damage. I took the decision to have a Hadley Crank and con rods, having the 3 bearing engine converted to 2 bearing by Vince Leek, I also hade a remote oil filter fitted and rebuilt the engine myself. There was not much change fro 2k, but this engine should go on for ever. well I hope so. You could go on and have a racing cam , Su carb , bunch of banana exhaust. and so on.

Location: Basingstoke

Location: Shropshire

Hmm, not exactly great, then. But that's why I didn't want an A7 engine in the first place. The crank snapping frequency seems to have gone astronomic, along with the costs of services and those new cranks that everybody seems to be able to just drop in as and when the need arises. A crank breakage would leave us without the car, I'm afraid.
So, can used 3 bearing cranks be had? Used ones, I mean. £800 for a Phoenix isn't on for us. I spent nearly that rebuilding my Reliant Fox engine as it was our daily driver, but I couldn't justify that for a hobby, even though my son and I are now sharing the project and costs.
The 3 bearing engine I have has never been used beyond testing, so it is effectively new. That must count for something. The car won't be thrashed, trialled or raced. Just enjoyed on the road.

Are there no tweeks, or dodges that helps increase the life expectancy of these things?

Martin

Right OK, there are many many 3 bearing engines out there, there has been for seventy plus years, it all depends on how lucky you are and how you drive it. I personally have broken three but I did tend to thrash my cars a bit, old age and spending £' s has slowed me down a bit. from what I can gather it is getting the centre main to run true is the problem. ask the experts to point you in the right direction, I know a man north of the border who might put you straight.

Location: Basingstoke

Interesting article, that. So it's mainly a factory problem. How did they get away with that?

The Speedex site cure makes sense, providing we can find some oversized shells to experiment with!

Thanks for the info.
Martin

Location: Shropshire

Derek, there's always a man somewhere who can put us right, but at a price!
I'm looking for a way of doing the most we can ourselves. Neither of us is a mechanical fool by any means, but neither are we cheque book enthusiasts!

Martin

I tell you now Martin, there are a lot of guys on this forum who will give you the very best advice and at the very best price,FREE

Location: Basingstoke

Sorry Martin, Ian is right. You simply can't run Austin Sevens on a shoestring these days if you want something that is usable and reliable. Of course you can build more modern engines etc. for far less than a Seven. That's because parts are more plentiful for the more modern engine. With scale comes economy. If you want to run your three bearing engine with any degree of reliability then I sincerely hope it works for you. I've been around Sevens since I was 14 years old. I'm now 61 and I wouldn't touch a three bearing engine but that's my experience. I hope yours is different. That experience has taught me that the only way to properly do something is do it once, do it right. Most of us have run cars on a shoestring and have learned that it's false economy in the long run. Breaking a crank is one thing. It's the damage it does to the rest of the engine that is the real consideration and that can be considerable. Been there, done that and very much hope I don't go there again.

Sorry if you found Ian's comment about the Corsa offensive. Frankly, I thought it realistic. However, calling Austin Seven engines 'silly little' things might be considered a touch offensive by some - particularly when they might have been involved with them for most of their lifetime. You asked for opinions about three bearing Austin 7 engines. You got some. They don't suit you but we can only give our considered view based on experience. To do anything else would be incorrect.

Steve

Location: Nr. Selby, North Yorkshire

Martin, trust me, I tell it as it is not how I would wish it to be; I too would like to be able to nip down the local scrappy and pick up a decent A7 crank for a couple of quid but, I can't.
As for my Corsa comment being "snobbish and offensive" frankly, it was neither, until a couple of months ago I ran a 03 plate 3 door Corsa here. It was a realistic suggestion for sensible motoring on the sort of budget you quoted.
I PXed the Corsa for £700, MOTed for the next 12 months and a reliable daily drive. If you can find a running reliable Austin seven for that kind of money today, come back and tell me about it.

Ian Mc.

Location: Shropshire

I heard somewhere that Austins were having trouble with 3 brg engines before the war,any body know if this was true?
I would have thought that it possible to get 50000 miles out of a 3 brg crank engine before the crank broke.
From a person with long term use of A7's he said a 1 1/8 would last c50k ,a 1 5/16" c100k miles.
I do personally think fitting a more modern engine to a seven is a bit of a cop out,but do appreciate its much cheaper,£2k to build a good A7 engine nowadays is cheap.
Austin 7 parts,new and secondhand will continue to become more expensive with the loss of certain long term suppliers and less quality used parts around.
Have to agree with Ian,if you want a cheap runabout,go for something more modern.

Martin

Budget Austin motoring is still to be had, trust me.

Be patient and you'll find a good engine, I bought what appears to be a 'rebuilt' engine plus four speed (crash) box with all ancilaries about 12 months ago for £500 off e-bay. I figured the bits were worth what I big, and upon inspection iv'e bought a good one, all be it with an Austin crank and a low chassis crankcase. It'll be going in a high chassis car.

Previously I half fancied making one of these fit http://www.ebay.co.uk/itm/AIXAM-500-2002-2-CYL-DIESEL-ENGINE-KABOTA-/121141255248?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item1c3494dc50
The engine is smaller, unburstable, Japanese, revs a bit higher than an Austin, with a little more horses. I expect if you turned the wick up a bit in the pump would go rather well, and to top it off will run quite happily on neat cooking oil.

Would probably sound like dumptruck going down the road however!

hi martin,

to try and push this one back on track, and tackle the subject of why not use a 3 bearing engine.

my feelings are most people don't like the three bearing engine when it comes to rebuilding one.

the biggest problem on the 2 bearing engine was when the crank broke. 99% of the time it was on number 4 or the rear bearing jernal.

Austin tried to remedy this with the 3 bearing engine.

they must have done most of there work on the bench and thought eureka we`ve done it.

however the engine twists with the chassis, and causes the crank to run out of line at times. the result is ware in the centre main bearing, which allows vibration. and the crank then brakes the centre main web.

they only moved the problem.

here is were most people don't want a 3 bearing. for those who can afford a new crank phoenix will only make one off 3 bearing cranks from solid billet. cost £1,300 5 years ago. NOW?
next is everything has to be built to a high standard to get it to run together. were as the 2 bearing engine is more forgiving to those with limited skills and tools.

if your 3 bearing engine runs, then use it. but it does leave you with that feeling of how long is a piece of string.

good luck tony. (watching the canaries make a mess of the footie)

"Ian I think it's you who have a weird idea of times. My idea of prices is relatively recent. In the 50s, whole cars could be driven home for £8. In the 70s and even 80s it was still possible to build up a decent car for very good money. This ridiculous pricing has only been around for a few years."


Martin if you think 50s, 70,s or 80,s are relatively recent its probably why you think think things are expensive today.

Martin. To my way of thinking, if it's an Austin Seven then it should ideally have an A7 engine. If you have a good three bearing unit then why not use it and have some fun? You have nothing to loose and it should be a doddle to fit. So long as you do not intend to go racing with it and you just want to enjoy some A7 motoring then (if you treat it with respect) chances are you will have no serious problems. If the crank does break, then cross that bridge when you come to it.

By the way; Austin Seven engines are not "silly".... they are something of an acquired taste and even a challenge at times but we all like tinkering with them.

Location: Derby

I think it all got a bit gloomy and even off thread yesterday. I was pleased to read Ray's input above. Martin was after "the truth" which I think comes in three parts: 1) if fitting a 3 bearing engine into a special, beware of the potential to put strain on the crankcase as described above 2) the crank must be free of cracks, as shown by magnetic particle inspection (MPI test), and be true
3)getting the centre bearing in line is crucial - the crank must spin freely before moving on with the rest of the engine assembly - see the Speedex notes.
In other words it demands good engineering. Tony Johns made 3 brg engines race!!
Regarding cost/availability of cranks you need to belong to the Bristol Club!! We have more than you can shake a stick at for very low prices! After that it's up to the member to check out that it's got potential!
I suggest Martin strips his engine sufficiently to see how freely the crank spins and determines (by "Speedex method") if there is excess clearance of the centre main. If it looks OK and spins OK I would take a gamble on the crack aspect if he is confident of low useage.

Ron

Location: Thornbury

There are very few alternative engines that will fit in an Austin 7 chassis.

I fitted a SAAB 3 cylinder 2 stroke engine + Austin 7 gearbox in a Box saloon for Barry Argent. It was dreadful!
He soon took the Saab engine out and fitted an Austin engine. The saloon was converted to a sort of 6' 3" RP but he never resolved the problem of very narrow doors, so he used it without. I wonder where it is now?

Previously Barry had an Austin 7 pick-up with a BMC 'A' series engine. Of course the engine would not fit in the chassis so it sat on top and drove the back axle through a modern prop shaft working at extreme angles.

I don't think the Hillman Imp or Reliant engine will fit in the chassis.

750 formula cars generally got rid of the forged nosepiece and used a space frame built with the chassis members wider apart .

Don Rawson has been racing a 750cc Coventry Climax engined Austin special for some years. http://www.750trophyracing.co.uk/the-formula/9-1-sporting-regulations-general.html

There have been quite a few specials built recently using a Big 7 chassis. This chassis has a much larger space at the front of the chassis and it is possible to fit all sorts of engines.

Location: Oxted

Martin, I wanted a period engine for my special and like yourself it had to be done on a budget. I fitted an 1172 Ford e93a. Not too difficult to fit and was common practice in the 1950's. Limited to 3 gears though!
I will add that the whole project was built from bits, and a complete car wasn't destroyed!

Martin

You realy must join a local club!!!
I was a member of the Cornwall club for nearly 10 years and found the help and advice I was given priceless.

I purchased my pile of bits, scrounged and begged lots of others and built my special for not a lot more than is being quoted for just an engine in this post.
BUT you must bear in mind that your scrapyard special engine is likely to fail at some point. The point people on here are trying to make is that for a belt and braces reliable proper job, then a fair bit of money is needed, Pheonix cranks etc.
But you don't have to go down this route as long as you accept the fact that things will go wrong sooner or later.
My engine was 2 scrappers built into 1, the crank was ground to fit the only rods I had because I could not afford to have rods remettaled! I then hand scraped the bearings. Eventually after a couple of years the rear main started spinning so I Loctited it back on. A short while later it spun again so I stripped it down and spotted the damage to the bearing journal on the crank and also the nice crack at the rear web! So another crank was supplied by a club member bearings re scrapped and we were off again. A piston broke up so I bought just 1 and fitted my rings and carried on.
In approx. 10 years I built 2 different specials and 4 different engines all from mostly the same pile of scrap I started with. Total cost for everything was probably in the region of £4000 spread over 10 years of fun, trials and tribulations! I could write a book on the bodges and breakages I overcame, but to me this was all part of running the Austin. I always wore old clothes when out for a drive and carried a good toolkit because usually something broke or fell off.
You can still run and build a special on a shoestring, I know because I have done it. Don't believe those who say it cannot be done these days. BUT BUT BUT you really do have to belong to a really good club and build up a network of like minded friends to help you when things go wrong as they almost certainly will on a regular basis.

Don't lose heart keep at it but please remember if you adopt the scrapyard special approach then you will have to accept the problems that come with this concerning reliability. I enjoyed it, but its not the approach that will suit everyone, particularly those with large bank accounts!

The people offering advice on here are being very honest with you and trying to save you much heartache but if you are anything like me you will find a way to cobble something together for next to nothing and most likely upset a few rivet counters as well.

Believe me if you look hard enough the spirit of old fashioned special building is still alive and well, its just a bit harder to find these days.

Best regards

Steve

Spot on. I've also found it much more rewarding,in both senses, to do things on a shoestring. I have rarely spent more than £1000 per year building & racing.

Frank,
I agree with what you say, and I guess my expenditure is similar,but how much value do you put on the hours you've worked?
If you can't do your own fettling, its an expensive hobby, these days.

I have three 2 bearing engines for two RP's, as one begin's to sound 'off', I replace it with the spare engine and rebuild the 'off' one.

I've yet to have a 2 bearing crank break since 1961.
I too have heard the 3 bearing cranks break, but this has been explained above.

If I was to buy another engine, 2 or 3 bearing, that seemed OK, I would put it in a car and go..
just see what happens. A7's are my hobby, I'm lucky in that the cars, after priming the fuel pump, start and go, as good as my modern, which is a £700 (4 years ago) 1995 Rav4 with tow bar etc.,

So, if you have a 3 bearing engine that feels OK,
and you want it for daily usage, use it,
or like me, get a Modern < £1k too.

My cars are under a car port, not in a garage - there's a A7 resto project in there - so the mist, wind, spiders, etc., rolls in and covers them, but they are used every week and reliable.

Location: Very edge of Europe - West

Frank,
I guess I got into it for the same reasons as you. Back in the 1970s/early 80s, I could afford it, provided I did all the work myself, and did VSCC trials, racing and sprints as well as 750MC stuff. After a while I realised I enjoyed the fettling as much, if not more than the driving. Eventually I drifted away into modern racing, but honestly, it wasn't as much fun, and I started doing the Bert Hadley Championship when it started, and have done so ever since.

In view of the high cost of an engine rebuild has anybody considered fitting on air filter, particularly on cars with updraught carburettors to stop all the dust thrown up by the front wheel from being inducted to accelerate engine wear?
This would be relatively easy with the 24T2 carburettor but would mean disabling the choke on a 22FZB and 26VA. I noticed this when watching a saloon driving down a dusty road during our glorious summer.

By 1930 the Colonial FZB had an air filter and 'air strangler' fitted - although I have only seen a few here.

Tony.

Location: Malvern, Melbourne, Victoria, Australia .

Im new to the world of tuning small Austins, and have read this thread with interest, However Im not new to tuning, Having spent most of my car life with 105E Anglias and Cortinas, I have never broken an engine, except for a split liner, I used to experiment with parts from different engines, Things like Datsun 180B cranks in crossflows, gives you a forged stroker crank and 1800+cc. or even the Fiesta Diesel crank offset ground will give you a good crank, but a lot of work to get the weight down.
What Im saying there must be other ways to build a strong engine, I have not done any research, but Fords made a couple of 3 bearing engines which are still easy to find and not expensive, 100E, the early Anglia 105e and Classic all had 3 bearing engines. Counterbalanced too, They all may be dimensionally be miles away, but Being an Engineer, I tend to "look outside the box". Another option I suppose could be a billet counterbalanced crank made to Austin dimensions, probably cost prohibitive, but an option. going this way gives you an option on on what rods to use, you could find some quality OEM forged rods, even forged pistons that could be modified to fit, make it long stroke you bring up the torque, which is acceleration, make it short stroke, you put the HP up with revs, which gives speed.
Sorry if this way of thought causes upset, But A7s have been modified since their inception, perhaps not with as much Foreign internals, Im just offering suggestions.

Location: United Kingdom

Ah so somebody knows what the export air filter arrangement looked like. The list of spare parts shows a 22FZB without strangler, an air filter with no visible strangler, an export air strangler control rod BE 90 and different accelerator control parts to clear the filter. So how was the strangler arranged Tony?

I assume it was like a throttle butterfly, but I have no idea how it was assembled.

Tony.

Location: Malvern, Melbourne, Victoria, Australia .

Ian

Your background sounds very interesting!

However with regard to Austin Seven engines I don't see the need to reinvent the wheel....

We have available the various Pheonix cranks in splash and pressure feed and 2 different diameters, plus there are a number of rod choices to pick from.

A combination of the above will build a reasonably bullet proof 2 BEARING ENGINE!!!

The 3 bearing as discussed in this thread is another matter entirely, but as there are not many used then most people just use the 2 bearing with the aforementioned parts. You can I believe convert a 3 bearing case to a 2 bearing crank and therefore use a Pheonix 2 bearing crank in it.

As for using proprietary parts then the older Reliant engines have certainly had internal bits robbed in the past..... Look in the Green book and fitting a Reliant crankshaft is covered in detail, but of course this is largely irrelevant today as the arrival of cranks like the Pheonix and associated rods have made it simple and easy to build up a good bottom end.

Mind you I have to say I like your thinking and there are always some new ideas going to surface, trying to take advantage of modern materials and build techniques, particularly for budget builds.

Steve

OK - here goes with my two bob's worth:

I don't race any of my A7's so they aren't subject to racing or competition stresses however...

If I own something mechanical such as an A7, then it has to work. It has to start and run when I want it to and take me where I want to go (within reason) and with a good chance of getting there. If it doesn't, then it either gets sorted until it behaves or else it goes the journey.

When I bought an A7, I joined the club, listened to sage advice, read all I could and then made my own mind up. Two of my A7's originally had 3 bearing engines. I had both of them fully rebuilt by Ian Bancroft who converted them to 2-bearing engines and fitted Pheonix cranks. They should outlast me easily and I do not expect in my lifetime, to ever see a broken crank or a rod coming out the side of the crankcase.

I consider that if you want to enjoy running a 70+ year old car such as one of our A7's, then it will cost you. How much depends on what you want to do with it and how much you are prepared to spend. But it is an inescapable fact that it WILL cost you.

Sic factum est.

Location: West Torrington

Hi
My Ruby has a three bearing engine in it. The block is dated February 1937 and is sleeved and bored again to +20 thou. I have now driven this car for over ten thousand miles, with just one top end overhaul, but no other serious attention. I must admit that I often wonder how long the crankshaft will last – I would certainly feel more confident running a two bearing engine with a Phoenix crank in it, given all the reports of crankshaft failure with three bearing engines. However, some of these engines must have done 100,000 miles or more (though perhaps not on one crank), so is the problem that the remaining crankshafts are tired by now? What would be the likely life expectancy of a newly manufactured three bearing crankshaft in a well set up engine?
Regards
Colin

Location: North Cheshire

Colin

A properly set up 3 bearing engine with a new crank should be more durable than a 2 bearing.

There are three basic problems

One is that new 3 bearing cranks are currently basically unavailible unless you have a one off made. I suppose you could say that they are availible at a significant cost, but so prohibitive that owners tent to hack the crankcase and fit a 2 bearing.

The second is the issue with the middle bearing being out of line, there are various 'dodges', most of which are in engineering terms ****. A proper job needs money spending with a machine shop, or the kit to do it yourself. This adds to the cost of sorting a 'proper job', and is another reason owners go for the 2 bearing conversion.

The last is the lubrication issue with the middle bearing, this is really a simple fix.

That's one that hasn't broken in the last 20 years then, Fred.

Ian Mc.

Location: Shropshire

As mentioned above , a well maintained 3 bearing engine should be good for 1000s of miles, if it is driven with some respect, yes an Austin 7 will do 55/60 MPH but continuous use at these speeds as many are will soon see it break, It is rather like driving a modern on the red line all day and every day. The desire to keep up with modern traffic is strong and many get used to hearing the engine screaming and think of it as a natural way of driving, which it is not! Treat a 3 bearing with respect and it will last for years.

Location: Pembrokeshire

Hi Martin,

I built my special with a 3-bearing engine which I have used aggressively on VSCC driving tests and on the road for over 5 years. I used standard engine mounts on three of the feet and an arrangement with rubbers then big washers and a valve spring before the nut on the final foot. I had not issues other than over carburation by using an HS2 SU on what is a standard engine.
I have recently changed to a highly tuned engine and removed the 3-bearing as a going concern and backup should I ever have any issues with the other engine.
I do agree with one of the other commenters that running A7s is no longer a shoestring operation.
I may consider selling my spare 3-bearing in the future as its just sitting on my engine stand with all ancilliaries etc.

David