Which engine building for a 1275cc BMC A series?
Discussion
First priority is reliability, then speed; we really want to just jump in and go, but go fast...
It'll be road use, at least to start with (depending on how precious we feel about it once finished)
Transaxel 'box.
Hi Si!
yup, still getting it 
just got to get married first 
Will be picking it up in October, so I doubt we'll get it sorted before the IVA test comes in over the SVA test 
I'm based in Bedfordshire.
It'll be road use, at least to start with (depending on how precious we feel about it once finished)
Transaxel 'box.
Hi Si!
yup, still getting it just got to get married first Will be picking it up in October, so I doubt we'll get it sorted before the IVA test comes in over the SVA test I'm based in Bedfordshire.
Edited by Foolish Dave on Thursday 24th April 16:16
Ask these guys here....
http://www.turbominis.co.uk/forums/index.php
They will know who to go to, and who not to go to.
http://www.turbominis.co.uk/forums/index.php
They will know who to go to, and who not to go to.
Is there any reason why your wanting to use an a series?
I only ask as I have been working with them since I was about 7, and while having some redeeming features, extreme reliability and high performance are not particularly amongst them, and certainly the two do not go hand in hand.
The A series is essentially quite a poor design, in that it isn't crossflow, it has siamesed ports, and is really close to it's limits of boring out (you can take it out to nearly 1500 by playing with offset boring/cranks/rods) it is also not a particularly amazing engine to drive in any way, will not be easy to mate to a transaxle although I can't see why you need to unless your mounting it in the cockpit or using a torque tube.
If your limited to engine size there are better options out there.
If your not limited to engine size there are far better engines out there.
If your limited to period engines there are better options out there.
If your limited to cost there are better options out there.
If your limited to space there are better options out there! Seeing a pattern?
If for some reason it has to be an a series though then assuming were talking in line to mate to a midget/marina box (hint use the marina it is vastly stronger) use a marina 1.3 A+ engine, MG Metro head, and your choice of cam to do a cheap good base to build on. BMW K1000 head makes a hell of an improvement relatively cheaply. Turboing is rarely the success people imagine, and the further you tune it the less time between rebuilds I'm afraid.
I only ask as I have been working with them since I was about 7, and while having some redeeming features, extreme reliability and high performance are not particularly amongst them, and certainly the two do not go hand in hand.
The A series is essentially quite a poor design, in that it isn't crossflow, it has siamesed ports, and is really close to it's limits of boring out (you can take it out to nearly 1500 by playing with offset boring/cranks/rods) it is also not a particularly amazing engine to drive in any way, will not be easy to mate to a transaxle although I can't see why you need to unless your mounting it in the cockpit or using a torque tube.
If your limited to engine size there are better options out there.
If your not limited to engine size there are far better engines out there.
If your limited to period engines there are better options out there.
If your limited to cost there are better options out there.
If your limited to space there are better options out there! Seeing a pattern?
If for some reason it has to be an a series though then assuming were talking in line to mate to a midget/marina box (hint use the marina it is vastly stronger) use a marina 1.3 A+ engine, MG Metro head, and your choice of cam to do a cheap good base to build on. BMW K1000 head makes a hell of an improvement relatively cheaply. Turboing is rarely the success people imagine, and the further you tune it the less time between rebuilds I'm afraid.
It's an A-series - there's very little out there that fit's the packaging requirements and those that do require stricter emissions.
Sorry - I was having a brain freeze - it's inline, not transaxel. It's a Type 9 box mating to the A-series.
I'm waiting on Swift Tune to get back to me - may give them a call today.
I'm not looking for Earth-shattering power, 90-100 bhp will be more than enough to be going on with. The big thing is the car will be left for periods of time - esp over the winter - and we want to be able to jump in and go without fiddling with timing or carbs, etc.
I don't mind spending a few hours a month making sure it's all just-so, but not huge chunks of time more regularly than that.
Sorry - I was having a brain freeze - it's inline, not transaxel. It's a Type 9 box mating to the A-series.
I'm waiting on Swift Tune to get back to me - may give them a call today.
I'm not looking for Earth-shattering power, 90-100 bhp will be more than enough to be going on with. The big thing is the car will be left for periods of time - esp over the winter - and we want to be able to jump in and go without fiddling with timing or carbs, etc.
I don't mind spending a few hours a month making sure it's all just-so, but not huge chunks of time more regularly than that.
Well in that case I would suggest Marina A+ block. Marina crank. MG metro pistons. MG Metro cylinder head. 1.5 ratio rockers. Fast road/rally cam. Duplex timing gear off Midget. Gas flow the head. Fit either 1 x 1" 3/4 carb for low down grunt or 2 x 1" 1/4 for top end. A webber on this spec engine will be a total waste of money unless it is spending all its time on W.O.T. I.E. Racing.
With the work to the head, and a bit of tweaking on a dyno you should see your 90-100 I got just sub 100 out of almost exactly the same spec engine I built years back, except my was 1310 with T slot pistons.
I would also suggest that you at least consider the Marina/triumph box as opposed to the type 9, it is plenty strong enough, 4 synchro, you can get an overdrive version from spitfire/herald etc. Which will give you your 5 gears, and it doesn't need the expensive conversion kit, also the marina box with the midget 1500 gearbox mounts (fit straight on same box) makes a very easy package to mount in to a chassis.
Must say though in your position I would be looking at a fiat 2.0 twink with 5 speed box.
With the work to the head, and a bit of tweaking on a dyno you should see your 90-100 I got just sub 100 out of almost exactly the same spec engine I built years back, except my was 1310 with T slot pistons.
I would also suggest that you at least consider the Marina/triumph box as opposed to the type 9, it is plenty strong enough, 4 synchro, you can get an overdrive version from spitfire/herald etc. Which will give you your 5 gears, and it doesn't need the expensive conversion kit, also the marina box with the midget 1500 gearbox mounts (fit straight on same box) makes a very easy package to mount in to a chassis.
Must say though in your position I would be looking at a fiat 2.0 twink with 5 speed box.
wildoliver said:
Well in that case I would suggest Marina A+ block. Marina crank. MG metro pistons. MG Metro cylinder head. 1.5 ratio rockers. Fast road/rally cam. Duplex timing gear off Midget. Gas flow the head. Fit either 1 x 1" 3/4 carb for low down grunt or 2 x 1" 1/4 for top end. A webber on this spec engine will be a total waste of money unless it is spending all its time on W.O.T. I.E. Racing.
With the work to the head, and a bit of tweaking on a dyno you should see your 90-100 I got just sub 100 out of almost exactly the same spec engine I built years back, except my was 1310 with T slot pistons.
I would also suggest that you at least consider the Marina/triumph box as opposed to the type 9, it is plenty strong enough, 4 synchro, you can get an overdrive version from spitfire/herald etc. Which will give you your 5 gears, and it doesn't need the expensive conversion kit, also the marina box with the midget 1500 gearbox mounts (fit straight on same box) makes a very easy package to mount in to a chassis.
Must say though in your position I would be looking at a fiat 2.0 twink with 5 speed box.
As matter of interest a friend of my fathers built a Westfield XI with Fiat twin cam/five speed box (form a 131 supermiafora) about 20 years ago, it was a total flyerWith the work to the head, and a bit of tweaking on a dyno you should see your 90-100 I got just sub 100 out of almost exactly the same spec engine I built years back, except my was 1310 with T slot pistons.
I would also suggest that you at least consider the Marina/triumph box as opposed to the type 9, it is plenty strong enough, 4 synchro, you can get an overdrive version from spitfire/herald etc. Which will give you your 5 gears, and it doesn't need the expensive conversion kit, also the marina box with the midget 1500 gearbox mounts (fit straight on same box) makes a very easy package to mount in to a chassis.
Must say though in your position I would be looking at a fiat 2.0 twink with 5 speed box.
wildoliver said:
Is there any reason why your wanting to use an a series?
I only ask as I have been working with them since I was about 7, and while having some redeeming features, extreme reliability and high performance are not particularly amongst them, and certainly the two do not go hand in hand.
The A series is essentially quite a poor design, in that it isn't crossflow, it has siamesed ports, and is really close to it's limits of boring out (you can take it out to nearly 1500 by playing with offset boring/cranks/rods) it is also not a particularly amazing engine to drive in any way, will not be easy to mate to a transaxle although I can't see why you need to unless your mounting it in the cockpit or using a torque tube.
If your limited to engine size there are better options out there.
If your not limited to engine size there are far better engines out there.
If your limited to period engines there are better options out there.
If your limited to cost there are better options out there.
If your limited to space there are better options out there! Seeing a pattern?
If for some reason it has to be an a series though then assuming were talking in line to mate to a midget/marina box (hint use the marina it is vastly stronger) use a marina 1.3 A+ engine, MG Metro head, and your choice of cam to do a cheap good base to build on. BMW K1000 head makes a hell of an improvement relatively cheaply. Turboing is rarely the success people imagine, and the further you tune it the less time between rebuilds I'm afraid.
I'm not questioning your knowledge, there are a lot of people who know a lot about the a-series and from certain perspectives it can be considered a poor design, but it is a 50's design and has outlasted most of its competitors.I only ask as I have been working with them since I was about 7, and while having some redeeming features, extreme reliability and high performance are not particularly amongst them, and certainly the two do not go hand in hand.
The A series is essentially quite a poor design, in that it isn't crossflow, it has siamesed ports, and is really close to it's limits of boring out (you can take it out to nearly 1500 by playing with offset boring/cranks/rods) it is also not a particularly amazing engine to drive in any way, will not be easy to mate to a transaxle although I can't see why you need to unless your mounting it in the cockpit or using a torque tube.
If your limited to engine size there are better options out there.
If your not limited to engine size there are far better engines out there.
If your limited to period engines there are better options out there.
If your limited to cost there are better options out there.
If your limited to space there are better options out there! Seeing a pattern?
If for some reason it has to be an a series though then assuming were talking in line to mate to a midget/marina box (hint use the marina it is vastly stronger) use a marina 1.3 A+ engine, MG Metro head, and your choice of cam to do a cheap good base to build on. BMW K1000 head makes a hell of an improvement relatively cheaply. Turboing is rarely the success people imagine, and the further you tune it the less time between rebuilds I'm afraid.
Without a different head or turbocharging you're really limited to the 120-130bhp without it becoming too undrivable.
With Turbo and the 5 port, the MG Metro Turbo challenge cars were running 200bhp (although that is a race engine), rumour or has it the factory cars were more like 220.
The K1100 or K1200 helps on that front, or the Kad 16v or a good 8-port head.
I know of at least one A-series running a K1100 and turbo'd producing in excess of 300bhp reliably. Its in a mini, so the gearbox lasts about 5mins, but its fun when its running!
What I'm trying to say is it can be done, although probably for the cost you could do better looking elsewhere.
For what this guy wants a 1293 in an A+ marina block and an Mg Metro cam or maybe a 276 and 12G940 head will probably cover what he needs. at 90-100bhp, he's well within tolerance.
I don't want to push out more than 120bhp - this would make the car ... interesting to drive around in: The 65bhp and 72ftlb from the standard 1275cc is engough to zip around in when the wet mass of the car is only just tipping 450kg.
We're looking at 100bhp and 100ftlb region.
I have an estimate from Nick Swift of Swift Tune which is in the ball park of what we want and seems to have a very solid service offering.
I'll have a look at the others cited at the weekend, ta
We're looking at 100bhp and 100ftlb region.
I have an estimate from Nick Swift of Swift Tune which is in the ball park of what we want and seems to have a very solid service offering.
I'll have a look at the others cited at the weekend, ta
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