building a 1380 engine
Discussion
im about to start building a 1380 for mini but im not sure what parts i need to purchase? i.e will the standard con rods be alright ? and what other parts will need upgrading to make it reliable ? im looking to get 120bbhp out of the engine
and any suggestions on a cam shaft? i would like one that picks up at 1500 rpm
i have already got a 11 stud large valve head with double strength springs and it will have a 45 webber
and any suggestions on a cam shaft? i would like one that picks up at 1500 rpm
i have already got a 11 stud large valve head with double strength springs and it will have a 45 webber
aferris18 said:
im about to start building a 1380 for mini but im not sure what parts i need to purchase? i.e will the standard con rods be alright ? and what other parts will need upgrading to make it reliable ? im looking to get 120bbhp out of the engine
and any suggestions on a cam shaft? i would like one that picks up at 1500 rpm
i have already got a 11 stud large valve head with double strength springs and it will have a 45 webber
You might want to ask if there is any decent written material about!!and any suggestions on a cam shaft? i would like one that picks up at 1500 rpm
i have already got a 11 stud large valve head with double strength springs and it will have a 45 webber
DV
Like many on here I started out on the A-Series and still have a soft spot for it.
There's nothing that you need to know that isn't written in plain english in here:
http://www.amazon.co.uk/Tuning-British-Leylands-En...
I'm sure you could get second hand on amazon or ebay
Not only will you learn the in's and out's of the A-Series but you will also gain knowledge that applies to every internal combustion engine. I've bought hundreds of auto books over the last 20 years but none were more valuable than that was when I was starting out.
There's plenty of people on here who will help you with your build but you would be far better off reading a few books, doing your own research and formulating your own ideas then use forums like this as a final sanity check before you start spending money.
How would you know that any advice you are given is worth listening to if you don't at least comprehend the basics yourself.
Good luck.
There's nothing that you need to know that isn't written in plain english in here:
http://www.amazon.co.uk/Tuning-British-Leylands-En...
I'm sure you could get second hand on amazon or ebay
Not only will you learn the in's and out's of the A-Series but you will also gain knowledge that applies to every internal combustion engine. I've bought hundreds of auto books over the last 20 years but none were more valuable than that was when I was starting out.
There's plenty of people on here who will help you with your build but you would be far better off reading a few books, doing your own research and formulating your own ideas then use forums like this as a final sanity check before you start spending money.
How would you know that any advice you are given is worth listening to if you don't at least comprehend the basics yourself.
Good luck.
I am by no means and expert, but trying to get 120bhp from a 5 port mini engine which picks up cleanly from 1500 rpm might be a bit tricky?
My 1380 supposedly has 120bhp, but stil itching for the first drive as it nearing the end of its recommissioning!
I have driven it up a service road moving it around, ony slowly in 1st and 2nd, and it seems perfectly docile at low speed however I have been warned that it is not really happy below 2,500rpm in 4th, time will tell!
I have the build sheet for the engine ( Swiftune block and head ) and it has things like a 296 Scatter cam, so getting that power has a few
downsides.
Nowadays though, you have more options and maybe take a look at a BMW 16v bike head, might give you the power you are after but a bit more civilised??
My 1380 supposedly has 120bhp, but stil itching for the first drive as it nearing the end of its recommissioning!
I have driven it up a service road moving it around, ony slowly in 1st and 2nd, and it seems perfectly docile at low speed however I have been warned that it is not really happy below 2,500rpm in 4th, time will tell!
I have the build sheet for the engine ( Swiftune block and head ) and it has things like a 296 Scatter cam, so getting that power has a few
downsides.
Nowadays though, you have more options and maybe take a look at a BMW 16v bike head, might give you the power you are after but a bit more civilised??
hi everyone thanks for all the replies!
i already have that book mtrehy and d.v but i was just after a definitive yes or no but that book is terrific! its a great help!
but i didn't realise 120bhp was alot to ask for from a mini engine perhaps i should do a little bit more research and ideally i want to steer clear of scatter cams as it will still be my everyday car so it could make it a little impractical
the bmw head has been a option for a while but im finding it hard to find information about it
like does the head or block need any machining or studs moved etc ? i dont want to dive in the deep end and get stuck really aha
i already have that book mtrehy and d.v but i was just after a definitive yes or no but that book is terrific! its a great help!
but i didn't realise 120bhp was alot to ask for from a mini engine perhaps i should do a little bit more research and ideally i want to steer clear of scatter cams as it will still be my everyday car so it could make it a little impractical
the bmw head has been a option for a while but im finding it hard to find information about it
like does the head or block need any machining or studs moved etc ? i dont want to dive in the deep end and get stuck really aha reading back through i didnt ask a simple question aha sorry so i will try again... will i need to upgrade con rods or not ?
and how would the 286 cam run below 2500rpm? would it not idle well and splutter about alot ?
i have only built a 998cc engine that isnt too highly tuned so i havent got much of a idea of a -A series engine so i will apologise in advance for the some silly questions i may ask
cheers guys
and how would the 286 cam run below 2500rpm? would it not idle well and splutter about alot ?
i have only built a 998cc engine that isnt too highly tuned so i havent got much of a idea of a -A series engine so i will apologise in advance for the some silly questions i may ask
cheers guys
My historic rally Cooper 'S' has 115 bhp. It's a well-built 1310 cc lump with everything lightened and balanced. It has 11.1:1 comp ratio and a head with 36 mm inlets and 30.5 mm exhausts fully flowed by a real professional who, sadly, is no longer with us. Cam is a 286, carbs are twin H4's, dizzy is a custom Aldon.
It really won't pull below about 2800 rpm when hot at more than about 40% throttle opening. Sure it will run below 2800, but the available power and torque is less than with, say, a 266 cam.
Also, to keep it on the cam I run a 3.9:1 final drive ratio and a closeratio straight cut gearbox, so cruising speed is limited due to it only having 14.5 mph/1000 rpm in top gear. Peak power is at 6400 and it needs to run up to 6800 to make sure it's always in the strong part of the power band. To say that it's horrible in traffic and in a town is an understatement, but on a rally special stage it's just right.
If you want/need 120 bhp with a good bottom end, forced induction is really the only practical way to go in order to get a satisfactory torque band.
It really won't pull below about 2800 rpm when hot at more than about 40% throttle opening. Sure it will run below 2800, but the available power and torque is less than with, say, a 266 cam.
Also, to keep it on the cam I run a 3.9:1 final drive ratio and a closeratio straight cut gearbox, so cruising speed is limited due to it only having 14.5 mph/1000 rpm in top gear. Peak power is at 6400 and it needs to run up to 6800 to make sure it's always in the strong part of the power band. To say that it's horrible in traffic and in a town is an understatement, but on a rally special stage it's just right.
If you want/need 120 bhp with a good bottom end, forced induction is really the only practical way to go in order to get a satisfactory torque band.
Hello thanks for the replies everyone.
And I have that exact book already it's amazing the amount of knowledge you can pick up from that book I even used it to build the 1060cc engine I have now how ever its not quite as fast as I have always wanted it to be The trouble now is I'm a apprentice so money is a little hard to come by but u don't mind spending money where it is needed so I just some knowledge from experiance rather than a salesman down the phone trying to drive a sales.
P.s I really appreciate the work you have put in over the years David you have really pushed the limits of most cars and made it Posdibly for anyone with a spanner to do the same in there shed!
And I have that exact book already it's amazing the amount of knowledge you can pick up from that book I even used it to build the 1060cc engine I have now how ever its not quite as fast as I have always wanted it to be
The trouble now is I'm a apprentice so money is a little hard to come by but u don't mind spending money where it is needed so I just some knowledge from experiance rather than a salesman down the phone trying to drive a sales.P.s I really appreciate the work you have put in over the years David you have really pushed the limits of most cars and made it Posdibly for anyone with a spanner to do the same in there shed!
The thing is you seem to be wanting a 120HP engine, want it to pull cleanly from idle AND want to do it on a very tight budget.
The way an engine behaves is a compromise in many ways so setting yourself a sensible target to begin with is an important first step in project success. DV's book is an excellent source of information to acquire the knowledge for setting sensible project boundaries.
As an example, although relatively cheap nowadays, building an all steel bottom end capable of sustaining 8500RPM seems out of the question in your case. The reason why RPM capability is so important, is that it correlates directly with your choice of cam which dictates the RPM bandwith in which (max) power is made.
Accordingly, imo you'd have to begin with setting a budget and carefully map out the parts you currently have vs. what they're capable of in standard guise, as well what can be done to increase their RPM capability / fatigue life. Again DV's book is the most excellent source for this.
Next you'll be talking to your machine shop about costs of 1380 bore and hone, decking the block, machining for centre strap or line boring for steel centre main, shot peening rods that you yourself have lightened etc. You'll find that costs start adding up very quickly, especially when you throw pistons, rod bolts, vernier wheels etc. into the equation. Again your job is to know in advance and work within your budget.
A 286 cam peaks at around 6500-6750 RPM, in order to make gear shifts fall back into a favourable rev range you want an engine that is able to cope with at least 7250 RPM safely. If your budget allows for such an engine to be built then by all means use a 286 cam....
....however do realise that the 286 makes its power higher up in rev range at the cost of the lower range. Where do you see yourself driving most of the time, 3000-5500RPM point and squeeze busy traffic or 6000RPM open lanes / trackdays??
The reason I ask this is that a 286 can be made to behave in the lower rev range, especially on a 1380 vs. 1293, it does however take very careful tuning of both fueling and ignition. Mappable ignition as I run on my 1380 / 286 scatter has proven a very substantial help in making the engine tractable low down....again this comes at a budget.
To sum things up, ask yourself whether on one hand a torquey 95HP engine based on a carefully built 1380 standard reconditioned A+ bottom end with steel center strap best fits your demands and budget, or whether a peakier engine fits the bill. Use DV's book to carefully pick a target within this bandwith....
Hope this helps!
The way an engine behaves is a compromise in many ways so setting yourself a sensible target to begin with is an important first step in project success. DV's book is an excellent source of information to acquire the knowledge for setting sensible project boundaries.
As an example, although relatively cheap nowadays, building an all steel bottom end capable of sustaining 8500RPM seems out of the question in your case. The reason why RPM capability is so important, is that it correlates directly with your choice of cam which dictates the RPM bandwith in which (max) power is made.
Accordingly, imo you'd have to begin with setting a budget and carefully map out the parts you currently have vs. what they're capable of in standard guise, as well what can be done to increase their RPM capability / fatigue life. Again DV's book is the most excellent source for this.
Next you'll be talking to your machine shop about costs of 1380 bore and hone, decking the block, machining for centre strap or line boring for steel centre main, shot peening rods that you yourself have lightened etc. You'll find that costs start adding up very quickly, especially when you throw pistons, rod bolts, vernier wheels etc. into the equation. Again your job is to know in advance and work within your budget.
A 286 cam peaks at around 6500-6750 RPM, in order to make gear shifts fall back into a favourable rev range you want an engine that is able to cope with at least 7250 RPM safely. If your budget allows for such an engine to be built then by all means use a 286 cam....
....however do realise that the 286 makes its power higher up in rev range at the cost of the lower range. Where do you see yourself driving most of the time, 3000-5500RPM point and squeeze busy traffic or 6000RPM open lanes / trackdays??
The reason I ask this is that a 286 can be made to behave in the lower rev range, especially on a 1380 vs. 1293, it does however take very careful tuning of both fueling and ignition. Mappable ignition as I run on my 1380 / 286 scatter has proven a very substantial help in making the engine tractable low down....again this comes at a budget.
To sum things up, ask yourself whether on one hand a torquey 95HP engine based on a carefully built 1380 standard reconditioned A+ bottom end with steel center strap best fits your demands and budget, or whether a peakier engine fits the bill. Use DV's book to carefully pick a target within this bandwith....
Hope this helps!
Edited by Evoderby on Wednesday 25th January 10:51
Edited by Evoderby on Wednesday 25th January 11:06
3.1 diff with 10" wheels runs 120 mph @ 6500 RPM, whilst a 3.44 diff 'only' does 107 mph again @6.5K
A 3.9 diff more associated with sprints does 95 MPH at those revs, this also seems a good ratio for drag racing as it makes most effective use of 4th gear. A standard 1st gets very short though with this, making a close ratio box a welcome option.
So the question is what do you want????
A 3.9 diff more associated with sprints does 95 MPH at those revs, this also seems a good ratio for drag racing as it makes most effective use of 4th gear. A standard 1st gets very short though with this, making a close ratio box a welcome option.
So the question is what do you want????
evoderby i think you have saved me alot of wasted time and money!
i can ow see i will be asking way to much of a A-series engine to do all the things i want and still produce 120 so i think the plan will be to keep standard bottom end but lighten the con rods and crank and out a centre strap on the crank and just do the little things D.V states in his book look smoothing out the inlets and other little things and see what i get really.
so time to start saving cheers everyone for your help !
i can ow see i will be asking way to much of a A-series engine to do all the things i want and still produce 120 so i think the plan will be to keep standard bottom end but lighten the con rods and crank and out a centre strap on the crank and just do the little things D.V states in his book look smoothing out the inlets and other little things and see what i get really.
so time to start saving cheers everyone for your help !
Getting advice from David Vizard on tuning Mini's is almost as challenging as a Jaguar E type buyer getting advice from Sir William Lyons, personally.
You are one lucky man!!
Cooperman has pretty well covered the process. As others have said, getting tractability and smooth power is the real essential of good Mini tuning.
David Vizard has written many expert guides on A series engine tuning.
He was and still is IMO the worlds foremost A series tuner which is why I said what I did above. No one in the world could give you better advice. I always followed his luminary advice and proposals when I was racing Mini's thirty years or more ago. It certainly worked for me.
Buy his books and read mark learn and inwardly digest the detail.
Everything you need every option, every technique, every alteration is in those books. They constitute the bible on A series tuning and cannot be bettered. To this day.
I drive three Minis for fun, two tuned 1300+(ish) engines one with a K series twin cam MGTF high output set up. The K series will eat the other two.
As Henry Ford said " There Ain't No Substitute for Cubic Capacity": he was right.
I also have a Midas with a 1340cc engine and various other A series cars.
I am a great fan of the A series.
The K series does beat the A series because of size and breathing (Twin OHC/OHV.
However I would far rather drive an A series over, say, to Italy and back.
The K series would probably blow its gasket on the Mont Blanc route. The A series simply never blows head gaskets IMO. Unless you make it.
However the A series transverse set up does raise problems with transfer gears and a gearbox lacking decent hypo lube oil. It leaks oil like a sieve. Whatever you do.
Enjoy your Mini. You should get plenty of fun and reliability,
Read David Vizard's books. Nothing is better for A series detail.
Good Luck!
You are one lucky man!!
Cooperman has pretty well covered the process. As others have said, getting tractability and smooth power is the real essential of good Mini tuning.
David Vizard has written many expert guides on A series engine tuning.
He was and still is IMO the worlds foremost A series tuner which is why I said what I did above. No one in the world could give you better advice. I always followed his luminary advice and proposals when I was racing Mini's thirty years or more ago. It certainly worked for me.
Buy his books and read mark learn and inwardly digest the detail.
Everything you need every option, every technique, every alteration is in those books. They constitute the bible on A series tuning and cannot be bettered. To this day.
I drive three Minis for fun, two tuned 1300+(ish) engines one with a K series twin cam MGTF high output set up. The K series will eat the other two.
As Henry Ford said " There Ain't No Substitute for Cubic Capacity": he was right.
I also have a Midas with a 1340cc engine and various other A series cars.
I am a great fan of the A series.
The K series does beat the A series because of size and breathing (Twin OHC/OHV.
However I would far rather drive an A series over, say, to Italy and back.
The K series would probably blow its gasket on the Mont Blanc route. The A series simply never blows head gaskets IMO. Unless you make it.
However the A series transverse set up does raise problems with transfer gears and a gearbox lacking decent hypo lube oil. It leaks oil like a sieve. Whatever you do.
Enjoy your Mini. You should get plenty of fun and reliability,
Read David Vizard's books. Nothing is better for A series detail.
Good Luck!
imho 120bhp on a 1380 on a budget and driveable isnt going to be easy, ive got a 1380 with a 286 with a 45dcoe on a sc box with sc 1.1 drops and a 3.7 fd. mines circa 110 bhp and similar torque, the car is fairly lightweight perspex windows and comnposite panels. to a degree its quite driveable but takes some warming up from cold, next to nothing below 2-2.5k even above thats its not silky smooth.
Evoderby, thanks, you have just confirmed my suspicion that some info I have is wrong. I have been told by the guy who used to ( and still will ) maintain it for me that the car tops out of revs at about 100mph, abeit getting there quite quickly, but a 3.1 diff should give a higher top speed? It definately runs out of reves not lack of power and crap aero, so I guess it is probobly not a 3.1 . I will use the car for sprints and hillclimbs so 100 mph is plenty for me.
I guess there is only 2 ways to find out for sure, strip it out and look, or GPS... :-)
I guess there is only 2 ways to find out for sure, strip it out and look, or GPS... :-)
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