Tuning a 948cc Engine
Discussion
Hi All
First post here. I have a 1958 Morris Minor with a 948cc engine. I am looking to tune it and am wondering the best way to go or would it be better to install a 1275cc and tune that? I am looking at using supercharge to give the engine a real boost.
My aim is to be able to climb hills quicker than 30mph!
Thanks for the help.
Rich
First post here. I have a 1958 Morris Minor with a 948cc engine. I am looking to tune it and am wondering the best way to go or would it be better to install a 1275cc and tune that? I am looking at using supercharge to give the engine a real boost.
My aim is to be able to climb hills quicker than 30mph!
Thanks for the help.
Rich
Certainly a 1275cc swap is the easiest, strongest way to get that gain, but you may not wish to do that for other reasons.
In which case you need a copy of David Vizard's Tuning the A-series engine.
Not only a classic text, and v good value, but every concept explained in there is fundamentally applicable to any other engine you might want to play with
It's a model of clarity in technical writing and also a cracking read to dip into - my copy is 15yrs old and I'm not parting with it (though not owned an A series for at least 13...)
In which case you need a copy of David Vizard's Tuning the A-series engine.
Not only a classic text, and v good value, but every concept explained in there is fundamentally applicable to any other engine you might want to play with
It's a model of clarity in technical writing and also a cracking read to dip into - my copy is 15yrs old and I'm not parting with it (though not owned an A series for at least 13...)I'd go for the torque of the 1275 but then you might need front discs?
For the 948 a Mini Cooper head (998cc cooper) with casting number 12G295 has a better shaped combustion chamber with less shrouding. Also i think bigger valves. Add either twin 1 1/4 su's (which i think i have in the garage- if you're interested message me) or a 1.5 single su off an older type metro.
Ideally fit a better manifold and exhuast to continue with the improved flow.
I'm not sure how lot this will cost, its been a while since i was into mini's. I'd still go for the 1275 and then maybe tune that though
For the 948 a Mini Cooper head (998cc cooper) with casting number 12G295 has a better shaped combustion chamber with less shrouding. Also i think bigger valves. Add either twin 1 1/4 su's (which i think i have in the garage- if you're interested message me) or a 1.5 single su off an older type metro.
Ideally fit a better manifold and exhuast to continue with the improved flow.
I'm not sure how lot this will cost, its been a while since i was into mini's. I'd still go for the 1275 and then maybe tune that though
"David Vizzards bumper book of tuning everything A series but mainly minis" 
I don't have an A series any more but it's one of those books that I will always keep!
As above, there's no point trying to tune a 948 when you can get the power easily from a 1275, which is an easy swop and if you really want more power can be increased to 1340, warm cam, twin carbs - first mod though is better brakes! Marina uprights I think to be able to use discs, but I don't imagine there are many Marinas at the scrappy any more, but someone must do a conversion kit.
5 speed box apparently makes a huge difference on Spridgets, don't know how easy it is to convert a Minor. You could also change the diff to a later Midget 3.9 or 3.7.
I don't have an A series any more but it's one of those books that I will always keep!As above, there's no point trying to tune a 948 when you can get the power easily from a 1275, which is an easy swop and if you really want more power can be increased to 1340, warm cam, twin carbs - first mod though is better brakes! Marina uprights I think to be able to use discs, but I don't imagine there are many Marinas at the scrappy any more, but someone must do a conversion kit.
5 speed box apparently makes a huge difference on Spridgets, don't know how easy it is to convert a Minor. You could also change the diff to a later Midget 3.9 or 3.7.
JHL may be able to help you - http://www.jlhmorrisminors.co.uk/index.php
Ah, just remembered this, Series 3 Minor.... http://www.morrisminor.org.uk/index.php/series-iii... should give some ideas!
Edit - Practical Classics article here
Edit - Practical Classics article here
Edited by john2443 on Tuesday 30th July 08:50
I had a mk1 Sprite in the sixties that I modified the engine in for all sorts of motor sport. It was my daily car as well. The engine was bored to 998 and used Cooper rods and pistons. You could get a special crankshaft then, a Red crank, made from forged steel. A 649 cam and a Cooper S head, twin 1.5" SU's, 13:1 compression ratio and it reved to 8500, not much power below 4000 though. All sorts of other mods to make it as reliable as possible. I fitted a Post Office van diff. to the back axel, 12.5 mph per 1000 rpm in top. Went like the clappers, up to 100!
hmmmm just bought a 58 frogeye sprite so also interested in this, but dont want to change the 948cc capacity to keep it original.
Would quite like to put (perhaps) an unshrouded A+ mg metro big valve head on it though and the cooper rods etc mentioned above.
4 into 1 manifolds would be allowable, but keep the SUs.
See it for the first time tomorrow, bought blind, excited and worried!
ahhh that would be a 3 into 1 manifold.
Perhaps also a longer final drive to relax chugging about (or maybe at the diff?)
So looking for tips on just very light tuning, help with breathing for economy as much as power.
Doubt it will ever go over 4500rpm, as it is 57 years old and "heavily patinated" with no plans to restore it either.
Would quite like to put (perhaps) an unshrouded A+ mg metro big valve head on it though and the cooper rods etc mentioned above.
4 into 1 manifolds would be allowable, but keep the SUs.
See it for the first time tomorrow, bought blind, excited and worried!
ahhh that would be a 3 into 1 manifold.
Perhaps also a longer final drive to relax chugging about (or maybe at the diff?)
So looking for tips on just very light tuning, help with breathing for economy as much as power.
Doubt it will ever go over 4500rpm, as it is 57 years old and "heavily patinated" with no plans to restore it either.
Edited by bencollins on Saturday 27th June 06:51
bencollins said:
hmmmm just bought a 58 frogeye sprite so also interested in this, but dont want to change the 948cc capacity to keep it original.
Would quite like to put (perhaps) an unshrouded A+ mg metro big valve head on it though and the cooper rods etc mentioned above.
4 into 1 manifolds would be allowable, but keep the SUs.
See it for the first time tomorrow, bought blind, excited and worried!
ahhh that would be a 3 into 1 manifold.
Perhaps also a longer final drive to relax chugging about (or maybe at the diff?)
So looking for tips on just very light tuning, help with breathing for economy as much as power.
Doubt it will ever go over 4500rpm, as it is 57 years old and "heavily patinated" with no plans to restore it either.
It's been a while since I messed with Minis and A series engines, but from memory you can't fit a MG Metro head (big bore) to a small bore engine. You'll be restricted with the 12g295 cooper head or a 12g202.Would quite like to put (perhaps) an unshrouded A+ mg metro big valve head on it though and the cooper rods etc mentioned above.
4 into 1 manifolds would be allowable, but keep the SUs.
See it for the first time tomorrow, bought blind, excited and worried!
ahhh that would be a 3 into 1 manifold.
Perhaps also a longer final drive to relax chugging about (or maybe at the diff?)
So looking for tips on just very light tuning, help with breathing for economy as much as power.
Doubt it will ever go over 4500rpm, as it is 57 years old and "heavily patinated" with no plans to restore it either.
Edited by bencollins on Saturday 27th June 06:51
hi thanks, ill need to pick the right header then.
According to bugeyeguy this is what is needed.
Big valve head, header, better exhaust, new larger carbs.
... sounds about right.
For some reason it only has one carb. Its a very early example, but sure that is just a dodgy repair someone did, rather than an early variant.
Anyway, its very "heavily patinated" but goes smoothly and drove it 150 miles home yesterday so not bad going
The charm of the car is off the scale, love it!
And the love is universal, bizarrely the resprayed it from speedwell light blue to italian red.
Might switch it back sometime never in the future.
According to bugeyeguy this is what is needed.
Big valve head, header, better exhaust, new larger carbs.
... sounds about right.
For some reason it only has one carb. Its a very early example, but sure that is just a dodgy repair someone did, rather than an early variant.
Anyway, its very "heavily patinated" but goes smoothly and drove it 150 miles home yesterday so not bad going
The charm of the car is off the scale, love it!
And the love is universal, bizarrely the resprayed it from speedwell light blue to italian red.
Might switch it back sometime never in the future.
I've just bought one this week too. It's a 1958 model and fairly standard as far as I know. I bought it more or less by accident as I certainly wasn't looking for one.
I only saw it because it was in storage at the same place as one of my cars. An old chap had owned it for years but his wife was finding it a bit too much. Next thing I know I'm a Sprite owner. Loads of history and the original buff logbook.
Not sure I'll be keeping it long as I already have too much on the go.
Don't know much about them so this thread is interesting for me too.
I only saw it because it was in storage at the same place as one of my cars. An old chap had owned it for years but his wife was finding it a bit too much. Next thing I know I'm a Sprite owner. Loads of history and the original buff logbook.
Not sure I'll be keeping it long as I already have too much on the go.
Don't know much about them so this thread is interesting for me too.
Blimey that looks awesome, congrats!
mine is distinctly shonky, no i mean charming *ahem*, by comparison. Theres a blooming nice one here for £10k http://www.carandclassic.co.uk/car/C614751
but the rest are either basket cases or mint, not much in between. I paid £6200 which i think is cheap, but obviously if i fixed everything that would take me way above £14k for a minter. Still i didnt have £14k sitting about
Planning to do the bare minimum and drive it A LOT.
mine is distinctly shonky, no i mean charming *ahem*, by comparison. Theres a blooming nice one here for £10k http://www.carandclassic.co.uk/car/C614751
but the rest are either basket cases or mint, not much in between. I paid £6200 which i think is cheap, but obviously if i fixed everything that would take me way above £14k for a minter. Still i didnt have £14k sitting about
Planning to do the bare minimum and drive it A LOT.
wildwoods said:
Hi All
First post here. I have a 1958 Morris Minor with a 948cc engine. I am looking to tune it and am wondering the best way to go or would it be better to install a 1275cc and tune that? I am looking at using supercharge to give the engine a real boost.
My aim is to be able to climb hills quicker than 30mph!
Thanks for the help.
Rich
Will a K-series fit? Make sure any changes are reversible.First post here. I have a 1958 Morris Minor with a 948cc engine. I am looking to tune it and am wondering the best way to go or would it be better to install a 1275cc and tune that? I am looking at using supercharge to give the engine a real boost.
My aim is to be able to climb hills quicker than 30mph!
Thanks for the help.
Rich
I have mk1 midget with an early 1098 engine, which has the same size main bearings as the 948, because of the small main bearings it was not recommended to supercharge or make any decent power upgrades to it. I think a 1275 would be easiest but the amount you would have to spend to get decent power from it you would be better just getting the k-series then you would have all the power you would ever need for a morris minor
V8 Fettler said:
I could get the speedo needle round to the fuel gauge in my second Mini. Something else I should have hidden away in the lock-up for a few decades.
My dad used to have a mini van that started life as a 1,100cc & would accelerate to 'empty' 
No idea what was done to it as I was too young to remember.
eccles said:
It's been a while since I messed with Minis and A series engines, but from memory you can't fit a MG Metro head (big bore) to a small bore engine. You'll be restricted with the 12g295 cooper head or a 12g202.
You can - you need to pocket the block to accept AEG163 or 12G1805 or 12G940 1300 castings. Common practice in Mini Se7en race engines.Decent inlet +1.5 SU, and LCB/exhaust and a warm cam will liven the Moggy up. See these fellas:-
http://www.aseriesspares.co.uk/
Edited by FWDRacer on Wednesday 1st July 14:05
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