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850 Engine Upgrades


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#16 dangreen

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Posted 16 November 2019 - 08:33 PM

The 850 engine is awesome.. accept it and respect it...

Still gets you there....

Eventually.


Haha. Yeah, I wasn't around even when the final "proper" mini rolled off the production line. I only recently learnt to drive and it's a different experience to drive a mini and I guess this is part of it

#17 dangreen

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Posted 16 November 2019 - 08:34 PM

If your going to change cams, valves, cranks and pistons just change the engine...


Fair enough

#18 dangreen

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Posted 16 November 2019 - 08:39 PM

Driving an 850 Mini in modern traffic and on motorways requires skills that most modern car drivers don't really need or have long forgotten. Such as reading the road ahead.....anticipating what is happening to traffic way ahead to minimise the need for any braking.....
eg:-
A start from standstill at traffic lights in a low power car is much slower than slowing down well in advance and keeping the car moving until the moment the lights change, even a little forward momentum will mean you can accelerate away far more quickly.
Hills and inclines are hardly noticed even in modern small cars but in an 850 Mini you will gradually slow and eventually struggle unless you are in the right gear early or have seen the incline ahead in good time and so got a good run up coming down the previous descent !
It can be fun when you get it right but can also be stressful when you get it wrong and can't make it past a lorry on the motorway with your foot flat to the floor, while losing speed and unable to drop back due to a queue of impatient modern cars sitting on your rear bumper !!


Yeah, it's a completely different experience to my winter car. Or any other car I have driven (apart from my dad's 1970s mgb). I do enjoy driving it and I guess not being able to cruise as well is part of the experience. It's crazy how much more you have to do driving a classic car. Even starting it takes a certain finess. I love the whole experience though. It's so much fun and it's quite amusing to watch my friends try to start my car or ask what the choke does

#19 ads7

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Posted 16 November 2019 - 09:08 PM

My 850 tops out at 75mph with a hs4 1 1/2" carb fitted with AAU needle, ramair filter, medium bore lcb & far too large diameter 2" exhaust (which actually loses power) - I'm switching to a maximum 1.75" pipe leading into either a sprite MK1 back box or rc40 unit.

Yes it's noisy, sounds about to explode at 'max' speed! Need to check my bulkhead for unsealed holes and add soundproofing methinks

Edited by ads7, 16 November 2019 - 09:10 PM.


#20 unburntfuelinthemorning

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Posted 16 November 2019 - 09:29 PM

Standard 998 Mini on the M23 on the way back to Cambridgeshire via the M25 and A1 after visiting the Minis at Brighton around 1990 ish.  Around 2 hours and 120 miles each way.  The speedo needle stayed there most of the day.  It was my brother's Mini, wasn't particularly well maintained but did long journeys quite regularly at this speed clocking up thousands of miles.

 

Id9JCJy.jpg



#21 DeadSquare

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Posted 16 November 2019 - 10:58 PM

 

50 years ago, I fitted a '2A 948' cam and S exhaust to a friends 2nd hand 850 Mini Van, no other mods, and it did over 250,00 miles at 80MPH, five days a week from Bromsgrove to Bristol and back.


Right, so basically it's fine to drive fast a lot and I shouldn't really worry about it

 

 

The 70 year old 803cc A series was a quite satisfactory engine in a Morris Minor / A35.

The 65 year old upgrade to 948cc substantially beefed it up.

The reduction to 848 retained the beefyness, but reduced the strain on the crank because the stroke was reduced, and the Mini is lighter than the Minor,...........so, the 848 engine has a 60 year old well proven history and is under stressed.

 

In full race form, they could produce 80 BHP and be revved to well over 7,500 RPM between gear changes.

 

You will know when you have driven it too fast................................................you get a letter in the post.



#22 dangreen

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Posted 17 November 2019 - 12:33 PM

My 850 tops out at 75mph with a hs4 1 1/2" carb fitted with AAU needle, ramair filter, medium bore lcb & far too large diameter 2" exhaust (which actually loses power) - I'm switching to a maximum 1.75" pipe leading into either a sprite MK1 back box or rc40 unit.

Yes it's noisy, sounds about to explode at 'max' speed! Need to check my bulkhead for unsealed holes and add soundproofing methinks


I've managed to push mine to a similar speed although it also sounded like it was going to explode. I've had to replace some sound deadening foam that has rotted away but need to find something better than just basic foam.

#23 dangreen

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Posted 17 November 2019 - 12:35 PM

Standard 998 Mini on the M23 on the way back to Cambridgeshire via the M25 and A1 after visiting the Minis at Brighton around 1990 ish. Around 2 hours and 120 miles each way. The speedo needle stayed there most of the day. It was my brother's Mini, wasn't particularly well maintained but did long journeys quite regularly at this speed clocking up thousands of miles.

Id9JCJy.jpg


Cool. I don't do any long stints and my car has actually been to le mans (not for racing, just to do a few laps with a previous owner) so I guess it should be able to handle a little 15 minute journey along a dual carriageway at 70.

#24 dangreen

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Posted 17 November 2019 - 12:40 PM


50 years ago, I fitted a '2A 948' cam and S exhaust to a friends 2nd hand 850 Mini Van, no other mods, and it did over 250,00 miles at 80MPH, five days a week from Bromsgrove to Bristol and back.

Right, so basically it's fine to drive fast a lot and I shouldn't really worry about it

The 70 year old 803cc A series was a quite satisfactory engine in a Morris Minor / A35.
The 65 year old upgrade to 948cc substantially beefed it up.
The reduction to 848 retained the beefyness, but reduced the strain on the crank because the stroke was reduced, and the Mini is lighter than the Minor,...........so, the 848 engine has a 60 year old well proven history and is under stressed.

In full race form, they could produce 80 BHP and be revved to well over 7,500 RPM between gear changes.

You will know when you have driven it too fast................................................you get a letter in the post.

Blimey. That's not far off what the 1275s produce stock! I guess there's nothing to worry about. Also quite an interesting little slice of BMC history.
I plan to fit a tach soon so that should also put my worries to bed since I'll actually be able to see how many revs it's doing.
No letters through the post yet thankfully but that did make me laugh. I sometimes joke that it'd be very difficult to speed in my car since it's so slow but it makes it better since you can have more fun and get the most out of the engine even on British roads with our speed limits.

#25 unburntfuelinthemorning

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Posted 17 November 2019 - 01:45 PM


 I sometimes joke that it'd be very difficult to speed in my car since it's so slow but it makes it better since you can have more fun and get the most out of the engine even on British roads with our speed limits.

 

That's a major reason I went back to Minis.  I'm having far more fun driving them than the faster cars I've had.

 

Modern cars are so fast now you're over the speed limit in seconds and while that can be fun in some ways there's that fear of losing ones licence too easily.  If you're caught doing more than 30 mph over it's not good.

 

Similar story with grip, modern cars have loads but it's difficult to use it all and drive on the limit on the road.  With the Mini it's normal to drive on the limit as it's not as fast and you learn how your vehicle handles.  Someone compared the difference to someone dancing in dance shoes with low grip where you can break traction in a controlled manner or dancing in work boots where you clomp around with more grip but if you break traction it's over.



#26 dangreen

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Posted 17 November 2019 - 07:55 PM


I sometimes joke that it'd be very difficult to speed in my car since it's so slow but it makes it better since you can have more fun and get the most out of the engine even on British roads with our speed limits.

That's a major reason I went back to Minis. I'm having far more fun driving them than the faster cars I've had.

Modern cars are so fast now you're over the speed limit in seconds and while that can be fun in some ways there's that fear of losing ones licence too easily. If you're caught doing more than 30 mph over it's not good.

Similar story with grip, modern cars have loads but it's difficult to use it all and drive on the limit on the road. With the Mini it's normal to drive on the limit as it's not as fast and you learn how your vehicle handles. Someone compared the difference to someone dancing in dance shoes with low grip where you can break traction in a controlled manner or dancing in work boots where you clomp around with more grip but if you break traction it's over.

Yeah, I totally agree. Good analogy!




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