Engine recipe..

General Chat with an emphasis on BMC Minis & Other iconic cars of the 1960's.
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Engine recipe..

Post by gs.davies »

So, I’m most of the way through what is turning out to be a 2500 mile round trip.

I’ve used a load of oil and whilst the cars gone well, for the sort of things I want to do in it, I need more go. A lot more go.

If I was to build an engine capable of propelling a Mini at modern road speeds for hours on end, what would I need in terms of power, torque and specification? And by modern road speeds, I anticipate seeing some German motorways in the next twelve months.

Staying with the wand change, I think the 3.2:1 I’ve got is pretty good, but would consider taller.
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Re: Engine recipe..

Post by coopertim »

Talk to Oz, OAP he will build you a stonking motor!
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Re: Engine recipe..

Post by gs.davies »

coopertim wrote: Mon May 29, 2023 11:42 pm Talk to Oz, OAP he will build you a stonking motor!
I know.. I think that’s likely to be out of bounds in terms of cost though.
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Re: Engine recipe..

Post by 251 ENG »

The bigger the engine capacity the better
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Re: Engine recipe..

Post by Exminiman »

If you are looking for reliability, smoothness and decent MPG you could start of with a cam like a 256 profile, a single carb 1.5 SU and engine balanced.

Engine should be built with tolerances to suit long motorway miles in mind I would add some ZX1 after its been run in as well..

5 speed box would be ideal, depends on the engine you have or want, presumably they do helical gears in them still ?

From memory Dave Vizard gas a chapter about economy in the yellow book..might be worth looking it up
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Re: Engine recipe..

Post by gs.davies »

I’d love a five speed, but not sure how that could work with wand change.

Still want an 850 like appearance.
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Re: Engine recipe..

Post by Exminiman »

Are you planning to replace the 850 ?
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Re: Engine recipe..

Post by mk1 »

If you want an 850 like appearance then it will have to be an 1100 based unit. But that is going to struggle to give the 70 - 80 bhp you would need to be looking at to give you your proposed requirements.

Personally, if it was me, I'd be thinking about a big bore unit.
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Re: Engine recipe..

Post by Andrew1967 »

I’ve got a pretty standard (standard cam etc) 1330 S engine with a 3.1 diff S box and that pulls well and copes easily with 70 for long distances …

Go big bore … in my opinion a small bore engine can be made up to S power but it’ll be over stressed and never really be the same or better. Not that I know a huge amount about tuning but it makes sense really.
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Re: Engine recipe..

Post by Polarsilver »

Spend circa £4k on 5 speed box + £3k on re-con 1275 short engine + Head + Carbs + Cam etc .. add it up nothing is cheap these days. :roll:
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Re: Engine recipe..

Post by rolesyboy »

Go 1275. Swap the engine back when you’re done. Simpler, cheaper and easy changeover.
If not I’ve got a VTEC kit at mine Gary.
You can buy a tin of bronze green and brush paint it if you want the authentic look :D
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Re: Engine recipe..

Post by Alex »

1098+ on a 4-synch magic wand 1128 gearbox with a 3.1 diff.
Keeps the look, will cruise at '70' all day long without much effort.
Metric is for people who can't do fractions.
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Re: Engine recipe..

Post by gs.davies »

Alex wrote: Tue May 30, 2023 10:49 am 1098+ on a 4-synch magic wand 1128 gearbox with a 3.1 diff.
Keeps the look, will cruise at '70' all day long without much effort.
That’s pretty much what I have. It’s developed some issues on the run to IMM and back but where it really did struggle was some of the mountain passes. Whilst I couldn’t do Grand St Bernard as it was closed I did do the climb into Chamonix the other side and it was on its knees, grovelling up the hill, pulling strongly but 30 mph in third tops.

I’ve not ruled out big bore engines for this purpose and as I learn more about what I want from it, so the spec will grow.
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Re: Engine recipe..

Post by mab01uk »

gs.davies wrote: Mon May 29, 2023 11:25 pm So, I’m most of the way through what is turning out to be a 2500 mile round trip.

I’ve used a load of oil and whilst the cars gone well, for the sort of things I want to do in it, I need more go. A lot more go.

If I was to build an engine capable of propelling a Mini at modern road speeds for hours on end, what would I need in terms of power, torque and specification? And by modern road speeds, I anticipate seeing some German motorways in the next twelve months.
For a lot more go with 5-speed gearbox at reasonable cost with reliability and modern road speeds for hours on end, plus seeing some German motorways in the next twelve months....sounds like one of the modern engine conversion for Minis with a suitable front subframe such as Allspeed is needed? https://www.allspeedengineering.com/ind ... -11-19-08_

Engine Conversions on TMF:-
https://www.theminiforum.co.uk/forums/f ... nversions/
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Re: Engine recipe..

Post by gs.davies »

mab01uk wrote: Tue May 30, 2023 8:05 pm
gs.davies wrote: Mon May 29, 2023 11:25 pm So, I’m most of the way through what is turning out to be a 2500 mile round trip.

I’ve used a load of oil and whilst the cars gone well, for the sort of things I want to do in it, I need more go. A lot more go.

If I was to build an engine capable of propelling a Mini at modern road speeds for hours on end, what would I need in terms of power, torque and specification? And by modern road speeds, I anticipate seeing some German motorways in the next twelve months.
For a lot more go with 5-speed gearbox at reasonable cost with reliability and modern road speeds for hours on end, plus seeing some German motorways in the next twelve months....sounds like one of the modern engine conversion for Minis with a suitable front subframe such as Allspeed is needed? https://www.allspeedengineering.com/ind ... -11-19-08_

Engine Conversions on TMF:-
https://www.theminiforum.co.uk/forums/f ... nversions/
I’ve only just got over letting go of single leading shoe brakes, and whilst my purist tendencies are strong, this is beyond the pale (but completely true!)

😂😂😂
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Re: Engine recipe..

Post by mab01uk »

gs.davies wrote: Tue May 30, 2023 8:07 pm I’ve only just got over letting go of single leading shoe brakes, and whilst my purist tendencies are strong, this is beyond the pale (but completely true!)

😂😂😂
:lol: :lol: :lol:
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Re: Engine recipe..

Post by timmy201 »

My 1100 cruises nicely at 100kph and doesn’t have problems going up hills. I don’t really get a chance to take it much faster as near me there isn’t many 110kph zones. I put in a 3.44 diff and I feel it’d definitely take a 3.1 with no problem

If I was planning on going on long trips more often I’d probably detune it a bit to cope with any fuel quality I come across

I think a pretty standard spec 1275 would be a much nicer option though if the budget allows
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Re: Engine recipe..

Post by CooperTune »

My solution to current highway speeds in my classic mini. 1275 Cooper S block bored to 1360cc with SW 5 -07 mildly ported 940 MG Metro cyl head surfaced for 9.5 CR. Std 1.3 forged rockers. Cast LCB exhaust manifold with Maniflow down pipes and RC40 kit. Along with the Rover Cooper HIF44 and intake. What makes it all come together is my custom gear box. DAM 5626 with the ultra wide ratio gear set and two O/D drop gears and a 2.76 CWP. It will run 70 mph at 3000 RPM all day long. I have tasted 96 mph at 4000 RPM. I'm currently building the 5th gear box to this spec. I'm out of parts to do additional units. I have found even with roll up windows wind noise above 70 mph is very uncomfortable. With wide ratio gear set there is 1000 rpm step between gears. There is no good reason to shift to 4th gear below 50 mph. Steve (CTR)
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Re: Engine recipe..

Post by mk1 »

Q: What "Ultra Wide Ratio" gear sets are currently available?

Q2: What are "two O/D drop gears"?
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Re: Engine recipe..

Post by BAD942B »

CooperTune wrote: Wed May 31, 2023 1:56 pm With wide ratio gear set there is 1000 rpm step between gears.
thats not a big or wide rpm drop between gears, can't remember what the rpm drops on my SCCR 4 synch but at 7k change point it wasn't much
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