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1275 Engine Rebuild


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#76 Minigman

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Posted 15 March 2019 - 07:01 PM

Why not fit one of the rubber type coil and distributor covers? They’re a bit of a bugger to get on, but once fitted work very well.

#77 Will96

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Posted 15 March 2019 - 08:01 PM

Don't think I've come across one of them. Got an example? :)

#78 cal844

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Posted 15 March 2019 - 08:32 PM

I wouldn't bother spending all that money. You'll be better off getting AC Dodd to rebuild your current dizzy and fit an electronic ignition kit... if its an A+ engine you could buy a 65D type dizzy that will do the job and be about £40 second hand with the loom and coil.

I have fitted the 65D type dizzies to 2 998 A+ mini engines and both ran well, the car in my Avatar has had a second hand one fitted since we restored the car in 2010.

#79 Will96

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Posted 15 March 2019 - 09:09 PM

Sorry, the new dizzy would be going towards the 1380. 998 is currently in my car and is a lost cause for now

#80 gazza82

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Posted 15 March 2019 - 11:37 PM

http://www.minispare...s/Ignition.aspx

#81 Will96

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Posted 21 March 2019 - 02:03 PM

Sorry been away for a couple of days, thanks for the recommendation, looks like it would definitely be an improvement over the rubber glove so I'll have a look into it as well as the vaseline solution to try and improve it then

#82 Will96

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Posted 27 March 2019 - 04:33 PM

Coming back to a topic I've previously discussed, diff ratios. I know we've talked about 3.1's and 3.44's, but I've talked to a friend of mine that suggested a 2.9 ratio, as i would offer more comfortable motorway driving, whilst given the potential to put my foot down when already going 70mph to overtake whilst still not having to breach 5000rpm. I'm aware of guesswork's site and had a look at it, the thing i was more curious was how limited the acceleration would realistically be in a 1380? 



#83 imack

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Posted 27 March 2019 - 05:53 PM

Years ago I had 1380 clubman estate fitted with a 2.9:1 final drive and a standard wide ratio gearset. Engine was basically an Austin 1300gt (70bhp) engine bored to 73.5mm, 10:1cr, lightened flywheel with orange clutch cover, standard cam, standard twin hs2's, janspeed lcb and twinbox rc40.
The 2.9 final drive really suited the torquey nature of the engine, it was a great 'sleeper' car and a pleasure to drive.

#84 Will96

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Posted 27 March 2019 - 06:17 PM

Sounds good. Realistically I think having a gearbox weighted on the acceleration side of things will just result in spinning my wheels more often than I already do, especially in the wet. So having that top end power might be more beneficial for what I'm wanting from this build

#85 dodge44

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Posted 27 March 2019 - 07:40 PM

Coming back to a topic I've previously discussed, diff ratios. I know we've talked about 3.1's and 3.44's, but I've talked to a friend of mine that suggested a 2.9 ratio, as i would offer more comfortable motorway driving, whilst given the potential to put my foot down when already going 70mph to overtake whilst still not having to breach 5000rpm. I'm aware of guesswork's site and had a look at it, the thing i was more curious was how limited the acceleration would realistically be in a 1380? 

Have been running a 2.9 diff with standard gear set, a Kent MD266 cam, 1330 lump, large valve head, and twin HS2 SU's for nearly 20 years now and the only thing I would say is if the engine is not entirely 'on song' you will find yourself dodging between 3rd and 4th gear in town traffic as it's right on the edge with the torque so choose your cam well to suit. 2.9 diff great for motorway driving though, which is why I went for it but with next to none of that now a change is 'on the cards' and return to my first 1275 engine which started life in a Riley Kestrel. Current thoughts are 3.1 diff as it's paired with a CR box and a vintage Piper HR270/2 cam but now I've said that I await the flak.. (!)



#86 Retroman

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Posted 27 March 2019 - 11:28 PM

Coming back to a topic I've previously discussed, diff ratios. I know we've talked about 3.1's and 3.44's, but I've talked to a friend of mine that suggested a 2.9 ratio, as i would offer more comfortable motorway driving, whilst given the potential to put my foot down when already going 70mph to overtake whilst still not having to breach 5000rpm. I'm aware of guesswork's site and had a look at it, the thing i was more curious was how limited the acceleration would realistically be in a 1380? 

 

Even a mildly tuned 1380 needs some revs

 

With a 2.9 at 70mph its only 3600 revs and whilst probaly on cam 70 to 90+  time will be enough for a sandwich

 

realistically in todays traffic you won't do much if any overtaking with a 2.9

 

A 2.9 is an economy diff



#87 Moke Spider

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Posted 28 March 2019 - 04:45 AM

I couldn't think of anything worse than a 2.9 in anything.

 

It might be OK-ish on the motorway, but something like a 3.2 would be better even here.

 

When not on the motorway, it would suck any life that the engine would otherwise have, right out from under it.

 

Personally, even taking in to account motorway driving, a 3.44 IMO is the best all round compromise.



#88 Will96

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Posted 28 March 2019 - 08:42 AM

Noted. Thanks guys, originally I was thinking of running a 3.1, to which I was trying to avoid buying one if I didn't have to, so I checked one of my gearboxes and found it had a 3.44. I've got one more to check, to which if it's a 3.1 or 2.9 I'll leave it be and run it, just if I had only got 3.44's then wondered whether it'd be worth changing it. The 2.9 been half the price of 3.1'

#89 dodge44

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Posted 28 March 2019 - 09:04 AM

Bear in mind there is no definitive answer to diff ratios *only opinions* so here are mine...

[Background : 1962 Mini MK1 SDL bought in 1987 with a very tired 1974 dated 998cc and rod box installed vice the original 848cc and magic wand, so frankly a blank canvas. Replaced with a 1275 Riley Kestrel engine with remote box / 7.5 disc brakes / servo etc. in 1990]

1990-92 : Ran a 3.6 diff with CR box. 1st gear was as good as useless but great at the traffic lights Grand-Prix. Brilliant at sprints and twisty winding lanes but IMO not a common user with a 1275 engine - no need.

[Rebore to +40, 1310cc]

1992-2000 : Ran a 3.44 diff with CR box. Agree with Spider it's by far the best all round compromise I have driven over time for perhaps sub-thirty mile distances but unless you spend a Kings ransom on sound deadening it gets very tedious over distance. For many years I was doing 100 mile+ weekly trips from Dorset to Oxford and to Shoreham-on-Sea with some of it a concrete road surface and you could step out of the car buzzing but also rather gaga at the end of a journey, and forget about having a conversation at anything other than a shout with your passenger on the way!

[Piston ring broke so new block at +60, 1330cc]

2000-Present : 2.9 diff - Conversation is at least an option even on the concrete surface Puddletown bypass and you have more than enough grunt with a 1275 for manoeuvring but do have to learn to 'use the gears' elsewhere. Not a problem out on the open road at all but as already eluded to it does get a tad annoying around town at times. 2.9 is quoted as an economy gear but I'm minded to think it was also offered to resolve the 70mph cruising issue. It's worth bearing in mind these cars were sold new to 'civilians' back in the day, who were not necessarily Mini enthusiasts and by the 1980's this was a BIG issue. Use the gears and a 2.9 diff is just fine. You might even have some friends who don't mind travelling in the car as well...


After nearly 30 years of 1275 motoring I'm already minded to go for a 3.1 (or 3.2) as the next option. The car is still a daily driver but with no regular long distance travelling these days a diff change is perhaps long overdue. Given I’ve run the options either side of it over considerable time - got to be worth a go? The re-lined Kestrel block is ready and waiting...

 

 



#90 Will96

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Posted 28 March 2019 - 10:31 AM

Very useful response Dodge, thank you. As you rightly said it's opinions. Different diffs are useful in different situations. Currently I don't know what diff is in my car but it's a 998 and I'm doing weekly trips Lincoln to Sheffield, so about 40-50 miles, and I'm sat at about 60mph at about 4000rpm. Which does get uncomfortable and drones on a bit towards the end of the journey. But I will be doing more town driving when I have a more reliable engine in. From what you've said a 3.1 would be about perfect. But the price of it would draw funding from somewhere else in the project which I want to avoid where possible




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