21 replies to this topic

[AGRO_RB]

Recently won an auction for a 1275 engine, not entirely sure what it's out of yet however I doubt it's 11 stud as they are hard to come by here, so it'll more than likely be ex-Allegro or Austin 1300.

Rather than fart around with my 998 I'm obviously going to put money into this, the owner has informed me the head is off as they were planning on a 1380 build but have since lost interest in the project. I am prepared to spend some money building a bulletproof engine that will handle high km daily usage, the odd track day etc. What's the best path to go down here? Should I only go oversize if need be or is it worth doing from the outset? Any recommendations for cam, pistons, rods, bearings etc? Also will my rejetted HS4 work or should I look to go bigger, I.e. Weber, Dell'orto etc? Tips on ignition, exhaust and final drive ratio would also be great as I'd rather do everything once and do it right :)

[mini_mad_andy]

My thought path was exactly the same as yours when I came to build my engine; I decided on boring a 1310 (previously bored from 1275) block out to a 1330 more as piece of mind, I increased the compression ratio slightly, used a big valve unleaded head, a  mild cam, and a Hif 44 as they're better under heaving cornering (what mini's are built for!).  

 

This setup produced a good pulling engine, but was also extremely reliable. I would not hesitate to build to the same spec again, although I may add duplex adjustable timing to get it spot on, and the simplex seemed a bit noisey.

 

Hope this helps, Andy.

[AGRO_RB]

Cheers for that :)

Is there much difference between the HIF44 and HS4? I like the ease of setup with the HS carbs, the biggest problem with an HIF44 in NZ is finding one!

I assume pistons are available off the shelf to suit the likes of the 1330? I've also heard stories of blocks cracking between cylinders on bored out engines, is this only on the bigger stuff like the 1380? 1330 sounds like it'd be a good compromise, you don't know what the bore measurements were do you?

[minimadles]

1330 is just a +60 thou overbore

[Cooperman]

If you go to 1380 the bores must be re-bored 'offset' to keep cylinders 2 & 3 with sufficient metal between them. This makes the machining expensive and when a further re-bore is needed the block may well be scrap or require special non-standard liners to be machined & fitted.

The difference between 1330 (i.e. +0.060") and 1380 is very little in performance terms. It may knock a few 1/10s of a second off a lap time, but otherwise it'll now be noticed. The key is to build a well-engineered and properly built engine.

[ACDodd]

Mild cam torque pump is the route to a long life as is proper run in an controlling the fuel mix.

Ac

[AGRO_RB]

So, worth going to 1330 or just leave it? Was apparently a superb running engine before the head was removed. I haven't actually seen it yet, picking it up on the 4th when I get home

[ACDodd]

The first thing you should be doing is to strip and measure up the wear. Then you can set your budget then you know what you can afford to do.

Ac

[minidaves]

and dont forget to offset the bore if doing +60

[Cooperman]

I never offset the bores at +0.060". At that size there are no gasket issues and when a further bore is necessary the standard sleeves fit and you can go back to 1275 with no problems and at reasonable expense.

[ACDodd]

Ooh Yes Dave is right I always offset bore if going to plus 0.060" this way the block life is maximised and can be taken to 73 and 73.5mm with minimal metal removal. Sometimes they do not clean up going from +0.060" to 73.5mm in one go if offers have to be put in.
Offsetting also means oversize sleeves can be fitted to save a block after it has been bored to 73.5mm.

Ac

Edited by ACDodd, 25 December 2013 - 12:51 PM.

[Cooperman]

I have never gone beyond +0.060" and I recently had a +060 block which I fitted standard sleeves to and bored back to 1275.

That way it can go a further 3 over-bores before it's 1330 again, by which time I'll be long gone .

That way we keep A-Series blocks for the future generations at minimal cost.

Personally I've never been a fan of really big engines in Minis unless they are for specific competition applications.

With a classic Ford Kent Engine it is possible to bore large without offsetting and to sleeve back on original bore centres, but the 1275 A-series doesn't offer that luxury.

[86mayfair]

In terms of the rest of it, a Swiftune SW5 cam paired with a good head will give very good all round torque, power and road manners and a CSI electronic distributor will give very efficient runnning and again an improvement in torque etc. Swiftune sell a version with their own preset curves in too. A decent LCB and Maniflow or RC40 exhaust system will give you a nice sound and the best performance. It's generally considered that 1.75" is the best diameter for most road engines

[racingbob]

 my car has mg metro engine

mg metro cam

stage 3 head

maniflow stage 2 system

engine balanced

med substack with itg filter

3.4 dif

 

very happy with this as could be used as a day car

with this set up, but goes realy well as well

 

might give you some ideas

[AGRO_RB]

Cheers for the insights lads, have emailed a mini specialist up in Auckland asking what they can offer as some parts are bit harder and more expensive to obtain here.

Is there a list of engine codes for 1275s? If it's not an 11 stud motor I'd be interested in knowing what it's from before I decide what to do.