10 replies to this topic

[slegersmini]

Right okay so i am rebuilding my engine completely, ideally looking to bore it out as i need new piston rings and i belive the block will probably be scored.

i always hear different things from different people as to what is best to go for when getting an A series engine rebored.
Some people say that less is better for reliability, but there is always the old additch that you cant get good power till you bore it out big...

i am not after a massively high performance engine as it will be a daily drive, i was thinking of a 1293 or 1330 at the most but maybe a 1380 at a stretch... I would be running it on a hif44 carb which i am using currently on my 1275.

ideally i want to get as close to 100bhp without going over it as there comes a need for more expensive things like a different gearbox and diff...

It is also said if the final drive is changed on the mini it can make a fast amount of difference on the performance but i thought this would depend on everything else in the first place as well...

i am not sure of my current gearbox drive but i know the engine is 1275cc other than that i am not sure as i have no details on the engine apart from what can be seen on the outside and the number on the front of the block has been removed, because the car itself is registered as a 998cc.

The budget on this project is not massively high as money is being spent elsewhere on the body work and respray.

i have a few hundred pounds to spend at least, with a good base i belive i can get some good figures.

I am going to do the usual things with a rebuild... clutch, big end bearings, shell bearings and maybe even the flywheel...

Anyone have any suggestions of how to go about this or how to go this and how much things should cost as this is my first rebuild...


Anything would be helpful like what have you guys done in a similar way? cheers

[haz]

basic block bores and hones dont vary much in price, the overbore (1380 or 1399) tend to cost 20 or 30 quid more, worth it imo

id say go for the 73.5mm bore (1380) so you have the option of a 74mm rebore later in its life rather than scrapping a block when its worn, some people even go for a 1330 for this reason.

Pistons is the main expense here, a good set of 73.5mm pistons and rings will cost you probably £200.

A crank re-grind is adviseable, £80? You'll need a full set of bearings £100 (including fitting & reaming cam bearings)

Then it all depends on your budget, camshaft choice is next, and then cylinder head (the major horsepower factor for A series)

you can spend anywhere from £300 - £2000 on a head. Putting your old head back on would do it no favors, it just wouldnt be able to breath well enough.

Bore & hone - £120ish
Pistons to suit - £200ish
Crank grinding - £50-100 depending on what needs doing
Bearings - £100
Cam - depends what u get, average around £100
head - probably around 450 minimum really
gearbox refurb - anywhere from £50 - £300 depending on whether you do it yourself & stay standard components
Centre main strap, deck block, chemmy dip etc - £150

you might be lucky with 100bhp at the flywheel on that kind of spec (assuming a 276 or SW5 cam or something mild)

thats just the basics and you're already at £1200, a racing clutch and steel flywheel is another £200 at least... you'll need a decent dizzy or megajolt, £150. Rolling road sesh £70ish. you could put high lift rockers on £120, it goes on and on and on.

and on.

[slegersmini]

Well i have a set up with a 1275cc block and deep dish pistons at the moment.
i was going to go for a lightened duplex timing gear set up,1.5 roller rockers, sw5 cam or a 286cam, along with a lightened flywheel, i currently have a gasflowed head which has been ported and skimmed to raise the compression ratio, along with a minispares high flow manifold to go to Hif44 carb along with a pipercoss air filter.

Mainly following keith calvers advice on here; http://minispares.co...le.aspx?aid=297.

After speaking to people with mildy tuned engines they seem to be saying a similar thing. Bearing in mind I have money a fair amount of money which, i am spending on the rebuild of the car as well, and also to make sure i dont get killed by the insurance costs either!

I have some of the main parts at the moment i am going to look for some other parts, the gearbox and the crank are quite good at the moment so i wont be doing too much with that as its in good condition the only thing i might do is get it reground and the power shouldnt be too much to handle on there.

£70 for a rolling road session cor i dunno where you go!! i can get it for a lot better price!!

[haz]

ahh well that makes things a great deal cheaper if you have the head already

you MUST regrind your crank if its not been done recently, its not so bad if its in reasonable condition and running standard power but for what you're doing its really a good idea to make sure the crank is running perfectly, whilst im on the subject, as you probably already know, balancing the crank, pistons & rods and clutch assy is also a good idea.

you'll get away with a standard gearbox but if i was doing it and the gearbox was off, then i'd want to have the baulk rings replaced and inspect all the parts for wear, as everyone will tell you, uprating the diff to a 4pin is always a good way to go

[Sam Walters]

get a standard mg metro engine and put a cross pin diff on it. slap a turbo on it and a turbo box on it, get the gubins for a turbo and your upto your 100bhp for alot less then you would think. id say around 400-500 pounds if your carefull.

[slegersmini]

get a standard mg metro engine and put a cross pin diff on it. slap a turbo on it and a turbo box on it, get the gubins for a turbo and your upto your 100bhp for alot less then you would think. id say around 400-500 pounds if your carefull.

after inspection and looking around i have a 1275 mg metro engine in there atm...

i am still in two minds though....

Get a half engine kit or rebuild my one... Hmmmpf!!

[slegersmini]

,

£70 for a rolling road session cor i dunno where you go!! i can get it for a lot better price!!

im guessing you just mean a 20 quid dyno run. he means a rolling road tune, mine normally cost about £110! for a few hours.

we have someone at our local club whos dad owns one

[Guess-Works.com]

firstly remove the 100hp figure from your mind, cheap engines don't deliver 100hp... aim for 80's

to do that you'll need a good cam, sw5/276/286 are a fair choice

Decent head, an MG head is an ideal choice but needs to be the LEADED variety (bigger valves) and do a little work on the ports with a dremmel or such like nothing major just ease out the flow.

If you're going for a rebore, whatever size, aim for a compression ratio between 10 and 11:1

use a decent distributor either leccy or points

Maniflow Phase 2 LCB and pipe of your choice - 1.3/4" or 1.7/8" diameter, nothing silly like a DTM

HIF44 with a ram pipe/trumpet and filter.

No need to do expensive work on the crank, nor strap the engine..

Duplex chain if you want... vernier adds cost, where sometimes an offset woodruf key will do the trick.

Jobs pretty much a goodun.

Lightened flywheels will only increase the pickup of the engine, not the power, std gearbox will be well up to the job in terms of gears etc... recommendation would be to fit a central oil pickup, and either a competition diff pin or x-pin diff.

[Paul Wiginton]

I would say speak to Steve or Lee at MED and get a 1380 kit and exchange everything you have, this is relatively inexpensive. It will include rings fitted to pistons fitted to rods, block bored and honed and decked to the correct height, crank reground etc. This way you have nothing to worry about in the way of dry builds, measuring and machining, its all done for you. Then you can either build it up yourself or get someone competent to do it for you.
This will give you a nice torquey engine which is very driveable depending on camshaft which they will advise you on.
This reliability thing that a lot of people worry about is dependant on how you treat it and how high it revs. If like me your engine spends its life at 9,000 rpm it dont last long, but what Ive suggested above wont rev that high anyway so theres nothing to worry about as long as you keep up regular maintenance.

Paul

[Jack Jones]

my build cost just over £750
1330cc
minisports kent cam 296 equivlence (i know, but it works) kit that was
duplex timing chain
new crank bearings
centre oil pick up
new oil and water pumps
mg metro head, skimmed alot i think it was about 40 thou (compression ratio of 12/1)
ported and polished not to much tho needs more i think
new dizzy because mine didnt have one tis standard tho

does need a rolling road session
dunno what hp its running but its quick

[Paul Wiginton]

I would say speak to Steve or Lee at MED and get a 1380 kit and exchange everything you have, this is relatively inexpensive. It will include rings fitted to pistons fitted to rods, block bored and honed and decked to the correct height, crank reground etc. This way you have nothing to worry about in the way of dry builds, measuring and machining, its all done for you. Then you can either build it up yourself or get someone competent to do it for you.
This will give you a nice torquey engine which is very driveable depending on camshaft which they will advise you on.
This reliability thing that a lot of people worry about is dependant on how you treat it and how high it revs. If like me your engine spends its life at 9,000 rpm it dont last long, but what Ive suggested above wont rev that high anyway so theres nothing to worry about as long as you keep up regular maintenance.

Paul

depends what you define as inexpensive.
Med quoted £3500 for that work for judy, weve managed it at a ford racing specialists for £1200
and lots has been done. we do have a nearly new med crank though, bargain off ebay.

That would include crossdrilled, wedged crank, balanced crank, balanced rods and modified head I bet.

Paul