metro turbo rebore?
Turbo Mini Forums

hi, i am thinking of buying a metro turbo engine and i wondered if i could rebore it to 1380? would this give me much more power and would modifications would be needed apart from larger pistons?

thanks ben

yes you could,
but will not have that much more power....,
certainly too little , a 1310cc one (+ 40 minispares) will go just as well and will get better concerning reliability.

If you are going to rebore an a series to 1380 (which is about as big as you can go) then I wouldn't waste your money on a metro turbo block. buy any old a series 1275 and use that. Go and spend 50-100 on something that needs a rebore.

The only differnce in the short engine of a metro turbo are the pistons (which you obviously don't need) and in some a hardened crank.

Make sure you choose a cam and head to suit your spec.

I strongly disagree in you logics. A Metro turbo block is just the same as any other A+ block and worth nothing.

An A block however is infact worth something. Just call Swifty

As a reply to what you asked from. bore the block to the next oversize and fit decent pistons. It has been proven taht going 1380 won't make that much more difference in practice.

Yep I have some 73.5mm pistons and all my blocks were STD I was very reluctant to take one straight out to 73.5mm so I have bought's Johnny's old block from this site which is currently at 73mm. Hopefully I will be able to rebore and use this, saving my standard blocks.

If something is worth doing, it's worth doing half of.

V, I was just refering to an 'A Series' as an engine type not defining that he should use an A or an A+ block

How much we talking V? as i have one and could do with some coinage.

On 17th Jun, 2010 Vegard said:


An A block however is infact worth something. Just call Swifty

Call Switfy and find out

I guess they are after them for this new mini race series thing after the goodwood revival.

If something is worth doing, it's worth doing half of.

On 17th Jun, 2010 Sprocket said:

On 17th Jun, 2010 apbellamy said:
If you are going to rebore an a series to 1380 (which is about as big as you can go)

Erm, you can get 74mm pistons for these. That makes 1399cc

If something is worth doing, it's worth doing half of.

I have one, soon to be and even better torque monster, so

that's why I said about

the benross motor is 1380 & runs 73.5 accralite forged pistons and its not a snail .......click on the links below

fab, theres no reliability issues with mine yet & and its been worked VERY! hard.

one thing is though john once you go that size the blocks scrap after that, it will not take another rebuild unlike if you bored it plus 20 then say plus 40 and then plus 60 though you have 3 reboars there

There's no reliability issue with YOUR,
ok with this
but I've seen too much reliability issues going to 1380 the last one being an oil way opened into the bore which weren't at the assembly stage, oil pressure did it ... then it does cost..

I don't mention bore scrapping, head gasket issues,center between 2 and three cylinder burned to blue etc...
things that I never met under +20, +40+60 rebores,

then I can certify that engine on +40 rebore equal if not better any 1380 power unit wit the same specs and that's na ( appart for the goggle eying)

then with a turbocharger on his bum (arse?) I guarant it will be better.

I'm sure your mini's driven hard, but would it take a race day? how many miles does it have under the clock?
I know that you can drive hard on road and last for long as you're about at full charge 10% of the time and that's a lot with a turbomini on the open road.
But as soon as you meet a track the same turbo engine will certainly blow were a 1310 one can be build to live with.

I'm would not go over +40 for a turbo engine, then whatever about reliability and that's the important fact it will not make less power than an overbored engine

i'm with fab on this one

i've had 1275, 1310, 1380 and now 1293 and all were turbo and pushed hard, as far as i could tell the bore made little difference, maybe the 1380 had a bit more low down/off boost

BUT with the 1380 the bores went oval and crushed the sides of the cast omega pistons and as such scrapped the block and pistons. this engine was built by a highly respected engine builder who also checked it over after it failed and who also built its replacement.

the 1380 lasted approx 2 years and when it failed it was scrap. the 1293 that replaced it was built back in 2003, has just been apart for the second time as i keep getting overly happy with the boost and melted a piston but the bores are still perfect.