turbo pistons or ?
Turbo Mini Forums

Hello, i have a 1275 engine and box with 27.000 miles on it and want it to run a turbo, so my question is what way should i go with it, do i keep the standard pistons and have the CR lowered via the head, or find a set of pistons and con rods from a turbo? i have read that the turbo piston rings are no longer available is this right ?
cheers Rusty.

Id the bores are in good condition, I would get a set of metro turbo pistons and some total seal rings. Should be a pretty good setup. You'll probably still need to get some meat taken out of the head though.

Ah ok that info will help me out a bit, so you can get piston rings then that is good news, the pistons and con rods i have are no good for my need then ?

The rods are fine as are the pistons, until, as you will, you turn up the boost.

If you keep to sensible boost (under 10psi) and use an intercooler you should be fine - I used standard MG Midget pistons and they gave no trouble, even whe I inadvertently gave them 20psi for a few short bursts.

Problem is, if you adjust the head volume to suit the standard pistons you might end up with too low a CR if you later swap to different pistons -it all depends how much trouble and money you wish to invest, really.

it always comes down to money
so con rod fine but pistons not so good, well i am on the look out for some turbo pistons with or without conrods, are my conrods the same as turbo ones? as i am not so up to speed with turbo bit what numbers should i be on the lookout for ?

Edited by rusty998 on 4th Apr, 2011.

Everything in a turbo block is the same as standard, bar the pistons.

Same for the head, with the exception of the valves.

As Andy has said, the conrods are the same.

In my experience, the pistons are stamped "20831" in the crown, usually with a large "A" or "B" nearby!

I have run 2 Metro engines with 'non turbo' pistons over 4 years with 9-10psi and had no problems at all regarding the pistons themselves. Had plenty taken out of the head though.
Just my experiences

I have always thought it would be fun to stick an unskimmed 12g295 on a boggo 998 and just wind the boost up till it blows.

Just to see what they can actually take with good timing and fuelling.

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

Think I better add to that. I only ever run that boost with V-power. There was a week or so last year when I was so skintight I had to use normal fuel I ended up turning the boost right down until t stopped detonating. It Wasn't nice.

Brilliant info, I would like to assemble my Turbo Marina (currently standard) about to bolt all the turbo conversion bits on and once I'm happy with it all and I get some more money, I will sort the compression ratio out properly by buying dished pistons and get the block bored out at the same time.

Would you recommend two head gaskets? Just for now? or just a very low boost? Using standard head at the moment.

low boost. No more than about 4 psi to be safe

I reckon you could get away with more than 4psi especially with a decent intercooler and a good setup

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

Where are you based as Benross did my head for a very fair price. It's well worth it to have piece of mind. And more boost. As I think 4psi would just make me want more. 10 feels quite nice lol.