Is anyone still using minispares mega pistons?
Turbo Mini Forums

Given the number of faliures I doubt it, but thought I'd ask.

I have just been browsing the various sites of piston suppliers and everything seems to be getting very expensive. I was therefore considering whether the mega pistons could be considered for a 16 valve engine that is unlikely to suffer from detonation.

The omega pistons look good, however despite the minispares ones appearing heavier they look tough as old boots in comparison, and in a short stroke engine turning to 8500rpm toughness I feel would be useful. I suppose loosely 8500rpm on the short stroke engine could be regarded as 8000rpm on a standard stroke engine.

What sort of rpm's are people turning cast pistons too? Is the DON still running mega pistons?

I use them in all my engines, but they are all 998.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

I am and swear by them!

the "least touch of detonation" and the lands break up ............ if you keep them out of det and the fueling right they are OK like the DON mini ......better to use them for a N/A build in my book

cast omegas, forged or accralite forged fit them forget them. providing the above adivece is heded

all the power the engine makes is above the piston ...... you you want the best..........simple as that

Edited by BENROSS on 3rd Dec, 2010.

I need a dish of 6cc plus say 2cc for the valve cut outs to give me my desired compression ratio for the short stroke engine.

My main concern is whether the cast omegas will be up to 8500rpm or not.

Here is the solution, but at 460 quid plus the cost of getting them pocketed for the k-head they will work out a lot more expensive. though it will save the cost of getting the megas modified for floating pins. I guess I'll just have to bite the bullet and build what will be a bloody expensive bottom end.


http://www.med-engineering.co.uk/product_d...00&vlang_id=543

Edited by minimole23 on 3rd Dec, 2010.

What about these?

http://www.med-engineering.co.uk/product_d...12&vlang_id=555

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

How big are these valve cuts?

How long do you intend to keep the engine at 8500rpm?8500rpm wont be a problem with decent cast pistons.

for a cast piston, Omega would get my money.

Edited by Sprocket on 3rd Dec, 2010.

yes the omegas are well proven race piston you can get these both in 6cc with the accralites its an offset dish.

i dont think you will achieve 2cc from the valve cuts alone i have recently achieved 8cc out of a cosworth piston for a bristol engine and there is not much left of it haha

Speeding is like masturbating, everyone does it, but not all of us film it and put it on the internet

[quote=fab,8th Oct, 2010]fuck off

On 3rd Dec, 2010 Sprocket said:
How big are these valve cuts?

How long do you intend to keep the engine at 8500rpm?8500rpm wont be a problem with decent cast pistons.

for a cast piston, Omega would get my money.

Edited by minimole23 on 3rd Dec, 2010.

If you are machining the valve cuts to suit the engine, then you need only the minimum. The only problem with doing this is that all the pistons are then different. If you look at the MED piston, its valve cuts are overly large because they are infact oval, larger 'diameter' than the valve itself, and deeper, to ensure that whichever block you use them in, at which ever deck hight you end up with, they won't hit the piston.

If you machine the pistons individually to suit the engine, you can get away with far far less say 1cc max. I did measure the pistons below before and after, but I have forgotten the numbers now, but it was defo no more than 1cc. 0.75cc springs to mind for some reason

hi do you mind if i ask a question as you sound like you know what your talking about
i have a 1275 mg metro engine in my mini with the turbo gear
but i have not changed the pistons what will be a safe boost
and if i machine the head at each dish will this make any difference
regards Bill

I was reading an article by keith calver about pistons, and I wonder if I have stumbled over the reason why the later mega pistons have dropped ring lands whereas the earlier ones appear not to.

The article is dated in 2005, and it mentions that AE were going to stop producing squeeze cast pistons due to cost. Now could it be that these later pistons are conventionally cast hense why at the first sign of det they shit themselves. Here is the quote

"Unfortunately AE have judged the process to be too costly to continue with. Their continuous development program enabling them to produce cast pistons of a very high quality, making squeeze casting redundant as far as they are concerned"

Heres the article its about mid way down.

http://www.minispares.com/Articles.aspx?ty=ad&aid=345

Edited by minimole23 on 6th Dec, 2010.

Good find. I would agree that seems like proof that something did indeed change.