Mini spares MEGA pistons
Turbo Mini Forums

Hi

Im after some advice and info on Mini spares Mega pistons. I can see many old posts referring to broken ring lands cause buy fuelling and detonation. Even the mini spares site advises only 5psi boost. These all seem old posts and threads. The reason i ask is i had my half engine built by someone else and he advised the pistons would be genuine parts and when checked I have MEGA pistons. This is not my only issue with the build but I would just like to know if anyone is using these currently without issues? As they are in and I have paid for them I really dont want to pay again. But i dont want problems when built. The engine is only being standard build. Nothing fancy. As far as im aware original metro turbo engine was 7psi and mini spares advise only 5psi. confused. I am at the final point of building [again after poor work] and would like any advise on CR to use safely with these pistons

Thanks

Rob

I don’t think there’s many people running the Mega pistons these days. Once upon a time they were a common choice.
It appears that the earlier ones were better from what was said on here.
I think MS probably say 5psi to simply cover themselves. As you’ve already got them fitted and the block bored to suit I’d be inclined to use them if you’re only looking at 7psi.

Phil.

Edited by Turbo Phil on 28th May, 2020.

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I seem to remember Rich' (Turbo hogster) having multiple failures with them (possibly 3), but if memory serves correct his engine was a big bore big HP motor.
It may be worth having a fudge with the search button?
All depends what power your aiming for with the engine I guess?

Shane

Edited by shane on 29th May, 2020.

Thanks for the replies. Not aiming for massive power. I am agreeing with the point of they are in and ready so use them. I have mailed MS to ask for some detail on there info as it does seem odd. Just seems no recent info on them. loads of old posts seem to appear when i make searches. Must be someone out there using them.

Thanks

Rob

They'll be ok for low boost, but you don't open yourself up to any future proofing should you want more power (most turbo owners end up wanting more).

agreed. Owned a few turbo cars over the years and the quest for more is addictive. But on this car im trying to stick to as original as possible. Most things are original parts were possible. Few exceptions as some bits just can not be found anymore. But my aim is to achieve reasonable power for a mini by using the turbo engine. My issue when i sought more power from previous cars was reliability. Things always breaking. That was possibly the way i drove them as well.. Im planning to do a large amount of miles in the car when its done. Just for fun. Not a daily driver.

I have a set left over from the Don rebuild, unused with kad 16 valve cutouts, and bigger 10cc dish, purchased 2008


9600 rpm, and 260+ hp,

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I have a hunch the early robust ones were squeeze cast, with a switch in production conventional casting subsequently.

As they are in there I would just use it, but make sure compression ratio is correct if things have been skimmed. Also make sure the fueling and timing are spot on.

Do it good, do it once. As it is only a half engine you’re talking about I’d throw them out in the blink of an eye.

Do it good, do it once. As it is only a half engine you’re talking about I’d throw them out in the blink of an eye.

The same goes for my post :)

Must admit im a little concerned that no one is saying they are using them. Just another cost to get new ones. Someone must use them.

Most people went to Cast or forged omega pistons after the issues, so hard to know if there has been any upgrade in specification since.

Id be inclined to use them if your not going to be chasing power. Just ensure as mentioned that fueling/timing/static compression ratio are correct.
You just have remember that when the inevitable quest for more power happens you'll potentially be going back to replace them.
Shane

As they are in i think i will use them. If no one else is using them maybe i can offer some feedback when up and running. Engine is very close to completion now. Few setbacks with it but will be done in the next few weeks. All i have to do then is complete shell rebuild.

Hope to get it sorted this year.