Just taken the Sprint\'s engine to bits
Turbo Mini Forums

Well as it was breathing heavily at idle (and has been for a long time, before I fitted the FI), it was time to see what was wrong.

Every piston has a cracked ringland, arse. Luckily I have a spare set of new pistons, so will be back together tomorrow. The new pistons will drop the CR a bit too.

For all the wet manifold sceptics, there was definate differance in colour between the outer and inner spark plugs, bot were acceptable colour though, but the inners definately richer.

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

pisser.

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

Although one of the sceptics, I would say, from your description, it was probably already damaged before you fitted the EFI.

Bad luck.

Spark plug colours as expected, but it really doesn't tell you anything. AFRs could be a little bit out to do that, or miles out.

Put twin widebands in, you know you want to :)



(edit -spelling)

Edited by Rod S on 26th Oct, 2011.

Schrödinger's cat - so which one am I ???

that on std998 pistons? are they the same as the 7ptt racer?

Yes i moved to the darkside

Instagram @jdm_brett

Same pistons that I've been using for years, first ones I've broken.

The damage was done very early on when the actuator was fooked and kept spiking the boost.

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

Thanks for sharing that with us Wil.

Any chance of a photo of the cylinder head chambers as a point of reference?

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

bad luck buddy, glad you found the faults at the end of the season and now just before an event. I'm going to do a full strip down on my engine in the next few weeks, although running great at the moment (apart from lose trigger wheel) not looking forward to what I'll find :(

Team Racing

I'll get one later, there is an obviouse differance that shows that the differance is possibly worse than a carb. Whch is interesting.

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

Head photo

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

Not bad at all really will, and if the cr's lower then the boost ca go up.lol

jim its not the 7port sprint its will road car.

rick

That doesn't look any worse than mine to be honest.

In the 13's at last!.. Just

On 27th Oct, 2011 wil_h said:
Head photo

Edited by Paul S on 27th Oct, 2011.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

so what pistons are going in now wil ?

Paul - Not sure what the shiney bits are, flash related bright spots, not obvious on the head. Not suer about AFR spread, but it runs rich im most areas at the moment, this is because of the amazing breathing system I developed to get rid of the smoke.

Hopefully the new pistons will get rid of the heavy breathing and I can remove the system. this will make setting the fuellling easier and more stable, so I can hopefully get it a bit leaner. But obviously not too lean.

I had a set of the Aus hypertecs handy, so banged tham in. They're good for this engine, but not sure I'd use them in the hillclimber.

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

they are good pistons will there are ones a level up about 20 pounds more maybe, they are made for Forced induction.

how many miles till this 998 pistons died?

Sorry to heart that mate, Glad you have a spare set all ready to fit.

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

Have you got a link to the better pistons?

Hard to say how long they lasted, but it was not a piston failure, it was a boost control failure that broke them. I've had the same pistons in the hillclimber for years, no problems.

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

I didn't realise that the P20950 pistons were NLA. That's a bit of a blow for 998 Turbo builders.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Indeed. Minispares stopped having them made owing to a quality issue. They have replaced them with a powermax piston I think, but it's only available in +40.

However, I reckon that it would be easy to get powermax to make a +20 or a +0 from the same casting as the +40. I'll either lean on Minispares to get some done, or contact powermax directly when I need some.

As it happens I have a full set of hypetecs in store, they just need a dish machined in them.

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

As an update, the car is all back together, no smoke, runs a treat.

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

I see that Minisport.Aus are doing 1098 falt topped pistons from Mahle in +0.020/40/60.

We could always use them, but would need to skim the block by 0.150". But then there would be issues with pushrods and pulleys hitting the head etc.

Anyone seen the Mahle pistons? Do they have oil drain holes or slots?

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Hey will they are the Graham russel pistons. He designed the hypatechs and make ones up from that again.

Il give him a call and find out more info for you.