Ooooo now this is interesting!!
Turbo Mini Forums

matt you may be right ,but i did bring a big block chevy meziere electric water pump back from vancouver for 38 quid !

paul thanks for that ill hopefully let you know this weekend if i can take you up on it if thats ok .may be a good solution , i dont really know what people have revved the slotted ones too? maybe madmatt would know ?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Miglia racers have used the Rover pistons up to 8500, but then they are usualy replaced after 500 miles

slotted pistons are ok for mild compression & 7000rpms-ish,,, they distort lots ater that tho,,, with big comp ratios & big cams make for high revs & high chamber temps the tops of them wobble around working back n forth, back n forth & eventually crack & if kept on reving they pop the tops off them,,,

But for the average hard road & casual track use they`re fine-ish

My dad`s design piston he went for holes instead of slots back in 1969, maybe he was the first hey Sprocket?
(That was an attempt at humour)

& Robert, you still win the most cost effective conversion, just because it needs pistons & re-bore now is beside the point, that`s all just after the fact

good on you fella, keep up the good work

www.miniman.com.au

"""LazyGoodForNothingSmartArseKnowItAllBackYardMiniMechanic"""

On 24th Mar, 2009 MadMatt said:
slotted pistons are ok for mild compression & 7000rpms-ish,,, they distort lots ater that tho,,, with big comp ratios & big cams make for high revs & high chamber temps the tops of them wobble around working back n forth, back n forth & eventually crack & if kept on reving they pop the tops off them,,,

But for the average hard road & casual track use they`re fine-ish

My dad`s design piston he went for holes instead of slots back in 1969, maybe he was the first hey Sprocket?
(That was an attempt at humour)

& Robert, you still win the most cost effective conversion, just because it needs pistons & re-bore now is beside the point, that`s all just after the fact

good on you fella, keep up the good work

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Thanks Robert, appreciate it greatly man

The hypertechs are fine for big revs, they seem to handle well in lots of very fast race minis here...

Edit--> i actually havn`t seen or heard of one cracking yet... so i would be very confident with them.

There are still better pistons tho

Both Graham Russels own Pistons & the later model JP big bore pistons are absolutely "Un-breako",,, The JPs are a tad heavier tho, however there is soo much room for removing meat from them to even up that extra weight without compromising the integrity or strength of the piston, but they cost more, so GRs pistons are selling far better than the JPs,,, & yeah Sprocket The JPs were designed by my dad,,, & whatever beef you have with me & all my dribble i hope you get over it... i have & just trying to make light of things, please lets just be friends?

I apologise for my mistake with professing to be the first turbo twinky ok? It was in a certain context & wasn`t meant to be a "claim" more of a point to show that Greg Temkin was the first & that Morspeed wasn`t,,, certainly not meant to take anything away from Jimsters mantle & he knows that... i think (hope) most people do.

But back when i was a kid, i used to always be the first to school & ,,,,

Edited by MadMatt on 25th Mar, 2009.

www.miniman.com.au

"""LazyGoodForNothingSmartArseKnowItAllBackYardMiniMechanic"""

The hypertechs are fine for big revs, they seem to handle well in lots of very fast race minis here...




matt does that include the slotted ones ?do you know how much revving a slotted one has taken in the past ?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Here's a piccie:

The one at the back is the 1293:

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."

The slipper piston with slots should be no big thing as you shouldnt be using a slipper piston in the A series on a high reving motor anyway, in the pic above the 998 veriety piston on the right is looking like a good piston, the 1275 ons on the left look like standard replacement pistons.

Like I said, the Miglia boys used to use the standard Rover A+ pistons for 500 miles ish, but then they are reving the nuts off the engines for most of those 500 miles. How long do you intend to be at 8500rpm Robert? more to the point, what sort of revs are you looking at taking them to will your cams allow 8k+?

If I was you Robert, I would get the 73mm Hypatecs with the holes.

http://www.minisport.com.au/prod27.htm

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."

cr probs and more money paul , hmmm ,at the mo feedback im getting from aus is that the slotted hold up well ..still investigating .im not remotely worried about using a slipper piston at high rpm ,in fact i think they are better ,its only the slotnosity im concerned about .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Edited by Sprocket on 26th Mar, 2009.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Did you say something Robert?

paul could you measure the length of the slot for me ,inner and outer ? i say that cos i think the ends of the slot taper in ? may be wrong though !

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

The slot has been cut with a slit saw.

The length of the slot is 37mm at the OD and 24mm at the ID.

The crown is increased in thickness at the slot location.

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."

Keep an eye out for some Cooper S or Metro Turbo +20 pistons on ebay, there have been a few sets since the begining of the year. They should be the ticket

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

I don't know about the heat treatment, but I guess it would stuff it up.

The biggest problem would be distortion due to the heat, as the slot is inside the oil ring groove.

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."

Just reach for a new tube of JB Weld.

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

ok ,well so far i have realized i have 3 good plus 40 turbo pistons ,

and im either going to weld up the other one where the ring lands are damaged ,or find another one !
so ill put a wanted in and see what turns up .
i have some of the right rods for welding a piston ,and have found a chap who welded his pistons completely around the top ,and then machined them ,fortunately the top of a piston IS round ,and so its lathable . the process seems to be to heat it up to 150 degrees ,then weld it tig then let it cool .

im hoping the turbo pistons dont have any super spanky heat treat to be ruined ! but if it has then ill assume his forged ones did as well ,and he put something like 1.8 bar into his on 10 to 1 cr ,with massive knock ,and they survived ,hed already broken the top ring land right off with detonation .!

the budget may still be on !!!!

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Does the tensioner prevent you from fitting a water pump?

I don't think the a series is as forgiving as the V8 when it comes to being run dry.

no rob , i may fill the block with concrete ,then spray the outside of it with liquid nitrogen ?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Whilst you're at it you might as well chuck a bit of LN2 on the IC that'll keep the ACTs down.

Edited by Rob H on 21st May, 2009.

Ive got some lno on the floor of the kitchen ..... would that work ?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM