Hi,
I was wondering if anyone could offer some technical assistance please...

Please refer to the attached picture of Endyn's Rollerwave piston:

I have the following questions:
The dimple on the piston crown, is that orientated towards the flywheel end?

Given the information provided by JLM:
For some drooling: these pistons are at TDC; they "deck" at about -.030, meaning the wedge shaped areas are .030" + the head gasket thickness (.025") from similar wedge shapes on the head (squish band).

By comparison, the stock S pistons deck .130 or so in the hole, plus the center is depressed and there is no squish band.
With a high lift cam (shrick), will the valves clear the piston crown do you think?

With the Crower con-rods I have (also from Endyn) will the orientation be so that the oil notches in the big end face towards the front or back of the engine?
I don’t think that the answers are limited to Endyn/Crower, so I hope that someone with knowledge in engine design can help me out please.

Many thanks in advance ^-^
Henry

 

The only thing I can tell you about these Rollerwave pistons is maximusmini had them installed in his twincharge MCS, and the post-assembly chassis dyno yeilded a 10whp loss versus the stock pistons at the same boost level.

 

Ah great...

Any more for any more?! I don't know what's up with the formatting above! Sorry about that...

Henry

 

Probably because Endyne increases the compressions ratio.

 

I was thinking the same and in itself, this is no bad thing, so long as you can map the ECU accordingly so the engine doesn't detonate and pull timing which is where a lot of power is lost on dyno runs.

Back to the original post, if anyone knows which way the balancing 'dimple' on the piston crown should face (crank nose or flywheel way round) please let me know!

Same for the rod orientation.

I am thinking that I will need to get Cometic to make me up a thicker gasket to lower the compression ratio and to help with clearance, because the last thing I want to do is to put the car together, turn it over and the first thing I hear is valve to piston contact

After having my car off the road for 2 years, that would probably tip me over the edge...:impatient

Cheers,

Henry

 

check with "he who shall not be named." hes had some experience with those pistons.

 

Glad to see that you've got your car back

 

Out of curiosity why the interest in the Endyns? JE and Wiseco both make forged setups in OEM bore and small over bore. They do not affect compression ratio nor change the design to an interferance setup. Seems like the endyns just raise more issues than they solve.

 

Dunno if thats fair. Endyn believes in a total system approach. Based on Ryphiles comment, the pistons were not a good match for the application. Only maximusmini knows how he spec'd the pistons. Does that mean they are bad pistons? I don't think so since Endyn has years of experience with turbo and supercharged engines.

supercoopers, did you talk to Endyn about piston orientation and valve clearance? I'd be surprised if they could not provide definitive answers.

 

For the best information Henry, contact Larry personally and have all the build info handy.

The Rollerwave pistons are made by Wiseco to Endyn specs and then Larry performs proprietary final shaping for both his performance ideas and the intended application; correct usage is the responsibility of the engine builder or purchaser. I don’t doubt there have been mismatched installations as a result of communication inaccuracies. Perhaps too many assumptions by purchasers thinking one size fits all or Larry thinking the purchaser knew what they were doing (there is a written disclaimer on the web site). These types of mistakes can be found with the best of other piston makers as well.

Will the others who have installed aftermarket pistons with re-worked heads please share how they arrived at the sweet spot for quench, the exact compression ratio they are now running, how much was milled from the deck (head to be more precise, the term "deck" is ambiguous), how they determined what the gasket thickness should be, and what is their current and former VE? In other words, why has it worked for you in concrete terms?

 

To be fair, I didn't say they were bad. I said they raise more issues than they solve. What is the primary goal with aftermarket pistons? Primarily people do them for:
1-stronger internals for high boost or high performance applications (>300whp), or
2-overbore and again, increased displacement and performance.

Both of these can be accomplished with pistons that do not alter compression or introduce the issues of valve clearancing.

To that end I went with Fireballed Pistons, manufactured by JE, stock bore. Compression was maintained at stock 8.3:1 I am running an OEM gasket and had no milling performed. I did not have any installation issues, and have had zero problems with them to date. Considering the 400whp conditions these pistons function in, that is pretty concrete results. I am not the only customer of Fireballed running this setup.

 

The JE pistons are flat top which alters the shape of the combustion chamber; they are combined with a modified head which I don’t think would have not received any milling at all, what measurements have verified CR as unchanged?

 

Ahhh. Sorry. Head work is Fireballed stage 1. You'd have to ask them what the specifics are for milling. Are the stockies dished? I did not take note of this when I pulled them out and replaced them.

 

Hey Everyone,

Thanks for your posts

Paul: Thanks, I did get the car back in the end but had to resort to every measure in the book (solicitor etc) to get him to finally give MY property back! Took over 3 months of levering in the end...wouldn't wish such an ordeal on my worst enemy! Anyway... When I got it back (only this week) it's evident that NOTHING has happened in 2 years save for a rebore on the shortblock. To say that I am gutted is an understatement...

AZMCS: Thanks for your input as well. The reason I went with the Endyns was that I bought these in November 2005 and at that time, noone besides Endyn and Omega UK offered a piston upgrade for the MINI.
I intended to run a twincharge setup, hence why I forked out for the pistons and rods. I am sure that they will do the job admirably (Weiseco and Crower don't make toilet brushes after all) so long as they are installed correctly. Should I have to do it again, I would go the simpler route of CP/JE pistons.

Astrochex and K-Huevo: Thanks for your valuable input. I will contact Endyn today, but was hoping that someone could provide a real-world second opinion to the information I get from them. I trust them entirely, but it always helps to put one's mind at rest if there is a cosensus of opinion on something

Cheers,

Henry

P.S. Any further input, please keep it rolling in

 

Good to hear man. Good luck with the project!

 

To Conclude this thread and for anyone seeking similar information:

1) The dimple on the piston crown faces the timing chain end of the engine.
2) The rods are orientated in exactly the same way as the stock rods
3) There are no clearance issues (valve to piston crown) with a high lift cam and these pistons (according to Lary at Endyn)
4) There are 3 rings on each piston: The top ring is copper in colour, the middle grey/black and the bottom one is a standard-type oil ring with a sandwiched corrugated ring between two thin rings.

Hope that helps someone one day

Cheers,

Henry

 

How high will be the compression ratio with the pistons?

 

Henry-

great info and great follow-up. Thanks

 

When I talked to them last fall they told me 9:1

 

^^ what he said . The car will definitely require a dyno tune to make sure that it doesn't pull timing all the time. I'll keep you posted...

Cheers,

Henry

 

Thanks for info

 

So how is the build coming on, have u set a date when you want it done buy?