OnyxEros

Ok guys the form is being filled out as we speak
Basic stats
90mm Dome 12:1 CR
Daily driver, Minimal hot lapping

Here are your choices
Honed Pin Bore (pin fitting)
Contact Reduction Grooves
Accumulator Groove
Lateral Gas Ports (10)
Vertical Gas Ports
*Both*
Ultra Groove
Ultra Groove with Lat Ports
Ultra Groove with Vert Ports
Double Pin Oilers
4 Bottom Pin Oilers
Plunged Valve Reliefs (I think ill have to do this anyway)
Tulip Valve pockets
Notch Skirt (Mandatory)
Offset Pin

If you don't know what any of this means don't respond, if you have a suggestion on what will help with the reliability aspect with respect to the custom features above please share.

Coating is a given
Chris

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VVL?
IX MR?
A race????

 

ussil80

go with the gas ports... soppose to act like a vacum pump on the motor... adds some HP

NAracer

You know you got a second buyer here, cash ready, when you get them... exactly like you said daily driven, occasional thrashing. One point I would raise is that the reliefs need to be big enough for BIG cams (jwt) when they come (for me that is, not sure if you plan on getting them)

All together big THANKYOU for all the research and hard work you have put in.

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Franklin cams this... stock valve springs that...

I don't care I have a GTR

bigtoe

Gas Porting, increases the cotact load of the ring tothe bore. Simply by exposing the back of the ring to combustion pressure across the area of the ring's thickness. This is used in conjuction with low tension rings. It's a good idea for a drag motor. Not for a daily driver, you will suffer accellerated ring / bore wear as a result.
Lateral gas ports are cleaner than vertical because they are "hidden" from the combustion gasses due to the fact that they sit above the groove / ring perpendicular to the ring land. The vertical ports are directly in communication with the top of the comb chamber and tend to clog up with carbon over time.

You want max contact area with the grooves for maximum vertical load support and sealing. You also negate the value of the "ultra" groove if you do not lap the rings on their flat sides to the groove.

Ome of what you have listed is redundant to a certain extent. Such as, *both*, maybe some rocket scientist has, but I can see no value in vertical and horizontal gas porting.

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BIGtoe

Beware of, "Repetitious Mupitism"

OnyxEros

All things listed are directly from JE's catalog. all of the *both* and combinations are what they can do.

Bigtoe what you are sying is that Lateral gas ports are a good idea?

NAracer - I will be getting the valve reliefs cut deep enough to run up to 13mm lift. I will also be sending a 16ve piston along the way so they can see the valve size because im not 100% sure and i don't have a caliper accurate enough to give a great reading.

Keep the suggestions coming as soon as these are made i will share the job number with the forum so I want to get it right.

hybrid D E T

*edit*

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Chuck
Shamless Myspace plug
1988 B12 Nissan Sentra SR20DET
1991 240SX SR20DET, Project 240SR
1991 NX2000 SE-R Cup #75
1991 Nissan Sentra SE-R, 24 Hours of Lemons

bigtom

why dont you just buy the pistons i already had designed. it is almost exactly what you are talking about. they are the perfect VE piston. pm me for info i have pictures. they are ultra lightweight too. but they are 87mm.

OnyxEros

Im making 90mm pistons 2.2 or bust!

NAracer

DUDE!! One day I'm coming to the baddass US and I'm buying you beer!!!

hybrid D E T

Honed Pin Bore (pin fitting)
Accumulator Groove
Lateral Gas Ports (8)
Double Pin Oilers
Plunged Valve Reliefs (no you don't need these for 12:1)
oil squirter notch (Mandatory)
skirt coating

mpg9999

"and why"

hybrid D E T

Pin fit because you need the clearance to physically fit the pin in the pin bore. The factory SR20 piston has a pin fit range of .0006 to .0010 I believe. For the VE you will be good at .0007. This clearance is also necessary so that oil can lubricate the wrist pin. Without it, it would be the equivalent of running a piston to wall clearance of zero.

2nd land accumulator groove provides more crevice volume behind the top compression ring. This crevice volume reduces back pressure on the top ring, promoting top compression ring seal.

Lateral gas ports- Big Toe pretty much hit that one on the head

Double forced pin oilers This is basically a oil drain back in the oil ring groove that channels excess oil to the wrist pin instead of just dumping it out the inside of the piston. This will increase wrist pin lubrication and pin bore longetivity at high RPMs. On turbo applications this increased lubrication will also help transfer heat out of the pin bore to prevent gauling which can eventually lead to a catostophic failure.

Skirt Notch- to clear the VE/ DET oil squiter

Skirt coating is optional; however, the factory part has it and it will reduce friction

Plunge pockets are for maximum compression part where the designer is struggling to achieve dome volume. You will not need this to make a 12:1 VE part

hybrid D E T

Tom's pistons already have all of this and the features I've mentioned above. His valve reliefs are both deeper to run big cams and also larger in diameter to clear oversized valves. This has all already been figured out, it would be simple for him to change it to a 90mm bore and he could probably get it for cheaper too.

OnyxEros

thnx for the info

SENTRASER

Any updates on these yo?

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~Ryan
1992 NX2000 Hardtop
1989 B12 AWD wagon
1996 200SX SE-R Slowly geting the boost-treatment.

BerBer5985

wow....I swear I started reading this post and thought I had wandered into another world....I'm apparently in the wrong place here....right over my head...haha....good luck with all that though....sounds good to me

OnyxEros

In about 3 weeks the pistons will be in my hands
CP 90mm
They did some window millings and minimal dome with 16ve valve reliefs (i sent my 16ve piston along with the order)

When i get them back first i will need to use one to sleeve the block then I will coat them