OST and JE Piston develop a new 4AGE piston

[oldeskewltoy]

This is not meant as a for sale thread... my intention is informational - about a new option for 4AGE pistons. If this is deemed "For sale", I'll follow it up there...



To try and make a long story somewhat shorter.... many of my clients have no decent mid-high to high compression pistons available. The pistons begin with the TVIS catalyst pistons(9.4), TVIS non cat(10.0), and smallport pistons(10.3), the 9.4 require MASSIVE head and block work to get "high" compression from... The non cat pistons, are better, but still require large amounts of head and block work. The smallport pistons are finally reaching appropriate levels... BUT... with ALL of the Toyota 16V pistons, they have a SERIOUS flaw... the oil return for the oil rings is a slit. This slit doesn't offer enough support to the 2nd compression ring leading to land failure-piston failure.

MOST aftermarket high compression 4AGE pistons are high domed, with MASSIVE valve reliefs... almost all of the aftermarket pistons are designed to accommodate O/S valves. I found nothing high compression available that was designed for a standard valve head...



About 6 months ago an artist friend showed me how to do castings using two part silicone....








Along with the above casting I collected 3 pistons - 9.4, 10.3, and an old TRD (13101-AE851)





The TRD is the same TRD shown in the TRD Bible - AE86 group A engine manual. My goal was to replicate the good part of the TRD... while leaving the bad part in the past. The good = the crown, the bad = the skirt. Why is the skirt bad? In a 4A the rod to stroke ratio is bad. This causes the 4A piston/rods to go through very substantial arc sweeps. Because of this (in many cases) a minimal skirted piston doesn't last long in a 4A.


Along with the 3 pistons, I included an 18/40 rod, and a 20/42 rod and sent all of them to JE Piston.



My goal was to develop a moderate to high compression piston that offered as much squish as possible, AND offer as flat a piston crown as possible. While keeping the longevity up by employing a full skirt.



The above piston in an undecked block, under a 36cc chamber running a stock head gasket... these pistons can offer a static CR as low as 10.6 to 1 (with an .030" machined crown). At the other extreme, with a decked block, small - 33cc -chambers, a stock gasket, and full crown... these pistons will deliver a static compression of 11.8 to 1.



In MY OPINION - These pistons DO require "finishing"....





There are 4 "peaks" that require removal, each is at the outer edges of the valve reliefs. A view showing said peaks removed...

[bermy]

hmmm nice thread.

I'm straying a lot off topic here, but do you have a complete TRD piston set? I mean the 1.58:1 R/S ratio of the stock 4AG need a wide skirt... my 1.79:1 R/S doesn't... making them ideal pistons for me

Mmmm long rods!

[oldeskewltoy]

hmmm nice thread.

I'm straying a lot off topic here, but do you have a complete TRD piston set?

For long rod pistons.... I believe I might have access to some used ones... what bore?

[bermy]

For long rod pistons.... I believe I might have access to some used ones... what bore?

What ever you can get your hands on

...but standard bore would be even better.

You can PM me the details.

[rallysprinter]

OST, you've got my interest.

From the part number for the rings in that photo, it looks like for 82mm pistons. Being a custom job, I guess the pistons can't be obtained in smaller sizes, such as 81 or even 81.25mm (staying under 1600cc)?

[oldeskewltoy]

OST, you've got my interest.

From the part number for the rings in that photo, it looks like for 82mm pistons. Being a custom job, I guess the pistons can't be obtained in smaller sizes, such as 81 or even 81.25mm (staying under 1600cc)?

Your guess would be wrong.... these are my design, and they are available.

They were designed by me and JE Piston for 81, 81.5, and 82 bores, I can ask if they can make them in 81.25. They are also available in 18 and 20mm wrist pin.

So this doesn't change into a for sale thread... if you are interested please send me an email to [email protected] - Please title it "OST/JE Piston"



Here are a few photos of the crown during design

[Sam_Q]

A pity this isn't about 20V engines. Those morons still don't seem to know that there are two different chamber sizes, that and not posting the weights.

[oldeskewltoy]

A pity this isn't about 20V engines. Those morons still don't seem to know that there are two different chamber sizes, that and not posting the weights.

Oh... good point........






For comparison...
OEM 9.4 to 1 TVIS piston (for 18mm pin) 308 grams -- pin 89 grams = 397grams
OEM 10.3 to 1 smallport piston 326 grams -- pin 91 grams = 417grams
OST/JE piston 286 grams -- pin 68 grams = 354grams




Concerning 20V development... I see no reason you can develop it...

[oldeskewltoy]

I've had a few people...who need to keep under 1600cc... for competition purposes, ask me if these are available to fit an 81.25mm bore(81.25 x 77 = 1597cc).... so I sent an inquiry to JE Piston, these are also available in 81.25mm, at the same price!!


So bores available: 81mm, 81.25mm, 81.50mm, 82mm. Pins available: 18mm, 20mm (likely 19mm too - just not confirmed)

[oldeskewltoy]

I've had a few people...who need to keep under 1600cc... for competition purposes, ask me if these are available to fit an 81.25mm bore(81.25 x 77 = 1597cc).... so I sent an inquiry to JE Piston, these are also available in 81.25mm, at the same price!!


So bores available: 81mm, 81.25mm, 81.50mm, 82mm. Pins available: 18mm, 20mm (likely 19mm too - just not confirmed)

Good news... Bad news.....

Good news, these pistons are basically fully customize-able now. Custom bore, custom compression height, any wrist pin you want....

Now the bad news... I can no longer sustain the price... cost now is $750.00 (US dollars)per set, PLUS freight