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Ibreakstuff

ej205 pistons into ea82t?

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I have been researching forged pistons/rods for a few weeks now, just wanted to post an idea for more advice. I only found 1 post with a similar idea but nothing came from it.

 

It should be possible to use off the shelf ej20 92mm pistons with custom connecting rods (shorter, length not yet calculated) with the EA crank pin bore size (48mm) right? I understand that the dish volume will have to match to keep the CR close but flat top off the shelf pistons should be doable. Are there any other issues that could arise from this that I have not thought about?

 

The benefits would be a larger (offset?) wrist pin and possibly more affordable vs both custom forged rods and pistons.

 

Please don't tell me to ej swap, I'm being serious here.  :horse:

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have tried thiss a bitt the 2.0 pistons fitt the bore on ea81 and ea82 and if you press out the wrist pin bushing the ej pin fitts the ea rods have not put a engine together yet but should work i have a 2.0 piston here and a ea piston here to compare the 2.0 turbo pistons in a ea engine whould be good upgrade

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"stroker" rods made for putting a 2.5 crank into a 2.2 might be just the right thing.

 

They are shorter than 2.5 rods, have the same 48mm crank pin should fit EA82 crank,  and correct wristpin size for EJ pistons?

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I have been "blue skying" on this issue before.  I hadn't considered EJ25 rods.

 

You could also take a page out of Jeszek's book and look for piston's from alternate Makes.  Nissan VG33 0.50 over pistons have looked like a possibility.  IIRC they have equivalent bore, same wrist-pin size as the EA82 and about the same compression height.  They are also used in the supercharged versions of that engine. Domes are kind of wonky, and they are not lower compression on the supercharged engines.

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have tried thiss a bitt the 2.0 pistons fitt the bore on ea81 and ea82 and if you press out the wrist pin bushing the ej pin fitts the ea rods have not put a engine together yet but should work i have a 2.0 piston here and a ea piston here to compare the 2.0 turbo pistons in a ea engine whould be good upgrade

 

Interesting. Ea wrist pins are 21mm, ej's are 23mm. I never considered that an EA rod would fit an EJ wrist pin. I'll to take another look at the ea rods.

 

Can you measure the compression height of the ea and 2.0 turbo pistons (center of wrist bore to top of piston)? This is the one measurement I have not been able to take yet.

 

"stroker" rods made for putting a 2.5 crank into a 2.2 might be just the right thing.

 

They are shorter than 2.5 rods, have the same 48mm crank pin should fit EA82 crank,  and correct wristpin size for EJ pistons?

 

Yep, the 48mm crank bore rods are from phase 1 ej motors. The deck height on the EA82 block is much smaller (~184.15mm) than the ej205 (201mm) so the rod might have to be even smaller. I'm waiting on more accurate mics and a new bore gauge (in the mail), when they arrive I'll measure everything out and confirm.

 

I have been "blue skying" on this issue before.  I hadn't considered EJ25 rods.

 

You could also take a page out of Jeszek's book and look for piston's from alternate Makes.  Nissan VG33 0.50 over pistons have looked like a possibility.  IIRC they have equivalent bore, same wrist-pin size as the EA82 and about the same compression height.  They are also used in the supercharged versions of that engine. Domes are kind of wonky, and they are not lower compression on the supercharged engines.

 

Lol, blue skying would pretty much sum up every idea I have had for this car.

 

Interesting idea there tho, I'll look at other makes too then. When I get everything measured out I'll start contacting all the pistons makers, they could have an off the shelf piston for another make with the right specs. I'm jumping a similar hurdle for head studs.

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By my redneck calculations, I need rods in the neighborhood of ~118mm 4.6457" (center to center) depending on several variables yet to be determined.. which seems very short. I guess shorter = stronger? The rod:stroke ratio would actually be ideal if close to that.

 

dh - (ct + ch)

 

 

bore: 3.622" 92mm
stroke: 2.6378" 67mm
deck height: ~7.25" ~184.15mm
crank throw: 1.3189" 33.5mm
compression height of ej20 cp piston: 1.285" 32.639mm
Edited by Ibreakstuff

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Skip the rods and the forged pistons and just go straight to the water/meth injection. Without detonation and high egt's the stock parts will hold up to a lot of power. ea82t's are a disposable engine anyway, so go for massive power the cheap way and if it doesn't work, then build a fancy engine.

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Skip the rods and the forged pistons and just go straight to the water/meth injection. Without detonation and high egt's the stock parts will hold up to a lot of power. ea82t's are a disposable engine anyway, so go for massive power the cheap way and if it doesn't work, then build a fancy engine.

 

While I do see your point, this project is strictly for learning purposes.. So why the hell not go full tilt and have some fun with it. I have an ej255 wrx motor waiting to be built as well, but I've always wanted to build a monster ea82t.

 

This motor will be beat on in autox/rallyx so I don't expect to get 100k out of it, but I would like to see what it is actually capable of. When I get bored with it, I'll move on and swap it.

 

I thought all motors are disposable?

 

This whole project came along due to a car crash and a whim..

Edited by Ibreakstuff

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How fancy do you need your studs?  I plan to get some B9 threaded rod, and cut to length.  Not pretty, not ideal, but cheap and available.

 

OOps!  Typo: should have read B7 threaded rod.

Edited by NorthWet

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How fancy do you need your studs?  I plan to get some B9 threaded rod, and cut to length.  Not pretty, not ideal, but cheap and available.

 

I wanted to increase the head torque to at least 60-65 psi, with timeserts so I don't chew threads. The jury is still out, but I would love to find a common thread size/pitch arp studs in the correct lengths. The alternative is to have some paeco studs made (grade 8).

 

What is the tensile strength of B9 threaded rod? And is it torque to yield?

 

I'll be running a stock wrx TD04L, so I don't expect to be pushing the boost pressures beyond its efficiency. And not even close until all the supporting mods are sorted.

 

And I am going to try a MLS head gasket first, If that doesn't hold I'll look into ringing the block and/or copper gaskets.

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where did you find a mls headgasket for a ea82t?

 

"Gaskets to go" Its a company ran by an ex-pat based in Thailand. They are fairly popular in the VW scene. They make custom MLS gaskets with no min quantity or tooling fees.

 

The alternative would just be to run felpro permatorques and cross my fingers.

Edited by Ibreakstuff

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Sorry, my earlier post had said "B9" when I meant to type "B7".

 

ASTM A193 Grade B7

Chromium Molybendum steel, normally AISI 4140, heat treated to
28-32Rockwell Hardness, 125,000 PSI tensile strength, 105, 000 PSI
yield. It will hold it’s strength to 1000 degrees F.

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Sorry, my earlier post had said "B9" when I meant to type "B7".

 

ASTM A193 Grade B7

 

Chromium Molybendum steel, normally AISI 4140, heat treated to

28-32Rockwell Hardness, 125,000 PSI tensile strength, 105, 000 PSI

yield. It will hold it’s strength to 1000 degrees F.

 

That would probably work fine, definitely better than stock bolts. I still have not crossed this road yet tho, I'll post here if I find any other solutions for studs.

 

Paeco studs are grade 8, which is around 150k PSI tensile strength (~400$ for a set with nuts, ).. Arp is around 180k PSI, but custom 11mm studs would kill a good portion of my budget.

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Really and truly, tensile strength is not much of an issue here.  I have never heard of anyone breaking a healthy (non-corroded) headbolt/stud in a Subaru.  It is far more common to pull the aluminum threads out.

 

Since I was going to go with non-standard studding, I was not going to worry about maintaining  the original thread.  7/16". 12mm. or 1/2" rod is readily available and cheap.

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I'm curious on these MLS gaskets.

 

TimeCerts should allow you to torque headbolts to desired lbs

 

I believe I tightened mine down to 56lbs-ish without touching a thing.

 

Still sorting out the haltech system before any street time, I think my biggest challenge is 550cc injectors were a tad too big, but with a TD04 and AWIC I should be able to put down good numbers

 

Will let you know the outcome.

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Had a broken head bolt on ej 2.2 other day was 3 in of bolt in case was no way to save it had to change block one out of 100 but very diffacult to deal with. I had tried to run a ea81 with ej 2.2 pistons i bored the block to the 2.2 piston size but was not enuff liner left but the 2.0 pistons are very close. And i dont think running without a wristpin bushing whould be a problem as its a floating pin

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Just found this thread yesterday. Here's the specs on a piston I have installed at the moment in an EA82.I installed top and second rings and the inner pin lock. I installed a .065 headgasket and snugged the head bolts down, installed the cam case. Rotated cam both ways, valve interference with that dome. I hand polished the pin bore after knocking out the bushing. I also upgraded the piston pins to a thinner "bearing steel". The piston sits .020 above the deck, I'm not positive how much I took off this block...mabie .006?

 

I've repeated the camcase to heads off and on a few times. I stacked two headgaskets and bolted it together with no valve to piston interference. Of course, using two of those headgaskets wouldn't work for me. Too much piston to head clearance. Anyway, conclusion, I'd need to have the pistons fly cut for valve clearance. and the piston doesn't fit the combustion chamber. It's adds quench in that trench that circles around them. I can get .040 quench. piston to head, with this piston. That's right where it should be for the piston. Anyway, when I pull it apart again, I'm selling these.

 

P1030192_zpsc01a5342.jpg

 

Brand new, unused set of ARIAS Custom Pistons for Subaru EJ20 WRX 2.0 liter, with turbo, supercharger and/or NOS.  Fits stock OEM Subaru sleeve bore, no boring required. 
Brand: ARIAS PISTONS
Material: Forged 2618 non-silicon
Bore diameter in./mm: 3.622 / 92 (OEM)
Stroke in./mm: 2.953 / 75 (OEM)
Compression ratio: 8.5:1
Crown style: Thermal dish
Compression height: 1.295 in.
Pin diameter: .905 in. (OEM)
Wrist Pin Style: Floating
Pin brand: ARIAS 1018
Ring brand: ARIAS 1.2-1.5-4.0mm
Pin Material: 1018 case hardened
Weight Matched Set: Yes
Quantity: Sold as a set of 4 (pistons, pins, rings, single locks)

 

These ARIAS pistons were custom made in batches of 40 for a customer who declined the order.  The pistons, pins, rings and locks are in new excellent condition.  They are precision machined and fitted with a medium-duty pin guaranteed up to 20 pounds boost.  Stronger pins are available - please email for an additional quote.  This application is not available in the ARIAS catalog as a shelf part number.  Comparable sets cost up to $585 on the ARIAS website.  Five (5) kits are available.

 

ARIASEJPistoninEA82TT_zpsc63bb5b2.jpg
 

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Still that leaves the piston pin diameter issue unsolved, doesn't?

 

By the way, the EA rod journals are 45 mm... So the EJ25D rod does not fit (48 mm journal).

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You mean running no bronze small end bearing in the rod? Unfortunately direct contact between wrist pin and rod are not a good pairing when it comes to friction.

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You mean running no bronze small end bearing in the rod? Unfortunately direct contact between wrist pin and rod are not a good pairing when it comes to friction.

 

If you look around, no pin bushing has been done and is being done. Pin material is crucial and or the coating. Coating for the bores or the pins could be dry film lube too or diamond like. I have a set of rods I've reworked extensivly. I need to post a pic...There are ways to increase oil to the pins, clearances play a factor. Bearing steel pin with coated pin bores is what I have in mind. Pin bores are very smooth typically even after pressing the bushing out. I've got a set polished with 1000 grit wet after I knocked the bushings out.

 

I chamafered the oil supply passeges in the rod end and chamfered the pin bore it's self.

Edited by Quidam

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Been working on a set of rods. Bushings out, lots of grinding so far. Then to the machine shop for shot peening and big end rebuild.

 

 

SubaruEA82Rods_zpsea50af43.jpg

 

 

 

 

SubaruEA82RodPinEndBushless_zpsae43a193.

 

The fatter pin is oem sti.

SubaruEA82ConnectingRods_zpscead2097.jpg

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