2G Can new OEM 95 piston's be purchased anymore?

[Justin DuBois]

Alright, so I have a question for you - Pistons.

I'm breaking down a 6-Bolt, and I'm looking to build a 1G rod, 8.5:1 or higher CR 2.0L short block.

I dunno if I can keep the stock bore or if I need to go 020, or 040 over yet. I need to have this measured before I purchase the slugs, but I don't know where or what pistons are available.

Can OEM 95 piston's be purchased? If no, what other options are there these days?

 

[pauleyman]

OEM? Dunno but i have to ask why would you do this? The cost of machining and hassle doesn't seem worth it in this day and age.

 

[Justin DuBois]

OEM? Dunno but i have to ask why would you do this? The cost of machining and hassle doesn't seem worth it in this day and age.

Thank you for the new thread.

This is why I'm asking. In this day and age, what is a cost effective solution?

 

[curt-s]

So, not aftermarket?

I think eBay is the only source of non-OE style pistons. I wouldn't bet on any of their quality.

 

[pauleyman]

Thank you for the new thread.

This is why I'm asking. In this day and age, what is a cost effective solution?

Cost effective is vague. What are you trying to do?

Wiseco | JNZtuning.com

 

[Justin DuBois]

Cost effective is vague. What are you trying to do?

Wiseco | JNZtuning.com

Trying to rebuild a 6-bolt, and replace the 7.8:1 pistons with 8.5:1 or higher compression pistons.

I’m not trying to beat the world. I’m happy with the 1G rod 2G piston results I have today - and i’m looking to get into the 400hp arena with a slightly bigger turbo.

 

[pauleyman]

If you're saying you already have machined 1g rods then can't you just buy any OEM equivalent pistons? NPR etc?

I didn't call a dealer but online sites say discontinued for OEM.

 

[curt-s]

I found a few 6bolt sets but that's still 7.8
Even if you did the 6/7 combo that's, what, 8.3:1?
You're looking at aftermarket for anything 1g rod with 8.5+, and that's going to be uncheap.. but as said, that's relative. People save every penny, some won't bend over to pick up a ten.

 

[Justin DuBois]

If you're saying you already have machined 1g rods then can't you just buy any OEM equivalent pistons? NPR etc?

I didn't call a dealer but online sites say discontinued for OEM.

Sorry for the confusion.
I have two motors. The one in the car has 1G rod 95 pistons. The one on the stand has 1G rod 1G pistons, and I’m rebuilding the one on the stand.

 

[97egl]

NPR pistons are very close to an OEM equivalent piston. You'd have to have the small rod ends machined by a machine shop to accept the 22mm wrist pins that the 7 bolt pistons will have. (You probably already know that)

Another option is evo 8 pistons. They bring the compression up to around 8.8:1 (To get the 8.8:1 they have to take all the material from the top side of the small end to raise the compression height of the piston)

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[Mech Addict]

Mitsubishi MD307819 PISTON & PIN ASSY

Mitsubishi MD307819 PISTON & PIN ASSY. New & genuine Japanese car parts. Fast shipping. Low prices. Request a quote from Amayama Trading Co. online.

www.amayama.com

They seem available, at least ordered from Japan. I would often give jnz a call about oem parts before trying to order directly from Japan. Sometimes Amayama would not actually have parts available that they showed were available.

 

[Canadian_CD9A]

Mitsubishi MD307819 PISTON & PIN ASSY

Mitsubishi MD307819 PISTON & PIN ASSY. New & genuine Japanese car parts. Fast shipping. Low prices. Request a quote from Amayama Trading Co. online.

www.amayama.com

They seem available, at least ordered from Japan. I would often give jnz a call about oem parts before trying to order directly from Japan. Sometimes Amayama would not actually have parts available that they showed were available.

Amayama is notorious for this, and for overcharging on shipping. If anyone can get them in North America, it's JNZ. Also look into Evo 1 or 2 pistons (don't use Evo 3), which are 8.5:1 equivalents.

 

[1990TSIAWDTALON]

I have a 6 bolt, rebuilt with NPR pistons and I feel just fine about them. As mentioned, if you want to run a set of 2g's, the rods need to accommodate the 22mm wrist pins that come with 2g pistons.

 

[steve]

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I wonder who all at RRE might have been involved in getting that diagram circulated?

 

[dwb]

This ^^^ ebay NPR pistons. Comes with rings and wrist pins.
I did this exact process summer of 2021. 1g 6-bolt rods with 2g pistons in a 6-bolt block.
The most difficult part was finding a machine shop to machine the rods and mount the pistons. I had shops that insisted the rods be sleeved/floating (they don't). Other shops had no clue what I was talking about. I ended up pressing off the 1g pistons myself, printed off the spec sheet listed above in this thread, and then drove the rods and new pistons around to various shops. I even included a single wrist pin from the 1g pistons as an example for how much to machine down (no idea if they used it). When the machinists SEE what they are working with, it's much more clear than trying to explain it over the phone. I think I ended up spending around $250 for all four rods to be machined and pistons mounted.

When it came to installing the rings, I used the 2g FSM for ring gap specs. 1g FSM has different specs and the included rings with the 2g NPR pistons don't match 1g specs.

 

[curt-s]

I was remembering wrong.. 2g/1g is still 8.5:1.
Is that comfortable to 400hp with the piston not being as beefy as 1g?

 

[97egl]

I was remembering wrong.. 2g/1g is still 8.5:1.
Is that comfortable to 400hp with the piston not being as beefy as 1g?

It'll be fine as long as the tune is good.

Stock bottom end 2g's start to show weak points around 450ish but usually it's the rods or bearings that guys have issues with after multiple passes. Normally when you do see pictures of someone that had piston issues there is obvious detonation, or they didn't gap the rings enough and the rings butted against each other. I would not be worried about the pistons being the weak point.

 

[Justin DuBois]

I wonder who all at RRE might have been involved in getting that diagram circulated?

I'm gonna go with Mike W, and Robert G on that guess. Robert and Chris taught me all the motor stuff back then.

I have a 6 bolt, rebuilt with NPR pistons and I feel just fine about them. As mentioned, if you want to run a set of 2g's, the rods need to accommodate the 22mm wrist pins that come with 2g pistons.

Yeah - NPR pistons - that is what I mean by cost effective. Now that I have found a Machine shop that isn't scared to talk to me, I think I'll propose this and have the rods adjusted for 2G slugs, so my world of parts can interchange between the two motors.

 

[1990TSIAWDTALON]

My machinist reworked my Manley I beams that were for 21mm pins so I could use 22mm pins (and .250 wall thickness) and he charged me $20/rod. He did all 4 "by hand" and they felt perfect. Just for comparison.

 

[Justin DuBois]

I was remembering wrong.. 2g/1g is still 8.5:1.
Is that comfortable to 400hp with the piston not being as beefy as 1g?

Not sure what you mean.
Stock 1G pistons are 7.8:1
Stock 2G pistons are 8.5:1

 

[curt-s]

Not sure what you mean.
Stock 1G pistons are 7.8:1
Stock 2G pistons are 8.5:1

Yeah, for some reason I had this thought of the 2g/1g combo being 8.3:1 but that's not even possible since the stroke is the same as is the rod centers and wrist pin locations. I'm old.

 

[19Eclipse90]

It'll be fine as long as the tune is good.

Since this has been said, why not consider 6-bolt non-turbo pistons, axe any machine work to the rods, and get 9.0:1 right out the box?

 

[Justin DuBois]

Since this has been said, why not consider 6-bolt non-turbo pistons, axe any machine work to the rods, and get 9.0:1 right out the box?

Hmmm - I dunno about the ring land strength of that Idea - but maybe you have a part number for those to reference?

Anyone done that?

 

[19Eclipse90]

If you’re looking at NPR, it looks like the turbo version crosses to 11-546 (MD129232) and the non turbo version to 11-540 (MD129922).

This thread has a couple members mention they’ve used N/T pistons in turbo cars: https://www.dsmtuners.com/threads/l...ing-an-n-a-6-bolt-4g63.540407/#post-153852474

Worth rementioning - it’s all in the tune.

 

[97egl]

Hmmm - I dunno about the ring land strength of that Idea - but maybe you have a part number for those to reference?

Anyone done that?

Yes @Spleen8urLSX has done it. I belive he was around or above the horsepower you are wanting but I can remember for sure. Hopefully he can chime in here.

I'll take a picture here of the difference between the 1g turbo and n/t ring lands. It's not a lot especially considering the turbo is dished and has less material supporting it from behind. Glad @19Eclipse90 mentioned that. Could save you a lot of work.

Non turbo 6 bolt NPR pistons are also available on ebay but are getting harder to find.

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