NPR pistons/rings -- who uses them? Are these any good?

As the title says, I have found some engine builders (on ebay ) installing NPR pistons and rings in EJ257 blocks. But info on the web is scarce about this brand.

 

Is there anyone on the forum who has any info about this brand? Also, anyone using these for a while? Are there any better than OEM (i.e. less prone to fail due to detonation)?

 

 

Here is the US version of their site: http://www.npramerica.com/nprofamerica_product.html

Bored so I decided to do a little bit of searching on the internet. Apparently there is two different NPR Brands. Nippon Racing and Nippon Piston Rings. Nippon Piston Ring is supposedly Japanese brand comes in a Yellow Box with NPR circled. People used these to build Hondas and DSM and it raises compression.

 

While Nippon Racing comes in a white box with npr in black lettering. These are Chinese knock offs.

 

You might of read some of this on the internet also, but if you didn't thats what I found out about them

 

As for them in our cars? I believe most people will just get oem or forged. Good luck with the search.

Would be best to skip it. When I researched replacing my block, it was cheaper/better just to get an OEM EJ257 block. If you are going for power, rebuild with forged.

You've been around here for awhile, surely you've read my thread in my click here link in my sig.

 

What are your HP goals then lead you to thinking you need pistons ?

 

pog0 is telling you the same thing my trusted machine shop told me back in 2012. That's the same shop that helped us build the 1.6L single cam Civic to 586whp. I trusted what they said, 125,000 miles later the EJ257 is still running great.

I am almost positive I need a shortblock. But I don't really want to replace it with more of the same, which can 'easily' suffer from cracked ringland due to detonation. I want something a little tougher which does not hurt the bank too much. This guy on ebay, who supposedly has rebuilt lots of engines, sells ej257 blocks with these NPR pistons and rings, ARP ROD BOLTS, king race bearings, including new oem oil cooler, oem oil pump, and oem water pump for 1950$ including shipping. He claims these NPR pistons and rings are much tougher than oem...

It's not the engine, its the "tune".

I know. But these stock pistons are a bit too sensitive...

And we had the same tuner.

I'd suggest watching a few of this channels videos , they often end up rebuilding engines after someone took short cuts or from poor workmanship.

https://m.youtube.com/user/bollunjanumberone

 

Reason I bring this up, I would not expect great quality work from someone flogging engines they rebuild, on eBay. You won't know what you're getting unless you take it apart (which obviously you wouldn't normally do).

 

I'm sure NPR pistons and rings are fine if they are properly installed and all clearances checked with the right measurement tools. I would not trust an eBay seller to do that correctly...

Yeah. I understand. I'll check your video.

I have used these piston rings in my engine. About 12k miles on them atm. About 0.5 qt oil consumption per 3k miles.

 

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Which pistons did you go with? Any mods to your car?

Stock pistons, arp head studs, sti 11mm oil pump, king performance race bearings, intake, cnt downpipe, magnaflow exhaust. Built for reliability, not power. Dynoed at 255whp.

 

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I see. What made you select these rings?

 

 

And here is the ebay sale I was referring to: https://www.ebay.com/itm/SUBARU-WRX-STI-EJ257-COMPLETE-SHORTBLOCK-ARP-ROD-BOLT-NPR-PISTONS-OIL-WATER-PUMP/273844308285?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908131621%26meid%3Dd72a33d3b2df407189afe18999cb478b%26pid%3D100678%26rk%3D3%26rkt%3D15%26sd%3D141677451542%26itm%3D273844308285%26pmt%3D0%26noa%3D1%26pg%3D2481888&_trksid=p2481888.c100678.m3607&_trkparms=pageci%3A613144e6-d62a-11e9-adfd-74dbd18013c9%7Cparentrq%3A2acf9b7416d0aadcc7867a9effb0a7c1%7Ciid%3A1

BC Stage 3 Cams BC0622 $650

BC Springs BC0600 $215

Manley Turbo Tuff Extreme Duty Pistons 632800CE-4 99.50 -17cc 8.5cr $650

Manley H-Tuff Rods 15024-4 $275

ARP Head Stud Kit 260-4701 $185

Subaru STi 11mm 15010AA360 Oil Pump $130

Subaru 10105AA720 Engine Gasket Kit $235

Cost to rebuild longblock, includes hot tank and 10k rpm balance, with King Bearings $1815 and whatever extra if they need to readjust the heads after assembling longblock.

Total $4155

 

That's what I paid to get a rebuilt longblock. Haven't started it yet so.... who knows lol!

I like Manley pistons, tight tolerances and forged.

https://www.ebay.com/itm/2004-2013-Subaru-Forester-XT-EJ25-2-5L-Impreza-Baja-EJ20x-EJ255-Engine-Motor/233310326447?

 

Used longblocks for 1350 !!! OMG !!! These motors are getting cheaper and cheaper.

I saw one from a jdm vendor in immaculate condition. Complete engine with the turbo, intake manifold, etc.... 55k miles. 1300$! Supposedly passed compression test. And it's local!

 

 

Edit: never mind. it is an ej20x

Edited September 13, 2019 by xt2005bonbon

yea, stay away from that 2.0 nonsense.

 

So you don't know what is exactly wrong with your block but its still operational?

 

If that's the case your in my shoes exactly... I couldn't get my car etuned because I was chasing some dragon, so I decided to pull my block apart completely to find the issue, and I found I had cracked ringlands. If you catch the problem before it explodes then your in good shape. My cylinder walls were fine as well as everything else, so it was a simple rebuild. It gets expensive when you have to fix spun bearings, gouged cylinder walls, bad cylinder heads, etc.

 

Have you pulled the motor or torn it down?

And when i linked the used block , i was not trying to imply to install a used block! For the experienced thats a great price, if its in working order, to start a project, especially if it comes with all the parts in the picture. New heads are like 600 a piece, and block halves are another 1200 or so. So if your were planning to rebuild a motor, that's not a bad price to pay for heads and block. **** the old internals!

My engine is using a lot of oil, despite the spark plugs looking OK, and barely any oil in the intake track and intercooler. I have personally adjusted my valve clearances (on the driver side) 40k ago. Spark plugs are somewhat new, coils are fine. I am almost positive injectors are fine. Did a compression test a month ago. Ended up getting 115 on both #2 and #4 and 130 on #1/#3. BtSsm does report at times some roughness on #4 and rarely on #2.

 

But last two weeks, engine remained off as I was going to replace my leaky radiator. When it was ready to fire her up, she definitely sounded like a low comp engine (not first time she does that after remaining off for several weeks). She did start fine though with misfires on #4 which went away ~5-8sec after start up. Car runs fine. Does not throw a cel since misfire count is rare and very low when it happens. But I know something is up. Aaaaand I just swapped my good ol vf40 with a JMP vf52 .

have you done a compression and/or leakdown test? thats pretty much the only way to diagnose a shortblock. Did you retune the car after installing a new turbo?

Yeah. As I said, I did a compression test yielding smaller numbers on the driver side compared to the passenger side. This was done cold. Did not do a leakdown test as I usually expect to leak at the rings when done cold (this happened to me before even though I had a super tight valve).

Currently self tuning for the new turbo with the help of an experienced Subaru enthusiast

if your not driving the car, then i would pull the motor and pull it apart to see whats really going on. The condition of the cylinder walls, journals etc. should give you a better idea of what route to take.

Is there a reason you're not just rebuilding your block with better pistons? Is it just a cost thing and hoping these would be a good deal?

 

 

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I just wanted to throw some new rings on and those were the only ones I could find.

 

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