I am building the EJ25d and EJ22E frankenmotor for my Westy - My oil rings in the EJ25D block are all gummed up so I figure I would install a new set of rings.

 

Listed on the Small Car Performance website (they are local to me in Tacoma) they state they have sourced OE Subaru rings from the Manufacturer - they don't list who the manufacturer is but I have found out they are selling NPR rings calling those rings OE for Subaru.

 

I know they (NPR) do supply OE rings for some Japanese makes, but I have never heard anything conclusive who makes the Subaru rings. Searching here I have not found a lot of info on whether these rings are any good or not.

 

Can anyone chime in with regards to the NPR rings? Good, Bad, no issues?

 

Thanks

OEM supplier could vary by model, engines, and even years, or have multiple suppliers...making that up, but there are myriad of variables. Subaru could outsource that mid-production or mid-year. Subaru is married to spec's, not the source.

 

I like to know and find OEM suppliers of critical engine parts too and finding OEM manufacturers often seems harder than it should.

I search the parts manufacturers website or try to find some history about the company. If they make OE parts for some makes, pretty good chance they have made OE parts for the make you're looking for at one point or another.

 

As Gary said, specs and suppliers change from time to time. The manufacturer that made the original rings for a certain engine may not even be in business anymore. The vehicle manufacturer just finds another source. There is usually a test cycle to determine which rings they find suited to their needs, then they make a deal for an order based on cost and production times.

 

http://www.npr.co.jp/english/company/business.html

 

TOYOTA Motor Corporation, NISSAN Motor Co., Ltd., MITSUBISHI Motors Corporation, MAZDA Motor Corporation, HONDA Motor Co., Ltd., ISUZU Motors Ltd., FUJI Heavy Industries Ltd., DAIHATSU Motor Co., Ltd., SUZUKI Motor Corporation, HINO Motors Ltd., UD Trucks Corporation, MITSUBISHI FUSO Truck & Bus Corporation, YAMAHA Motor Co., Ltd., KAWASAKI Heavy Industries, Ltd, Daimler AG, BMW AG., MITSUBISHI Electric Corporation, MITSUBISHI Heavy Industries, Ltd., KOMATSU Ltd., KUBOTA Corporation, ISEKI&Co., Ltd., MITSUI Engineering & Shipbuilding Co., Ltd., Hitachi Zosen Disel & Engineering Co., Ltd., Akasaka Diesels Ltd., KOBE DIESEL Co., LTD., HANSHIN DIESEL WORKS., LTD., HYUNDAI HEAVY INDUSTRIES Co., Ltd., MAN DIESEL SE

Especially when it comes to things like the rings. $150 @ the dealer vs $40 on flea bay!

I read the Mitsubishi guys love the NPR piston & ring sets.

I'm running NPRs in my franky. 240psi on all 4 cylinders... I'd say they're decent.

I'm running NPRs in my franky. 240psi on all 4 cylinders... I'd say they're decent.

 

Wow, that is a lot of cylinder pressure. Stock EJ25D and DP EJ22 heads? How thick of head gasket .051"?

 

I was wondering what kind of cylinder pressures the Franks put out.

EJ25D block, EJ22E SP heads, .040 MLS head gasket. I'm right about 11k miles and compression tests about a week ago put all 4 at 240psi.

Someone correct me if I am wrong but doesn't 240psi equate to about a 16:1 compression ratio?

Someone correct me if I am wrong but doesn't 240psi equate to about a 16:1 compression ratio?

 

http://en.wikipedia.org/wiki/Compression_ratio#Fault_finding_and_diagnosis

There is, however, no formula to calculate compression ratio based on cylinder pressure

Someone correct me if I am wrong but doesn't 240psi equate to about a 16:1 compression ratio?

 

Calculated it at about 11.2:1 given the shaved heads, thin HG, and displacement.

I would think that a bit high. The Frankenmotor is usually something like 12:1.

I've tested a few stock EJ22 engines and they come in at about 190 - 200 psi. Stock compression ratio is supposed to be about 9.7:1.

As a ratio, that works out pretty evenly.

9.7*20=195

12*20=240

Of course these numbers mean nothing scientifically. :-p

 

16:1 compression would be way outta the ball park for an N/A EJ engine though.

If you have 240psi cranking compression....that's excellent, and the cam would have to figure into that calculation.

 

Need engine management?

If you have 240psi cranking compression....that's excellent, and the cam would have to figure into that calculation.

 

Need engine management?

 

Yes I do lol. Looking into PP6 and dyno tune through Pre.

I'm trying to calculate my Compression Ratio for my build, I keep finding conflicting numbers for the EJ22 DP heads: are these corect numbers:

Combustion Chamber Volume: 41 cc's

Piston Dish Volume: 12 cc's (would that actually be measured like (negative) -12 cc's

 

Thanks

I like NPR Rings just fine. Use them all the time.

Yes I do lol. Looking into PP6 and dyno tune through Pre.

 

I would rethink that. PRE is less than stellar in my experience - I have quite a few of their unhappy customers. They couldn't tune a PP6 on a 92 SS. I'm building him a MegaSquirt because it runs so badly...... You should see the hack work they do! I just opened a tranny they replaced third gear on to find three gear teeth left inside of a very dirty transmission case. Luckily no damage was done but the customer was right to be concerned when two teeth showed up on his drain plug. I found another inside when I opened it.

 

Talk to Jared of PDX tuning. Or I can let you know when I get all the bugs worked out of my MegaSquirt build.

 

GD

I like NPR Rings just fine. Use them all the time.

 

+1

 

That's what I always use too.

Well I got my new NPR rings - Check out the box:

 

 

It says Fuji right on it, So I think it gives cred to these being OE.

 

$25.49 Shipped!!

Edited November 2, 201213 yr by franklinstower

I read it as saying "Fit for Fuji EJ25" and I have seen both they aren't identical but I think the quality is about equal and I like installing these more-much easier to get the oil rings on right.

Some say i will never get the rings seated with out a hone, which i am not doing. I had frozen oil rings so i was re ringing only. Non detergent 30 weight should help them seat, correct?

Do a light hone. You need SOME kind of fresh crosshatching for the rings to bed correctly.

No hone required. Honing is an old wives tale debunked in the 70's.

 

Only needed for chrome rings or as the final stage to a boring operation.

 

GD