Moly Plasma Rings?

[siteunseen]

Anyone have a recommendation for a set of rings?  Like everything else, there's too many choices on the internet.  I've found Sealed Power and Hastings have a set of premium rings, moly faced.  Has someone recently purchased a set for 83mm bores?

 

Thanks for any help,

Cliff 

[djwarner]

I recently bought a set of Grant Piston Rings, though I haven't installed them yet. Have no idea of the quality.

 

www.grantpistonrings.com

[siteunseen]

I recently bought a set of Grant Piston Rings, though I haven't installed them yet. Have no idea of the quality.

 

www.grantpistonrings.com

Thank you sharing that.  I started my hunt last night and wasn't able to talk with my Nissan parts until this a.m.  I gave him #12203-E3100 and he said it had been superseded with 12033-A8620 (I'm pretty sure that's the number) and googled it for me.  Said it popped up as a Grant chrome ring.  Are your's chrome?  Parts guy said OE was chrome from Nissan.  I've read that a new cylinder wall works good with chrome but molly was a better choice for a slight honing like I'll have to get.  Maybe they have come up with a better seating chrome ring?

 

I just looked at your link, thanks again, and they have chrome and plain for the 83mm bore.  I wonder what plain is?

 

EDIT:  Okay, looking at how cheap the price is for the "plain" I'll say they're cast iron

[Chickenman]

Jock Rhoades at Bill's Datsun Shoppe near Portland Oregon built my new L28. He used regular Cast Iron rings. Makes sense. He's been building Datsun engines for over 37 years. He uses Moly or regular Iron rings depending on whether or not engine is re-bored and honed or just needs a quick de-glaze of the cylinder walls..

 

Moly faced rings require a very fine bore finish to seat properly. Final hone must be done on a Sunnen honing machine. You cannot get a proper finish using a DIY Ball Hone. Very good sealing and very long life with proper bore finish. OEM by all engine manufacturers since the early 1970's.

 

Regular Cast iron rings will seat on a much rougher bore finish. What you would get with a DIY ball hone. Relatively fast seating  miles and will last nearly as long as Moly rings.

 

Actual " Chrome " rings are seldom used on Automobiles with the exception of Dirt Track racers or Baja Racers. The exceptionally hard wear surface of " Hard Chrome Faced " rings is required to resist the grinding effects of minute sand particles that invariably get injested by the engine. Even the best Air filters allow some extremely fine dust through. Dirt bikes also use " Hard Chrome " faced rings. They are not required nor desired on street cars or Pavement race cars. 

 

I've had lots of engines built over the years. I have specific machine shops that I trust with my engine building. They've  all said that Moly rings MUST be finish honed on a Sunnen or similar automated honing machine. The piston ring Manufacturers also have Tech sites online that will confirm these facts.

[Chickenman]

Thank you sharing that.  I started my hunt last night and wasn't able to talk with my Nissan parts until this a.m.  I gave him #12203-E3100 and he said it had been superseded with 12033-A8620 (I'm pretty sure that's the number) and googled it for me.  Said it popped up as a Grant chrome ring.  Are your's chrome?  Parts guy said OE was chrome from Nissan.  I've read that a new cylinder wall works good with chrome but molly was a better choice for a slight honing like I'll have to get.  Maybe they have come up with a better seating chrome ring?

 

I just looked at your link, thanks again, and they have chrome and plain for the 83mm bore.  I wonder what plain is?

 

EDIT:  Okay, looking at how cheap the price is for the "plain" I'll say they're cast iron

I don't think your Nissan source is correct. I was a Nissan partsman for over 17 years and still have connections to Nissan Canada.

 

All GENUINE Nissan rings for the L-series are Moly top rings. With usually a regular iron second ring.  12033-A8620 is no different. 

 

Grant is NOT the OEM manufacturer of rings for Nissan. When your parts guy Google the Nissan part number I think he missed the fact that 12033-A8620 is used as a CROSS REFERENCE by Grant ONLY as a fitment guide.

 

Genuine Nissan rings ordered from Nissan are going to be Moly faced top rings.

 

Edit: I just checked with one of my " Trusted " Nissan partsmen just for curiosity. 12033-A8620 is still a good number, no stock in Canada, but still available out of Japan. He hasn't ordered any in a while, but as far as he knows Nissan still has the same ring suppliers from Japan as they've always used.

 

I've done some searching online, and 12033-A8620 is available as a GENUINE Nissan part ( supposedly) from several online sources. Probably NOS.

Edited February 13, 2015 by Chickenman

[Chickenman]

I've used Grant or Hastings rings on everything from Small Block Chevies to Datsun A12 engines. Decent quality ring. You just have to decide on the bore finish. As stated above, Moly faced rings should always be finished on an automated honing machine like a Sunnen.

 

Regular cast iron rings with no face coating can be used with a backyard ball hone. Moly's can't.

 

BTW, the actual ring material can be cast iron, ductile iron or even Stainless Steel.  Each has different characteristics designed for specific applications. Ductile Iron and SS are more durable and are used in High performance applications. IE: High RPM, Forced induction, Nitrous and Diesels. The face material, Moly or Chrome, is usually Plasma sprayed on separately and is very thin.

Edited February 13, 2015 by Chickenman

[madkaw]

I purchased OEM replacement rings from ebay and they were NOS Napa/Dana/tokeomi rings. Cast with the top ring having a special wear surface, but don't know if it is Moly, but I know it's not chrome.

Rings looked okay with just a cast second ring, but i decided to get the matching Sealed Power rings to match the pistons. My machinist also insisted on a Napier second ring for oil control.

I also found out that .030 pistons and rings are a bit tough to come by anymore.   

[Chickenman]

^ NOS Nissan rings would be a Moly faced top rings. Kind of a lighter grey in clor than the actual ring material.

 

Pretty sure the second ring on OEM Nissan rings is a Napier. They usually have an ID mark on the top of the ring so that you don't put them in upside down.