Grant Piston Ring Quality Control (Gap Variation)

[240260280z]

Just doing rebuild for first time and learning a lot.

I just came across different ring sizes in the same package and it seems unusual. Is this a quality control issue or is it normal? (GRANT P1297.000 from Black Dragon)

Here is what I measured in the set of new top rings (I measured ring gap in same cylinder & same depth):

2 X 0.53mm

2 X 0.50mm

2 X 0.45mm

My cylinders measured with same ring are (Top Bottom):

1 0.44 0.44

2 0.44 0.44

3 0.43 0.43

4 0.44 0.44

5 0.44 0.44

6 0.53 0.47

With this set I should be able to achieve:

1. 0.41

2. 0.41

3. 0.43

4. 0.44

5. 0.36

6. 0.45

However the spec is 0.23 to 0.38mm so all but one cylinder will fail.

The bores are in spec so it seems the "standard size" rings are too small to begin with. It seems like a manufacturing error to me?

I will have to order a new set so should I choose oversize rings and file even though the bores are standard?

Should I stay away from Grant?

I talked to a friend at the local machine shop and he said that slightly larger ring gap is not significant for non-race applications. He said studies by Hastings have shown this. I also found a summary of a JE study with similar findings.... this counters the FSM so which trumps?

Edited May 31, 2011 by Blue

[Z train]

I've been wrenching for 40+ years.I've never heard of "Grant".Spend the money on known names.

[westpak]

No help on Grant never heard of them, the engines I have done (only a couple) have been with the rings that came with the pistons I bought, but those rings seem way off specially if the bore is standard.

I was talking to the machinist about my upcoming build on my L24 and he suggested this time to get rings from http://www.totalseal.com/ and go with a gapless second ring, I am just getting into the research part of this build so can't help much more but figured this might provide you with an option

[siteunseen]

How did theses turn out Blue?  I'm having a hard time finding rings that I like.

 

Thanks,

Cliff

[240260280z]

I did not use the Grants and let the machine shop turn key it when they rebuilt the short block.

I supplied bearings and seals however.

[Diseazd]

I agree with Westpak.....Total Seal are the best I've used.....I didn't use the gapless rings though.....just went with their regular rings. Nissan rings are my second choice......the oil rings and spacers are so nice on either set of rings. Hastings oil rings suck, as do ITM rings. I use Nissan rings with ITM Pistons and throw the rings away.

[Chickenman]

Grant is a very common name in the Automotive Industry. They've been around since 1922. Very popular with machine shops that build " Meat and Potatoes " Domestic engines. Main stream rings generally for stock or Industrial engines. Nothin' fancy, but they've been around a lot longer than Manufacturers such as Total Seal.

 

Hastings has been making Piston rings and other automotive parts since 1915. I don't like their oil control rings either.

 

 I normally use Sealed Power Moly rings on SBC's. Nissan rings on Nissans.

[Chickenman]

Just doing rebuild for first time and learning a lot.

I just came across different ring sizes in the same package and it seems unusual. Is this a quality control issue or is it normal? (GRANT P1297.000 from Black Dragon)

Here is what I measured in the set of new top rings (I measured ring gap in same cylinder & same depth):

2 X 0.53mm

2 X 0.50mm

2 X 0.45mm

My cylinders measured with same ring are (Top Bottom):

1 0.44 0.44

2 0.44 0.44

3 0.43 0.43

4 0.44 0.44

5 0.44 0.44

6 0.53 0.47

With this set I should be able to achieve:

1. 0.41

2. 0.41

3. 0.43

4. 0.44

5. 0.36

6. 0.45

However the spec is 0.23 to 0.38mm so all but one cylinder will fail.

The bores are in spec so it seems the "standard size" rings are too small to begin with. It seems like a manufacturing error to me?

I will have to order a new set so should I choose oversize rings and file even though the bores are standard?

Should I stay away from Grant?

I talked to a friend at the local machine shop and he said that slightly larger ring gap is not significant for non-race applications. He said studies by Hastings have shown this. I also found a summary of a JE study with similar findings.... this counters the FSM so which trumps?

Always go with the ring manufacturers specs. The rings could be made out of a different material that has a different expansion rate than the Factory rings. Ring material can be regular Iron, Ductile iron, Steel or Stainless Steel. And various alloy combinations in between. All have different expansion rates and different uses.

 

Same with pistons. It's now 2015... not the early 1970's and technology changes.

[siteunseen]

My Nissan Dealership can't get rings, Courtesy doesn't have them either.  So where are y'all getting these Nissan rings????? 

[djwarner]

I happen to have a set of Grant rings waiting to go into my rebuild. Since Chickenman mentioned modern materials, I pulled out the instructions that came from Grant. Step 4 states:

"Check piston ring end clearance. Check in cylinder near bottom of ring travel. Ring end clearance should be approximately 0.003" to 0.004" per inch of cylinder diameter."

With our 83mm bores in the L24's, this works out to 0.249-0.332mm. Nominally, this is 0.29mm. Blue said the average gap would work out to 0.416mm or about 0.126mm too large on average. Since this is a circumferal measurement, it equates to a diameter that is 0.040mm undersized. Or conversely, it could be said the bore is 0.040mm (0.0015") oversize relative to the rings supplied.

I think the operative word in the instructions was "approximately". The critical dimension is the low limit. Too low and the gap closes down to solid as the engine warms. When this happens, the rings dig into the cylinder wall with catastrophic results.

Remember the allowable taper on the cylinder is 0.008" compared to the calculated 0.0015" oversize. Since Blue's cylinders had little to no taper, I would not think the excessive gap would be a problem.

Of course, this comes from someone who hasn't rebuild an engine in over fifty years. If I'm full of it, please educate me.

[siteunseen]

I read some good stuff last night about Grant's C1297 rings, they could be the ones for me.

[Chickenman]

My Nissan Dealership can't get rings, Courtesy doesn't have them either.  So where are y'all getting these Nissan rings????? 

I'm in Canada, But my " guy " at Nissan says he can still get them from Japan. Still a good number and active for the 12033-A8620, the latest super-cede in Canada. I didn't check over-sizes.

 

I have seen NOS of Nissan rings repackaged as some bizarre brand when I had my engine rebuilt in Portland. I'll try and dig up the name. They were definitely 100% Nissan rings. Or a bloody good copy, right down to the Nissan Cello bags and factory Nissan identification markings on the rings themselves.

 

Something weird like " Dr Japanese " or something....

 

Edit: Doh... Just give Jock Rhodes a call at Bill's Datsun Shoppe in Clackamas Oregon. He has a huge stock of NOS Nissan parts. Depending on your engine year and model, he may have genuine Nissan rings sitting on his shelf. Not the Bizarro re-packaged stuff ... but genuine Nissan NOS.

 

Jock Rhodes - Owner

Bills Datsun Shoppe

16087 SE Evelynn St,

Clackamas, Oregon

97016

 

Work; 503 656-0756

E-Mail: jockracing@comcast.net