Hone pattern, rockwell hardness, ring tension

matty169 said:
Don't ask me..... I dont know chit!
Click to expand...

Oh, but you do.

I wasn't questioning you. That wasn't my intention. I didn't have a chance to read your link. I was glad to see you back in the thread.
I just thought we were talking about the same means to an end.

The reason I asked about other mechanisms in the design is because I think I've seen patterning in the bottom of the compression rings on a couple of applications.

From my Not-So-Smart phone
 
I was being serious. I dont know squat about ring design in diesels. I wasnt being a wise-ass.
 
I will see what I can dig up from my garage.

I've always been curious about the balance between ring gap for a full tilt engine vs tolerance for blow by.

From my Not-So-Smart phone
 
I will see if I have anything worth posting on diesel specific as well besides longevity and high heat resistance. Food for thought, look at the ring locations between a gas and diesel. I remember reading an article Smokey had written that the early days of racing the rings sat quite a ways down from the crown-top much like the diesel ring packages are.

Looking forward to what you have in the garage Biggy.
 
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One of the down sides to a keystone ring in a performance diesel application, is that when you increase piston to wall clearance, the ring to land clearance increases because of the ring taper.

Paul
 
mu2a3avy.jpg



And Paul is correct. But what is the trade-off to not using the design?
From my Not-So-Smart phone
 
I would say the keystone is only built to low rpm. You not only have what Paul says, but you have tapered sides with a point which can act as a pivot point if the wall (our bearing suface) becomes disrupting and effecting out stability.

Here is Goodson Engine's listings for stones
http://www.goodson.com/Goodson_Honing_Stones
 
Are there any blocks, Cummins, Powerstroke or Duramax that have higher nickel in them? In the sense of the SBCs that had a rating of 020 over the 010 castings?
 
justthinking

Honing an sleeve/block is more complicated and important than most of us realize. Size and true are as important as the hone technique. Heat created during the honing process must be accounted for. Super important! Hone finishes are determined by type of material of sleeve/block and type of ring package used. The Abbott/Firestone curve shows the load bearing extent of the cylinder finish. Ra (one value used for surface finish) does not tell the whole story. Rings have a tough environment to survive in. For a insight into what all happens read the Honing document.
qualityperformancecams.com
look under the Cam Science & Technology page
 
Thank you for the website.

From whats been covered thus far, would you happen to have anything to add in addition to your suggestion to read?
 
Keystone rings work well only when used in the designed size / clearance intended. Extra bore clearance changes the ring side taper to piston ring land clearance. To much ring movement to seal on the ring land equals more blowby and delays the ring seal to the oil film on the cylinder wall. Delayed ring seal means more loss of compression. Boosted engines respond well to extra top ring gap clearance to allow for ring expansion. Second ring end gap then becomes very important. The lowest tension ring possible that seals the bore (round and true) will provide the best result. Round and true bore will dictate how low of tension the ring can still seal with. Ring flutter control will decide effectiveness.
 
Top, intermediate and oil ring from a Cat 3406e 2WS ~1 million miles.



From my Not-So-Smart phone
 

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I am sure when you see gap increases, the increase shouldn't be too large because we must keep "seated" so I guess trial and error here is absolute. I wonder if anyone has ran gas-ports on a full-on race mill here?
 
Has anyone here seen a end gap too large that busted the ring lands on these? Have you seen any busted ring-lands Matty on those fleet engines you maintain? What about you Biggy?
 
Jumping back to Paul's post on piston to wall clearance, are you speaking of the less expanding cast pistons? Forged units expand quite a bit more than the cast units.
 
Only time I see broken ring lands is when some idiot uses starting fluid and has no clue........
 
Starting fluid and other overpressure situations. Mis-installation.

Nothing even a performance engine should encounter.

It might be worth mentioning that even aluminum crowns typically have "steel" ring land inserts.

From my Not-So-Smart phone
 
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