Piston rings,oil pump question?

[ramcharger]

68 Hemi GTS is a good and knowlegeble man and we hashed it out via PMs. It's all good my friend and I was bit "Hostile" due to my dam tooth. It really did hurt like hell. I publicly apologize for my hostility and I hope you accept my apology.... It's my fault and I accept responsibility. Same to you C130. I was in pain and it's no ones fault but mine. Please accept my apology as well and feel free to kick my *** for being an ahole.

Moper,

You @#$%$#$%^^! LOL, just kidding my friend! This place is great for sharing knowledge and I most certainly DO NOT KNOW IT ALL! lol. I can only share what I've learned over the years.

I also believe (but can't prove) that plasma coated moly rings were introduced for emission reasons due to the higher combustion temperatures needed at lean cruise and idle rpms to get the desired reduction of emissions rather than ease of break in. I dont think that a cast iron ring can survive under these new "lean" fuel injection conditions. I also think that factory cast pistons of 1990 and older had a larger tolerance in the ring grooves alowing more "ring flutter" and consequently more bore wear.

I'm still thinking about your deaccelerate theory in regards to negative cyl pressure and pulling in oil to lube the rings...... Neat idea and I never thought about it before......

We all know that hone angle is very important to ring seal/wear/break in. The steeper the angle, the less oil to lube the rings, the narower the angle, ring seating and oil consumption can become a problem.

Thoughts??

 

[dgc333]

Prove it. I'm being nice. When did Chrysler start using plasma moly rings on any cast iron block?????

Well my 85 Daytona 2.2 Turbo motor had moly coated rings (don't know if they used a plasma coating process or not), a high nickel content iron block and hypereutetic pistons. This all added up to 240,000 miles on the motor before my kid wrapped the car around a tree. I pulled the head on 89 Shelby Daytona to replace the head gasket with 176,000 miles on it and there was no ridge and you could still see remanants of the factory honing marks. Its all of these things that contribute to the longevity of modern engines.

There are two moly coating process the less expensive process that just puts a coat on the surface of the ring and the plasma moly process where there is a groove in the face of the ring that the moly is applied using as you might of guessed a plasma spraying process.

Moly or more correctly molybdenum disulfide is a dry lubricant similar to graphite. The material it self is hard but it has very low coeficient of friction and is why its used as a lubricant in grease, oil and on piston rings. Yes, over time it will wear off but but with the plasma coating process it will be there for the life of the piston.

As far as ring prices go Sealed Power plain iron rings in 4.030 size are $17.95, plain moly coated are $37.95 and plasma moly are $64.95 at Summit Racing. Can't see the economy in paying several hundred dollars for an over bore, couple hundred for a set of quality KB pistons and cheap out on the rings to save less than $50. Buy a set of quality moly rings.

 

[Longgone]

I agree with spending a little more to get a good quality ring set. Save money somewhere else on the engine.

 

[ramcharger]

Well my 85 Daytona 2.2 Turbo motor had moly coated rings (don't know if they used a plasma coating process or not), a high nickel content iron block and hypereutetic pistons.

Yes the mopar turbo motors used moly rings and a high nickel iron block. Not on a cast iron v8 as far as I know. :wave:

 

[moper]

My thoughts were the Magnum V8s started the use of molys... with hypereutectic pistons, in 1992. Ram, the angle of the hone is important, but not as much as you think. If you search around, look up laser honing and you'll see what I mean. The hone process uses a harsh abrasive to "cut" away the material. If you have ever run a cotton rag thru a rough honed bore, it shreads lint off the rag because it doesnt cut really, it tears away metal. That leaves very sharp and "high" points on each side of the hone mark. (think of a dish of pudding and run your finger thru it lightly.. the edges of the mark will have "high spots" like mountains wiht a valley between them. That's what a single hone trace looks like under a microscope. It's hard, or next to impossible to seal the valley, if the tops of the mountains are left intact. Oil fills the "low spots" and helps seal the cylinder in these cases. Which is why (1) older cars smoked a little before the rings seated, and after the bores get scored in use); (2) the process of wearing in the rings came into play by using light throttle load to seat the rings-it pushes them against the walls, and against the ring lands, so they can seat well; (3) chrome faced rings were invented-They are hard enough to remove the tops off the ridges of the honing, but not wear themselves. These last two were tricks to get the peaks of the ridges, and the valleys shallower so less oil gets used. Plateau honing does that same job, so the rings and bores last much longer with less oil use and combustion contamination. BTW Ram... You're older than I am...

 

[godfatherofchry]

holly hell you gys are killing me all the man whats to no is the best and chepest way to go!! good gref lets help him and then get tec.( to get back to the piont) tell your parts man you you want to rebuld your motor and not spend a lot of money iv done chep for around 400 bucks doing work my self .do you need anew pump take it apart check it clean put new spring in it good to go another 10000 mil. call ohio crank shaft co. tell the man what your doing and he will fix you right up ..and will run good .NOW if your talking about a go fast race motor then your talking about a differt horse.go fast isnt chep iv got a 360 with pucket ported heads that runs 13.00s drive evry day and rebilt it for 485.00$ 3yr.and still running good ..it all depens on what your going to do with it.