The definative re-ring poll...

[Ravenous]

This is a question I see come up all the time and am really curious about how many people have had good luck with a re-ring. I am getting ready to change the headgasket and was thinking about changing the bearings and rings at the same time... just to buy some time mind you.

I know this isn't the "ideal" way to do it so please do not post if you are just going to recommend boring and honing and did not try re-ringing the motor first. That isn't constructive to the validity of re-ringing the motor unless you did re-ring and had the motor fail.

If you have changed the rings in your motor please post what the results were before and after if possible (i.e. compression, longevity, problems, type of rings, so on and so forth). What I am really looking for is a resource for future searches so that people can come to one place and see how much of the demographic have had luck with honing, not honing, type of hone, grit of hone, gapless, gapped rings, how you broke them in...any and all info you can supply would be truly beneficial.

 

[groundPork]

Always do leak down test prior to dissassembly regardless of what you know or think you know happened to the engine... Always (exception... there is a hole in the block or the piston). It can often give you very important initial info regarding how and why the engine's not sealing. Always measure bore distortion prior to honing or ringing... they may be within acceptable tolerance that powered honing need not be done and perhaps a few passes with a ball hone may actually suffice. Then again, maybe they are distorted or worn enough to just need a light powered hone job. When using hard faced rings such as chromed, nitrited, and tool steels, always start with a freshly honed surface on run cylinders to ensure the ring is able to wear in the cylinder and conform to it's shape. Ductile moly rings are great all around, and can run in engines producing quite a bit of horsepower. They are not with out limitations however. Moly rings can be annealed and distorted much easier than most steel rings. They are basically ductile iron rings with Molybdenum welded into the faces of the rings which are then barrel lapped. They are most forgiving in less than perfect bores and seal quickly and easily, and are some of the least likely ring types to wear hard on soft iron bores. They are often not my first choice for a 4 cylinder that'll see 25+ Psi. or nitrous mostly because if detonate badly, you might knock the moly out of the face of the ring, which'll then be drug up and down the cylinder. I have my own particular preferences for bore finishes when it comes to building engines, but I always insist on anyone contacting the RING manufaturer for those direction, as they know way more about rings than even the piston manufaturers usually do. I have done installed all types of rings in many different bores, I rarely have seating problems that are actually the result of a defective ring. It's usally something I did wrong, or the customer did wrong. I say if the hole is straight, round, can carry only what oil it needs to proect the parts and seal, and has the correct included angle in crosshatch then it ought to seal just fine.

Great info to help better understand just how rings really do their jobs, and which ones do what.

http://www.riken.co.jp/e/piston/c/c.html

http://www.hastingsmfg.com/service_tips.htm

http://www.totalseal.com/howdoo.html

Theres so much to write on but fingers are getting cramps... Hopes this helps and doesn't just cause more questions...

 

[Ravenous]

That is the kind of info that I am looking for in this thread. Very informative and of course there is always more questions but that filled in a lot of the gaps. Thanks so much for a quality post.

 

[timloomis]

theres nothing wrong with re-ringing the engine.just dont do the idiot thing and reuse the rings after honing.you should always hone the block to,so the rings will set in,or youll just burn oil all the time.your basically doing a rebuild with what youve said though,minus all new gaskets.itll be fine.

 

[92awddsm]

My opinion(which has been debated here) is to always hone the block when doing a re-ring job. There is no real reason to do the lob only half way to later find out that it was a mistake. If you pull the engine down that far, it is a minimuch charge to have the block honed at the same time.

And as far as the rings are concerned, here is a breif rundown. For everyday purchase, there are only 3 ring varieties.
1) Chromoly rings/chrome faced rings- good for severe duty/dirty conditions. They last longer in dirty/dusty conditions but tend to take a long time to seat. They have a low tolerence to heat and tend to lose tension in high heat applications.

2)moly/molybendium rings- Less tolerent to dirt/contamination. Good heat distribution properties. Long lasting and stock in a 4g63t engine. Less time to seat than a full chrome ring. Less likely to break over the chrome or cast ring when subjected to extreme heat or detonation.


3)cast rings- No tolerence to dirt/dust. Wear quickest of all rings. Wear the cylider walls more than all other rings when used in a cast iron block. Very suseptable to damage/breaking in high heat/high pressure applications. Worst ring to use in a boosted application.

 

[Ravenous]

Great info, keep it comming. For every "For every my motor blows blues smoke" thread this is always the first diagnosis, this will help a lot of people...

 

[groundPork]

When begining with a harder metal, with better ductility, elongation, and overall toughness (mostly hardness) you'll end up with a ring less likely to be annealed by extreme heat of runnning lean. Also they are less likely to be anneled (softened... or lose hardness) in situations where high heat (big shots of nitrous or 30 + psi boost, and lean running) is being seen by the ring. If the ring softens it'll lose tension (can't seal the bore to draw in intake, can't control any oil at all... may allow oil in to cause detonation and as a result damage something). Also if you want to take it so far, they'll have a tendancy to flutter at high rpm, which will subsequintly damage ring grooves and lands ( far worse than a damaged ring alone, you';ll have to replace pistons). Cast materials of any kind while they can be hardened are almost never as strong overall as a steel counterpart. THERE IS NO SUCH THING AS CHROMOLY PISTON RINGS PERIOD. There are chromed steel, chromed ductile iorn, chromed stainless steel, stainless steel, ductile iron, hardened ductile iron, tool steel, gas nitrited steel, ductile (or plasma) moly, cast, and nodular iron rings. Chromium nitride (see chromed rings) is the coating often applied these days to the faces (only) of modern piston compression rings. It is applied to withstand wear, heat, and provide a very hard, non galling bearing surface to slide against the cylinder wall (thiink of those little plastic slider pads some people put under the feet of there heavy furnature). Yes they work so mcuh better in dirty environments than cast or Moly rings due to the fact that silt and sand can't embed itself in the face and scoure the cylinders.

Also ring side wear is much higher where cylinder pressure and heat are high. if the ring is becomming to soft on the surface to resist loosing material, then it will gradually not be able to seal gasses on it's side in states of vaccuum or pressure other than mid to peak loading, reducing efficiency at part throttle low load. Again, steel is a superior wear and heat resistant compared to most cast, ductile, or nodular irons. Yes, moly rings have shown over time to be one of the greatest ring material combos for so many applications, but cylinder finishing is approaching a point in many racing and OEM situations where the technology of the equipment used and skill and knowledge of the machinists are apt to compensate for the less than forgiving nature of hard rings which do break in very different from softer rings. And often they won't necessarilly take much longer if the propper bore finifshing is performed. I don't really recommend using cast rings in anything these days as they quickly soften, lose tension, lose material quickly, and crack easily under detonation or hard launches in heavy cars. Ever seen a motor that detoanted badly?.. top ring worn badly sometimes bent, top ring land lifted up and eroded, second land bent down pinching the second ring, and usually cracking it from the transfered force of the pressure spike... oil ring usually gets pinched too, sometimes smashed.

Now, all that being said, for us and the 4G6 bore sizes and typical compression heights we are fortunate to have many different materials, designs, coatings, and pricing available to choose from in piston rings themselves.. it's a job all it's own if anyone were crazy enough to tacle it. That doesn't mean if you step .005" to .020" outside that bore range, you'll still have viable options in regards to rings... Leave that to the experts, and ask lots of questions with out assumption to learn as much as possible, and let them know you're aware of such things. Given my druthers, if I knew the motor would never likely see regular duty at 25+ psi boost, I would use the moly rings, and research the best tuner I could. But, if youre not sure overbuild, take the time to research whos doing really good block work, don't settle for cheap machine shop price over quality and common sense.

Ok last thing before My fingers fall off ... I know this isn't a common thing with DSMer's but, this kick with ultra thin rings comming from overseas... While i think it's great for those who can make it work... concider all i've said before... the machinest's work, the tuners skill, and the break in will make or break any setup... thinner rings are not a super performance advantage in themselves, nor a fix it for rings not sealing or going bad. infact thinner the ring, the less likely it is to tranfer it's heat away from itslef to maintain a sort of stability in its metal properties. They're good... they're not alsways the answer though.

 

[Ravenous]

Since you have the expertise and understanding of how rings work, the difference in materials, and wear characteristics; What can you tell us about gapless rings? The benefits of a gapless top ring instead of second ring? In a re-ring with a proper hone, would a gapless ring be more tolerant in a slightly worn standard bore?

 

[groundPork]

Keep in mind that gapless rings are still made and offered in pretty much the same material as convensional gapped type rings. So you are still subject to the same characteristics of those material properties. That being said... I have used gapless rings before. They are usually comprised of a parent ring (stainless, chrome stainless, ductile moly... etc.) and a chromed steel rail (looks like a very thin oil ring scaper rail). Common sence at first would suggest that gapless rings could cope with distorted bore surfaces because the seperate pieces of the rings acted like independant suspension running over un even terrain (I know... exagerated, but bare with me)... also the absence of open end gaps as the overlapping keeps them covered... and because of their design they tend to have significatly higher radial tension that their conventional counterparts.

In the end, though, there is no end all beat all fix for bad machine work, a distorted bore, or bad tune up. Again, if the bore is straight and round, I would still cross hatch it to help the break in.

I know when installed correctly gaplesss rings are capable of giving less than 2% leakage dry, under only 30 psi of pressure (that's really good, and they'll do that pretty much for the life of most high performance engines). I have seen em used in 63's making 900 hp to the wheels, but I have my reservations about them at that kind of heat and cylinder pressure, and they're very expensive.

My advice if your going to use them. Check everything before assembly always... if you can help it get them for the top ring groove only (for big boost, high RPM). And Leakdown prior to break in, after, and after some mileage.

Treat them like conventional rings in that simply swapping in different parts is not the way to solve sealing issues... You won't learn anything that way, and You may end up spending lots of money you really don't need to.

 

[Ravenous]

Well that certainly addressed my concerns. I appreciate all the extra time you are spending in this thread. It is truly beneficial to me and I am certain it will be very beneficial to many other as well.
Thanks again,
Chris