Piston Ring Gap [Merged 5-7] gapping rings pistons end filing

[ITSME4G63]

What I posted is what I did on mine, and the car has compression up the ass, doesnt burn oil for shit either.

 

[diambo4life]

Are you doing a rebuild WITHOUT the FSM?

Correct orientation is shown in the manual.

 

[92awddsm]

To be perfectly honest, the orientation doesnt really make a difference at all. The rings actually rotate in the bore so orientation changes after just one stroke.

 

[brianstalder]

Hi, I am currently rebuilding my motor. The bore is within spec of the factory, it is not over bored. I am using OEM standard size piston rings. Do i still need to measure piston ring gap even though everything is OEM and within spec? If I do, do I just put the ring on and measure it with a vernier caliper while the piston is out of the motor? Im confused on how to do this. Ive done alot of searching but im still not confident of how to do this or if i need to. Id really appreciate the help. Thanks, Brian

 

[toybreaker]

The quick and easy, (and accurate enough way) to check at home is to put the bare ring in the bore and measure the gap with a feeler gauge.

I like to use a piston to get the ring square to the bore.

Just clean the bore well.

Insert a compression ring in the bore, right side up.

Take a (clean) piston, and turn it upside down, and push the ring down the bore ~ 1 inch~ ish.

Now, you can measure the visible gap with a feeler gauge, and compare it to specs.

The main thing is to not be too tight, as the ring ends will butt up against each other, and scuff the bore.

One thing I always like to do is to shine a strong light from the bottom of the bore and eyeball the ring/cylinder wall contact. If you can see light along the thrust axis, the motor's got some roundness issues.

Good luck, and I hope things turn out well for you. The first couple of motors are kind of nerve-racking, you'll be fine.

 

[GVR4592]

The main thing is to not be too tight, as the ring ends will butt up against each other, and scuff the bore.

That's correct. If they're too tight they can also butt together and break the ring lands right off the pistons if detonation occurs.

Running them loose has another benefit, with a very small amount of leakage, the combustion gasses will help evacuate any oil that's been trapped by the rings. The goal is to help prevent oil from entering the combustion chamber, oil in the combustion chamber is like anti-octane, it can significantly lower the knock threshold of the engine.

 

[brianstalder]

What would you reccomend gapping them at for the looser fit?

Thanks alot to both of you, you were a huge help. My car has been apart for about 2-3 months now and im tired of driving the back up car .

 

[Gst18]

I bought a set of used .020 over ross pistons.
I looked and looked around and i dont know what to set the ring end gap for the top and 2nd ring.
I know that with more heat your supposed to leave a bigger gap.


Under the instructions it says to set it to manf. specs.


If anyone can help me out.
Thanks

 

[bfdahl]

I would call Ross direct @ 310-536-0100 and get the specs direct from them.

I will look for my sheet and PM you if i can find it.

the funny thing I remember about my set up was the the 2nd ring has a slighly wider gap than the top ring, the reasoning was that if the 2nd rings gap wasnt large enough the top ring could "flutter" and cause a loss of sealing capability.

I did what they said and it runs very well.

 

[Gst18]

anyone know what ross recommends?
Btw i plan to run a gt35 in the future for this at around 500 wheel.

 

[brute]

If I remember correctly, I did my TopLines at 0.0021.

 

[Elvenhome21]

Normally all rings except gapless are set with .003-.004 per inch of diameter of gap

 

[GVR4592]

anyone know what ross recommends?
Btw i plan to run a gt35 in the future for this at around 500 wheel.

Call them

 

[boosting_laser]

Hi guys & gals. I just received some info from an ITM tech, through a well known vendor I thought some of you might be interested in or have encountered yourselves.

The story:
I'm re-building my 6-bolt w/ the original pistons & ITM rings. When it came time to file fit the rings both "top" & "oil" rings where within spec. My concern is the "2nd" ring gaps measured @ .026" - .027" right out of the box.

Answer I received:
According to the tech guy @ ITM & I quote, "....the spec on the second ring has been opened up on purpose by the manufacturer to comply with the JIS standards for these engines. These are steel rings (as opposed to cast iron) and they intentionally want more gap on the second ring to allow for more oil return capability."

My question:
Have any of you heard or know of such "JIS Standards" or purchased rings with end gaps on the larger size right out of the box?

Thanks in advance

 

[420Adriver]

No but if that is the gap you should have no need for gapping it any further. I gapped my top ring at .020 and second at .024. I had no need to gap my oil ring rails because they were already gapped to the appropriate size of .015.

 

[boosting_laser]

No but if that is the gap you should have no need for gapping it any further.

I know, my question is directed towards having a gap on the larger end of the scale as opposed to the smaller end, right out of the box. Also, if anyone here ever heard of piston rings revised to comply with JIS standards. Thanks for your input, though .

On another note I did find this, but you need to purchase to download

JIS Standards

 

[alexg1323]

i built my last 6 bolt non turbo 2.0 using a topline rebuild kit that came with ITM rings in it. They were the same way your described. They were a drop in piston ring yet the gap on the 1st and 2nd ring were excessive. Not to the service limit but not within spec and not what i want to put in a fresh rebuild. I called up the wholesaler and they agreed to send me another brand. They then sent me perfect circle pistons rings, much nicer quality. I recommend calling the distributor you bought those from and asking for a replacement that is OE quality like they claim

 

[boosting_laser]

So I'm not the only one! I wasn't too convinced on the reason why the gaps where "opened up" from the factory. Like you mentioned I did end up e-mailing my supplier regarding sending me another brand set of rings. When I receive another set I'll post the results.........as if anyone cares

 

[Cesar]

I am installing manley pistons with manley rings.
.020" over.

I have placed the rings in the cylinder and squared it with the piston top.


I called manley, they reccomnended .015 for the top ring, even though I already have .025 on most cylinders and .024 on one. maybe machinest went over the .004" that was recommended. the bottom ring is .022, but the reccomend .012.

I intend on running about 20psi at most (maybe more, hehe...) maybe NOS.

Anyway, what do you guys think?

 

[boosting_laser]

Can you clear up a couple things first:

*Where the rings opened up to those specs or is that what they measured untouched?

*When you say the machinist went over .004", I take it you mean when boring the cylinders?

Just wanted to help make things clearer for others, thanks.

 

[Cesar]

the rings came like that, I didn't touch them.

Yes the machinist went .020 over and the clearnaces are suppose to be set to .004

 

[boosting_laser]

It seems that either the wrong rings where sent or the bores are too big. I'd talk to your machinist & maybe have him re-measure the bores & pistons again.

 

[damnslowtsi]

It is a good idea to order an oversized set of rings when building a motor. In your case it would be +.040 or .030 if that size is available. That way you have enough meat to work with and can set the gaps exactly where you want them. I 've heard many times, particularly about Wiseco combos (that's probably because it is the most used piston/ring combo it looks) that rings are a bit undersized. I 'd call Manley and ask if they would exchange them. If they refuse I 'd buy a different (+ size) set. Rings are cheap anyway. The gap you have is too big for a top ring. Bottoms could be left alone if they are at .022.

 

[damnslowtsi]

I very much do

What do you exactly mean by "opened up"? The fact that the gap is bigger on the second ring? If so, then it seems to be a thing of the norm today. In most contemporary designs the second ring is not a compression ring but an oil scraper. The gap in it is left bigger on purpose to bleed off any gasses that were able to make it past the first ring and to reduce the inter-ring pressure. That way the top ring is able to do its job better. It is probably safe to say that most DSM rebuilts these day have the second ring at .022-.024 so I wouldn't sweat much over yours provided your tops are in check.

 

[boosting_laser]

I very much do

Then I'll continue

What do you exactly mean by "opened up"? The fact that the gap is bigger on the second ring?

"Opened up" as in they where purposely design w/ larger gaps, than what the factory specs called for.

If so, then it seems to be a thing of the norm today. In most contemporary designs the second ring is not a compression ring but an oil scraper. The gap in it is left bigger on purpose to bleed off any gasses that were able to make it past the first ring and to reduce the inter-ring pressure. That way the top ring is able to do its job better.

You know now that you mention it I do remember reading that somewhere, but can't recall where.

It is probably safe to say that most DSM rebuilts these day have the second ring at .022-.024 so I wouldn't sweat much over yours provided your tops are in check.

.022"-.024" I wouldn't mind, but .026"-.027" seems excesive. I ended up ordering a set of HASTINGS & will compare these to the ITM's this weekend. Monday I'll post results