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Oem 1g Piston Ring Gap?

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STD size pistons dont need to be gapped because the rings are already pre-gapped

From what I am reading always it is always still good to check. I have new Topline Std Piston Rings and my compression is 120 I didnt gap them because someone told me the same thing you just did now im back at stage 1.
The Pistons Rings were set 120* apart however. Now that I took the piston back out after running engine. On one piston the rings are now about inch apart and on another piston the rings are about 1 1/2 apart!?New Head gasket and coolant and oil did not mid. My motor is now apart again I want to know the correct Std Piston Ring Gaps?
 
STD size pistons dont need to be gapped because the rings are already pre-gapped

Granted it's been a while since I've done a stock rebuild, I've always had to cut OEM piston rings. Sometimes I get lucky and don't have to cut much if any at all but more times then not, I cut them. Factory numbers are in the FSM or even a Haynes manual.
 
Granted it's been a while since I've done a stock rebuild, I've always had to cut OEM piston rings. Sometimes I get lucky and don't have to cut much if any at all but more times then not, I cut them. Factory numbers are in the FSM or even a Haynes manual.

From what I can see the rings are so close together it looks like it is barely a gap. Ima check it with the feeler gauge I just got and post back the numbers.
 
From what I am reading always it is always still good to check....

Thats true, good technique ;)

From the Mitsu Service Guide
Install the piston ring into the cylinder bore. Force it down
with a piston, its crown being in contact with the ring, to
correctly position it at right angles to the cylinder wall.
Then, measure the end gap with a feeler gauge.
If the ring gap is excessive, replace the piston ring.

Standard value:

No. 1 0.25-0.40 mm (.0098-.0157 in.)
No.2 0.20-0.35 mm (.0079-.0138 in.)
Oil 0.20-0.70 mm (.0079-.0276 in.)

Limit:
No. 1, No.2 0.8 mm (.031 in.)
Oil 1.0 mm (.039 in.)
 
Thats true, good technique ;)

From the Mitsu Service Guide
Install the piston ring into the cylinder bore. Force it down
with a piston, its crown being in contact with the ring, to
correctly position it at right angles to the cylinder wall.
Then, measure the end gap with a feeler gauge.
If the ring gap is excessive, replace the piston ring.

Standard value:

No. 1 0.25-0.40 mm (.0098-.0157 in.)
No.2 0.20-0.35 mm (.0079-.0138 in.)
Oil 0.20-0.70 mm (.0079-.0276 in.)

Limit:
No. 1, No.2 0.8 mm (.031 in.)
Oil 1.0 mm (.039 in.)
THANKS Alot and that for 6 bolt correct?

Okay first I think I did the Biggest newb mistake the second ring on all 4 pistons the word 1.5 Std was under the ring instead of facing upwards could that be one of the biggest issues? I checked the gap 1st ring was over 0.25 which is the last one on my feeler gauge and the 2nd ring was 0.16???? !!!

I see people who have .02 Over bore are gapping 1st ring around .20 and 2nd bigger around 0.22 . So how is it that mine 1st ring gap is way larger than 2nd ring gap
 
Standard value:

No. 1 0.25-0.40 mm (.0098-.0157 in.)
No.2 0.20-0.35 mm (.0079-.0138 in.)
Oil 0.20-0.70 mm (.0079-.0276 in.)

Limit:
No. 1, No.2 0.8 mm (.031 in.)
Oil 1.0 mm (.039 in.)

your still in limit, even that your using STD sizes the block has wear, and pluse hone..
for every .001 you open the bore you will gain Pi (3.141)

you said you have appox .025 on #1 Ring and .016 on the #2 ring
you are still within the limit specs so your fine..

we will guess that you have had the bore honed and it had a wear valve of .004
so with .004 x 3.141=.012564 add to your stock ring gap

so if you had the max new ring gap of .0157 + .01256 = .0282 ring gap now

with a turbo engine, it will not hurt to run a wider ring gap, yes you may smoke a lil, but if you run lean, it will keep the rings from butting and braking the ring lands
 
your still in limit, even that your using STD sizes the block has wear, and pluse hone..
for every .001 you open the bore you will gain Pi (3.141)

you said you have appox .025 on #1 Ring and .016 on the #2 ring
you are still within the limit specs so your fine..

we will guess that you have had the bore honed and it had a wear valve of .004
so with .004 x 3.141=.012564 add to your stock ring gap

so if you had the max new ring gap of .0157 + .01256 = .0282 ring gap now

with a turbo engine, it will not hurt to run a wider ring gap, yes you may smoke a lil, but if you run lean, it will keep the rings from butting and braking the ring lands

I didnt have it honed but I am now going to get that done so I dont know if you can use wear value. The 1st ring is over 0.25 1/4 in bore 1/2 way down turns to 0.25. The second ring is 0.16 1/4 way in cylinder 1/2 down its 0.02. Would that have to do with not honing? Is the 1st ring gap suppose to be smaller than the 2nd??

Also on the second ring it doesnt look like the OEM one. I think I put it upside down the words are underneath and has a inner little lip than a wider outter lip on ring but its facing up if I flip the rings the lip will be facing down and words up.
 
most of the wear will be in the first inch of the bore, that is where the rings push out the most on the power stroke.

the gap readings you are getting just show how the bore is tapered...
get the block mic'ed...and see what the real bore dia is... you may have to have the block bored and go with new rings and pistons.

normally #1 ring has the larger gap..
are you sure the ring gap on #2 is .020 and not .002 sort of hard to have the #2 gap get larger in the bore further down .. where #1 gets smaller further down
 
most of the wear will be in the first inch of the bore, that is where the rings push out the most on the power stroke.

the gap readings you are getting just show how the bore is tapered...
get the block mic'ed...and see what the real bore dia is... you may have to have the block bored and go with new rings and pistons.

normally #1 ring has the larger gap..
are you sure the ring gap on #2 is .020 and not .002 sort of hard to have the #2 gap get larger in the bore further down .. where #1 gets smaller further down

Yes the #2 is .002 the #1 is now 18 when I push is lower in the clyinder. So is that correct #1 having a larger gap? I thought the 2nd ring was always suppose to have a bigger gap then the 1st. What should I do from here take block to get checked and see what it needs pretty much? But what I want to know are my rings around correct spec. EVERY SINGLE thread I check the 2nd gap is always larger the 1st /Top Piston Ring. In my case im getting opposite!?
 
The 2nd ring gap being bigger is for ring flutter. I've got .020 and .022 and it doesn't smoke or burn oil at all.
Some blowby at idle but nothing out of the usual.
 
look at the chart DSM-pwr posted... in the first set of values, the #2 ring dose have the smaller ring gap....


No. 1 0.25-0.40 mm (.0098-.0157 in.)
No.2 0.20-0.35 mm (.0079-.0138 in.)
Oil 0.20-0.70 mm (.0079-.0276 in.)

if you get .002 anywhere in the bore .. that is way to tight and you will start braking ring lands..
find where you get the smallest gap, bottom of the bore.. and use that spot to gap your rings
or have the block bored to get the taper out of the cylinder

if you gap at the bottom of the bore, use the gap.. #1 Ring .010 and the #2 ring .008 and yes they will be wide gapped at the top of the block
 
look at the chart DSM-pwr posted... in the first set of values, the #2 ring dose have the smaller ring gap....


No. 1 0.25-0.40 mm (.0098-.0157 in.)
No.2 0.20-0.35 mm (.0079-.0138 in.)
Oil 0.20-0.70 mm (.0079-.0276 in.)

if you get .002 anywhere in the bore .. that is way to tight and you will start braking ring lands..
find where you get the smallest gap, bottom of the bore.. and use that spot to gap your rings
or have the block bored to get the taper out of the cylinder

if you gap at the bottom of the bore, use the gap.. #1 Ring .010 and the #2 ring .008 and yes they will be wide gapped at the top of the block

Thanks for all your help im going to just take it to machine shop and take it from there because your telling me complete opposite from what EVERYONE else post.. You can check every single thread and they all say there 2nd ring gap is larger and your tell me to have to the 1st gap larger. Even this guy just said 1st gap smaller
The 2nd ring gap being bigger is for ring flutter. I've got .020 and .022 and it doesn't smoke or burn oil at all.
Some blowby at idle but nothing out of the usual.
And you having a thunderbird as your main pic scares me..J.k But ya
 
what dose tha paper work that came with the rings say?

having the 2nd ring gap larger is not going to hurt...

I think your not getting what I have said.... if you look at the specs... they DSM factory manual even has the #1 ring gap bigger than the 2nd ring....

why the guys here have the 2nd ring gap larger is some DSM magic ....
but hit the websites up of perfect circle, Total seal, hastings.. ANY ring maker.. and read what they say.. I think they should know what they are talking about since they MAKE them

Oh... I drive a Thunderbird Turbo Coupe..... they dont break down as much as a DSM!! LOL almost...
 
I to bring back a thread from the dead. But I just went to gap std rings in and the first ring were all .016 and the second ring were .025. I know that is in spec but is that going to make it loose compression or smoke?...are the gaps different for a 7 bolt?
 
For anyone else coming over this thread the second ring gap is always larger than the first. The specs posted do not seem to be correct. Here's a pdf by Weisco saying the second should always be larger http://www.wiseco.com/PDFs/Manuals/RingEndGap.pdf
Also for both 1991 gsx and 1997 gsx according to mitchell on demand service manual the second ring gap is always larger. I will post actual specs for anyone to use.

1991 gsx ring gap specs

1991 Mitsubishi Eclipse 2.0L Eng GSX
Service Manual: 2.0L DOHC 4-CYL - VINS [R,U]

Print Date: 11/5/2016
ENGINE SPECIFICATIONS > PISTONS, PINS & RINGS SPECIFICATIONS
(1)
Rings
No. 1
End Gap
Standard .0098-.0177 (.249-.449)
Wear Limit .031 (.79)
Side Clearance
Standard .0012-.0028 (.030-.071)
Wear Limit .004 (.10)
No. 2
End Gap
Standard .0138-.0197 (.351-.500)
Wear Limit .031 (.79)
Side Clearance
Standard .0012-.0028 (.030-.071)
Wear Limit .004 (.10)
No. 3 (Oil)
End Gap
Standard .0079-.0276 (.201-.701)
Wear Limit .039 (.99)
(1) Press fit with load of 1653-3858 lbs. (750-1750 kg).

1997 Eclipse gsx ring gap specs


1997 Eagle Talon 2.0L Eng TSi
Service Manual: 2.0L TURBO - ENGINE CODE 4G63 - VIN [F]

Print Date: 11/5/2016
ENGINE SPECIFICATIONS
PISTONS, PINS & RINGS SPECIFICATIONS

Application In. (mm)
Pistons
Clearance .0012-.0020 (.030-.050)
Diameter 3.334 (84.98)
Pins
Diameter .87 (22)
Piston Fit (1)
Rod Fit (2)
Rings
No. 1
End Gap
Standard .0098-.0138 (.250-.350)
Wear Limit .031 (.80)
Side Clearance
Standard .0016-.0031 (.040-.080)
Wear Limit .004 (.10)
No. 2
End Gap
Standard .0157-.0217 (.400-.550)
Wear Limit .031 (.80)
Side Clearance
Standard .0008-.0028 (.020-.060)
Wear Limit .004 (.10)
No. 3 (Oil)
End Gap
Standard .0039-.0157 (.100-.400)
Wear Limit .031 (.080)
(1) Resistance to thumb pressure.
(2) Press fit with load of 1653-3858 lbs. (750-1750 kg).
 
The second ring is not always larger. I have been using larger ring gaps on the first rings literally for years. I had a very long conversation with Nick Arias about this over the phone. He gave me a game plan and asked me to stick to it and for over 10 years it has not let me down even using the opposite train of thought on 800-1000hp 4g63's. Combustion stays where it is suppose to and we do not have blow by where and when we don't want it.
 
I've never heard of MitchellOnDemand but I don't trust any numbers (for a OE rebuild) unless they come from the Mitsubishi Factory Service Manual (FSM).


From the actual '97-99 MITSUBISHI FSM...

Standard value:
No.1 ring 0.25-0.35 mm (.0098-.0138 in)
No.2
ring 0.40-0.55 mm (.0157-.0217 in)
Oil ring 0.10-0.40 mm (.0039-.0157 in)
Limit:
No.1, No.2 ring 0.8 mm (.031 in)
Oil ring 1.0 mm (.039 in)
Not arguing with you biglady, just posting the actual OE SPEC numbers in here from the FSM. Piston ring clearances should be in the SPEC of the piston manufacturer or whatever the engine builder recommends outside of OE.
 
I did not read the whole thread, so if this thread pertained to factory pistons it could be done a different way. I was referring to aftermarket forged aluminum pistons and rings.
 
I've never heard of MitchellOnDemand but I don't trust any numbers (for a OE rebuild) unless they come from the Mitsubishi Factory Service Manual (FSM).


From the actual '97-99 MITSUBISHI FSM...

Standard value:
No.1 ring 0.25-0.35 mm (.0098-.0138 in)
No.2
ring 0.40-0.55 mm (.0157-.0217 in)
Oil ring 0.10-0.40 mm (.0039-.0157 in)
Limit:
No.1, No.2 ring 0.8 mm (.031 in)
Oil ring 1.0 mm (.039 in)
Not arguing with you biglady, just posting the actual OE SPEC numbers in here from the FSM. Piston ring clearances should be in the SPEC of the piston manufacturer or whatever the engine builder recommends outside of OE.
MitchellOnDemand is an info site that shops pay for, like AllData. Alldata is an autozone company and MitchellOnDemand is own and operated by SnapOn. It supplies shops and DIY(separate site i think for DIY) with factory service, maintenance, and repair information, guides, specs, and procedures. Any specifications on site are pulled straight from factory service manuals
I only flagged to clear up the post on the OE ring gap specs as they were incorrect. I only flag to bring attention to something that could be wrong and potentially lead a lesser knowledged to do something the wrong way.
 
The second ring is not always larger. I have been using larger ring gaps on the first rings literally for years. I had a very long conversation with Nick Arias about this over the phone. He gave me a game plan and asked me to stick to it and for over 10 years it has not let me down even using the opposite train of thought on 800-1000hp 4g63's. Combustion stays where it is suppose to and we do not have blow by where and when we don't want it.
This is correct and is a good way to minimize blow-by. I appreciate the info and input. I only flagged for incorrect OE specs. Occasionally when surfing through the web I come across these old posts that contain incorrect info and I just like to flag for correctional purposes. The info you posted about aftermarket piston ring gap added good info.:thumb:
 
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