Do I have to take care about 2nd piston ring end gap?
#1134423
12/15/11 10:44 AM
12/15/11 10:44 AM
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Joined: Aug 2007
Posts: 6,096 Valencia, España
NachoRT74
OP
master
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OP
master
Joined: Aug 2007
Posts: 6,096
Valencia, España
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what you read.
I'm begining to build the 450 stroker with KB215s ( again ) after lots of problems I have being comfronting with local guys and several mistakes on machine shops.
KB website says to take care about the 1st compression ring end gap. Being 4.362" bore it looks I need 0.0283 gap. I simply filed up to 0.028" and a little bit extra of free play to fit the feelers easily, not tight ( kinda to give the 0.003" the feelers doesn't have )
Now, The 2nd compression ring. I don't remember exactly what feeler made to fit just out of curiosity, but maybe it was kinda 0.010 gap.
Do I have to take care of that ?. I know KB website doesn't specify anything about that, but wondering based on your experiences
With a Charger born in Chrysler assembly plant in Valencia, Venezuela
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Re: Do I have to take care about 2nd piston ring end gap?
[Re: NachoRT74]
#1134426
12/15/11 11:33 AM
12/15/11 11:33 AM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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Yes KB's want .0065 per inch of bore for the top ring. On the 2nd ring KB wants regular which old school was .003" per inch of bore which was used for decades then lately there was a school of thought that the 2nd ring needed more gap to let gasses that make it pass the 1st ring to escape so people were saying .004" per inch. Myself on I go w KB on the top ring and stay with the tried and true .003 on the 2nd ring. Alot of people use a larger (.004 per inch) gap on the 2nd ring gap but I do not. I gap the same way I do on solids ie for specified .025", a .024 gauge held square has no drag and a .026" has slight drag but it's not a dealbreaker
live every 24 hour block of time like it's your last day on earth
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Re: Do I have to take care about 2nd piston ring end gap?
[Re: NachoRT74]
#1134427
12/15/11 01:21 PM
12/15/11 01:21 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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A lot of engine builders now are running the second ring gap at a couple thou larger than the top ring gap to reduce ring flutter... if it got past the top ring you dont want to hold it back and cause any flutter to both rings.... this is what I've been doing for some time now
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Re: Do I have to take care about 2nd piston ring end gap?
[Re: MR_P_BODY]
#1134430
12/15/11 02:48 PM
12/15/11 02:48 PM
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Joined: Jul 2008
Posts: 30,460 Florida STAYcation
dOoC
The village idiot's idiot
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The village idiot's idiot
Joined: Jul 2008
Posts: 30,460
Florida STAYcation
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Quote:
to reduce ring flutter...
What kind of ring groove clearance specs are you seeing ?
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Re: Do I have to take care about 2nd piston ring end gap?
[Re: MR_P_BODY]
#1134431
12/15/11 02:48 PM
12/15/11 02:48 PM
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Joined: Dec 2003
Posts: 16,844 Phoenix - surface of the sun
nomore65BelvJim
I Live Here
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I Live Here
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Phoenix - surface of the sun
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Quote:
A lot of engine builders now are running the second ring gap at a couple thou larger than the top ring gap to reduce ring flutter... if it got past the top ring you dont want to hold it back and cause any flutter to both rings.... this is what I've been doing for some time now
that makes sense
have you noticed any differences since you started doing this?
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Re: Do I have to take care about 2nd piston ring end gap?
[Re: nomore65BelvJim]
#1134433
12/15/11 03:58 PM
12/15/11 03:58 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
Quote:
A lot of engine builders now are running the second ring gap at a couple thou larger than the top ring gap to reduce ring flutter... if it got past the top ring you dont want to hold it back and cause any flutter to both rings.... this is what I've been doing for some time now
that makes sense
have you noticed any differences since you started doing this?
I cant say for fact due to I dont dyno my engines and usually it isnt quite the same set up
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Re: Do I have to take care about 2nd piston ring end gap?
[Re: DusterMan]
#1134440
12/16/11 08:15 AM
12/16/11 08:15 AM
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Joined: Jul 2010
Posts: 2,091 Delray beach, Florida
Performance Only
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top fuel
Joined: Jul 2010
Posts: 2,091
Delray beach, Florida
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if you gapped the top and second rings the same, the second ring gap will be larger in a running engine since it never see's the flame front and heat that the top ring will see. another consideration is the material the rings are made of. different materials have different expansion rates. a top ductile iron ring is more dense than a cast iron second ring. unless you have years of experience using all types of ring materials in varying applications to fall back on, your best bet is to follow the manufacturers recommendations regarding end gap. the only exception to that is when using the KB pistons it is imperative that you follow their top ring gap instructions instead.
machine shop owner and engine builder
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Re: Do I have to take care about 2nd piston ring end gap?
[Re: MR_P_BODY]
#1134442
12/16/11 06:29 PM
12/16/11 06:29 PM
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Joined: Dec 2003
Posts: 16,844 Phoenix - surface of the sun
nomore65BelvJim
I Live Here
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I Live Here
Joined: Dec 2003
Posts: 16,844
Phoenix - surface of the sun
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Quote:
Quote:
Quote:
A lot of engine builders now are running the second ring gap at a couple thou larger than the top ring gap to reduce ring flutter... if it got past the top ring you dont want to hold it back and cause any flutter to both rings.... this is what I've been doing for some time now
that makes sense
have you noticed any differences since you started doing this?
I cant say for fact due to I dont dyno my engines and usually it isnt quite the same set up
I was thinking more of a difference in the wear and tear on the rings and grooves/lands.
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