Thread:

Ring Gap?

With T seals you can be anywhere in that range and have no leakage. BTW a really old Sealed Power tech guide had some really good info on end gap. Basicaly a 4.03 chevy bore did not see much power loss untill about .028. The right finish seemed to be the focus.

Originally Posted by lbhsbz

Sorry to bring this one back from the dead...but I was just checking this out because I'm ready to start filing rings.

This chart is not a ring gap chart, but a wall clearance chart...just wanted to point that out so nobody sets up to tight.

The ring gap chart is here...on the SECOND page...

http://www.jepistons.com/dept/tech/d...instrc4032.pdf

Looks like for our applications they're calling out .055-.070"


Just since this is my first marine engine....10.5:1 496 N/A in a flat...just a hot rod...not racing it.

I'm planning on gapping at .024 top and .027 second. should be safe, while still leaving a bit of room if I want put a bottle on it some day. Comments or thoughts?

should be fine with that.

I have read every post 10 TEN TIMES to make sure I dont f--k up but i am still gonna ask before i start filing. BBC 60over JE PISTONS speed pro rings, TWIN TURBO TOP-28 2ND -34 OIL-15 CLOSE ? Don,t wanna beat a dead horse on this topic but I would rather ask and than **** it up . THANKS

Originally Posted by cougar63

I have read every post 10 TEN TIMES to make sure I dont f--k up but i am still gonna ask before i start filing. BBC 60over JE PISTONS speed pro rings, TWIN TURBO TOP-28 2ND -34 OIL-15 CLOSE ? Don,t wanna beat a dead horse on this topic but I would rather ask and than **** it up . THANKS

Hey cougar. Lots of guys missread what what I stated. .004 not .040 per inch of bore! If you are running the squeeze than go alittle wider. IE .004 x 4.251 = 0.017 add the cold shot and add two to three. I have seen guys with small motors go .020 on the top and .018 on the second and not have a problem. If you really want to get good info on NOS p.m. 71 hallett. Dude knows the cool feul REAL well. M

Originally Posted by cougar63

I have read every post 10 TEN TIMES to make sure I dont f--k up but i am still gonna ask before i start filing. BBC 60over JE PISTONS speed pro rings, TWIN TURBO TOP-28 2ND -34 OIL-15 CLOSE ? Don,t wanna beat a dead horse on this topic but I would rather ask and than **** it up . THANKS

Different brands of rings specify different gaps. What do the instructions say that came with the Speed Pro rings? That sounds big to me,, .015" on the oil ring should be good, most will be more than that out of the box.

Thanks guys, Speed Pro general spec is about like everyone else's,that said ,TOP/.026 2ND/.028 AND OIL AT.015 final comp ratio calc to 8.3 with.040 head gasket.THANKS FOR INFO MAY HAVE TO YANK LS-6 OUT OF MY 70 EL CAMINO AND GIVE STEEL A RUN FOR HIS MONEY IN HIS 68 LOL

Originally Posted by cave

ol guy do you run a super chiller? I tend to flat foot it from end to end.
I'm afraid with the way I run it the heat would be greater with a blower.

If you get the feul air ratio right, heat in the blower should not be a problem! When I have ran blowers on the asphalt or water I have never even thought of a chillerBut then again I really haven't ran to many blown motors on the water HARD for more than a quater mile! The one that I did build was 13 percent over driven and that was in a river racer boat and when things got warm I would hammer the boat and the frost on the blower would build back up. For some reason the blower motor trend has gone to way underdriven and that will create more heat in the blower. This calls for an analogy, Shape your'e mouth like you are going to say the word "who" then suck in lightly and then hard. at first you feel slightly cool on your'e lips then the harder you breathe in the cooler the feelings get! that is the original design behind a blower(this is not a sexual thing) That would be where the air/feul ratio comes in. If you want to build a blown motor for cruising then keep this thought in mind

Originally Posted by wagspe208

Holy Christ....030....040..you guys are putting way to much thought into this.
I am a guy that will over complicate almost anything.
Many a blown gas endurance piece (big ass pleasure boat with blown intercooled pieces) are running with .0045 to .0055 gap per inch of bore..Go to .006 if you are the nervous sort.
These are 36 to 45' pieces.
Bolt the thing together and thrash the hell out of it.
Most internet experts have never filed a ring in their life.
Good luck
Wags

Hey wags I agree with the most guys part! But when I worked for Sealed Power on the Speed pro division, I learned alot about rings and all concerned, and yes I have a ring file in my play room. I was also in the tech room when the hypreutectic composition piston was designed and know more about that composition of materials than I will admit. A Speed -Pro KX ring calls for a certain gap to eliminate ring chater and retain ring ratchet for best sealing in the bore and keep from having ring butt problems on a normal teperature engine. 160-210 degree operating temp is optimum for any engine!

Originally Posted by cave

The Marine factor is not included. Being that most of my boating is done in summer time here in AZ, the water temp is around 80 to 90°. So the cold water factor really doesn't play into my equation. I also have a oil cooler water warmer.

Using .002 as a cold water factor gives me .03171 @ .03 I should be OK.
.02 was the low end for marine cold water pick up.

I visited some wheres around 4 different sites that had .004 as a normal base value. The addition of a blower bounced around from .002 to .006 with 3 out of 4 having the .002 - .004 values.

I'm getting it now.

Cave, cylinder temps play heavy on the expansion and contraction of pistons and cylinder walls. then you throw the frost at it and the guys bring up good points as to ring butt. Temps climb and drop with the addition of nos. M