Box Stock

pro clone ring gap

Head 109/.280
Springs RaceCity
Installed Height 19/21
Valves 2.44
Flow Intake
Seat Height INT 0.008
Seat Height EX 0.013
Head Gasket 0.01
Flywheel ARC/39 deg
Coil 0.075
Cylinder Clearance 0.005
Piston Spec Std
Comp Ring 0.007
Middle 0.015
 
I set my top as close as I can get it .0005 2nd ring @ .002 and gap the oil rings at .005 and clip land off the retention ring until it slides through with almost no effort. After break in my gaps are .006 on the top .008 on the second. Imo if set any bigger, the gaps are far to large after break in resulting in more compression loss, and shorter service life.
 
You don't seem to be worried about the oil ring not supporting the piston and rod assembly with it that loose or are you changing it frequently?
 
Halffast66 said:
I set my top as close as I can get it .0005 2nd ring @ .002 and gap the oil rings at .005 and clip land off the retention ring until it slides through with almost no effort. After break in my gaps are .006 on the top .008 on the second. Imo if set any bigger, the gaps are far to large after break in resulting in more compression loss, and shorter service life.
Click to expand...

I am shocked that you see your top ring go from .0005 to .006 after only a break in, something is up there. What cylinder finish are you starting with?
 
If rings are prepped with good process and not set up with tight end gaps they'll be very close to what you set them at after running under a load for extended time. Some diff in drag and hp when going from .002-.003 end gap vs ideal in my opinion of .007-.008 on comp ring. Comp ring needs to rotate and seal to ring land(just as important as cylinder seal).
Evause
Www.racingcarb.com
 
After break in of the engine with a properly prepared cylinder the ring end gap should increase minimally. If it is increasing by .005" as stated above I do think something is amiss.
 
In a "race" engine, I have never seen more than .002 increase in ring gap. I have seen huge increases with really really wore out engines with huge hours on them. Very soft cheap rings will seat very easy but wear more. A bore finish that is honed with a very rough hone may allow ring gap to grow from a lot of wear. Not sure how to get .005 gap increase from just break-in. Starting with less than .002 can easily result in ring bind if you don't get some wear pretty quick. Just my experience. Good luck.
 
The reason he seen it increase to .005 was because the ring got hot and expanded. Thus causing it to wear excessively and gain end gap.
The perfect gap is the gap that when the ring expands the end gap Is dead 0 for a perfect seal. When he set it at .0005 and the ring expanded it wore excesively and when it cooled back down it had a larger gap. I used to use this method because I theory after break in it gives you a perfect end gap. Bit quickly learned all the other ill effects make it not worth it
 
If .0005" top ring end gap is necessary, why do Automobile engines generally use .004" - .005" per Inch of cylinder bore for the top ring gap, which is recommended by the ring MFG also? You DO have oil running around in the engine and in the cylinder bore to seal the .005" end gap. You are creating more problems with too tight a gap ( ring end butting comes to mind ) than the minute HP loss ( if any at all ) IMO.

Dave E.
 
You must log in or register to reply here.
Back
Top