correct end gap for Axtell (cast Iron 3-13/16)

[conv90]

There is always some confusion on end gaps.. (at least for me)
I know that cast iron cyl made by Axtell do not expand as a normal one so the gap should be greater.
So the Axtell reccomendation of 6 x bore for 1st TOP ring and 4 x bore for the second ring can be good??
3.8125 x 6 = .0232" --->top ring runded to 0.024
3.8125 x 4 = .0155" ---->2nd ring rounded to 0.016

So why sometimes someone tell that the second must be greater than the top one or equal to the top one??

I read somewhere that greater end gaps on 2nd ring can lead to better ring seal..
-Beppe-

[aswracing]

Yes, for a long time the thinking was that since second rings don't get as hot, they don't need as much end gap. However, it's been shown that control of the pressure trapped between the rings is more important to ring seal, and a wider second ring gap actually promotes that. So the trend with most piston and ring makers lately has been more toward wider second ring gaps. Seems backwards, but there it is.

Part of it is driven by the piston design, too, for example a piston with an expansion groove between the rings will not benefit as much by staggering the ring gaps with the wider one on the second ring.

[conv90]

...and i the case of a 3-13/6 Axtell cast iron cyl with flat top pistons with 1.200" compression height(if i rememer corrct) (for a street driven sportster occasionally slammed with strong accelerations and about 10,5:1 CR) which ring end gaps you suggest?
thanks

[aswracing]

Whose pistons?

[conv90]

piston are flat top the ones in AXTELL kit .. I bougth some year ago.. they are JE pistons with axtell code 801-570A
and rings are 596-505 SPEED PRO 3-13/16+005 RINGS . I bought ALL many years ago maybe 2002 or 2003.. LOL

[aswracing]

Well, you know what's coming next ... you REALLY need to ask Axtell.

[conv90]

Hey Aaron , is there a way to contact you private?
I'm searching XB heads for my project.

BTW, I gapped the rings in a safer side.
.0235 Top and .245 2nd

but (as always ends) I xaggerated in on piston set and ended to .025 on Top one and .026 on the 2nd.

Is it best I ENLARGE the perfect gapped ones? (to end with Exact the same dimensions).

OR
If I stay with this minimal difference, Is it best to use the BIG-gapped ones on the front or on the rear cylinder??

Thanks
my email: beppe_lisco@yahoo.it

[aswracing]

Beppe ... sure you can contact me anytime ... aaron at hammerperf daht com will get you right to me.

I completely spaced that you were in Italy ... let me give Axtell a call here in a few hours when they open, and see what they recommend for that kit, I'll get you an answer.

[conv90]

thanks. I'll be out for weekend. I`ll probably read in monday when for sure i'll send u a mail too