Ring Landing Spec

[thenige]

Hi all,

I have started to install a set of KB198s into my 350 SBC and I have my 1/16; 1/16; 3/16 spec rings to match the pistons. The rings are plasma moly.

I'm checking the ring landing clearance in the pistons and I cannot even fit a .002 feeler in there. That is the smallest I have. The rings will fit in the landing and rotate however I am concerned that with the heat building they may seize up in the landing.

I'm going to check the part numbers I was sent again (i.e., in case I was sent the 5/64 ones sent by mistake) , however does anyone have a minimum spec that for a landing clearance for a KB piston (or in general)? I'm also going to call KB on Monday to see what they have to say.

Regards and thanks,
Nigel

[MrPbody]

Nigel,
Usually, .004" is enoough, BUT... Those KBs are notorious for ringland and ring problems. Be sure to follow gapping specs to the "letter". That is, the instructions that come with the pistons, NOT the rings. Let United (makers of KBs) give you the side clearance specs for the lands.

Jim

[thenige]

Thanks Jim.. I have a call and email into United.

I spoke with the machinist I use and he gave me some help based on his experience also.

Some resources I did find, after I changed my search to "ring groove clearance" include:

http://www.dol.net/~dave.reed/tips.htm says .0015

http://www.hastingsmfg.com/Service%2...of_pistons.htm

http://www.deves.com/tips.html if greater than .006 then must be replaced

http://www.autozone.com/servlet/UiBr...3d80050e24.jsp normal .002 - .004

http://www.tpub.com/content/construc...5-1185_221.htm says .0015 to .002

http://www.federal-mogul.com/fmeconn...loads/1205.pdf min .001 to standard of .002 - .004

http://www.rosspistons.com/custom_ring_grooves.php std of .002 - .004 min of .0015

http://www.rosspistons.com/pdf/ross_...stallation.pdf between .001 and .004

United really need to update their website with better product information.

Cheers,
Nigel