std bore = 73 mm (1 mm = 0.0393701 in) (73 mm x .0393701 in = 2.8740173 in) (2.8740173 in x .004 in = 0.0114960692 in) rounded off to the nearest thousandth = .011" or ten thousandth = .0115"I'm installing some 13.5 :1 pistons in my stock bore 1000.
The box says .004" for each 1" of bore, so that makes my stock bore about 0.10", right?
Should all the rings have the same gap?
Any advice here would be greatly appreciated.
Makes sense and good advice. Loose tolerances equals less friction that may or may not translate into a safe or consistent increase in power. Not to mention your throwing away engine life if that is a concern. And knowing how far you can or should go is where experience comes into play.On the clearances for power topic, opening the piston to wall clearance up reduces friction. It also makes it tougher for the rings to seal and shortens ring life. You can easily loose in leakage what you gained in friction reduction.
Yes, for that ring. Chrome can be really hard to get to seat. A first class hone job and an agressive break in are good ideas. Moly is also used, and easier to seat. The current state of the art are IVD coatings. The problem with coatings is they're really thin. Once they're gone, the ring wears out very quickly. A strong argument against aftermarket air filters.Wiseco quotes the XA top piston ring as .031" alloy steel, ferrox coated, chrome faced. Is the sealing face chromed?
Depends on what else you did to the block, including both piston to wall clearance and deck height. When I send a block to millenium, I pretty much automatically have it decked 0.008". This puts the squish within reason with a standard Commetic 0.030" gasket. I take more off of my personal stuff when it's not for high milage street use.What thickness head gasket do you use with these pistons?
If we start with a steel ring for a 73 mm (2.874") bore, it has a length of 9.0244". Steel has a coefficient of thermal expansion somewhere between 6 and 9 E-6 in/in-F. If we heat that ring from the 60 F in our shop to 200 F in the running motor, it grows somewhere between .008" and .012".Even with the higher compression there still isn't much to gain from a minimum setting?
Good link, I buy a couple copies of Circle Track a year for articles like this one, but seem to have missed that one.Yet the car guys seem to be obsessed with end gaps.
GSXR750s use similar numbers since '96, a ZX10 spec is .006" - 0.012". All Nickasil bores.The standard or spec Suzuki end gap of the top ring is 0.003"-0.008" and a thickness of 0.0382"-0.039", thicker than the Wiseco ring.
I took an early TL1000 apart once and it had the L shaped, "Dykes", or pressure backed ring (PBR), so I don't doubt its in there. It's an expensive version of gas porting. The idea is to reduce ring friction on everything but the power stroke, and to increase sealing.The K5 supposedly has a new top ring. I say "supposedly" because that technical document is full of crap..
Okay, maybe not crap but some inaccuracies seem to have crept in, and yes thank Jeff and Northface.[...]I found that document informative (Thank you JeffW and Northface), what did you find wrong with it?
Okay, maybe not crap but some inaccuracies seem to have crept in, and yes thank Jeff and Northface.