I am rebuilding a 91 Madza 2600i engine. The engine has been bored .020
oversize. The new piston side clearance is .0023. Madza specs call for
.008 to .014 top ring end gap. When I check ring end gap on the new
oversize rings I am getting .022 (at the bottom of piston travel). The
ring manufacturers have a standard of .004 end gap per inch of piston
diameter making my acceptable ring gap .01456 (3.64 x .004). I have tried
3 sets of new rings from 2 manufacturers and each is checking from .020 to
.025 end gap out the box. I feel this is incorrect and may cause me
problems if I use them. I am told that ring manufacturers are notorious for
producing rings with excessive end gap. Rebuilding this engine is too
expensive to "build-in" a problem.
My question is how do I correct the problem? Another set of rings may be the same. I am using name brand chrome rings. Would using a set of .030 rings work (which should allow me to set the end gap myself) or would the .030 in a .020 oversize bore cause me problems? Some have told me that the end gap I am getting now is acceptable even though it is not what is specified by the manufacturer. For info, the ring groove side clearance is good. Any comments or suggestions would by greatly appreciated as I am ready to build once I get over this hurdle. Thanks.