Hey guys I always hear so much about setting the end gap on your rings and what not, now wut exactly are u doing when u do this and why would u do it? is it a must when building a motor?

 

the name pretty much says it all. you check the gap, as in where the opening is on the ring. yes it's important, i'd think you'd be a fool not to considering how easy it is to do and the damage it can cause or preformace lost if not correct.

 

To add a little bit, you insert the rings (by themselves) into the bore, use a piston to move them down some and make sure they're in "square". Remove the piston. My guess is regular builders have a dowel to use, and don't use pistons.

Ofcourse this is only accurate if the bores have been machined and have no taper or out-of-roundness.

Measure the gap where they start to connect, if too small, you need to file the gaps to open them up. They make a tool for this that eliminate the slices on your fingers from holding the rings in your hands and using a file.

To answer if it's important..yes, reason is as the rings/pistons expand, you don't want the ends to contact, could lead to ring land failure of the piston, broken rings, etc.

Excessive ringgap would lead to loss of compression.

 

The reason you do it, is because the rings heat up considerably during operation; when they heat up, they grow; as they grow, the ends get closer and closer; if they touch and the ring continues to try to grow from further heating beyond that point, it's instant destruction of pistons (they'll literally blow the ring lands off the pistons), trashed bores, etc. etc.

It's better to have slightly too much gap than not enough. Obviously you want to try to have as little gap as possible while still leaving a safety margin.

 

Most of the garden variety ring sets come pregapped for your application and all you are really doing is double checking to make sure all is well (your engine was bored correctly, the rings were packaged correctly, etc.) but high performance rings and/or high performance pistons have tolerances that the builder must meet by gapping to the spec he needs. Piston application, power adders, etc. will determine this ring gap. The instructions should be with each performance ring set to guide you. If the piston has specific ring gap needs, that instruction will also be included in the package.