Lapping piston rings

[Dwight Southerland]

Originally Posted by impstocker

I remember a Hot Rod magazine article on Dave Boertmans 1969 Chevy Biscayne N/SA 350/255 engine. They went through the motor and how it was built, a very technical article. Quite honestly at that point it was hard for me too understand but it was a start. You don't find technical atricles like that today in car magazines anymore, "just order a crate motor" or call somebody (engine builder) seems to be the norm. Just my 2 cent.

Will Lamprecht 65 Impala I/SA

Good point, Will. Many people are so overwhelmed with the technical part of building engines that they believe that the "high tech" referenced in marketing of services and products is the only source of a competitive engine. So the vast majority of racers "buy" the work and the parts, and the expense goes up (again!). Or people get discouraged because of the cost to the point that they do not participate. Then the sources of information go away since demand diminishes and people do not want to jeopardize their livelihood.


If you can change your mindset to be satisfied with "competitive" not "ET killer", that is the first step to having the inspiration to do your own engine work. After a few serious builds and intense striving for information and skill, it is amazing how much you understand. You then have a reference base of knowledge that helps you to glean more information from everything you read, even advertisements.


Another good article to read is the one about Wade Owens 283 engine:http://www.hotrod.com/how-to/engine/...tor-283-chevy/


I personally want to encourage you. I follow your threads and posts and I sense that you are doing so many things right. Keep it up and never be shy to ask questions.


In reference to the lapping of piston rings, there is some benefit to that. Some companies offered the tools for sale if I remember correctly. The additional piece of understand that needs to go with that is that as you lap the rings, you take material off and so the ring gets thinner. Then the clearance increases for the ring land and sealing efficiency sealing suffers. It is the same effect as wear from running the engine. So, you either start with a thicker ring, or you narrow the ring land. In old days, we would press the piston top to compress the top ring land (not too cool) or machine the piston for some items called "ring land restorers" (looked like radial spacers that fit into a specially machined groove at the top or bottom of the ring land and were made of some hard spring steel). Sealed Power/Speed Pro sold the spacers and a specially shaped tool to fit a lathe. It worked okay and was even legal in Stock eliminator with OEM pistons. Today, I might be inclined to order my pistons with thinner ring lands.


Dwight Southerland