Discussion and questions related to the course Practical Engine Building
I assembled my sr20 short block recently and the instructions that came with my CP pistons didn’t mention the oil ring expander going up a specific way (ie where the join is the ends should point down as per the pactical engine building video). I can’t remember which way up I installed mine, so what I want to know is how critical is this and is it worth pulling my pistons out to check or correct this? The block is assembled but no head on it yet. It is a 90mm bore sleeved and stroked sr23 which has made over 400kw in the past.
In my experience the orientation of the expander isn't critical. The expander is only there to support the oil ring rails which do the job of scraping the oil from the bores, and as such it's not too important.