Today in our engine shop, we were doing some R&D (research and development) on how we could gain about 10hp by changing parts that were already on the engine. Keep in mind this is a race engine, so it already has all the 'trick' parts installed. (light weight flywheel, carbon pistons and rods....) One of the most effective modifications that we did to the engine, was shaving 100 thousandths off each of the rod bearings and cutting a 200 thousandths wide groove in the main bearings. This in turn made the contact surface smaller for the crank, which in turn reduced friction. We ended up exeeding our goal of 10hp by 1hp and we gained 5hp just by shaving the bearings.... Just thought I'd let you all know, I found it kind of interesting.
what did you guys surmise might be the long term effects of this to the engine? Any issues with the balance of the crank being thrown out with the lesser contact or being less stable? What about accelerated wear to the remaining area? Just some thoughts...obviously in a race engine it would be less of a concern than a daily driver!
this is interesting.... Another question for you. How did you decide how mush to shave? Is there some formula, or did someone say let's shave this much and see?
We measured the bearings and discussed how much we thought should come off. Since this was just a development engine (dyno bitch), we decided to take off more than we actually will on the customer engines to make sure that they would not fail. I am curious to see whether the bearing are 'floating', moving from side to side. In theory, they shouldn't move since they are torqued, but when your at 7,500pm for 30 min. straight, it makes you wonder. As far as long term effects, I would say that after an entire season, there would probably be a more noticeable wear pattern in the center of the crank/rods, but as you said, they're race engines, so as long as the engine lasts about 8 months...