Please keep in mind, when Mr. Ruggles wrote his book his #'s were for a performance set of circumstances.
Side clearance #'s are overlooked more often than i care to mention and few people check them when rebuilding. Yes, they need to be correct and imo as close to the tight suggested clearance as possible. .020 seems real big (imo). Add up all the side and rotating clearances and you've found the low idle pressure #'s...
too many "internal" oil leaks.
I have seen most stock cranks at the high side or out of spec. Only way to fix it is get another crank or a wider rod. I have built several engines slightly out of spec(after many aurgements with machine shop) and not had one issue.
The more clearence the more oil that gets sprayed under the piston( and leaked out to the pan,cam etc). I was worried about the oil over coming the rings and creating a smoker. I keep the actual rod bearing clearence to about .0015.
In a perfect world I would like to set them in the middle of spec.
I'm with you. I think the important consideration is to not have it too tight. Too tight can mean inadequate oil circulation to keep the rod bearings cooled. The loose side should just be a matter of common sense. There's just no need for .030" side clearance on a rod.
i agree with you totally-------besides if you are rebuilding an engine with stock crank and rods it is what it is and there is not too much you can do about it--------i've built over 60 of these engines with great success and i dont' even bother to check rod side clearance-------BUT I will spend hours or even days to get the mains and rod journal clearance exactly where i want it ...........RC
There are other issues to consider for keeping side clearance within reason. At some point in time things are past there usable life. I wish getting a CS rebuilt wasn't a lost art but with today's economics, it's a lost art.
We can all beat on this till the cows come home and we all have our own way of doing things.
I do things with performance objectives in mind, your typical rebuild operation doesn't (can we all agree on this)?
That's why it will cost you to get a pro to do your work and your local re-builder is at the other end of the scale or why Ruth's Chris Steak House is next door to Burger King and Wendy's and that's why I didn't build the crossovers in my corner horns.
You know at one time GM offered a .010 over sized rod. According to my books Standard width was .842-.846 and the .010 over rods were .852-.856. There were no over sized(as in width) bearings offered. The Buick V-6 was the only engine I can think of that had a wider rod. But than they never offered a thicker main bearing to take care of the crank either. The GM engineers must have had a reason to offer a wider rod IMO.