I freshened my 367, FIVE winters in a row, looking for surprises to take care of, before they became an issue. That's how much I didn't trust the "pro-shop's" assembly work...... even tho they handle almost all the local circle track work.. Plus it was my first trip into pushing 185 to 200psi (alloy heads), so I was looking for signs of detonation (which I never did find).
During those FIVE freshenings;
Twice I changed the rings,
Once, no twice, I changed the top ring gap, and once the second as well.
One time I changed the rod bearings,
Once I cut the decks,
Once I shaved the decks,
Once I had it line-honed,
Once I had the bores opened up a tad,
Once I replaced a migrating pin-bushing,
On time I resized a rod, and
another time I replaced a different rod.
I never kept track of anything...... because I never thought it would one day be important. I had not yet discovered FABO, at that time.
Having said that, turning torque in the short-block, was always important to me. And so my rule was;
As long as each additional piston/rod, going into the short block, increased the turning-torque* required, by a similar amount, I was happy.
In my engine, the drag was always on the rings. How do I know that?
Because one atta time, I fit every rod to the crank prior to installing the crank into the block, and gave each of them a lil spin after measuring the clearance.
And One atta time, I set the naked pistons into their specific holes, and watched them drop of their own weight.
And one atta time, I made sure the wristpins were correctly clearanced.
So by process of elimination, the turning torque revealed only the tight rings. After I installed Plasma Moly file-fits on my KB107s, with "towing" ring-factor clearance of .008, the turning torque became significantly less.
The very first assembly was done by the pro-shop. And that engine was prone to locking up every time I shut it off; and it hated traffic; it even ran hot on the hiway. To say I was frustrated would be an understatement. To it's credit, it ran gangbusters in third gear with 3.55s. I tried everything, with very little improvement. Finally, I added a half a thou (average) of bore clearance, and added .006 thou top-ring end-gap,and added .002 second gap; and got control of it. That allowed her to run a 195 stat, with no more issues. The Moly-Plasmas went in on a later freshening.
The point is this;
IMO, with KB107s, the .0065 plain cast-ring, ring-factor that results in .026gap, in a 4.04 hole, is too tight.
IDK if it needed to be as much as .008 factor, but since it solved my problems, and the engine was killer-strong; I never tried less. That was the end of the mods. The next freshening revealed nothing amiss, so was the last one. That was 2004 or 2005. Since then, actually in total, that engine has well over 100,000 miles on it now; I'll guess about 60,000 since the Plasma-Moly rings went in.
As to the turning torque;
If I had to guess, I'd guess about 4 or 5 ftlbs per piston assembly, so total of 32 to 40?, and with the "loose" Plasma-Moly file-fits, a lil less; say 3 to 4 per piston; but it's just a guess.
I was never sorry that I installed those Moly rings nor about the slight rattle at start-up due to the additional skirt clearance,(now, IIRC, pushing .004 or a tad more skirt clearance) which only manifests at the beginnings and ends of the season; and goes away in just a few seconds. Otherwise, it doesn't seem to be a problem.
To walk you thru reassembly; there are a bunch of smarter than me guys here on FABO, including several? current and past engine-builders. And A bunch of hobbiests like myself.
Best of luck finding your problem, and I hope it's a cheap fix.
*not the breakaway torque
