Hey guys, I've got this posted in the Prelude and the Hybrid forums, but no bones, so thought I'd try here too. I've also now sent emails to Crower and Carrillo, but no responses yet. Here's the skinny...

I'm planning an 87mm x 97mm build for my daily driver when I get my tax refund. The plan to date is f23 crank & rods with f20c pistons in an h22a4 SH block (w/ h22 head). I'll probably start a build thread soon, but have this one big question before I commit to it...

The one piece I know already is the f23 rods will have to be bored out slightly on the pin end to accommodate the .904 wrist pin size of the f20c pistons. The thought would also be to cryo the rods before doing machine work to hopefully add a little strength to them (and ARP bolts). The big question for me is the difference in the pe width; the f23 rods are a mere .780", but the f20c rod pe width (and therefore rod opening on the piston) is .938" from what i can gather.

Is this bad news for the rod? Will it put a lot of stress on the rod if the small end can float side to side much? There aren't any specs in the helm's for tolerances of the pe width that I could find, so is this even an issue if the side of the rod is never in contact with the piston?

If I need less clearance, what about adding material to the sides of the rod? Feasible? Reliable? Stupid? Custom rods are out of the question.

 

any educated ideas? i'd like to at least hear some discussion about possible effects of this combo. my biggest concern is if the rod will try to flex side to side because of the large amount of space, but honestly i'm new to engine building, so i'm not really sure. can't get anything from the rod manufacturers apparently, so I might try some piston makers next...