I have a couple of engine builds I'm in the process of in addition to the constant consideration of continuing to play with the F22A. One of them is an F20B that I will be stroking to 97mm with an F23A cankshaft. Many people go this route and retain the F23A rods and incorporate either custom pistons or bore for K20A2 pistons. However, I'm a fan of using long rods.
I have an extra set of F20B rods that I want to use in this build. Those who are dimension-savvy will know that doing so will mean a 4mm increase in wrist pin height using the 145mm F20B rod over the 141mm F23A rod. This will necessitate custom piston with a much lower compression height. Judging by some of the off-the-shelf items available for Hondas and other makes, I'm okay with this. I wanted to ensure that I'd have enough room for the oil ring to not interfere with the wrist pin and that each ring land would still have sufficient thickness. I could have made this process easier on myself by rebushing the rod for a 19-20mm wrist pin but I chose not to. That's not set in stone at this point, though. Neither is the oil ring height. I'll go down a little lower if Wiseco is okay with it. The resultant compression height should be 26.5mm with a .020" protrusion from the deck height.
You may also be keen on the fact that an F20B rod shouldn't fit on the F23A rod journal because the journal is too small. The diameter is the same 45mm but the width is too narrow for the rod. The journal is .780" while the rod is .935". Your options here are to grind the big end of the rod to match the journal width, grind the counterweights of the crankshaft journal to match the width of the rod or go for broke and buy custom rods. I'm going with the second option because I finally found a machine shop willing to do it. They're going to grind it out a reheat treat the surface and I'll be able to retain the B16/B17-spec rod bearings.
They will also be boring the block to 86mm(maybe 85.5mm) for a little bump in displacement and to freshen up the cylinder walls. The block will be using the main girdle from the F23A because it is much beefier and bolts into the block in 10 more locations than the F20B girdle. It will need a little bit of clearance modification but I'll take pictures of all that. This will require me to have the block line honed also just to sure things up.
There are a couple of other things they're having to do also and I think it's all coming in at a pretty decent price. Of course there will be much more stuff to do once it's further along but I'm really excited to get it started. If you have any questions or want to insult me for going this route, let it fly.
I have an extra set of F20B rods that I want to use in this build. Those who are dimension-savvy will know that doing so will mean a 4mm increase in wrist pin height using the 145mm F20B rod over the 141mm F23A rod. This will necessitate custom piston with a much lower compression height. Judging by some of the off-the-shelf items available for Hondas and other makes, I'm okay with this. I wanted to ensure that I'd have enough room for the oil ring to not interfere with the wrist pin and that each ring land would still have sufficient thickness. I could have made this process easier on myself by rebushing the rod for a 19-20mm wrist pin but I chose not to. That's not set in stone at this point, though. Neither is the oil ring height. I'll go down a little lower if Wiseco is okay with it. The resultant compression height should be 26.5mm with a .020" protrusion from the deck height.
You may also be keen on the fact that an F20B rod shouldn't fit on the F23A rod journal because the journal is too small. The diameter is the same 45mm but the width is too narrow for the rod. The journal is .780" while the rod is .935". Your options here are to grind the big end of the rod to match the journal width, grind the counterweights of the crankshaft journal to match the width of the rod or go for broke and buy custom rods. I'm going with the second option because I finally found a machine shop willing to do it. They're going to grind it out a reheat treat the surface and I'll be able to retain the B16/B17-spec rod bearings.
They will also be boring the block to 86mm(maybe 85.5mm) for a little bump in displacement and to freshen up the cylinder walls. The block will be using the main girdle from the F23A because it is much beefier and bolts into the block in 10 more locations than the F20B girdle. It will need a little bit of clearance modification but I'll take pictures of all that. This will require me to have the block line honed also just to sure things up.
There are a couple of other things they're having to do also and I think it's all coming in at a pretty decent price. Of course there will be much more stuff to do once it's further along but I'm really excited to get it started. If you have any questions or want to insult me for going this route, let it fly.
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