Hi, I am building what I guess could be called a G21 (it seems the popular thing when combining F and H motors to call it a G, I may as well do the same.) This particular combination is based on an H23A1 block, head, intake, but uses F20 and H22 bottom end parts.

Block: H23A1 bored .025" (orignially 87 mm)
Crank: F20A - 88 mm
Rods: F20A - 145 mm
Pistons: H22 Type S
Head: H23A1

Displacement: 2100 cc
Compression ratio: approx 11.5:1
Rod/stroke ratio: 1.65:1

Any thoughts/comments would be greatly appreciated

 

sounds like a homemade f20a dohc engine to me with 2mm of overbore on teh block.

 

sounds good...keep us posted on the progress

 

i thought they called it a "G" because they had a H head on a F block.. what your doing is building your H motor with F parts..


Modified by EK9-Stealth at 8:39 PM 11/8/2005

 

its called G because its between f and h

 

the f20a dohc has the h23 head on the f20 block from teh factory.
thats why think calling it a "g" is funny, only thing i see unusual is overboring 2.5mm on 85mm sleeves to run the larger pistons. seems dangerous to me withotu seleves.

 

well no1 really ever called this setup a g....only with the combos of f22/h22, f23/h23, f22/h23, f23/h22

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SB tuning &raquo;</TD></TR><TR><TD CLASS="quote">well no1 really ever called this setup a g....only with the combos of f22/h22, f23/h23, f22/h23, f23/h22</TD></TR></TABLE>


i am doing the f23a1 block with 3/4 deck plate w/h22 head...r/s of 1.65
w/a 97mm stroke.


harv

 

yes, yes i remember lol...whats gonna be the displacement again?

 

Well, the primary reason for going about this projhect the way I have is the H23A1 has a closed deck design, something I wanted from the beginning. The twin cam head was another selling point. The stock rod ratio of the H23A1 is not favorable to me, so the conversion to F20A/B crank/rods/balance shafts not only took the rod ratio from 1.48:1 to 1.65:1, but it allows me to use whatever H22 piston I like, in this case, oversized Prelude Type S pistons. This puts displacement at around 2100 cc and compression just over 11:1. This engine should have a smooth torque curve and enough power to leave the old F22A6 in the dust. With the mods, I hope to see at least 170 crank hp, so, when I get the combo tuned on the dyno I'll let you see what I got out of it.