Ok my friend sold me his h23a vtec for almost nothing after he spun a rod bearing. The crank is in pretty bad shape. I know this is an oddball motor for sure but it seems to have 55 mm mains. I wanted to know if i could use my f23 crank i have laying around and rods in this motor and make a torque monster vtec. I used the zeal calculator and found out the f23 crank and rods with a k24 piston will make the compresson i want and not have the pistons sticking out of the block. I would like to know if anyone makes forged pistons and rods for the f23 because i dont feel like this setup on stock parts will hold up to well woth the high revs it will need for power. Id like to see 250 whp and 210wtq n/a if posable but also be reliable. Any ideas would be great. Ive done alot of reserch and just cant find anything to help.
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This is entirely possible. If you use K-series pistons, or aftermarket versions of them, you'll need to turn them 180-degrees inside the bore when installing them. Effectively, the intake valves will be lining up with the exhaust valve reliefs in the pistons. This is necessary because of the wrist pin offset in K-series pistons being opposite what it is present in F/H-series pistons.
Your issue will come with the FRM cylinder liners. You can either have the engine resleeved or you can find a piston that's FRM compatible with an 87mm bore and a 30mm compression height. Two that come to mind are F20C pistons and F22C pistons. The F20C will give you slightly higher compression with its 2cc dome. The only issue here is the fact that the F20C and F22C pistons use a 23mm wrist pin instead of the 22mm all other F/H/K-series engines use. You can have your rods rebushed for the larger pin to alleviate this.
Or, you can just use your current H23A VTEC pistons and be okay with the pistons sticking out of the bore by .5mm. The F20B pistons stick out that much from the factory.My Members' Ride Thread - It's a marathon build, not a sprint. But keep me honest on the update frequency! -
Does the h23a vtec use floating wrist pins? Cause if i use a f23 rod i will need a piston with a floating wrist pin. Also will the stock f23 rod handle high rpm? I ask cause all the cams ive found have power bands over 8000 rpm.Comment
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Yes, they are floating wrist pins.My Members' Ride Thread - It's a marathon build, not a sprint. But keep me honest on the update frequency!Comment
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Ok cool. In that case i will get some crower rods and use the stock piston with a thicker head gasket
Do you know what the specs are on the h23a vtec piston or where i can find the specs. Id like at least 11:1 compression is why i ask on 93 pump gas. She will be a daliy/strip car.Last edited by Jarrett; 06-19-2014, 04:10 PM.Comment
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I know it uses a 30.5mm compression height. The dome volume is debated but many people say it's right around 0cc once the dome and the valve reliefs cancel each other out. Measure for yourself and find out. Then post the information.My Members' Ride Thread - It's a marathon build, not a sprint. But keep me honest on the update frequency!Comment
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Will do and thanks for the info.Comment
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Since im gonna have the pistons out im gonna replace the rings. Does it use the same rings as the other h series motors?Comment
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Yes.My Members' Ride Thread - It's a marathon build, not a sprint. But keep me honest on the update frequency!Comment
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