Bolt ons...discussion

[AFAccord]

Hey Jason, what all would be needed to run K20 pistons? New valvetrain and tune?

The K20a3 pistons would give you 11.0:1 compression, and the K20a2 pistons would give you 12.4:1. Both would absolutely require a stand-alone engine management or OBD1 conversion, a good tuner, colder spark plugs, some grinding of the valve reliefs on the pistons, and you might as well upgrade the fuel system, replace all the bottom-end bearings and seals, and clay the motor while you're at it, just to be safe. You'd benefit greatly from an aggressive cam with that much compression, but that just makes your P2V clearance even more likely to disappear, if it even exists @ 12.4:1.

 

[mraw112]

I really doubt the valve relieves will have to be cut deeper. The k20 and f23 have the same compression height, and As far as I could research the same deck clearance. Also I would assume the k20 also has a lot more lift on their cams. I would say that you could put mild cams on with out having problems. Does any one make a thicker head gasket for us. that would give you some form for some aggressive cams. Also The head ccs of the k20 head is almost the same as ours. The reason we get so much higher compression with there pistons, is because our stroke is huge

 

[AFAccord]

I really doubt the valve relieves will have to be cut deeper.

Not deeper buddy, wider. I'm very curious how you intend to fit a 34mm valve into a 30mm valve relief. Please do share.

 

[BlkCurrantKord]

Hope it melts a little first from detonation

 

[mraw112]

Damn I never thought about that. Im surprised we had bigger valves. Now that you mention it. we probably also have a narrower valve angle so the will probably have to be cut deeper and wider. But didnt someone do a g23 swap with k20 pistons. I just looked it up and the

H22
I-35
E-30

k20
I-35
E-30

 

[thejameshimself]

Hope it melts a little first from detonation

ha. or maybe after breaking off and bouncing around it'll shrink a bit

 

[AFAccord]

Damn I never thought about that. Im surprised we had bigger valves. Now that you mention it. we probably also have a narrower valve angle so the will probably have to be cut deeper and wider. But didnt someone do a g23 swap with k20 pistons. I just looked it up and the

H22
I-35
E-30

k20
I-35
E-30

Our (F23) valve's aren't larger than the K's. The problem occurs when you flip the K20 piston 180 degrees to remedy the wrist-pin offset, and put the F's 34mm Intake valve heading for the K20 piston's 30mm exhaust relief.

 

[hiddengamer7]

So to fit the k20 pistons, for sure I will need the valve relief's milled?

 

[AFAccord]

"Worked"... I would call it. You're not really 'milling' them down. Just expanding them to accommodate the larger intake valves.

 

[mraw112]

I had no clue they even did offset wrist pins in car engines anymore. What does flipping it around do? It would still have an offset, just towards the intake side tho. Also wouldn't the wrist pin offset

1- reduce rpm stresses.
2- reduce compression a tad. The piston would travel up less because the rod length would now be a hypotinouse