K20 pistons (you bet!)

[hatchninja]

i actually haven't been drinking much at all. My job doesn't require me to work if I don't want to, which is not good for my paychecks. Luckily I'm getting a lot of side jobs doing clutches, timing belts, etc.

[hatchninja]

finally getting caught up on my bills. The CRX is soon to get out of the body shop, so I'll need a motor to put in it. The shop where I used to work is holding a complete running f22a6 motor for me, I just need to get it and tear it down. Then take the block, pistons, and rods to the machine shop. After the machine work is figured out it the motor should come together pretty easily.

Then comes the nightmare of putting it into the car.

[kouzie]

[wed3k]

i may choose this route to get a better quality piston for a cheaper price. i need to work out the wrist pin because the grooves will be reduced since we will need to bore the wrist pin bores.

my boss also has a contact with CP pistons, so lets see what we can get.

[hatchninja]

Been looking into the rod bolts. Apparently F22parts.com had some made (probably just got ARP to make a batch of them) http://www.f22parts.com/item_rodbolts.htm

Sweet, with rod bolts I'll be a little more comfortable revving the f22 (still probably only to like 7500)

Been talking to the guy who will probably build my engine for me (trading some b-series parts if everything works out) So things may begin to come together rather quickly if everything goes well.

[hatchninja]

unconfirmed, (awaiting confirmation) but the ARP GSR rod bolts are said to work.

Also, I'm in the process of gathering information to make a sticky thread on H-T concerning building a solid budget F22 bottom end. It will address K20 pistons in the F22, K20 pistons in the F23, K24 pistons in the F23, and rod bolt info. It is clear that the F22 and F23 rod bolts are different.

(further confirming my suspicion that F22parts.com is a crock of shit)

[hatchninja]

http://honda-tech.com/zerothread?id=1317688 F23 with K20a2 pistons

ok it was confirmed for me that ARP rod bolts for a 96 GSR work on F22/H23 rods.

(8:07 PM 1/8/2008) thehatchninja: Hey dude,

I'm trying to compile all of the F22/23 N/A build info (K20 pistons, which rod bolts etc) I found a thread where you said something about using GSR specific ARP rod bolts in F22/H23 rods. Can you explain what needs to be done, or do they work without modification.
(9:28 PM 1/8/2008) alterdcreations: yep the bolt right in. 96 gsr arp rod bolts

[wed3k]

all you need to do is just measure the diameter and length *shrugs*

i can probably find some from a domestic application if i really wanted to. its all about being a pioneer.

im also using pressure plate, flywheel and possibly the harmonic balancer bolt from ARP.

[hatchninja]

all you need to do is just measure the diameter and length *shrugs*

i can probably find some from a domestic application if i really wanted to. its all about being a pioneer.

im also using pressure plate, flywheel and possibly the harmonic balancer bolt from ARP.

Well the GSR bolts work, and searching for 30minutes on H-t was just easier than taking the stud out and measuring it.

I dropped my F22A6 + K20z1 pistons + 272 cam off with my engine builder today.

A lengthy discussion that I had with PirateMcfred on H-T concerning K-series pistons in the F/H.

The K-series pistons have the wrist pin offset towards the intake side by about a tenth of an inch. The F23 has an offset towards the exhaust side of the piston. H22 and H23 do not have an offset.

On the K-series the cumbustion stroke pushes the intake side of the piston's skirt into the cylinder wall. Put another way the side with the intake valve reliefs receives the largest amout of sideloading. The H22 and F-series has the most side loading on the exhaust side. When you use the K20 piston in the F-series the exhaust side of the piston receives the most side loading. It was not really designed to handle the same loading as the intake side.

The pin offset helps straighten the rod out to reduce piston side loading. The top of a piston will see about 2500psi pressure on the combustion stroke and only about 300psi on the compression stroke. The idea of the wrist pin offset is to straighten the rod angle out on the combustion stroke to reduce friction on the pistons skirt and to improve the mechanical advantage of the crank's lever arm on the cumbustion stroke. It's more efficient in transfering the linear motion of the piston into rotation of the crank.

Benefits of reduced side loading is you can have a smaller piston skirt and a lighter piston that facilitates higher rpms and better wear characteristics and longevity and ultimately more power.

If you use k20 piston in F-series engines and you line up the intake valve reliefs with the SOHC valves the wrist pin is offset ~.200" towards the other side of the engine. The issues are:

The piston skirt loading is on the wrong side of the piston.
The rod angle is much more severe in the F22 and F23 than the K20 and add more load to the piston skirt and will affect longevity.
The pin offset will exacerbate the rod angle, increasing the side loading even more and affect torque output.

Another consideration of the K20 piston is the difference in skirt design versus the F/H-series. The F22 and H22/H23 skirts are HUGE and distribute the side loading better than the narrow, short K20 piston skirts. The F23 has a lighter piston design and it's asymetrical. The side that gets the highest side loading is larger than the other and the pin is offset to reduce the load too.

So yes, it will work. Yes, it has been done. Yes, it's a lot cheaper, but it's unknown how long the combo will last. The "best" solution is to line the exhaust side of the K20 piston up with the intake vavles in the F22 head. I don't know if this will cause clearance issues so clay and then have the valve pockets machined to accomodate the cam you intend to use if there are issues.

[hatchninja]

crushing it with the knowledge!1

[TheChosenOne]

I know I am leaning towards boost, but we gotta keep this alive.

[hatchninja]

K20Z1 pistons have been fitted on the F22A rods (piston has been turned so k20 exh side is on the F22A intake side for reduced sideload), ARP rod bolts have been pressed in, but the forgot to cut the 34mm intake valve reliefs into the pistons. I should have pics soon.

[wed3k]

pimp shit, i think i am going to change my mind and sleeve the block and use prelude type S pistons.

but i already have my G23 build going anf my next f22 is going to be a bullet proof bottom end with nitrous.