03 CIVIC SI WITH K20A2 HEAD & PISTONS

[J MAN]

I thought I would jump out of the Drama Tree and talk cars with you.

We(ALAN COX AUTOMOTIVE)are rebuilding my 03 Honda Civic Si & upgrading most everything. After several Track Days & Over Revving the Motor, it was time to make this step.

REBUILD.
NEW ROD BRGS
OIL PUMP HOUSING & GEAR

UPGRADES.
EXTRUDE HONED RSX TYPE S HEAD
PORTED & POLISHED INTAKE MANIFOLD
RSX TYPE S PISTONS & RINGS
HONDATA K PRO ECU
EXEEDY STAGE 1 CLUTCH KIT
KNOWLEDGE PERFORMANCE LIGHT WEIGHT FLYWHEEL.

We are consulting with Knowledge Performance who will also be doing the Hondata K Pro & Tuning.

My question is, has anyone ever heard of this being done? I am keeping my 03 SI Block.
Kevin at Knowledge said he knows of one person that did it.

The pistons upgrade from 9 to1 comp to 11 to 1.5.
We found a few minor differences between the motors but not much.
The K20A3 (SI) is the same except for the Pistons & the Cams.
There are a few technical differences but it looks like Honda went out of their way to make the K20A3 weaker by designing a weird looking piston that lowers compression and putting in the weaker cams which have less lobes to open at VTEC. In fact, I really don't have VTEC in the since of the old B Series Eng.

Any pointers out there?

J Man

[Bruce Leroy]

1 min search


After reading another post on this today, I finally threw my hands in the air and decided to write something up. The following is just my basic opinion on things (and others from this and other boards). Could a mod please sticky this (if they feel it is useful enough that is).

K20A2 Cylinder Head Swap
The following is a guide that I put together because, frankly, I’m sick of seeing these topics pop up all the time.
All of the information used in this guide was found via the EPHatch search button, and personal experience from doing the swap myself.
I suggest having a good mechanic perform the following swap for you. I am no responsible for you digging into your engine and ruining it. You do it at your own risk.

Tools needed:

10mm open end wrench and socket
12mm open end wrench and socket
17mm open end wrech and deep socket
19mm deep socket (for crank pulley)
Torque wrench
Honda crank pulley holder (this is not needed if you know how to lock the flywheel)
Feeler Guage (for valve adjustment)
1/2" drive ratchet with 1/2" drive extension (8" recommended, this is needed to hold the crank pulley holder)
1/4" driver ratchet (for smaller misc bolts and nuts)
I used a craftsman 1/2" breaker bar to remove the crank pulley with a 36" 1/2" drive extension.
** Note: This is not a complete tool list, if you have more to add that I missed, please PM me and I will add it. Thank you.
Things recommended to order from Honda
Intake Manifold Gasket (or Hondata)
Exhaust Manifold Gasket
Head Gasket (you MUST get a new one)
Head Bolts
Honda-Bond
310cc RSX Type S fuel injectors (must have)
RSX-S spark plugs (not needed, but recommended)
RSX Type S ECU or Hondata K-Pro (you must have one or the other, I recommend K Pro)
The procedure:
**Note: The following is a list of what happens during the swap. If you want more information (which I’m sure you do), I suggest buying a Helms manual, which will guide you step by step of the following list.
Remove coil packs, spark plugs, and valve cover
Turn crank to TDC
Remove crank pulley
Remove intake manifold and exhaust manifold
Remove VTC actuator
Remove passenger side motor mount (make sure you remove the crank pulley before you do this, or the engine will just torque over and you will have a harder time removing the pulley bolt)
Remove timing chain case cover
Lock the timing chain auto tensioner using pin
Remove auto tensioner
Remove timing chain
Remove rocker arm assembly
Remove cylinder head
For installation, following the same procedure, but backwards installing new gaskets.
Before you install the valve cover, make sure to adjust your valve lash. The correct lash and torque specs for both the intake side and exhaust side can be found in the Helms manual for the RSX-S.
Remove old Honda-Bond from timing chain case cover, put new bead of Honda-Bond along edges
Make sure all bolts are torqued to specifications found in the Helms manual.
Pictures of my head swap can be found here (http://www.mikaeldoyle.com/headswap/)
FAQ
What is needed for an a2 head swap?
You will need a K20A2 cylinder head, RSX-S 310cc injectors, RSX-S (or K Pro) ECU, RSX-S spark plugs and new gaskets.
What can I use from my a3?
Besides what is mentioned above, everything else bolts up to the A2 head (exhaust manifold, intake manifold, valve cover, spark plugs, VTC actuator, timing chain case etc.)
Do you need to use ARP head studs (bolts)?
No, you do not. As long as the factory head studs are within specifications (check the Helms manual) then you can re-use them. I suggest going to Honda and buying new ones.

How long did it take you? Or what's the longest it should take?
It took me approximately 6 hours with a buddy. Many things can occur during a swap like this, as long as you do it properly (follow procedures) don’t be concerned with how long it is taking you.
If anyone here has done the A2 head swap, could they tell me what kind of power numbers that I can expect from my car with just the head, ECU, and injectors?
Power numbers are everywhere when it comes to this swap, because some people use stock RSX-S ECU while others have had their car tuned using K Pro. I would expect to see anywhere from 165whp to 200whp depending on your specific setup.
How high can I rev with the A2 head swap?
I have been revving to 8,000 RPM’s quite a bit with no problems as of yet. I would not suggest revving any higher then that on the stock block.
How reliable is the swap?
Quite a few people have completed this swap. One particular person (as of writing this up) has reached 20k miles on his and has reported no major problems yet. I personally have 3k on my setup, and have not yet seen any problems either.
Where is the best place to find an A2 head in good condition?
I found mine on Ebay quite a while ago. I would call local junkyards and mechanics. They should be able to help point you in the right direction. Also check out the classified sections of the boards dedicated to K series powered cars (ClubRSX.com, EPHatch.com, K20A.org, K-series.com)
If I use the A2 head will I be able to use aftermarket cams, springs and retainers designed for the K20A2?
Yes, you will. Just make sure you choose a cam that doesn’t need to be revved higher than 8,000 RPMs to make power and you will be fine.
If I put the A2 head on my car and decide to use the stock gauges will the needles hit each other?
No, the needles will not touch each other.
My question is how many of you have an A2 head w/ your A3 block and still have warranty?
If your problem ends up being engine related, your warranty will be void. If it has something to do with another aspect of the car, they should not void your warranty for having the head swap. If they do not want to cover your warranty even if the problem has nothing to do with the engine, you should look into the Magnuson-Moss Warranty Act. More information can be found at the following link.
http://www.ftc.gov/bcp/conline/pubs/buspubs/warranty.htm
Will I have “real” VTEC after installing the head?
Technically, yes, although all VTEC is “real”.
Will I have worse gas mileage after completing the head swap?
Before the head swap I averaged roughly 28-31 MPG on average driving in mixed conditions. Since the swap I have been averaging roughly 27-29 MPG with the same type of driving and conditions.
How much should I expect to pay for an A2 head?
I paid a lot more then I should have, because I was impatient and didn’t feel like looking around. I would not personally pay more then $700-$800 + shipping for one today.
I don’t have money for the 6 speed, do I need it?
You don’t technically need it to complete the swap, but it would be good to have. Read this post by anjapower, he goes pretty well in depth about why he was disappointed in not having the different transmission.
http://www.ephatch.com/forum/showthread.php?t=47322&highlight=head+swap
I don’t want to swing K Pro right now, how will the car drive with just the RSX-S ECU?
Simply, it will run like crap, but it will run. I really suggest getting K Pro so that you can at least do some mild street tuning.
What if I just get a VAFC? Will that keep me from dropping out of VTEC?
The problem isn’t falling out of VTEC; it’s falling out of the useable power band. I can drop my VTEC point way low, say 3,000 RPM’s and still be falling out of the power band. A VAFC is a good tool, but it is no where near the likes of K Pro.
Will I pass smog if I put on an A2 head?
I personally don’t know. But I really don’t see why you wouldn’t as long as there is still a catalytic converter on the car.

Will the base RSX ecu work with a A2 head swap? Some one said you can get it reflashed at the dealer to work like a type S ecu is this true?
No, the base RSX ECU will not work for the A2 head swap. You either need K Pro or the RSX-S ECU (But you can send out the base RSX ECU to Hondata to have K Pro installed on it). No, the dealer cannot reflash the base ECU to have the RSX-S tune.

Alright, that’s enough for now. If anyone sees any major discrepancies or has any useful information they would like added to this, please PM me and I will put it in here.

[J MAN]

Thanks for the info.;)

We are putting it back together now. The info confirmed what we already knew.:thinking:

I will post the numbers in a few weeks after I break it in.

Once again, thanks

J man

[i4_garage]

K20A3 does not have VTEC .... K20A2 does.... : )

[Vteckidd]

Actually, you didnt need to go throudh all that, you can make 180-190whp with the A3 motor :)

The K20A3 bottom end has similar block to the K20A2. Cranks are different. The head obviously is vtec ONLY on the exhaust side. the K20A2 has VTEC on both sides, traditional VTEC as most people think.

With Skunk2 cams for a3 available , power is attainable for those "forgotten motors"

[Bruce Leroy]

Actually, you didnt need to go throudh all that, you can make 180-190whp with the A3 motor :)

The K20A3 bottom end has similar block to the K20A2. Cranks are different. The head obviously is vtec ONLY on the exhaust side. the K20A2 has VTEC on both sides, traditional VTEC as most people think.

With Skunk2 cams for a3 available , power is attainable for those "forgotten motors"

THats what I was going to say, but he seems like he has his mind made up.

[Vteckidd]

ALso , i think you mean EXTRUDE HONE the intake manifold an PORT AN POLISH the head.

I dont think you can extrude hone the head.

POrting wise, iw ouldnt touch the RSX head at all. they flow enough to support 250whp.

We just built a K20A3 motor:
Type-S crankshaft
CP 12.5:1 pistons
Eagle Rods
ACL Race Bearings
K20A2 Cylinder head with Rocket Motorsports Valve Job
DC5R cams

http://chunky.darksci.net/images/blown2/7.jpg
http://chunky.darksci.net/images/blown2/8.jpg
Oringal motor was a TYPE-S motor that had DC5R pistons that exploded under high revs. We had a good crank, but no good K20A2 blocks, so we picked up an A3 bottom end for $100 and used it. the blocks are the same, internals are differnt.

should be in the 220-230whp range on a dynojet

let us know the numbers

[J MAN]

Mixed up the terminology.

Port & Polished Head
Extrude Hone Intake Manifold.

I am aware of the Cams from Skunk 2.
Budget says later.
I had a Head off RSX Type S for free and the Pistons were free too.
I have the Hondata K100 Ecu in the car already, so I will get it re flashed to a K PRO.

I have heard good things about Main Stream Performance, so I appreciate the feed back.
I will keep you posted on how it turns out.

J Man

[Vteckidd]

cool , let us know the numbers, interested to find out.

makes sense to me, parts were free hehe, thats always a plus

[J MAN]

We have the car finished!:yes:

I am running the car on my Civic SI injectors until I can get the RSX S Injectors bench flowed and repair two that are stuck open.

Its running on the Hondata K100 ECU with a Civic Type R Flash.
I will be heading to Knowledge Performance on Tuesday to have the K Pro Down Loaded and Tuned.

I do have a Check Eng Light on. The code says basically that the car is running too rich.

Just putting around till I get to the Dyno.

I will post more later.

J Man

[99SI]

Just hope that you aren't running TOO RICH. Since on a fresh motor if you are running very rich you run the risk of washing out the cylinder and having an unlubed cylinder with a big slug of metal running up and down it. That's a bad way to start a build, with scoring cylinder walls. If you're at 11.5:1 or 12:1 I wouldn't be concerned, but anything in the tens I would be scared. It seems odd that you would be rich with the Si injectors tho, I guess it just depends on that Civic flash that you are running. Good luck, I hope it turns out well for you. And yes, there are some great things going on over at Mainstream. I just hope with all this 2jz nonsense :D that people don't forget that they are still the #1 place for Honda/Acura.

[Vteckidd]

We have the car finished!:yes:

I am running the car on my Civic SI injectors until I can get the RSX S Injectors bench flowed and repair two that are stuck open.

Its running on the Hondata K100 ECU with a Civic Type R Flash.
I will be heading to Knowledge Performance on Tuesday to have the K Pro Down Loaded and Tuned.

I do have a Check Eng Light on. The code says basically that the car is running too rich.

Just putting around till I get to the Dyno.

I will post more later.

J Man

If you need TYPE-S injectors PM mei have a full set with a feul rail that i pulled out of a running motor.

Good to hear, your prob throwing an O2 code which is prob causing the car to run rich at partial throttle.

Get her on the dyno an get us some numbers, im sure itll be a VERY fun car to drive

[J MAN]

Not to go off the Subject, but whats the story on S2JZ??

As far as the running too rich, it could just be that when I ran the motor the first two days I had 2 injectors stuck open and that was just sitting in the shop, not driving it. They may have finished my 3 year old o2 sensor off.

It runs good except at 2000 to 3000 rpms where it stumbles.
I have not driven it hard and the light only comes on after I driven it a 100 miles or so and mostly if I am sitting in Traffic.

Its at Knowledge Performance now. Should pick it up Sat.

Not to kiss Main Streams rear but I saw one of your Honda S2000 on a website that had photos from NOPI.
600 + Horsepower.
We Turboed a S2K last year and had a lot of problems with it. In the end the Exhaust Manifold from Rev Hard was not large enough according to ED from Balanced Performance ad the Customer did not want to have one custom made.

We ended up with about 400 WHP but it runs better at 325.

I would be interested in a small story on that Main Stream Performance Turboed SK.

We have had much better luck with Super Chargers on that car.

J Man

[Vteckidd]

Not to go off the Subject, but whats the story on S2JZ??

As far as the running too rich, it could just be that when I ran the motor the first two days I had 2 injectors stuck open and that was just sitting in the shop, not driving it. They may have finished my 3 year old o2 sensor off.

It runs good except at 2000 to 3000 rpms where it stumbles.
I have not driven it hard and the light only comes on after I driven it a 100 miles or so and mostly if I am sitting in Traffic.

Its at Knowledge Performance now. Should pick it up Sat.

Sounds good, im interested in your numbers. The car prob has tip in lean problems which is why it stutters, that or your O2 as you said is bad, just partial throttle tuning, so she should purr once shes tuned.




Not to kiss Main Streams rear but I saw one of your Honda S2000 on a website that had photos from NOPI.
600 + Horsepower.
We Turboed a S2K last year and had a lot of problems with it. In the end the Exhaust Manifold from Rev Hard was not large enough according to ED from Balanced Performance ad the Customer did not want to have one custom made.

We ended up with about 400 WHP but it runs better at 325.

I would be interested in a small story on that Main Stream Performance Turboed SK.

We have had much better luck with Super Chargers on that car.

J Man

Well our s2k is no ordinary turbo kit . We fabricated everything on the car. The turbo manifold is a topmount, twin wastegate design. Its tubular and similar to the full race manifold. It also has a Topmount intercooler in the hood, so no big FMIC.

We used a 62-1 Ball Bearing Turbo with a stage 5 wheel rated at 680hp.

Its a built motor with Darton Sleeves, CP pistons, Inline Pro Rods, Ferrea valves, valvetrain, We ported the cylinder head very aggresively.

I suspect you had a bolt on REV hard kit which uses a LOG manifold. LoG manifolds are great for street applications, quick spool, but they suck for PEAK numbers. They just cant flow enough air. They usually max out around 400whp.

do you remember what turbo was on it? was the motor stock? if it was stock, those arent bad numbers at all.

We beat the Full Race s2K by a few whp with less boost so we were happy.

12PSI on pump gas
http://i24.photobucket.com/albums/c21/Vteckidd/s20002.jpg

15 PSI on PUMP GAS
http://i24.photobucket.com/albums/c21/Vteckidd/s2000.jpg

22PSI on PUMP GAS (100 octane)
http://i24.photobucket.com/albums/c21/Vteckidd/s2k.jpg

http://i24.photobucket.com/albums/c21/Vteckidd/Picture239_800x600.jpg

We are shooting for 700whp once we get the "new" turbo in

[J MAN]

Well I ended up with a pleasant surprise.
216 WHP & 145 Torque.
The Head I have came with ITR Cams.

Sad thing was, it all lasted for about 1500 miles before the Oil Pump Harmonic Balance Shaft Bearings spun out and chewed up the Pump.

Looks like I got lucky, did not blow the Motor.

We are replacing the Pump with a Type S Pump which does not have the Balance Shaft Assy .
Not sure why the K20a3's have that set up because we can not see that it does anything beyound splashing oil.

The RSX Type S Oil Pump mounts perfectly where the SI Pump does and everything looks good.

The Gear Sprocket on the Type S is bigger so we will have to use the Timing Chain off the Type S.

We are going to flush everything out and replace the Rod Bearings as a safety net.

It was fun while it lasted but now were back to the drawing board.

J Man

[Vteckidd]

Well I ended up with a pleasant surprise.
216 WHP & 145 Torque.
The Head I have came with ITR Cams.

Sad thing was, it all lasted for about 1500 miles before the Oil Pump Harmonic Balance Shaft Bearings spun out and chewed up the Pump.

Looks like I got lucky, did not blow the Motor.

We are replacing the Pump with a Type S Pump which does not have the Balance Shaft Assy .
Not sure why the K20a3's have that set up because we can not see that it does anything beyound splashing oil.

The RSX Type S Oil Pump mounts perfectly where the SI Pump does and everything looks good.

The Gear Sprocket on the Type S is bigger so we will have to use the Timing Chain off the Type S.

We are going to flush everything out and replace the Rod Bearings as a safety net.

It was fun while it lasted but now were back to the drawing board.

J Man

thats REALLY good power man, congrats!

just fix the oil pump problems and new bearings an you should be good to go