2004-05 cylinder head versus 2006+
 

There is some difference between them but does anyone know if a 2005 head can be used on a 2006. I know you can't use a 2006 on a 2005 but not sure about the other way around. Thanks.

The '05 head has the air ports into the exhaust passage unlike the '06. They could be welded shut but so much work is not the easy way to go.

https://cimg4.ibsrv.net/gimg/www.s2k...6b7022fbd8.jpg

The air injection system includes the part bolted onto the exhaust side of the head as shown.

Thanks. What's the purpose of those anyway?

Air is injected at start up and that heats up the cat quicker.

I always wondered why my car didn't have that part bolted to the side. Thanks again.

I thought I would update this thread with some information. If you have a 2006+ and want to use an earlier MY head, you need to seal up the holes on the outside of the head, but there is no advantage to welding shut the actual holes in the port.

Hi, I know this thread is old now... But I was hoping you could help me out. I have a 2006 S2K & my head gasket blew and warped my head & block around .002"- .003". Unfortunately, I took my head to a machine shop which used a belt sander to remove material from my head and just screwed it up. Then I took it to another machine shop to get it fixed and they screwed it up even more & now the head has had too much machined off to be useable.

I found a couple a few used AP1 heads for sale on the forums but I'm not sure what's involved to making them work. The questions I have are:

- How do you close up/plug the air pump ports in the AP1 head to work w/ a 2006 AP2 block?
- Will my 2006 engine harness, intake manifold, fuel rail & all the hoses be plug & play with the AP1 head? If not, which components wont work?
- Will my 2006 cams work w/ a AP1 head?
- Will the 2006 ECU work fine w/ the AP1 head, considering the 2006 is a 2.2L & the AP1 was a 2.0L?
- I still have my 2006 OEM valvetrain (valves, springs, retainers, guides, keepers, cams, rocker assem, cam caps, etc.); will all this fit plug & play in an AP1 head?
- Other than the AP2 retainers being a little better, is there any diff in the valvetrain between AP1 and a 2006+? Are they interchangeable?

I really need some help/advice. It's next to impossible to find a head from a 2006+ so it looks like my only choice is to use an AP1. Any advice/info you can offer would be much appreciated. Thanks much.

Thanks so much for the info/help Billman. The heads I'm finding aren't local, so hopefully the seller is being honest when they say they weren't overheated.

The owner of the head I'm considering says it's off a 2002 (88k miles) & never was machined/overheated. However, the head failed a leak down test on cyl 2 & 4, but had 240 compression across all cylinders when tested. I'm guessing the valve seals might be leaking; any thoughts? Is it still worth buying?

Also, I'd still need to have a machine shop cut fresh valve seats & lap the valve faces correct?

You mentioned that no ports need to be plugged & that the intake manifold will take care of that; but aren't the air injection/pump holes on the exhaust side of the head just above the exhaust manifold? The pic below shows what I'm referring to... Don't these need to be plugged? Sorry if this is a dumb question, I'm a noob & don't want to make a mistake on the replacement head I get. Any advice you can give is much appreciated. Thanks.

https://cimg9.ibsrv.net/gimg/www.s2k...5e8a11a274.jpg

should these holes be plugged on an AP1 head - they're on the exhaust side?
https://cimg0.ibsrv.net/gimg/www.s2k...279e4a5389.jpg

Those holes leads back to to intake side of the head and on a non dbw car it connects to the intake manifold.
Your dbw intake manifold doesn't have this opening and will just block it off.

Posting identical questions in multiple locations just fragments the responses.:banghead:

You milled the block. Not sure what effect this will have and it was noted but not answered in either of these fragmented threads.

-- Chuck

Thanks for clearing that up. I appreciate it. Are the intake/exhaust manifold gaskets & head gaskets all the same for all the S2000 years? I already bought the gaskets for my 2006. Thanks.

thanks for the info

Slightly different question from my side, have searched it, but just to make sure.

I have an early 2002 S2000. lower block is shot and I can get a new (F20c) 2009 lower block.

Is it plug and play, on my 2002 head, intake and harness / sensors? I believe it is, since there are almost no difference in the lower blocks through the years.

Thank you very much.

crank sensor needs to be swapped otherwise no difference other than displacement. If you're in europe disregard that last bit.

Both plug and sensor is different, you will also need to replace the trigger wheel.

Well it's not that hard of a job with the engine out, but you could always swap to a kpro ecu instead and keep it sealed :)
I also think the knock sensor is different on 06+ cars but not sure if that matters.

sorry i just saw your message. Like the others mentioned, the displacement went from 2.0 to 2.2L and as a result the power band was affected. The stroke was changed with and added 6.7mm, and I believe so was the rod ratio. You will not be able to rev a 2009 bottom end to the same redline as your AP1. The cranks sensor is diff, the compression went from 11:0.1 to 11:1, and I believe the bracket under the intake manifold that bolts into the block was changed.

I wasn't sure if you're getting a bare block, or if the 2009 block you're getting has the internals with it. Since the displacement/compression and stroke was changed you might want to check out if that affected piston to valve clearance at all, i don't remember off the top of my head, but I doubt it would be an issue. The 2006+ head an intake manifold casting are different and use less sensors and also don't have the air injection system and there's the change too DBW, but that shouldn't be an issue if your using your AP1 head and harness.

if you're doing all that work, it'd also be a good time to swap out AP1 retainer for AP2 and keepers if you haven't already done so.

it's not that hard to do in the car either. removing the crank pulley and the oil pan clearance will be your biggest battle if doing it in the car. with the motor out of the car, it's real easy but messy since Hondabond never comes out in a smooth evenly distributed line lol

Crank pulley is easier to remove in car IMO. Big ass 3/4 breaker bar, hand brake on all the way, transmission in 6th. She'll come out.

The crank pulley wants to stay on the car! We splayed the swivel end on a 3/4" drive 24" breaker bar pulling the crank pulley on a buddies 2002 car. Welded it in a fixed 90° angle to finish the job. We had 4- or 5-foot extenders on it and the special fitting that prevents the engine from turning. Still took two of us. I have no idea what tools would get this off the engine if it wasn't bolted solidly in place.

-- Chuck

Maybe you should read the message and not only see it ;)
He is getting a new F20C block, yes we got AP1 in all year cars over here in Europe.

Yes, thank you guys.

I got a new 09 F20c2 lower crate block and I just swapped the trigger crankshaft wheel, to make it compatible with my 2002 head and S2000.

I had the head refurbished and installed in all together, so basically a fresh/new engine!

Hey @Billman250 and @flanders I currently have my car at a shop and we've discovered that you do in fact need to plug a hole (or four) somewhere if you want to use the 2004 - 2005 head in a 2006+ car. The 2006 Intake Manifold does NOT seal the Secondary Air Pump passage in the 2004 - 2005 head. When the car was started exhaust gases were coming out of the 2006 Intake Manifold. See the picture of the 2006 Intake Manifold below:

https://cimg8.ibsrv.net/gimg/www.s2k...6c72954f8f.jpg

Good to know, I wonder if all years are the same or if Honda later figured it was unnecessary to machine that out.
Hope you don't need to remove the intake manifold to plug it.
Easiest route if it's already installed is probably just to fill that big oval hole with some JB weld.

@flanders We're going to pull the Intake Manifold, drill and tap the hole in the Intake Manifold for a 3/8" NPT plug, and then seal it off with a short NPT set screw style plug. Then reinstall the Intake Manifold.

**edit** Pulling the intake manifold is going to take too much work. We're going to try and fill the oval hole with JB Weld. If it doesn't work I'll pull the manifold and tap the runner as mentioned above.

As for the Intake Manifold, its the same part number for all 2006+ DBW cars. So for anyone wanting to use a 2000 - 2005 head or engine in a 2006+ car you'll need to seal the Secondary Air Passage somewhere.