Silver_Bullet_S

I have a 2006 S2000 which needs a new head and I picked up an AP1 head from a 2002 S2K. I’m confused about how this AP1 head will work with my 2006 AP2 bottom end and 2006 intake manifold; particularly regarding the air pump that is not used on the 2006+

I was told that I wouldn’t need to block off anything in the AP1 head because my 2006 intake manifold would already blocked off the air pump passageway, but this doesn’t appear to be the case.

The pics below are of my 2006 intake manifold. You can see that the port/hole/passageway for the air pump is in fact still present on the dbw manifold and this opening goes all the way through the intake manifold, to the outside where the air injection valve body would sit on top of an AP1 intake manifold. I can’t use a block off plate either because there are no threaded holes in my 2006 intake manifold to screw the block off plate down to since it doesn’t have the air injection valve body to begin with.

It seems that Honda only closed up the port for the air pump directly on the 2006+ head, but the 2006+ intake manifolds still have the passageway without the bolts holes for the air pump valve body.

Am I missing something here? Has anyone out there used an AP1 head with 2006+ intake manifold & bottom end? I don't want to have to get an AP1 intake manifold.

Do I need to tap and plug the hole in the AP1 head or in my 2006 intake manifold? What do I need to do to make this AP1 head work with my 2006 bottom end and intake manifold, or is it not possible?

Also, can I use my 2006 valve train, cam towers, rocker assembly, timing chain/timing gears, coils, and the 2006 gaskets (head/intake & exhaust manifold) with the AP1 head? Are all the port sizes the same?

I know the AP1 has two cam sensors, so can I still use my 2006 valve cover and wiring harness with the AP1 head? Thanks

Billman250

Silver_Bullet_S

So the first pic on my post was of a 2006 intake manifold and it does have a hole for the air injection where the manifold meets the head. I've included some new pics below to help clear up any confusion.

It appears the air injection hole is clearly present on a 2006 intake manifold and it goes all the way through the manifold to the outside where the air injection valve body/housing would sit like on a 00-03 manifold (see first 2 pics below). However, the corresponding air injection hole/passageway is not present on the 2006 head itself (see 3rd pic below).

It appears that Honda must've only made one casting mold for the intake manifold, thus the intake manifold for every year S2K has the flange and passageway for the air injection... BUT it's on the actual head itself for the 2006+ models where the air injection hole/passageway is blocked off/missing, not on the intake manifold as people seem to think. This means you can't use an AP1 head w/ a 2006+ intake manifold and block.

If anyone is trying to use an AP1 head with a 2006+ block and 2006+ intake manifold w/ DBW, they'd have to use a block off plate for the air injection passageway on the manifold. The problem is that the intake manifolds for the 2006+ models don't have threaded bolt holes to mount a block off plate (see pic 2). Is it possible to have a machine shop tap & thread holes for mounting a block off plate? Would this cause the head to crack in that area or would it have any negative effects?

If I can't find a way to get a block off plate mounted to cover the air injection hole on the manifold, I'll have wasted money on picking up this replacement AP1 2002 head; and I'd have no other option but to buy a new 2006 head which is crazy expensive.

Is it possible that somehow my car didn't come with an actual 2006 intake manifold??? Perhaps a previous owner swapped out the intake manifold from another year. The last pic below is a shot of the manifold that came with my car. Does that look like a OEM 2006 intake manifold? Is there a way to distinguish a 2006 year manifold from another year? Any tips or ideas you can give me?



air injection hole on my 2006 intake manifold


air injection valve mounting flange on my 2006 intake manifold


air injection hole is blocked off by honda on my 2006 cyl head


the intake manifold that came w/ my car... This is a OEM 2006 intake manifold correct?

Billman250

Car Analogy

Is the IM gasket different for dbw cars? If the gasket has this hole blocked, then it wouldn't matter if both IM and head have the hole, the gasket would plug it up.

Is there a year whose gasket has thos hole blocked?

Silver_Bullet_S

QUOTE=Billman250;24494413][/QUOTE]

yes, it is definitely an open passage way. I took a pic (see below) where I inserted a straw in the air injection passage way in my 2006 intake manifold and you can clearly see that the straw protrudes out where the air injection valve body would sit on the intake manifold; so the AP2 intake manifolds (including 04-05) definitely have an open passage for the air injection just like an AP1 intake manifold would. So it's not blocked off by anything on the 2006+ manifolds like people seem to think.

Also, you can't use a just a block off plate to close the passageway on the intake manifold either becasue there is a tiny hole/passageway in the side of the intake manifold mating surface that leads to the air injection passageway in the manifold (see 2nd pic below). I don't know what this hole does, but even if you use a block off plate, this hole would still be open and effectively a leak in the head.

What this means is that you can't use an AP1 head with 2006+ motor unless you plug the air injection hole on the intake side of the head itself. This plug has to be in the cylinder head itself and can't be in the intake manifold or be done with a block off plate becasue the tiny hole/passageway in the side of the intake manifold would still be open if you were to block it off in the intake manifold itself becasue its located in front of where a block off plate would sit .

I guess this why Honda has no air injection passageway in the AP2 heads cylinder heads (see 3rd pic below). They're using the same casting mold for all the intake manifolds for all the years of the S2000, they just block of the air injection passageway in the AP2 heads themselves and don't drill and thread the holes for the air injection valve body in the AP2 intake manifolds.

If anyone has a DBW 2006+ motor and needs a new head you either will have to get an AP2 head or plug up the air injection passageway in an AP1 cylinder head, you can't just use a block off plate or plug up the intake manifold itself.

SIDE NOTE: I now have an AP1 head for sale if anyone is interested.



air injection passageway on my 06 intake manifold


hole in the side of my 06 manifold which leads to the air injection passageway, this hole sits in front of where a block off plate goes so a block off plate wont help


2006 heads dont have an air injection hole in the head itself.

Silver_Bullet_S

all year gaskets have the hole so the gasket doesnt block off the hole

jwzimm

I would suggest that you tap the hole in the head and install a threaded plug with some sealant. That will effectively plug the hole and allow for a flush installation to the IM mating surface. It should not be too difficult to find a tap that will cut clean threads into the hole in the head and then you just find a threaded plug (typically with an allen key in the center to drive it) and install it.

Steps:

1. Measure the diameter of the hole to .XXX dimension
2. Select a tap based on that hole size. Look for a tapped hole that requires a pre-drilled hole that meets your measurement from step 1. You should use an NPT type thread as that will allow the plug to fully seal and be airtight.
2.a. If the hole is an oddball size and you cannot find a tap that will work, enlarge the hole slightly to meet the next size up tap.
3. Carefully tap the hole. Use good thread cutting procedures. Cut a thread and then back the tap out slightly to break the chip (you can feel it break). Use light machine oil to lubricate the tap as you go. Cut the threads deep enough to allow your plug to go in cleanly and sit flush. It is a good idea to back the tap fully out when you get close to the final depth and test fit your plug. Once you have the hole fully tapped clean out any chips in the hole.
4. Install your NPT thread plug with some Teflon tape or sealant. Be sure to get the plug good and tight into the hole to ensure it is an airtight installation.
5. Proceed on as normal.

If you are not comfortable with this, any machine shop worth their salt would have no trouble getting it done.