So I always liked the look of mechanical injection but luved the practicality of modern engine management systems like Meggasquirt. Tuning your car with a laptop seems so civilized:)

This is basically the same fuel delivery system I have on my current EFI manifold. It works great. The only issue is if you park the car for 10 min. when you restart it you get a bit of burble at idle from the hot fuel. Now that the intake isn’t sitting over the hot header this my go away.

This is why I redid the fuel block. Isn’t that better?

The brass fitting is for the oil return. That fitting is just a placeholder for now so don’t judge:)  The stainless bulkhead fitting is the rear oil supply line. All the fuel and oil fittings are Swagelok style double ferrule fittings.

There are a lot of reasons why I post the good, the bad and the ugly, but mostly because I think it really helps people realize just what goes into creating something that is truly custom. And why custom fabrication is so pricy.  Some time ago on HybridZ there was a thread about a hybrid Z car that was being sold for over a hundred grand or thereabouts. It was green just to jog some memories.  It kind of settled int those that couldn’t see the value and those that do fabrication that could. I’m being broad with my brush but you get the picture. I took one look at the pictures and immediately saw that kind on money in it.

So for this tale I’m the customer and the fabricator.  I’m at the point where I want to get going on the fuel system. I made all the injector caps already but I needed a fuel distribution block so I could do the hard lines. I discussed the options with my customer (me) and we settled on a straight block with the fuel lines one on top of the other. Much like the one I already had on my car. I did a 3D model of it which included measuring the space available, measuring the distance required between the fitting in order to get a wrench on them, inlet, outlet and mounting holes. The customer approved the 3D model and I commenced to machine the block. Since there was only one I had to baby sit every operation. No screw ups. I chewed up the better part of a day by the time I was done with everything including finishing. Now if you want my undivided attention for a day it’s going to cost you $400.00 or more. So the piece looked exactly like the 3D model and functioned exactly like it was designed to do. Except the customer (me) just didn’t like the look of it in application. The customer wanted it right so we started over with a new design. Now this one took about half the time since it used all the same general measurements and tool operations so the machine work went much faster.

So here we are with five or six hundred dollars in a simple fuel distribution block.

And that my children is why this crap costs so much:)

First design:

Second design:

One last pressure test before I start to assemble the head. Holds 40 psi no problem.

Finally rounded the corner and I feel like I’m officially in assembly mode. Got the valves installed.

Looking a little scruffy but you’ll have that with a prototype like this.

A couple of weeks ago a put the head back in the mill and removed the last of the Honda A3 design. The A3 uses an asymmetrical combustion chamber. I was going to do this mod when I do the stroker but it was bothering me. The head is now closer to the A2 chamber.

One more dry fit of the rockers. They line up really well on the valves. I’m glad I took the time I did to get it right. Plus I now have good data for the next head.

I had to bore the KA lower gear out to 35mm. I also had to make a couple of spacers so that it was as thick as the L6 lower gear. When I bored it out I lost most of the key way. It also made the hub area a little thin. I decided to make the outer spacer ring dished to slip fit over the hub to add a little strength.

Here are the 2 parts assembled.

And installed on the crank. I had to leave the gap between the gear and the spacers for chain link clearance.

Had to remove a couple links and add a half link.  I also had to cut down both guides.  The lead angles on the chain look pretty good. Time will tell though.

Test fitting before I broached the keyway.

Stalagmite of chips:)

Starting to get all the odds and ends wrapped up. It’s tough not getting too far ahead of myself. I want to stay productive but without cams I’m kind of at the end of the line.

I’ll finish up the fuel and intake systems in the next week or so.

So I took the head down to Scott’s Racing engines to get it Flow tested.

The before column is a raw port with only the machine work for the port matching done. The after has been cleaned up really quickly with a double cut round burr and then I hit it with a cartridge roll on a mandrel. All I did was remove the sand casting texture, blend the steps between the seats and ports, and remove the additional material from the halve guide bosses.

The clear acrylic manifold Had a 3.5″ bore.

They applied modeling clay to the intake ports to smooth the air entry and they held a tube against the exhaust port to simulate a header.

Here is the before port. You can see the steps between the valve seats and the ports are still there and the valve stem bosses are too long.

Here is my piss poor after port. You can see there is plenty of room for improvement with my porting abilities:)

This is a flow comparison chart don by Bryan Blake of BMC. If I trust anyones numbers it would be his. As you can see my head is well above the stock KA and really close to Bryan’s ported KA.

They are just initial numbers but they do follow what I hoped to see based on my port volumes. When I was designing it I looked up the kind of volumes the K20 head gurus were running and I tried to hit those marks. Especially on the intake. The exhaust is fairly close to the stock K20 in shape but the intake is mine from scratch. I started with the stock entry and exits and made it look pretty in between.

Started working on cam tower mods and oil distribution. The plan is to pull oil from the oil pressure switch bung and Tee it to the front and the back. The front was pretty easy because I had incorporated material in the casting. The rear…Meh not somuch.

Production heads will most likely use the #1 cam tower at the back to supply oil but that was proving to be impractical on the prototype so I opted for a different path. I took an extra #2 tower and made a manifold plate to bring the oil in.

I doweled both pieces to maintain alignment. I tapped the tower and it’s held together with three screws sandwich style.

Oil is fed in the bottom. and it’s cross drilled and plugged to supply the shafts

Tight fit but it will work.

Here are some process shots for those of you that are interested.

After rough surface and fly cutting.

Outlining the flange.

O-ring groove.

Port matched and injector clearance machined in. I’ll hand finish the injector area.

Got the manifold to head flange done. I still need to de-burr the sharp edges but I’m happy with the results.

Hard to tell in this picture but the ports match really well.

1/3 of a money shot:)

Should be able to finish up the other 2 tomorrow. Now If I could just get my valve cover I’d be set for a while.

Got started on the first manifold.

Probing the ports. This will establish my zero point. The cores were 3D printed and the ports ended up being 90.114mm apart. I can handle .114mm:)

Action shot of the fly cutter doing the finish pass. on the flange.

In order to make the linkage that came with my ITB kit work I needed to shift the ports .025” It is going to be a lot easier to blend the shift than rework the linkage.

I didn’t have a CAD drawing of the ITB so I traced around it, scanned it and then imported it into my CAD program. I’m happy with the fit.

WFO

Working on the injector bungs. I drilled all the way through with a .4375” bit then opened it up to .655” part way down. I use the method described here:

http://www.sdsefi.com/techinta.htm

It leaves an air gap around the injector body and help guard against heat soak. It’s the same method I used on my manifold and it survives August heat in Florida.

I pulled one of the injectors out of may car for a test fit.

That’s going to look really good!

Now that’s my kind of selfie:)

Finally got my intake castings in. They came out pretty good. I may need to tweak my pattern a bit.

A good part of the flanges will be machined away. I purposely made the a lot larger than I needed. I like options.

I left the intake to head port as an oval. I will machine in the injector port area after I have drilled the injector bung.

While I was waiting for the castings I went ahead and made my injector caps for the hard lines.

Not perfect but nothing I make is:)

Here is a shot of the first two ops

Next week I’ll have time to get on the manifolds. I can then start to do the linkage and fuel delivery.

Fun stuff!