Derek

Here is a link (I may have posted it before) about putting stock A2 cams in an A3 head and using the exhaust rockers on the intake. He killed the iVtec rockers but kept the variable cam timing. http://www.k20a.org/forum/showthread.php?t=66643 It's a pretty good thread with dyno results posted. Based on everything I calculated, my head in it's stock form will flow more along the lines of a ported A2. That remains to be seen obviously. I'm revisiting iVtec because I've had a few inquiries about it in PMs. But I'm only revisiting it to the point of making sure there is cast aluminum everywhere it needs to be in order for SOMEONE ELSE to implement. There is a whole ton of things that have to happen for iVtec to work. Cams and custom timing chain hub come to mind as well as a ton of extra machine work. Possibly custom cam towers or at the very least highly modified towers. Hopefully someone with really deep pockets will make this happen. If I had to guess I could easily see another $4000.00 or more for taking it to that level. But if someone was thinking about plunking down 40 grand for an OSG head, 15 or 20 grand for a 6 cylinder full iVtec head looks pretty appealing.

They call him "Stubby" Very happy with the fit. Made a mandrel to form the ovals. Should make for a nice looking header. Remember kids good fabrication is all about joinery. The better the fit the smaller the weld. The smaller the weld the less the warp. The flange and header will be mill finish. Going out today to Xnke for fabrication.

Finishing up a pattern today and I'll be able to work on the stubs tomorrow. Should be able to ship the flange, adapter and stubs tomorrow.

Not much to report. Waiting on the cam core castings. I got in a hurry when I was reaming the intake valve guide bores so the stock sized guides are too small. Fortunately SI Valves sells universal pre bored valve guides. They are manganese bronze. I have to machine the exterior to the correct size. After that the head is ready to go to Mazworks for the head work. I'm hoping to have it ready to go next week. When I have the head back I can determine if the cam bores are still aligned. At that point if they are good the cams will ground. The intake manifold printed cores are done and on their way to the foundry. I'm about a third of the way done with the manifold pattern. Should have it done next week as well. I was sick for a week so that kind of screwed up production.

NA.

As long as you didn't do it taking a dump you're probably still ok.

It's my understanding that it will be an equal length header. I don't know what denotes a "long tube" from a "short tube". I do know that the large radius bends right off of the head will not be needed as the OSG head (and motor) as well as the S20 is tilted the opposite direction as ours. I don't believe that changing the tilt will be necessary on mine. This means shorter radius bends can be used and still achieve a decent length. Derek

Well if December of 2007 is a few years ago then yes it "was" a few years ago:) You're getting old. That's the first sign. The big problem with it was I laid the base coat down too heavy and then cleared it too soon. It trapped solvents and the clear started coming off after about 4 years. I had to strip all the old clear and base off with a da. And of course there was new rust to be fixed.... I use products from Southern Polyeurathanes http://www.southernpolyurethanes.com. Their products are really great (as long as you follow the directions) and the price is amazing. The red is their house brand red base. I had a little problem laying down the clear and the owner spent 20 min on the phone with me getting it dialed in. Try that with PPG Hard lines are more work but you can't beat the look IMHO.

You and me both! There is still a butt ton of stuff to do though. Yes. One of the Hybridz family is helping me out with exhaust design and fabrication. I'm sure he'll chime in at some point. Got the intake manifold designed. I'm utilizing a balance tube like I did on my EFI manifold. It made my life a lot easier. By doing three separate manifolds it reduces my risk of failure. I'm 3D printing the cores and I ordered them today. The pattern will be conventional. I designed the flanges to be a lot larger than I need but I want to have options when I do the machining. I'm using the same injector boss mount as my manifold. This way I can hard line it if I want to. And I want to:) I got a call from the steel foundry and they are pouring the cams next week. Hopefully the first units will pass inspection. If they are good then I'll do some basic machining and then I'll ship them out to Isky for grinding. And I'm painting my car Base coat. Cleared it today. No time to do a proper job but it's been off the road for almost two years and I had enough. I wanted to drive it again. It'll look ok. Basically painting in my fab shop so you can only imagine how clean that is:)

Thanks. Originally I was going to cast it as part of the front cover. The general consensus was exiting the water over each exhaust port like the OSG head was a superior way to go. The production models will be that way. I'm going to machine a separate elbow for mine and incorporate it into the timing cover.

Been working on a bunch of stuff so I guess it's a good time for an update. Got the pattern done for the cam cores and it's sitting at the foundry waiting to be poured. Got the pattern done for the front timing cover and got the casting back from the foundry. Today I was able to finish up the machine work on the timing cover and head. The timing cover is a bit of a kludge as I had printed the mold before I fully finalized the timing cover. It works but it will be better in future versions. I had to get it cast and on the head so the machine shop could surface it all together. Here I've mounted the cover to the front of the head, machined the surface flush with the bottom and drilled the front holes for the lower cover. The front lip is a little thin. I'll add material to the pattern to thicken it up. I really should have left more material around the entire head. That way I could have made a cleanup pass around the whole thing. I have enough material on the valve cover to create a lip to hide it so it will look good when it's buttoned up. This head will have a water outlet on the side of the timing cover but future heads will use a coolant manifold like the OSG head. Very happy with the internal fit. I need to rig something for the front cover bolts. The holes are right on the step. I'll add bosses to the pattern so it won't be a problem later on. So I didn't try to make it fit this well but the "as cast" fit between the factory cover and my cover couldn't have been better. Of course it's in a spot where no one will see it Got the exhaust flange from the laser cutter. I machined an adapter block to go from a stock Nissan head to my flange. When bolted to the Nissan head it will position the flange exactlyish where it will be with the new head. This will allow the header to be fabricated on a car without being dependent on having the head. Next up is the intake manifolds and valve cover. I'm doing three separate identical manifolds. It's a little more expensive to cast but a whole lot safer as you're dealing with smaller items. Machining is easier as well. Will it ever end Derek

For sure. I remember adding that material to the intake side toward the end of the design proscess. My plan is to redesign it like the exhaust side. It looks a lot better.

Proof that most car problems can be solved in a moment of "reflection"

Please do!

That's one of the reasons I went with the KA setup. When I pulled the K20 chain out of the box I was like "is this a joke". It's soo small. Time will tell If the single roller will work or not. There is no way I'm going to make a set of gears until I see this one stretch

I need to mention that the Honda chain is a standard style chain and not a roller. Also it is closer to a .250 pitch not .125" Too many details rolling around in my head to keep it all straight:)

Single up top or on the bottom. Non of the KA sets that I saw have a double on the lower chain. I did see some that had a double up top and that set will work on my head as well. My theory is the roller rockers should reduce the forces enough so that a single row will work. The K20 only has a .125" pitch single row chain. It is also one single chain. The KA chain is .375" pitch. Because of these differences my gut feeling is it will be fine. When I build the head I'm going to buy a set of (probably) Brian Crower BC1040 springs. Even though my build would run on stock springs I'm hoping to replicate some of the stresses a higher HP build would have. This should give the valve train a pretty decent test. I realize there are more dynamics than just spring rate at play but it's the best I can do. Derek

Made a little progress Saturday. Machined the front of the head. I knew this was going to be a PIA from the word go. I just don't have a proper angle milling head to really go at it. I bought a used angle head on ebay a few years ago. It's designed for woodworking but it was cheap so I went for it. In the first shot I'm using the probe to indicate off of the cam bores. Here I'm surfacing the front of the head. The finish came out a lot better that I expected considering the rigging I had to do to make it work. Faced the upper timing chain tensioner and the upper chain idler mount, spot drilled the timing cover and tensioner holes. I'm going to drill and tap those manually as I didn't have anyway to hold drills in that angle head. No biggie. Got lucky on the pilot bore on the idler mount. You have to tap it on with a plastic hammer. The chain fits well. I knew I was going to make a spacer set for the bottom gear since it's a single not a double like the stock chain. The single chain tracks along the center of the guides now which is what I was looking for. Got the pattern finished for the front timing chain cover. That's heading to the foundry today. Hopefully they will cast it this week. Still have a lot to do but I feel like I have a little momentum. Derek

Got the head back from X-ray on Saturday. No big surprises. Here is a shot of the front half Here is a closeup of a known shrink porosity problem. I knew it was there because you can see it from the top. I wanted to leave it to see what it looked like in the X-ray. You can see it leads all the way over to the valve guide bore and in fact you can see it in the bore. I'll do a weld repair on the top and call it a day as it's too small a defect to affect the valve guide. Controlling solidification shrinkage is one of the tougher aspects of casting metal. We'll try something a little different on the next one. Every head will be x-rayed before they get sold. This way people can have confidence in the casting before they invest in machining.

I'll be supplying a cast steel core for an additional price. It will be up to the end user to make arrangements from there. I will also be providing the necessary data to have machined steel billet cams produced. But ultimately It's going to be up to the builder of the head to determine what they want.

Thanks Leon. I think it's important for people to realize just how much effort goes int producing things like this. In theory there is nothing going on with my head casting that would stop someone implementing iVTEC. But it would take a bit of engineering. I hope someone buys a casting and makes it happen as that would really be the best of both worlds. The way I beat...er...drive my car it would probably just be engaged all the time anyway:)

Cam scan Well everyone in the brain trust agreed that the numbers on the K20A2 cams would be a good starting point for my motor. I bought a used set of cams off of ebay. I used my structured light scanner to capture the lobe data. The scanner projects a light pattern against the object and photographs that pattern The software creates a mesh from the pictures. Here is a shot of a single pattern to give you an idea. I painted the cam white for a better scan. This is the resulting mesh. The mesh has holes as I only capture as much data as I need. I run a plane through the lobe so I can derive curves. And use those curves to develop a solid model. I can then use the deviation calculator to see where I'm at but I can usually tell if I'm off or not as I'm drawing it. On a larger project it's nice just to make sure I didn't miss a feature. Now I can start designing the cam core blanks and patterns.

Time to leave the nest! Heading to JAX for X-ray

Actually if there was a market I would make one but I think there are simpler cheaper options for 4 bangers. I could be wrong though as I've never researched it. It seems like the KA swap is pretty straight forward and affordable.

How about now So nice of you. It'll go out today Probably not