Finished up the manifolds for V3. These were tricky because the owner of V3 decided to
make my life miserable tilt the motor the opposite direction. He did this for looks plus he wanted to gain some distance for his induction system. I did a quick check on the 3D model and it looked doable.
Trunnion plate on the 4th axis comes in handy for this kind of stuff. DCOE pattern matched to 48mm.
Made a quick fixture/index plate to locate off of the DCOE flange. I find most people prefer that their carbs/ITBs line up when they are bolted to the manifold:) Port matched to the head and o-ringed. Rebello will blend the port match into the manifold. Since every build is different I figured the best way to handle it is to cast it a little smaller and then blend as necessary. The ripple pattern you see is from the 3D printed sand. There are certain angles where the layers on 3D printed items are fairly pronounced. I was surprised how well everything worked considering the manifold casting is 180 degrees out from it’s intended angle.
I kind of cheated this shot. The manifold has already been through the vibratory finisher so this is the final finish. I threw it back in the fixture to get the picture.
All done and looking pretty!
The manifolds are machined specifically for their position on the head.
Added a rib in the center so that if people have drop link type linkage they can mount the risers to it.
Manifold looks a little fugly in this shot but it really isn’t:)
I can relax a little:)
Just got done with their first bath. Still need de-buring and edge finishing but the majority of the work is done.
The VCT holes are drilled and tapped but they haven’t been drilled all the way through. Easily opened up with a drill if needed. The head has provisions for three sub plates. Timing chain idler, upper tensioner and a slack side guide pivot. The idler and tensioner are connected to the oil system and o-ringed. It is getting really crowded in there with all the oil passages, head bolts and cam tower bolts.
Next stop vacuum resin impregnation.
They are machined and somewhat finished. I’ve decided that since I don’t know what people plan to do for finishing that I would leave the final cleanup to them or their powder coater.
I sanded down all of the sand tears, Rand a DA over most of it and then ran them in the vibratory finisher.
The flange is grooved for a .125″ o-ring. I also machine in clearance for the cam towers and bolts.
There are 2 bosses on either side of the plug hole. This is for a KN20 COP. The bosses are positioned so that you can have the plug facing forward or backwards. It’s up to the end user to drill and tap accordingly.
Semi action shot.
So from V3 forward I have been working on making sure that people who wanted to upgrade to VCT down the road wouldn’t be stuck buying a whole new head. This has turned out to be pretty difficult but not impossible. Complete redesign of the valve cover and modifying the pattern, new timing cover design and pattern, modification to the front of the head and redesign of the cam towers. Finding room to fit two oil delivery systems was the trickiest part.
Here is a shot of two number one towers with the caps off. VCT on top and regular on the bottom.
The only modification to the head and cam towers to switch to VCT is to mill two channels from the 6mm holes out to the oil grooves. To be clear you will need VCT cams and all the timing and valving bits. My opinion on VCT is still that it’s probably an expensive gadget but I needed a new challenge and figured I’d see if I can make it happen. So if you are planning on a budget build I wouldn’t be holding out for VCT:)
Making some progress on the towers. There are a ton of steps and I’m trying to balance production vs ruining everything:)
Dual vises are nice but if you mess up you probably messed up two towers.
The jaws are doweled to locate the towers. The cap and base are doweled and will stay together throughout the whole process. Cut one side, flip, cut second side.
Action shot 🙂
After a trip through the vibratory finisher the cam bearings will be bored and the rocker shaft bores will be reamed.
Still lots to do.
The middle row are mine. I proof the code on them. If it’s good then I move on to the rest. So far so good.
Gun drilled S7 tool steel. Eight standard and two VCT.
My poor little lathe got quite the workout:)
These are the fronts of the VCT cams.
I’m copying the K20 dimensions as closely as possible. For some reason they use a very shallow feed groove on the cam bearing and a much deeper groove on the phaser end.
Number one cam tower with the VCT grooves machined in. The drilled holes lead down to the head and the grooves will line up with the cam when I bore the towers.
The letter C is where the intake cam will be. Although that is a coincidence as this is tower 1 set C. The next step is numbering the towers and after that they are machined as sets. I’m doing five sets this run.
Been kind of busy so I have neglected updating things.
Before I started machining the cam cores I needed to finalize the VCT plumbing. Here is a cross section showing the retard circuit. The oil comes up through the tower and enters the cam through the hole in the oil groove. It then travels forward and exits the front groove. Both retard and advance circuits are bidirectional so as oil enters one it exits the other. Honda designed it to move a lot of oil in order to have good response time at the phaser. Hopefully the changes I’ve had to make in order for it to fit in the new package won’t screw it up. Time will tell:)
This is the VCT intake cam. I’m drilling the control circuit holes. 4MM diameter 60MM deep in S7 tool steel. Did a bunch of tests before I did it and all and all it was fine.
Here is the snout after machining the end to size and cutting the oil grooves. I’ll cross drill the grooves in the mill when I do the lobes.
Here you can see the VCT intake, exhaust, and the rest of the non VCT cam snouts.
One down nine to go 🙂 All the lathe work is done on it and it is ready to go into the mill to machine the lobes.
Since I’m planning on trying out VCT on my build I figured I’d better finalize the valving. For me it’s alway a balance of (not necessarily in this order) function, manufacturing and style. On the VCT it’s always function first since what’s the point if it looks better than it works. I knew what valve I wanted to use ( manufacturing) and where it needed to go (function) but not how to make it work ( manufacturing ) and not have it be butt ugly (style).
I picked the valve I did because of the fact it came with it’s own manifold. This makes manufacturing a lot easier since I don’t have to do any precision boring. Since it’s an open pressure (bleed) circuit believe I need to locate the valve as close to the cam phaser as possible to try and minimize the response lag. I also have to deliver a pretty good volume of oil at times where a fast response is necessary.
I mapped out the valve with the 4 circuits. Oil in, 2 drains, advanced and retard.
The valve is a spring return and defaults to retarded cam position. Retarded seems to be the default for the phaser as well. Which makes sense.
Lets start with the fact that I’m not crazy style wise about hanging this valve off of the front of the timing cover. But it’s the closest I can get it to the phaser and still be able to plumb it. Here is a shot of the final plumbing. Red is oil in. Light blue are the drains. brown is retard and purple is advance.
Since I didn’t want the valve there to begin with you can imagine how I felt when I finally gave in to the fact that I needed a .625″ thick manifold block to handle all the cross drilling. I tried a bunch of scenarios but it would have added a ton of time to the machining because of doing that kind of work on a short production run casting is tough.
I also had to flip the valve 180 from my original position to get the advance and retard ports to match the head.
It’s all about compromises in life:)
Drove the car Saturday nite to pick up a pizza. Ran great. beat it as usual. Parked it overnight. Got up the next morning and fired it up ran a little rough for a couple of seconds then it ran a lot rough. Towed it to the shop, pulled the plugs and number 6 shot a geyser of coolant.
The #12 intake seat dropped out and the result was a wiped out chamber and piston. Bits of the seat smashed the quench area enough to deform and crack the head.
I’m about 99 percent sure it was improper installation at this point. The seat bore is not cracked and I never overheated the motor.
I was going to change it out at some point with a production head anyway but realistically with the current demand I have for heads it will be 6 months or more before I’ll be able to make it happen. I could repair it but since the motor is toast as well I’m better off concentrating on getting the heads into production.
Got the head back from the foundry and for the first time I have all the parts under one roof. Figured I’d take a family photo:)
Guess I better get busy on the milling machine!