So slowly but surely I have been chipping away at making the VCT fit in the available space. What a freaking PIA. The problem with timing chains is you are constrained distance wise by the pitch of the chain and the adjustment can be a bit coarse. Multiply that by two and you can see how it can get tricky. I model things the best I can in 3D but when it comes to something like this I find a hands on approach leads to a more satisfactory result.
Machined of the small gear from the KA24 idler.
I’m using a 5C expanding mandrel that I machined to fit.
Test fitting the Honda exhaust cam gear that I machined previously.
Happy with the fit for sure.
Quick test fit with the first idler sub plate. Looks good but I know from experience that there is a really long road from this point to the final fitting.
Here are the finalish mockup sub plates for the idler gear and the tensioner arm pivot. I may move the idler up another .010″ but I haven’t decided.
I do the majority of my prototyping in plastic. Easier to work with than aluminum and a lot cheaper. The idler plate will be steel and the pivot plate will be aluminum.
Upper tensioner mount.
The semi finished layout.
Upper tensioner is from a Mazda 626. Hybridz member Tioga turned me on to this one . I reshaped the contact shoe a bit and slapped it on there. It is a ratcheting style. They can be problematic if the lobe design on the cams are crappy. The constant pumping on the chain can break the pawls. I’m making the assumption at this point the Schneiders lobe design is a lot better than Cranes and won’t be a problem. I had to reshape the contact shoe and will probably work it some more if I stick with it.
Tight fit but the bottom line is….It fits. Which is a good thing since I committed to the cams before I knew for sure. Unfortunately I can’t access the VCT oil ports on the head because the idler gear is covering them but I already designed a manifold as a work around.
So if the pictures make it look like this was a walk in the park here is a shot of the different versions of the sub plates I made to get the relationship between all those moving components the way I wanted them as well as fitting in the space I had to work with.
Got the VTC cams back from Schneider so I was able to mess around a bit wit the upper chain.
Machining the center out of a stock Honda exhaust gear. Holy bajezas was that thing hard. I had to anneal the center to make any headway through it. Came out great though.
Looks promising but there is a lot left to do.
Best part is my stuff is always S/N001
I had powder-coated.com do the powder coating on my new valve cover. Same color as V1. Excellent quality as usual.
I’m a bit away from needing a finished valve cover but never underestimate the value in having it for motivation:)
So this is the big change I made to mine. This is to hold a mounting plate for the VCT sensor. Since it requires a special setup on the millI I only plan on making this mod on VCT specific builds or on special requests.
Took the heads to a local shop that I trust to surface the tops.
The bottoms are left as machined since the end user/builder determines how much they want to remove.
Did final pressure test today and no issues. A little hand work and the majority of my part of the headwork is done.
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.