Trying to get all all the incidental parts done so that when I get my head back from Xtreme I can concentrate on the final push. I’m locating the VCT valve in a different position than I had originally planed. I was unable to plumb it the way I wanted and that forced me to look at other options. I always hated the idea of hanging the valve off of the front of the timing cover. The control circuit is a little longer but I’m willing to take a chance for the sake of better looks.
Original 3D design:
It will hang below intake #1 and will be mostly out of sight.
Made the CPS mount for the back of the valve cover. This required a pretty major rework of the fuel distribution block and a new mounting bracket. I got really lucky with the block in that I didn’t need to start from scratch.
It only took two versions of the CPS plate and fuel block brackets and one version of the VCT valve bracket. I must be getting the hang of this:)
I’m convinced when they design a motor the first thing they do is the timing chain. Talk about restrictive.
SN005 is building a tall deck motor so I needed to work out what we were doing on the timing chain. I was hoping that my normal KA setup would work with a redesigned pivot for the tensioner arm.
Using my normal method of mocking up substituting plastic for metal.
Actually worked out better than the normal setup. It looks like the extra height on the head will allow the arm to clear the timing cover without modifying the cover.
It uses all the stuff from a KA24 timing chain kit except the bottom chain needs to be a 94 link instead of the 92.
I was trying to get the arm closer to the tensioner but this is the best I’m going to get. Each full link you add or subtract shortens or lengthens the chain by 5/8” so the adjustment is pretty coarse. The guides are stock out of the box Nissan KA24. The jumper brackets on the tension side are temporary. I’ll design something a little better.
I’m happy with the angle on the top tensioner. The upper brackets should start to become a standard item at this point. I changed the way the cam cores are being produced. I’m bringing the cams to length after heat treating and then shipping them to Schnieder for OD turning. This is giving me a lot more control.
This is what I settled on. A sub plate for the idler and a sub plate for the pivot guide and tensioner.
Then a spacer plate to bring the tensioner into the correct position.
I drilled the top gears so that they have 2.5 degrees adjustment and the cams are doweled to break that into 1.25 degree increments.
Bottom gear is new. It is a triplex 06P sprocket from Martin Sprocket with the teeth case hardened. I then bored, reamed and honed it out to 35mm.
Before and after.
The idea is that the inner and outer sprockets will provide strength to the middle driving set. This is way better than what I was running on the prototype. There is 3.5mm of adjustment front to rear via shim packs. This will make setting up the chains a lot easier.
Came together just fine.
Hopefully I’ll be able to get this kind of fit on the regular height blocks.
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:)