Cams showed up from Schneider today. Did a test fit and I’m able to spin them by hand. The thrust faces are a hair tight so I’m going to loosen them up a bit. Other than that they feel great. I have to stuff a crank in my mockup motor and then I can get started on the timing chain.
Trying out some new microphones. The placement on this video is one in the cabin and one next to the exhaust pipe. The exhaust mike is dominant at this point as you can’t hear the induction noise which in my opinion is the best part:) It’s a pretty accurate depiction of what’s coming out the back end though. I’ll shoot one with the mikes in the engine bay next. Shifting at about 6800. On the second run I hit the limiter in first. OOps. The camera mount sucks and I need to work on it. If you look closely through the shaking you can see the front of the car lift when the cam comes on. I drive it this way a lot. I just love the sound of it!
The head work on V2 is being done at Rebello Racing. I was interested in getting a head in his hands and everything kind of fell into place for that to happen. The only down side was they are always slammed so it’s taken a little longer than I would like. They worked the bowls a bit but other than that it’s basically the same as it was after the new owner smoothed it out. There was no major shape changes. Dave’s opinion is the head as it is now has the capacity to produce in the 420 HP range based on the numbers they got.
He is onboard at this point and will be offering and recommending the head to his customers. He deals with Schneider Cams and the cores are there getting the lobe profiles done.
I know it’s been slow going for while. It’s just amazing how long it takes to get things like this moving.
I’m attaching the flow sheet he sent me. Dave explained what the various flow scale references mean. I understood it to basically be a setting in the flow bench to make it emulate the bore size more closely. So as a point of reference the intake flow at .5 is 301 CFM after a correction of .680 is applied to the 443 above it. Rebello also runs his tests at 25″ WC.
I’ve incorporated the thrust area into the actual cam. The Honda and V1 has a washer that bolts to the cam. This change allowed me to strengthen the front of the cam and also do away with the cam gear adapters.
On the front of the cam I had 3 dowel holes drilled. The only way to adjust the cam timing on the K24 is to buy or make modified cam gears with offset dowel holes. The single dowel gives you 2.5 degrees adjustment at the crank per hole. By using three holes I was able to split that to 1.25 degrees advanced and 1.25 degrees retard. This is a big improvement over V1 with the adjustable hubs.
The cam is semi finished from Crane. The lobes will be dialed in buy whomever ends up doing the final grind.
Sorry for not updating this for a while but since this is a sold head the progress is subject to the new owners available time.
This is the head with all the initial machine work done. I pressure tested the casting at 75 psi and it held fine.
I messed up and spot drilled the wrong hole pattern for the exhaust flange. The head is 356 heat treated to T6 so I wasn’t too interested in putting any unnecessary heat on it by welding them up. They are behind the exhaust flange anyway.
The owner of the head did his own port cleanup. He is going to finish blending in the port match after the valve work is done.
The head has been vacuum resin impregnated and is at the machine shop having the valve work done.
Got V2 back from radiology and it looks great. The changes I made to the gating and risers solved the bad shrink porosity I had in the front.
Got it all set up in the mill.
If it aint crashing it’s clearance.
Got the bottom side completely finished.
Surfaced, head bolt holes and dowels, water passages.
Chamber roughing pass.
Finish pass completed.
The chamber size is 45cc’s. This should yield a 10.8:1 CR on the build without changing the pistons.
The head has been held up waiting on radiology testing so I’ve been working on other components.
So I bit the bullet and decided to try my hand at making cam towers. They are machined out of 6061 T6 and match the factory specs except for the cam bore size. I opened the bore up to 1.25″ since I have a nice Sunnen hone and the smallest it will go is 1.25″. I increased the cap thickness accordingly.
I also changed the design on the cams a bit. The front is the same as a KA24 and matches the cam gear. I’m doing away with the adjustable hubs and replacing them with multiple dowel holes and a drilled gear. With this combo I’ll be able to have 1.25 degrees of adjustment with 2 dowel pins. Stronger, cheaper, better.
I’m also incorporating the thrust bearings into the cams and having Crane grind them to size when they do journal #1. The main reason for this was it let me increase the diameter of the camshaft at the end. Mucho stronger.
I made a fixture plate to bore all 7 towers at a time but for right now I’m only doing one at a time. I bore each opening without moving the table switching the towers in and out. This way the bores are all in line. Went a lot faster than I thought it would.
The bores came out wicked smooth. Much better than the used towers I’m running on mine.
Sorry I haven’t posted any new content lately. I’ve been super busy.
I did manage to get this done though.
This is V2 of the head and most likely the production version. The major changes are:
I now have the water exiting over each exhaust port and flowing into a central tube. This is the same way OSG and others do it. I opted to try and make it part of the casting to save the cost of making a separate water manifold. Plus it’s a really good example of how versatile 3D sand printing is. The outlet is designed to be tapped 1 1/4″ NPT but you could easily weld something on instead.
I added a rear sump for the oil to drain into the stock oil return. This will do away with the external drain tube that I’m currently using.
I bridged the rear cam tower boss and added a connecter between the back of the head and the tower. This is where the rear oil feed will go.
I redesigned the combustion area so that it has plenty of meat for those who want to get creative.
There are a ton of little changes that reflect things I ran into during the machining of the prototype.
Here is a great shot that shows 3 of the upgrades. The sump, the feeder boss and one of the water exit ports.
Here is the combustion area. The sand is really rough because I went a little overboard blowing out the loose sand. It all get’s machined anyway.
Water outlet and core print in the front of the tube. The core prints are designed to be tapped 3/4″ NPT so that one could be uses for a sensor.
Now I just need to find time for the machine work
The valvetrain noise is not as loud as it is in the video. I have about 30 min. of run time on it. Pulled the valve cover a few times checking things with no surprises. The revs in the video are up to around 5000.
Now comes the long process of getting everything dialed in. There are a lot of loose ends.
I’ll probably start sleeping better:)