Tuesday, January 11, 2011

Terry Mayhugh's fabricated exhaust manifolds

Here are some pictures of the exhaust manifolds that I just completed for my V-4. I machined this from billet and then glass-beaded them to give them a 'cast' look. In another thread I showed how I created the intake manifolds from two identical halves, but I felt the exhaust manifolds needed to be machined from a single workpiece due to the extreme temperatures to which they would be exposed. I started with a suitably sized rectangular workpiece and then it it I drilled the long exhaust runner. I then drilled the two short runners as far as I could before the angle into the block flange became too acute. I then pressed plugs into the short runners to a depth such that half of the diameter of the long runner would be closed off. I also pressed pins into these plugs where the wall the manifold itself would eventually be as a safety measure to help secure the plug. Plugs and pins were also secured with high temperature bearing retainer. I then re-drilled the long runner to clear out the remnants of the two short runner plugs. I used a spherical D-bit to blend the long runner with the far-end short runner. I then machined the the top of the manifold and then flipped it over to mill the backside. This is where things get tricky. Finish machining the backside will cause the part to drop free before the machining is completed and so before starting the backside machining I epoxied the already top-side machined part to a plate that was secured to the workpiece with a number of screws. This kept the part stable after it was cut free from the workpiece and allowed me to do all the back side machining. After both sides were completed I heated the epoxy up to 200F and it released easily from the workpiece. Essentially no clean-up was needed and so I needed only to drill out the short runners from the block flanges to connect the runners to the already drilled portions. I then bead-blasted the parts to make them look cast. Two months of development work and about 4 hours of machining time per manifold. I'm glad its over but I'm happy with the result. -Terry

Sunday, January 2, 2011

Dave Sage's "Howell V8"

I finally finished the V8 version of Jerry's V4.
I haven't run it yet. I thought I'd post some pictures before it scatters around the shop.
It's hard to believe it's been three years or so in construction. I hope it runs.
The intake manifold is a prototype since I'm not sure how many carburetors it will require. I can add more or move them around by simply making a new top plate for the manifold.
Weather permitting, I'll bring it to Cabin Fever in a couple of weeks.
Enjoy !

Dave Sage


Really nice job. I'm working on the V4 and currently machining a set of intake and exhaust manifolds for it since I don't have the casting kit. I've finished the intake manifold and the exhaust manifolds are also nearly finished. I plan to be at Cabin Fever and hope to see you there.

Terry Mayhugh


Yes Terry I saw your post and pictures of the intake manifold you made. Nice work, you must be very CNC savy. I know I had quite a time getting the height above the block for the water passage connection, the angle of the runners and their connection to the heads, and getting them to all come together at the same time.
The manifold I have is a temporary outfit. The top plate comes off so I can make a new one to accomodate more carbs. Below the plate is just a big cavity to act as a runner.
 I'm pretty sure I'm going to need more than one carb but I started there. I made 6 carbs while I was set up to make them. Some for future projects I'm sure.

I really hope the weather holds so I can get to Cabin Fever (from Toronto). Please look me up. I'll be looking for all the V4's - hopefully you'll bring yours along regardless of it's state of completion.



The V8 is running ! 
And Yes I think it's going to need at least one more carb. If you look at Sherlines Craftsmanship Museum - Howell V4 build page, at the very bottom, you'll see the pictures and a video of the V8  running. Thanks to them for that. It's a really good page to look at just to get an understanding of what is involved in building the V4. 
Here's a direct link to the video

Still lots more work to do to get it to run better.