Marks Holt 75

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A little update on my progress. Working one handed is slowing me way down. I am wearing a fiberglass splint on my right hand to immobilize my thumb. My fingers work so I can still spin the hand-wheels on my lathe and mill.

I am trying to reproduce the look of the original engines manifolds as best I can. Here I am showing how I am going about the exhaust manifold. The photos show my step by step progress and are pretty much self explanatory, but if you have questions just ask. I'm missing a photo of the two halves being silver soldered together. I cut the outline of one half and kept the other half a rectangle for soldering to maintain rigidity.

Once the intake manifold is completed I will need to make some adjustments to fit them to the engine. And then I plan to sandblast them before nickle plating the parts. I am hoping after some running time the exhaust manifold will get some color from the heat.

Mark T

manifold holes.jpg

manifold pattern.jpg

manifold hollow out.jpg

manifold ready for soldering.jpg
 
One question: how do you get from the third to last picture (with the calipers) to the next one: sand blasting?

I used a Dremel with a small drum sander and a small pad sander attachment, then sandblasted. It didn't take very long but I was covered in fine brass dust. It is still a bit rough, I plan to detail it a bit better after I get the intake manifold made.

Mark
 
Hi Mark
When I made the drawings I drew the manifolds whereas a somewhat skilled machinist/builder could make them and still have them look acceptable. What you have done is what I would do but a lot of fellows don't have the ability or patience to carve shaped parts (manifolds) from solid.
I have been asked many times if I ever made drawings for the 302 V-8 engine and my answer was no. Not that I can't make them but to replicate the casting details would take three times as many drawings to show the shapes and how to develop them.
gbritnell
 
Very good piece of work I love it and the end result is great. How long did it take ?

I didn't keep track but probably around 16 hours spreed over many days. My injured hand slowed me down and keeps me from working more than a couple hours a day.

Mark T
 
When I made the drawings I drew the manifolds whereas a somewhat skilled machinist/builder could make them and still have them look acceptable

I hear what your saying George. Your model is so nice I just thought it deserved the extra mile. And I wanted to show what can be done even if you don't have a cnc. It really wasn't difficult, just time consuming. The biggest problem I had was finding the brass stock,

Mark T
 
Finally got some time to work in the shop. Spent the weekend making the intake manifold. Basically just a repeat of the process to make the Exhaust manifold. I am waiting for some 3-48 threaded rod for the mounting studs and the chemical dip to darken the brass. I will update this post with a photo of the completed mounted manifolds soon as my materials arrive.

As always thanks to those of you watching this build (25k views) and to those that have left a response. Nice to know your not playing to an empty house.

Mark T

halves silver soldered together.jpg

intake manifold roughed out.jpg

manifolds shaping tools.jpg
cut for holding clamps.jpg

Manifolds mounted temp.jpg
 
Outstanding work on the manifolds Mark!
 

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