Page 2 The project begins
Page 3 Front end and doors
Page 4 Body framing
Page 5 Wheel tubs and more framing
Page 6 Door openings and more on the body
Page 7 The frame
Page 8 Steering, shocks and engine mounts
Page 9 CAD, lasercut parts and intake.
Page 10 Transmission and engine mounts.
Page 10 Roof and more on the frame.

Karkmotuning

 

 

CAD, Laser cut parts and building an intake.


I had to learn how to draw in CAD to make all the flanges needed for getting the engine to run. Not wanting to use the original intake with throttlebodies, I had to design my own. This is a work in progress, but with the parts ordered, it's just filling in the blanks with some water pipe and sheetmetal to make a complete intake.

1. Upper intake flange ( with a bunch of 2" exhaust flanges to save material).
2. Top intake flange with holes for two four barrel carbs ( bolts to the #1 flange)
3. Drawing for the number 2 part
4. Four barrel carb flanges. These will be spaced up about an inch off the Top intake.
5. 2" exhaust flange
6. 2-1/2" exhaust flange.
7. Intake to cylinder head flange.
(June 2022)

A call came from the laser cutting company. The parts I had drawn and ordered were cut and ready for delivery.

I tried to lay out the parts like in the previous pic. Plans call for a modular exhaust, so that parts of it can easily be changed, eg. to a different type of muffler with just unbolting 6 bolts (after the replacement part is done, obviously), hence the wealth of triangilar shaped flanges.

The bigger 2-1/2" ones will be used as header collectors, and also on other projects.
(July 2022)


 

The intake.


All parts ( tube bends and sheet metal) had mill scale removed with acid, as discussed later.

Work on the intake runners started with cutting short pieces of straight tubing with a 13 degree angle, then a 37 degree angle of a pipe bend. Of course doing this cutting free hand with a simple jig, the angles not very accurate.

A. After cutting and adjusting, a piece and a bend were tacked together. 6 pieces were an average length, the six others were off, either shorter or longer, and got dedicated third parts to compensate.

B. Then they were welded to make 12 equal length runners.

C. All 24 welds were ground off, and the insides were smoothed with a small grinder with a rotating file.

Checking for clearance for the intake bolts under the plenum floor. This will be enough, but the intake will be very tall.



The intake off the engine to tack the intake runners to the flanges.

When eight runners were tacked to the intake flanges, it was all bolted back to the heads. Simple intake by the way, no water and no exhaust in it.

After some measuring and planning, a plywood template was cut with a hole saw, and it was used to cut the holes for the intake runners in the plenum floor piece.

After this the rest of the runners were tacked to the flanges, making sure they fit the already cut holes in the plenum floor.



The plenum is designed short, and the outermost runners will turn into the ends of the plenum by using tube bends cut to fit to the plenum end pieces. Form over function perhaps.

The holes in the plenum floor will be ground to fit loosely around the runnes, and the conjunctions will be ground round and smooth to promote air flow over the awkward angles.
Hoping to be able to weld this, without warping the flanges too much.

After welding the intake runners to the flanges, the welds were ground smooth.



The plenum floor was then welded to the intake runners, and the edges of the runners were ground to a rounded shape.

The parts for the plemum itself were cut to exact sizes, and the whole plenum was welded.



Finally we can see what the intake looks like with carbs and all. It's high and suitably impressive looking, but will probably just fit under the hood.

 

A solution to the mill scale problem

Mill scale is very hard to get ground off hot rolled steel. I heard about etching it off with mild acids, and thought I'd give it a try.
¨ Apple vinegar worked surprisingly well, on a warm day the mill scale was gone in about 4 hours.
I found 12% acetic acid, and it works about the same. It's cheap, and a little goes a long way, if you can find a suitable wide container to soak the pieces in,
At about 30 degrees C (85 F) four hours is enough, but in cooler temperatures, say, like under 20 C (70 F) the process can take up to a couple days.

It works amazingly well but is a bit smelly, so it's better done outside.

Four hours has passed, and all the mill scale sits on the bottom of the container

The parts are rinsed with water, and then washed in a weak soda solution to neutraize the acid, then dried.

After the acid dip, the mill scale is gone, and the parts can be sanded smooth with just sandpaper.

NEXT: Transmission and engine mounts.         Back to Karkmotuning