Home made intake manifold

[testiclease]

While my block is at the machine shop, I thought I would take some of the scrap aluminum I had and my bleak aluminum welding skills, and try and make an intake manifold.

I started by cutting the flanges off and milling them flat


Then inset a base for the runners


I made a box above the first runner for the water intake. Started with a sealed box.


Then tested it for leakage.


I then made the provisions for the thermostat housing.



Cutting the pieces for the plenum and mounting the carb mount is pretty strait forward.


Finished fitting the runners to the front plate. Nailed 3 and was a touch off on one.


Since I don't own a router, I tried running the router bit in a die grinder. Was a moderate success. Looks decent after some work, which i forgot to snap before i stuck it all together.


Once i had the runners welded, i polished up the discharge flutes.


Once it was all welded up, a quick coat of paint calls it done




You can see the spots were I'll need to run a hose to connect the water ports. I still need to get the hose the connect.


Im not sure what benefit if any this will add, but it was a fun project and will look good once on the car.

[testiclease]

I beefed up the water port a bit so I had some more meat the tread in the fittings. This is how it looks finished.

[turbo16]

I think you welds are really good ! you did however plumb the EGR port to the water outlet and that will not work out well for you.

[testiclease]

Yes, luckily i was warned about that prior to installing it.

Would have been a major mess

[pinkpanthr]

Know I'm late to the discussion but thought I'd add my two cents. Intake manifolds typically work best if there are some (not all) of the casting bumps left. The rough edges help for fuel atomization. Not sure how well a completly smooth setup is gonna work, how has it done for you? Definately looks cool.

[testiclease]

This has been an on going battle over the course of the season. A battle which 2 manifolds have won. I ended up making a smaller plenum version of this one and still ran into some problems.

The problem i have had is all the mixutre flowing to the back of the manifold. At idle i would get great vacuum, throttle response was good, and sounded really good with the Holley 350. But once moving, hitting around 40 mph all the fuel/air mixture would rush to the back starving the first 3 cylinders and flooding the 4th.



My second attempt had a smaller plenum, and runners moulded into the floor. Same problem but not as bad.

My conclusion is that virtually no plenum is needed. This winter i will either try another design, or just open up a stock manifold and swing the spacer to accept the Holley 350.

I ran the season with the stock manifold and weber 32/36. Worked fine once i figured out some of the bugs in the carb, but still having issues in transition.

I'll post progress over the winter