The Jag was in pretty dirty shape so figured to clean up as best I could. Turns out I have access to a sand blaster and the intake manifold is really dirty on the inside (soot carbon and all) any one ever attempt this??

Please let me know soon as you can hope to clean and put all back together while the weather is nice!

Thanks, Gee

 

Hey there Gee. When I removed the intake manifold to change the spark plugs I dremmeled away some of the cast aluminum at the entry way. There is a thick spine there that splits the air paths. I dremmeled it down to a knife edge for better air flow.

I don't imagine sand blasting away the grime would hurt. However, don't dare do that with the throttle body. Lol.

 

Sandblasting inside and out shouldnt' be a problem as long as you clean up really really good. I would caution that you make sure the blast media is silicon beads or nut shells. Regular grit will imbed and the ferrous elements in the grit will cause rust and scale.

 

geewillicurs, if you are pulling the intake off to sand blast it, take a little bit of extra time with a 60 grit sanding wheel and smooth out the cast surface. This won't take long and this will help with the air flow. In short what is happening is you will be decreasing the laminar boundary layer making the effective diameter of the ports bigger. Bigger ports means more air can flow for a given pressure drop.

If you want to understand laminar flow, think about trying to pull a sled across a painted floor (ie, your sanded surface) and a floor covered in sand paper adhered to the floor (ie, your cast surface). If you try and pull the sled across the painted floor, it will move fairly easy where the sandpaper floor will tend to grab the sled and prevent motion. In the case of air, if you have a rough surface, the surface will grab the air and slow it down causing the following air to run into this slowed down air and it will start it rolling. This causes a layer to form near the metal boundary where the air is moving much slower than the center. This effectively is choking the port and making the port "smaller", reducing the maximum power. If you smooth out the surface, less air can be caught by the surface, therefore less air is slowed down and more air can be maintained at maximum flow.

 

Last time I had my intake off (knock sensor) I used spray on oven cleaner (easy off) and a tooth brush to clean all the deposits from inside , worked like a charm.
and I did notice improved performance.
Perhaps it would be wise to media blast to outside and `oven clean` the inside

 

Is anyone polishing the intake or clear coating it? Eastwood has some high temp clear for AL. It is a large part of the motor. It would be nice to dress it up some. Paint it?

 

You might also look into extrude honing (aka Abrasive Flow Machining or AFM). Some swear by this method for improving flow of exhaust and intake manifolds.