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Attention Mike VV - aluminum filled exhaust bowl

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  • Engine: Attention Mike VV - aluminum filled exhaust bowl

    Hi Mike,

    I was looking at some of your head porting pictures.
    One has a caption "Whole chamber - Intake and exhaust bowls, all chamber details. Aluminum filled exhaust bowl."

    I can see a different color material kind of sneaking in along the (smaller) exhaust port.
    I wondered how that was holding up, and how how the aluminum was applied.


    Dan T

  • #2
    Hey Dan -

    Holding up, no idea. This is one of those porting works like I warned Tom and Jeff about on the Racing Site.. Looks good till you go hunting with a Sonic tester..too thin a wall section in the port roof..a LOT of work for nuthin ! A set of heads that flow 195/198cfm with a 1.800" intake valve at .500" lift...junk, just that fast..!

    Anyway, it's an old trick, nuthin new. Many before me have done it on other brand heads with the same single exhaust port.
    I figured that piston material would hold up well to exhaust heat.
    I actually melted old 289 pistons and poured the aluminum into the port from the manifold side. I packed the bowls tightly with an alum. dam I made up to keep excess alum. out of the port.

    I bought an 8" cast iron skillet from the used goods store. A normal torch tip or cutting tip wouldn't melt the piston, so I bought a Rosette tip. Expensive but worked well.
    I leveled the gasket surface and started pouring.

    After a little cleanup in the bowl...some file work on the gasket surface...done. At first, I thought good enough. But then thought that alum. expands faster and farther thAn cast iron. So I drilled a .625" hole down the center of the alum. "plug" to the port divider to help releave the stresses from engine heat.

    That's about it, till I used my Sonic tester in the ports.. I figured they'd be a great set of street heads..oh well.

    On the funnier side -

    My "test out the pour theory" 3/4 long head, (had the end cylinder cut off for measuring purposes).
    I had just put new, indoor/outdoor carpeting on my work bench two days earlier. As noted above, I "thought" I had packed the port tight enough so the molten aluminum wouldn't leak past. With the head level on the bench/fresh carpeting, I started pouring. Just as the crossover port became full, I noticed smoke comming out of the head..."what the hell I thought".... It was the brand new carpet, the exact shape of the center exhaust port. The liquid aluminum leaked past the dam I made and went all the way into and filled the common port area of the center port. The aluminum cools/solidifies fairly quick, I picked up the head to find the carpet burned to a crisp the shape of the port.
    As much as I wanted to be mad at myself, it was just too funny to be mad.