Tips on filling Exhaust Crossover

[Rich Biebel]

Originally Posted by ss3011

Thanks for the information . That early post has lots of good info. It looks like depending on how the exhaust flows, and how much heat transfer you get in the port, will determine what material you can fill the crossover with. Zinc alloy melts at around 750 degsF, and aluminum melts at around 1220 degsF. I think I will try melting down some old pistons, and see how that pours into the crossover. Thanks again !

That is how we did it in the shop I worked at. Melted old pistons down.... Used a big plumbers ladel for melting lead with a torch. It had a long handle....Melt pistons.....remove slag while it's liquid as it will form on the top.....

Pour in with intake flange facing down and a plate bolted on it to keep the aluminum flush. Aluminum will get solid very quickly. You can warm the head up some before pouring the molten aluminum in.

It's tricky.....and there is zero working time there....

If you pour too much in you will have to use a die grinder to grind it back....

I have seen some furnace type cement used that held up very well but never knew what product that was or where to get it....

[Ed Wright]

Originally Posted by Rich Biebel

That is how we did it in the shop I worked at. Melted old pistons down.... Used a big plumbers ladel for melting lead with a torch. It had a long handle....Melt pistons.....remove slag while it's liquid as it will form on the top.....

Pour in with intake flange facing down and a plate bolted on it to keep the aluminum flush. Aluminum will get solid very quickly. You can warm the head up some before pouring the molten aluminum in.

It's tricky.....and there is zero working time there....

If you pour too much in you will have to use a die grinder to grind it back....

I have seen some furnace type cement used that held up very well but never knew what product that was or where to get it....

This the only way I ever did it. Old Pistons.

[Dwight Southerland]

I have used pure plaster of paris (not the kind with silicon in it) with success. Just be sure there are no bubbles in it. The heat from the engine exhaust fires it like in a kiln. Harder than heck to get out after its been run a while.

[Ed Wright]

Originally Posted by Dwight Southerland

I have used pure plaster of paris (not the kind with silicon in it) with success. Just be sure there are no bubbles in it. The heat from the engine exhaust fires it like in a kiln. Harder than heck to get out after its been run a while.

Hmm, first I heard about that.

[Mark Yacavone]

I still use aluminum and a torch, but I don't fill it from the port side anymore..Too much room for error and extra work.
Instead I make little tin or aluminum tabs that are the shape of the passage, with a little tail on them ,which I prop up against a bolt stuck down in the valve guide.
I melt more than enough aluminum, skim, and pour it down in with the intake side horizontal, leaving it a little high. I then smack it with a hammer a few times while it's still warm. Grind it flush with a 40 grit soft disc and some cutting grease.
Pull the tabs and you're done.

I've been told by one of the best in the business that leaving the fill recessed back just a little, doesn't hurt the flow at all.

[Mike Taylor 3601]

I started using zinc years ago when a customer brought in some he had bought from Mondello,I buy mine half price of what Mondello got for it,have never had any of the zinc disappear ,burn out or erode or whatever you want to call it. I may switch to aluminum, because I always have barrel full of old pistons.
Do you just use plain old cast piston ?
Mike Taylor 3601

[Glenn Briglio]

Originally Posted by Mike Taylor 3601

I started using zinc years ago when a customer brought in some he had bought from Mondello,I buy mine half price of what Mondello got for it,have never had any of the zinc disappear ,burn out or erode or whatever you want to call it. I may switch to aluminum, because I always have barrel full of old pistons.
Do you just use plain old cast piston ?
Mike Taylor 3601

Use forged pistons. Some cast pistons have a steel insert in pin area.