Filling exhaust cross over

[Doom86]

Is there any filler you can use that doesn't require melting pistons and cans to fill the exhaust cross over ports on a SBC head? I don't own or have access to a oxy/acetylene torch which is a shame because I do have cast iron skillets and pistons.

I've read of some block filler's working but not certain obviously.

Thanks!

[6sally6]

How about stuff it full of Aluminum foil?! Simple is good.
6sally6

[PackardV8]

I just use a thin stainless steel plate on each side.

jack vines

[F1Fever]

jb putty in the intake cross over.

[CREngines]

rescor, castable alumina ceramic. buy it from mcmaster carr. works great but its expensive @ 90 bucks a box. a box would would probably do 10-15 heads.

[ZIGGY]

X2 on stainless plates.

[F-BIRD'88]

Some of the SBC smogger heads like the #4416 305HO heads have twin egr/exhaust riser passages on the center two exhaust ports.
So you want to fill them to stop the center exhaust ports from cross talking.
Has any one used Furnace cement? http://www.imperialgroup.ca/product.cfm ... roduct=366 Like this stuff. Will it stay in there?
What about using a furnace repair Firebrick trimmed to fit the passage as tightly as possible and cement it in there with furnace cement?

[Matt Gruber]

a friend used plaster of paris.
i made a plug from scrap 1/4" thick steel, and filled in the gaps with a dab of muffler cement.
i think it should be plugged as close as possible to the valve as it has been shown that the passage really disrupts flow, like down 20hp. i don't think a long passage blocked at the end is as good as blocked close to the valve, but i admit i never tried to prove it with a test. might not make any difference.

[F1Fever]

I haven't either but I know I've used jb putty or quick steel more times than I can count and have never had a problem.

[F-BIRD'88]

I haven't either but I know I've used jb putty or quick steel more times than I can count and have never had a problem.

JB Putty will withstand the heat in the exhaust port?

[John R]

X3 on the stainless plates.

Felpro makes intake gaskets with integral stainless steel heat cross over block off plates. Simple....

[ZIGGY]

I'd be interested in any hard information the head guru's may have on filling the passages completely vs. blocking with plates.

[Doom86]

Thanks for the the info. I've read it steals a fair bit of power even more so at higher levels.

These are smogger #416 casting GM heads I'm working on.

Here's a photo of exactly what I'm talking about so there's no confusion. This was taken before the final blending of the sweeper cut in the bowl. My plans are to fill the cross over all the way to the exhaust bowl and blend it in. With the stainless plate idea are you wanting to weld it in the exhaust port or are we talking about different things?



Stuffing it full of aluminum foil isn't a bad idea. I guess the only problem then would be figuring out how to keep it in there and uniform in the exhaust port.

I was wanting to try block filler, some say it works great and with a gallon costing $15 it's very appealing.

F1Fever you used quick steel for this? Just wanted to make sure we're talking about the same "part" of the head I know some confuse it. I tested Quicksteel out just to see how it handled it's self under extreme heat and it get's hard as nails held over a flame, not brittle or flaky. But I don't know how it handles it's self over time, or adhears at those temps, ect.

Thanks again all

[MadBill]

There's water close by, so the wall there shouldn't get nearly as hot as when exhaust gas was flowing through the passage. (Consider that hi temp silicone cooks at many hundreds of degrees less than EGTs yet works fine on the header flange, as long as the gasket doesn't leak at all.)

[F1Fever]

F1Fever you used quick steel for this? Just wanted to make sure we're talking about the same "part" of the head I know some confuse it. I tested Quicksteel out just to see how it handled it's self under extreme heat and it get's hard as nails held over a flame, not brittle or flaky. But I don't know how it handles it's self over time, or adhears at those temps, ect.

Thanks again all

yes, wrong part of the head, while the package claims "cylinder walls" I think the max temp is only around 500*f....