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Exhaust Chamber Temp.

1503 Views 3 Replies 3 Participants Last post by  GoneNova/406
i recently took a set of heads apart for porting and spring change that i bought nearly two yrs. ago and the metal used in this casting looks like the mix,the casting or something was wrong when they pour it.their ugly and should not be.anyway they don't really need alot of repair but rather a little dressing up.they did a bad job installing the seats and while porting them i was left with small gouges or cavities that need to be filled and reground or ported.on good advise i think high temp epoxy is the way to go.i'll know more after tonite cause i am going totry a little brazing in a couple of bad question is ,in trying to locate on the net hi temp. epoxy i need to know how hot the combustion chamber gets.any help would be appreciated.
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Way too hot for any epoxy.

Epoxy might be OK in the intake port near the intake manifold but anywhere near the seat it will fall off or burn. a little roughness is inevitable and won't affect flow any, I wouldn't worry about it unless the seats are barely hanging in there. If thats the case they need to be welded not brazed...regular brazing won't last either. Aluminum bronze brazing is suitable however, many aircraft valve seats are constructed of aluminum bronze.
I have to agree. EGT is going to be in the 1200-1400 range and there is not epoxy that will last in exposure to that.

If you are describing pors in the heads, I would have to be concerned about running those heads. If the casting is porous it is also weak and could give you problems. SBC heads are easy to find and cheap. Heck I have a set ready to bolt on sitting on ebay right now cause nobody wants them. People will just about give them away so there is no sense in running a set that is bad when you can get a nice set so cheap.

this is an area where i am not an expert but i've gotten this info from someone here who i concider to be credible.i did just begin a search last nite for epoxies and have found that they go upwards of two thousand degrees thats why i need to know pretty close what the heat range is for the exhaust chamber.i heard that gm uses devcon epoxy and this is the site i found last nite,
and i just started,there must be more.
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