Hot Rod Forum banner

Welding combustion chambers

12K views 8 replies 5 participants last post by  Augusto 
#1 ·
Raising compression ratio is a top priority here because of the 6.600 feet of altitude, since obtaining aftermarket heads or even domed piston is quiet dificult from here, I was thinking of weld filling the cc's of the sbc engines, I have some experience welding cast iron but have some doubts here, what kind of welding rod should I use? I always use pure nickel rods for welding cast iron, will brass rods used for brazing would work? they join cast iron pretty well also and is very easy to machine not so with nickel.
I have filled rice burner aluminum heads with good results but have never tried with good old american iron.
Please comment.
Augusto.
 
#4 ·
When I rechambered my heads, I completely disassembled them, heated them until red hot in an oven and filled them in with nickel while hot.

This is the only way I would weld the combustion chamber of a head. I've only done this once, but they haven't come apart yet...(knock on wood).
 
#6 ·
F-BIRD'88:
chevy 350 smog heads

bondo:
yes, I agree, but I think aluminum melting point is lower and heads are made of it, besides the heads never reach that temperatures, only the burnt gases do, they transfer part of that heat to the head but not all, most goes down the exaust pipe, in my karting racing motors wich have aluminum air cooled heads, the temp probe under the spark plugs reads around 350 deg and that is with a 45+ hp motor turning 19.000 rpm, the exaust temp probe reads 1.200 deg at full power.

I see no problem with brass, but that is only my opinion, I would like to hear from others since I've never done it and don't want to screw up, listening others opinions is great and improves knowledge.

Augusto.
 
#8 ·
I do have a set of 305 heads, I tougth 1.94 valves did not fit in this heads (I don't know where did I get this idea from) I'm gonna cc them to see what I got, thanks for the tip.
Any reccomendations for porting the 305's?
I bet some intake valve unshrouding must be done.
Augusto.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top