Idea for pulling dents from header.

Well I tried this method and I think it pushed the dents out a bit BUT it also pushed the pipes way out of line and cracked the collector right where the four pipes meet! I would like to freeze it one more time but am afraid too. I wrestled with it and got it bolted up to an old head. I think I will heat them up good with a torch. Hopefully after it cools they will stay in place.
Wayne

That's pretty clever, but I could definitely see it causing splits like that. I guess it's a bit easier to weld up a split though, so perhaps an imrpovement?

The split is not a big deal at all. The big deal is that all the head pipes moved out of place. Just like if you do a bunch of welding move on you. I should have bolted the head on before freezing being I have an old one.
Wayne

Del_Herring wrote: That's pretty clever, but I could definitely see it causing splits like that. I guess it's a bit easier to weld up a split though, so perhaps an imrpovement?

We used to do the freezer thing all the time will expansion chambers on two stroke dirt bikes, I guess I didnt get here in time to caution you about the cracking. If you keep a close eye on it, you can get it out of the freezer at the right time to prevent the spliting. maybe get an appropriatly sized inflatable plug like plumbers use, then you could shove it in past the collector, and inflate it with a long air chuck.