Removing a corroded bypass tube from a head. How?

[gs.davies]

In a straight race between two 850 heads, one of which needs a skim and a stud/eeziout extraction, the other a bypass tube replacement, I think I’m going to try to swap out a bypass tube.

How do I get the old corroded bit of pipe out? And then. Is is as straightforward as cleaning the thread out and screwing the new one in tight?

Is it also worth doing away with the bypass altogether whilst I’m at it?

E2D66F2B-F4B4-4311-84A4-19566F3DCB68.jpeg

[GraemeC]

Lots of well aimed heat.

[iain1967s]

I ended up chiseling the stub out, then drilled and re-tapped the thread.
http://mk1-forum.net/viewtopic.php?f=3&t=28445

[Andrew1967]

As Graeme says, well aimed heat will shift it. Done exactly that a few times now.

Run a tap down it to clean the thread and fit new one with some thread lock to be sure, as per Iain's advice.

[Spider]

I've never had trouble getting them out with heat. Some I've had to weld a nut or drop a bolt in to and then weld, to have something to grab a hold of. The heat from welding is usually enough to get them to move.

I have always blocked off the By-pass. Never had an issue from not having one. All the do is dump hot coolant back in to the pump, so you're heating the coolant that's been through the radiator. Dumb as dog shit.

[Fanfaniracing]

I also always block them.

It's just unnecessary.

I learned from my master, when blocking it, it's good to drill two or three 2mm holes in the thermostat.

It will improve the cooling system