Prior to a head rebuild, is it necessary to remove the three 7/16” hex socket plugs in the head valley? I’ve had a go at them and they don’t want to shift. Can the head be cleaned properly with these in place, or is it time for a bit of heat?
Mine were too stubborn for me so I let them be.
Unless the cooling passages are really crusted up, no real need to remove them.
I ruined a hex socket trying to get some out. Propane torch heat eventually helped get them out. Glad I did, there was corrosion in there.
You can kill corrosion with oxalic acid…I used a Behr product from Home Depot…wood and deck cleaner, I believe it is called…10% oxalic acid…worked great at removing crud and rust stains.
The head will get a chemi-clean at the engine machinist’s anyway so I’ll leave that to them. I might have a go with a bit of propane but unless they decide to move relatively easily I’ll let them be. It’s the original C-type head for this engine and car so I don’t want to risk any damage.
Thanks Rob, some gentle propane did the trick. Not too bad at all in there, but I’d like the chemiclean to be as effective as possible.
On a different note, the Otter switch thread holes on the inlet manifold had been badly damaged somewhere along the line. Two were stripped and one had a screw forced in at an odd angle.
I managed to get hold of a V-coil kit for 3/16UNC so have helicoiled these. Good kit, and the threads will now be stronger than original.
It’s no tapping at an angle, it’s the lens!
Roger
I have at least three intakes with bad otter switch holes. I don’t want to repair it by hand I want it in a vise on a milling machine where I can accurately drill for helicoils (or such). I hope you are right when you say new threads will be stronger than old.
It was drilled whilst correctly mounted on a professional pillar drill plate. That is a taper tap, it’s only going one way. Second tap next, didn’t need the bottom tap.
A good quality s/s helicoil is stronger than the standard aluminium thread of the equivalent size. The aluminium GT40 heads on my stroked 390 Ford motor came with the critical threads helicoiled from new.
Did you go with the big 445 kit? Edelbrock also helicoils their alum heads.
No Lee, it’s a 351W stroked to 393. I think it’s a nicer motor than the FE, but each to his own!
It was a bit too wild when I first built it, 450 bhp and a torque figure nudging 480 made it difficult to drive on the street so I toned the cam down a bit to a Lunati Voodoo. It’s in my ‘68 Mustang fastback, with a 5-speed.
Windsors are better engines than they credited for,
The NASCAR boys ran them…I didn’t think there was a GT40 for big blocks.