Long story made short.... I blew the rear expansion plug out of the 245 Bigger 6 in my truck. I'm pulling the engine tomorrow to replace all of them and fiddle around with a bunch of other stuff while the engine's out. Knowing how delicate they are, and Hen's teeth to boot... what's the best way to remove it from the cylinder head ? Should I leave it on and just tie up the tube ?
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It's a Bourdon tube for the temperature gage. On the engine end, there should be a small bulb. The bulb has a flange on it, and there is a hollow nut, much like a flare nut, that presses this flange against a seat to effect a seal. Usually there is a larger fitting, like a pipe bushing, that contains the seat for the flange, but I think I may have seen installation where the seat was machined into the head. If you see a small hex head, and behind it a larger one, you have the two-piece style.
You pretty much have to undo it, as the other end is part of the gage. You cannot cut the the tube. The flange nut should undo OK.Gord Richmond, within Weasel range of the Alberta Badlands -
I thought I had a picture of mine removed but I can't find it. Here is what I did find:
I took this apart 8 years ago so my memory may be fuzzy but as I recall the square-headed nut is what needs to turn. The fitting in the block is where the bulb seals and can stay in place. The critical thing is to not twist the tube so if it wants to turn with the nut you will have to work it loose.
NathanComment
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Well I sprayed a little penetrant on the 2-piece fitting(s) and got the outer one out without too much work. However, the suction caused by the sludge and moisture buildup required such pulling force that I decided to pull the dash gage and wrap it around the carb (yes it appears to be 2+ft. too long for this application.... Anyway, its out and after pulling the engine and expansion plugs got the usual qt+ of black oatmeal in the block..... Pipe plug did come out with a little heat.Comment
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And I goofed up, calling it a Bourdon tube. That's actually the sensitive element in the gage itself, a thin-walled flattened brass tube curled in a partial loop. Under pressure, it straightens ever so slightly, and through a linkage and tiny gears, moves the pointer.
The tiny tube that runs from block to gage is a capillary tube, and it and the bulb in the head are filled with ether.Gord Richmond, within Weasel range of the Alberta BadlandsComment
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Yeah Gord, but you have to admit a bourbon tube sounds more appealing.Originally posted by gordr View PostRon Dame
'63 ChampComment
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