Hi all - got a i4 gm head PO left out in rain. 1 valve arrived with both sides bust off and from hammering slightly mushroomed so its almost locked in.. guide has a tiny crack in it - this is more out of curiosity IF i can get it out.. any tips? freeze off on valve, heat outside? I guess trying to drill a valve out is just stupid - valve is behind stud but u get the idea i think..
See the yellow marker? You could see the remains of the valve there if it wasn't strategically hidden.
lol sorry guys was the only pic i could find - apologies! I will get a better one. will try the press and some freeze off on the valve and see how it goes :0 Might try and grind off the sharp edge with a dremel..
You might try a propane torch, and wick some candle wax around the stem before to press or tap on it.
Could you drive the valve stem back up slightly then grind off the mushroomed area so it is smaller than the guide then drive it down and out?
Can you tap it upward a little bit, and then file the mushroom part off? I bet if you then hammer it down (into the combustion chamber) using a drift it will come out without too much trouble. And we can't see much of your cat either! Hah! Rusty beat me to it while I was shopping for emojies.
We had an old man in town in my youth that removed twisted off bolts that way. Ran a tap through to clean things up but it didn't take much. You're replacing the guide so it would be worth a shot if the squaring off and punch don't work. Pete
If the valve guides are soft enough to drill,and you have a drill press or milling machine, you could grind the top flat, then drill a circle of almost touching holes through the guide, around the stem, then punch the stem and center part of the guide out.This might also make it easier to remove the rest of the guide.
I've taken a lot of things apart using an air chisel with an old chisel cut off and ground down to make a drift. Seems like that moves stuff a lot better than hand hammering or even a press.
If the head is/was any value, can you locate a shop that does tap removal (Tap-EX) most industrial cities have them. and can burn them out electronicly , ask a good auto mechanic where he sends the heads out to get the broken exhaust studs removed
I'd do the heat and candle wax or just soak the crap out of it with PB Blaster or one of the other good rust solvents until I could get it to move then cut the mushroomed tip off and drive it out. Main thing is don't get impatiant and beat on it too hard before it is ready to move. The guides will have to be redone but not all shops do guides the same way so you don't want to beat up what is left there or break it or drill it out if you don't have to.
Make sure you use the right size hammer! Lots of times I see mechanics try to use a small hammer in an attempt to “ drift” something and end up “ peening” it instead of moving it. Hammers come in sizes, just like wrenches, for a reason. Bones
Don't make this harder than it is. If the valve will move, even 1/8 of an inch, drive it upward, grind the mushroomed area down to where it is smaller than the guide and you will be able to drive it down and out easily. A little oil won't hurt.
How rare or hard to find is the head? If it is not that hard to get a replacement, then you can do some work yourself. If it would be hard to replace, then pay the pro at a machine shop.
When I think back about my time working at Automotive Machine Shops, I would recommend Fstarocka do the work himself, rather than pay for the machine shop "pro" do it. This is fiddly work, and careful work by one of us amateurs with decent mechanical ability should produce just as good results. The exception would be if it were taken to a shop with a Electrical Discharge device.
the heads not too hard to come by- but its totally usable.. i have the motor ready for rebuild.. i like the air hammer idea- ill put some heat onto it next week and see.. way too busy now finishing off a transom conversion on a boat from OMC to mercruiser :/ almost done! thanks for all the suggestions - ill see if i can pop it up a little, in the mean time ill soak it with some pb after heating it up - that always seems to draw the oil in better than cold
If the stem won't move up enough to grind the mushroom off, I don't see any functional damage that would be done by just grinding the top of the guide and stem off enough to remove the mushroom on the stem. Its probably going to need a new guide anyway so grinding the top off won't make any difference.
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