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breaking off stuck valve guides

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CO3A View Drop Down
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    Posted: 22 Nov. 2020 at 3:32pm
(later note: further down in this thread I explain how to break off valve guides without using a cold chisel and making a mess) 

Hey folks, I'm pulling the extremely worn valve guides from my engine with the pulling with a bolt from the top method, and having a bit of trouble. The first three have come put pretty well, but the fourth I have snapped two grade 8 bolts trying to get out. I have read a couple of references to driving the guides down and breaking them up with a drift of chisel as you push them down. 

Has anybody done this? Like I said, I have seen a couple of quick references to doing it, but far more info is out there about pulling from the top. I'm worried this could damage the block somehow. 
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Bruce W View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bruce W Quote  Post ReplyReply Direct Link To This Post Posted: 22 Nov. 2020 at 6:00pm
  The Service Manual for Universal Jeep Vehicles says to drive them down and out. Paragraph D-58, page 41. You do have a service manual, don’t you?
  There’s no need to break them up. There’s room in the valve spring chamber for them to come out. 
  Some of them come out pretty hard. I’ve had a couple that worried me. My machinist said that they sometimes come out easier after the block is cleaned. I’ve been wanting to try that “Freezeout” stuff on them but haven’t had a chance. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Oilleaker1 Quote  Post ReplyReply Direct Link To This Post Posted: 22 Nov. 2020 at 6:30pm
Another method the machine shop used on mine was thread the guide with a tap, screw in a bolt and slide hammer them up and out. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote CO3A Quote  Post ReplyReply Direct Link To This Post Posted: 22 Nov. 2020 at 8:14pm
Bruce, I do have the manual, but was under the impression from a number of  posts on this forum that there is not enough room to drive them out through the bottom without pulling the cam and tappets. The manual is not specific about this. It just says drive them down and out, or pull them if you don't have the fancy driver downer tool (I do have a home made one). When holding the intake valve guides up to the space it looks like one might have room if you took the adjuster off the tappet, but I don't think you would have room for the exhaust guides.

Oilleaker, I was thinking of doing this actually. I would need to order a  conversation coupling nut to attach the rental slide hammer to my 3/8 all thread. If I go this route I'll put pictures up here.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bruce W Quote  Post ReplyReply Direct Link To This Post Posted: 23 Nov. 2020 at 1:43am
  Hmmm, I see what you're saying. I guess I've never removed any with the camshaft and tappets in place. I'll be looking into that tomorrow.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bruce W Quote  Post ReplyReply Direct Link To This Post Posted: 24 Nov. 2020 at 8:46pm
  I just did some checkin' - I put one tappet and a camshaft back into a block that's torn down, and yep, sure enough, there's no way the guides can go down far enough to be driven out with the tappets in place, unless they are driven partway and then broken off. Man, I sure don't like the idea of breaking cast iron inside a block that is intended to run again! Shocked
BW

Edit to add: Maybe you could drive them down a bit to knock them loose, then pull them out.  BW
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Post Options Post Options   Thanks (0) Thanks(0)   Quote CO3A Quote  Post ReplyReply Direct Link To This Post Posted: 21 Dec. 2020 at 2:02am
Well, I've busted off 5 bolts, two being grade 8 trying the pull from the top method. I tried driving one guide down a bit to knock it loose (it took a lot of beating with a heavy hammer to budge 1/8 of an inch) then pulled from the top with 3/8 allthread. Snapped again! 

I experimented with putting an old valve guide in a nut splitter. The splitter crumbled the old guide easily and didn't send chunks of metal flying. I am going to try driving the guide down into the block and then crush it with the splitter to avoid swinging a hammer and chisel in the block. Will report back. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mark W. Quote  Post ReplyReply Direct Link To This Post Posted: 21 Dec. 2020 at 4:07am
Could you also score the guide with a Dremel tool and a little cut off disc? That would give the break somewhere to start.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote CO3A Quote  Post ReplyReply Direct Link To This Post Posted: 25 Jan. 2021 at 2:22am
Ok folks, I came up with a pretty good way for removing super stuck valve guides. I made a tool from a coupling nut and a 3/8 bolt with the head cut off to break the guides loose and beat them down a bit with a 5lb hammer. You will see in the picture it gets a mushroomed head from taking the brunt of the beating. Once I had beaten the guide down 1/4" I then switched over to an old valve guide (that had its outer surface ground down a bit so it could easily pass through the block) with a grade 8 bolt through it. If you don't have an old valve guide, you can just use a 4" grade 8 bolt with a nut (ground down to fit through the block) threaded on an inch or so. Drop the threaded end in the guide and beat away on the head. Once I had beaten the guide down about 1/2"-3/4" I put a nut splitter on the end hanging down in the valve adjustment area. The nut splitter does a much better job than a cold chisel as it doesn't make a big mess of metal shards, etc, and only takes a second to bust the guide off. The guides break pretty neatly. Once the bottom bit of the guide is broken off I continued beating the valve guide all the way out. For the last guide, I had to remove the motor mounts and lower the engine to get enough clearance to beat that guide out. For this one I would also put a piece of wood on the block as its pretty easy to slip with the hammer and hit the head surface. All in all, this method is a bit rougher than the pulling method, and I would rather pull them, but if they are stuck, and you keep breaking pullers, this method does the trick! 


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Post Options Post Options   Thanks (0) Thanks(0)   Quote 48walker Quote  Post ReplyReply Direct Link To This Post Posted: 30 Jan. 2021 at 1:21am
I like your solution, never had to remove valve guides but looks like that works pretty well
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