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Frozen Headlbolt--Did I Screw Up?


BigSix

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Hi All: Well, yeah, I already did screw up, but it's not broken yet, so here's the story. If anyone's got any tricks up their sleeves, I'd be eternally grateful. On the endless project of my buddy's 1970 Wheel Horse GT14, the Kohler 321S (14 hp) has a leaking head gasket. I dutifully ordered the gasket from Sandy Lake (in stock, no problems), pulled out my manual, and started backing the bolts out. The first two bolts were stiff, but broke loose okay. I decided to get the torque wrench, just to see how much torque it took to break the rest of them loose. They came so quickly I can't tell you if some of them registered any torque at all. The most were like 15 lbs. (max. torque is 25-30 ft. lbs.). THEN, I got the the last bolt (near the exhaust port and, btw, the leak is on that side of the engine, so that the bolts that had very little torque on them were NOT near the leak) and it wouldn't go. I put on like 60lbs. of torque, thinking it was moving, but like a dummy, I was looking at the torque meter (or just alseep? I dunno) and didn't really realize how hard it was turning. I turned it between 1/8 and 1/4 turns, then back, then did it again, thinking I was "working it." My fear, of course, is that I was twisting it, and the that the threads were not moving at all, in the cast iron block (alum. head). I then rapped on the bolt, with an extension and small ballpeen hammer, smartly, about 15 times, and retried it. It didn't seem to move at all at 60lbs. These bolts are approx. 2 and 1/4" long, and I'd guesstimate they're a 3/8" at most. I thought about heating the block with a propane torch, gently, but my Dad suggested putting the tractor back together again (I've got the fuel pump, carb and tank off for rebuilding) running it up to operating temp (mowing my lawn for a few hours) and THEN trying to twist the bolt out. The head's fairly accessible even with the tractor reassembled. I also soaked it with PB Blaster, after the fact, but I highly doubt it's gonna work it's way that far down into this If I twisted this bolt, 1/4 turn, back and forth twice, is it too weakened to come out, such that it will snap? So, does anyone have a better idea than running the engine up to temp and trying to turn the bolt out? How hard should I be whaling on this bolt with an extension and hammer? In the worst case, a machine shop can drill the bolt out of the block and retap it, right? *Gulp* At what cost? Thanks, :( Peter
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Whats the operating temp? If its apart you could always throw it in a heated oven. Im sure the wife or mother might have something to say about that though...dont do it when theyre there!
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I say apply more PB blaster over two or three days if neccessary and rap it every time you walk by it with a hammer and see if will give up. you really don't have a lot of choices and nothing to lose. You will be suprised what a hammer and a little patience will accomplish sometimes. BTW you can always buy a new head bolt if you damage the head with the hammer. If you can get a box end wrench on it you can also try putting pressure on the wrench while some one hits the head with the hammer. Good luck. And don't let this machine outsmart you.
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At this point it's not broken so you have options, 1 put it back together and run to operating temp and then try to remove the head bolt, 2 keep trying to remove as it is risking breakage somewhere unseen, or 3 cut or drill the bolt head off the bolt this will allow you to remove the cylinder head and give access to the lower portion of the bolt to apply the penetrating oil where it may have some effect, you'll also be able to heat the area of the block as well as being able to see if the bolt is turning or not. A good tool here is a stud remover which will grab what's left of the bolt or lacking that a good pair of visegrips (no imitations) or a good pipewrench. If you use the visegrips or pipewrench grab what's left of the bolt as close to the block as possible and go slow use heat and penetrating oil liberally. A last resort is to drill out the bolt if it breaks using a left handed drillbit which may twist the bolt right out. Good luck
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They come out alot easier when the engine is hot, i have had several head bolts and exhaust elbows stuck, that ease up when theyre hot.
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I'd go with a little heat in the area where the bolt goes into the block BUT install at least the 2 bolts on each side of it to relieve some of the tension on that bolt.
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Anything is possible. If Loctite was used, to cinch the head bolt down, Heat is required to remove the bolt. As Tiny suggests put a couple more bolts in it to reduce the pressure on the one bolt.
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I feel a lot better about my chances here, so thanks, you guys. I'm encouraged that heating it by running it can make a big difference sometimes (maxtorman1234), and I hadn't considered that Locktite might be involved (Leroy) but as abused as this machine was, it wouldn't surprise me. The previous owners all apparently were compelled to replace cotter keys with bent, rusty nails so, you get the picture. At this point, I will try sprayin' and rappin' on it, for a few weeks, when I walk by, (sandyhillbill) and I must say, I never thought about hitting it when there was torque on it, from a box end wrench, but I'm definitely gonna explore such less invasive options first, if it doesn't progress after I heat it up. If push comes to shove, I like Reed's idea (which I had considered, actually) of cutting the bolt head off, as opposed to just twisting until it breaks, for the reasons he lists, i.e, getting the penetration oil to the problem, and possibly spot heating the area of the block involved. I will definitely explore the stud remover, if I go this route, and I'd rather buy a set of left hand drills and gradually bore it until the bolt gives up, instead of pulling the engine for a machine shop to charge me on. It rained today, and I broke my toe (tripped over the dawg!B)) so I've had some more time to consider my options. As I said, (other than my toe and pride) I'm feeling a lot better about the options here, so thanks again for the advice and encouragement. Underneath it all, it's a wonderful machine, and my goal is to make it better, not worse, so patience is the key, of course. Peter
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I like the idea of putting a couple of the head bolts back in to release any pinch caused by their absence. You know how you tighten up head bolts using a side to side pattern, I think I would do the same in taking them out. Don't forget to follow up with the end result. We really do worry about other members and their machines:D Dan
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I'm not sure how you would cut the head of the bolt off without damaging the cooling fins. A die grinder would be the best way to get-er done if that was your goal. That practice is done so they can get a pair of vise grips on the bolt shaft and get the pentrating oil down the shaft. On reverse cut drill bits. They are very cool in helping to remove stuck bolts but if they are not long enough the machine shop would probably rather had it when they could see the portion to be removed.
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Peter, There was a thread, I think, in Shop Talk, about using paraffin or wax. I tried it on a stuck bolt only once so far and was pretty impressed. But you do need to heat things up. You can most likely get enough heat from a propane torch for this though. Joe
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You might try a brand of penetrating oil called "Gibbs". it can be found online. I'll post a link in another thread. Spray and tap.. I agree with putting a couple of bolts in on either side of the one you are unable to remove. As for bringing up to heat? The cast has a lower coefficient of expansion than the steel bolt, so you might be causing a problem rather than relieving stress. Simply, the bolt expands further, thereby tighening more in the hole at operating temps. Applying heat only around the bolt might work. And, wehn you rebuild...What kind of mower is the Kohler in? I have a Cub Cadet with a 12 hp kohler that was deadly on head gaskets, simply because of a gas tank mounting to a thin hot head. I have tried to find room for the tank elsewhere, but. Find a scrap yard with a different Kohler head. I replaced mine, finally, with a cast iron head, and have not replaced the head gasket since.
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