Helicoil insert for a stripped spark plug hole: Difference between revisions
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The tower completes the plug cavity from the head to the valve cover. It's a part of the exhaust cam bearing. The two cam bearing bolts hold the bearing wit the tower to the head. There is an o-ring between the tower and the head, but it should be ok to reuse. | |||
Because the tap has an extension on it that threads into the existing threads, the cylinder needs to be as close to bottom dead center as you can get it. When you're positioning the piston for the cylinder you're working on, turn the engine over until the intake valve rocker arm will just wiggle a little. That way both valves will be closed, but the piston will be well down in the bore, so it won't cause any interference with the Helicoil tap. Since the thread tap is a three-part tool (guide, reamer, and thread tap) there will be a good bit of it sticking down in the bore, and you don't want it running into anything. | Because the tap has an extension on it that threads into the existing threads, the cylinder needs to be as close to bottom dead center as you can get it. When you're positioning the piston for the cylinder you're working on, turn the engine over until the intake valve rocker arm will just wiggle a little. That way both valves will be closed, but the piston will be well down in the bore, so it won't cause any interference with the Helicoil tap. Since the thread tap is a three-part tool (guide, reamer, and thread tap) there will be a good bit of it sticking down in the bore, and you don't want it running into anything. | ||
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Next, fish out the thread using a piece of safety wire as a hook, and drape it over the side. Using a long, thin flathead screwdriver, knock the tang off while holding onto the string. If you're using a hemostat clamp instead, use that to hold onto the tang while breaking it off. | Next, fish out the thread using a piece of safety wire as a hook, and drape it over the side. Using a long, thin flathead screwdriver, knock the tang off while holding onto the string. If you're using a hemostat clamp instead, use that to hold onto the tang while breaking it off. | ||
Once the tang is out, put the tower back on the spark plug hole, then do the other cylinder, if you need or want to. Once you are finished, reassemble everything | Once the tang is out, put the tower back on the spark plug hole, then do the other cylinder, if you need or want to. Once you are finished, reassemble everything with the [[Torque Values|proper torque]]. The torque on the cam bearing (tower) bolts is 104 inch-pounds (8.7 foot-pounds). Go for a test ride. | ||
Again, not for the faint of heart, but definitely possible if you take your time and are very, very careful. | Again, not for the faint of heart, but definitely possible if you take your time and are very, very careful. | ||
And a final word from Dailyrider: "Working in that deep dark hole the plugs are in is no fun. You can't see anything, and it's very hard to feel anything; there's just no room at all. I would rather never do another one myself. It is a very tough job." | And a final word from Dailyrider: "Working in that deep dark hole the plugs are in is no fun. You can't see anything, and it's very hard to feel anything; there's just no room at all. I would rather never do another one myself. It is a very tough job." | ||