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Here's one - M14x1.5 with an M8x1.0 threaded center section for the knock sensor bolt. Not as long as the one you removed, but I'm not sure it matters. The sensor sits up on top anyway and is just sensing for knock.
Kind of end up with the bolt head below the deck so still faced with getting a socket on it. A bunch of spacers would be needed. I'm thinking about a long bolt to tap.
We could reach out to Carl, the collector of trashed blocks, for the proper bolt with the M8 thread in it. :-)
Kind of end up with the bolt head below the deck so still faced with getting a socket on it. A bunch of spacers would be needed. I'm thinking about a long bolt to tap.
We could reach out to Carl, the collector of trashed blocks, for the proper bolt with the M8 thread in it. :-)
I know he has one of my 87 blocks.
Why not thread an M8 bolt into the center with a jam nut on it, and then use the bolt to unscrew the plug if you need to get it back out. That's how I plan to install mine.
Why not thread an M8 bolt into the center with a jam nut on it, and then use the bolt to unscrew the plug if you need to get it back out. That's how I plan to install mine.
The problem as I see it is that pressure inside the block will want to push oil out the threaded insert. The M8 bolt holding the knock sensor will not be sufficient to seal the block from oil seepage. Oil in the valley is what I see.
The problem as I see it is that pressure inside the block will want to push oil out the threaded insert. The M8 bolt holding the knock sensor will not be sufficient to seal the block from oil seepage. Oil in the valley is what I see.
I'll let you know how it works out. I'm going to put sealant on the plug threads and the bolt threads which I think will take care of that. The pictures you posted of the threads you removed looks like they have sealant on them as well. I don't think the center threaded bolt will be more prone to leaking than the threads on the M14 plug.
Keep in mind that the knock sensor is a microphone of sorts. It's designed to pick up the knock vibration. Length of thread engagement is important, as well as not using a sealant. Find a fitting as long as the original. and either drill and tap it. Isolating the sensor with any type of thread sealant is the equivalent of wrapping the sensor in a shop rag and tossing it in the valley.
Keep in mind that the knock sensor is a microphone of sorts. It's designed to pick up the knock vibration. Length of thread engagement is important, as well as not using a sealant. Find a fitting as long as the original. and either drill and tap it. Isolating the sensor with any type of thread sealant is the equivalent of wrapping the sensor in a shop rag and tossing it in the valley.
What are your thoughts on using copper or aluminum crush washers instead. They shouldn't quell the vibrations we're trying to pick-up, correct? How are the current valley plugs sealed to prevent leakage - or is that why there's often oil in the valley of many motors?
05-13-2019, 10:21 AM
