Knock sensor position PCM Excalibur 330

[TMK]

Does anyone know if the knock sensor can be positioned in a T threaded into the block with a valve on the other branch of the T so one can drain the block without having to remove the knock sensor or does the knock sensor have to thread directly into the block?

[Skidave]

I know this was talked about years ago. I dont think anyone ever tried it. That sensor needs to physically sense the knock and I think the census was it would not work it if was removed from the block. Even if just a T fitting separated the sensor and block.

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[BrianW]

Follow-up question on this. As an alternative, has anyone drilled their own additional drain holes next to the existing knock sensors? Seems like a pretty simple thing to do and would make draining that location a lot easier. I have quick drain valves on all other locations on the engine, but would love to not have to take the knock sensors out each time (I use the boat throughout the winter). Thanks.

[jpwhit]

The current drain location has a reinforcing boss in the casting to strengthen the threaded area. It would be a very bad idea to drill a hole in another location. Not only would that location be too thin to support being threaded, you will create a location for a stress crack to form in the block.

It's also a bad idea to install a tee to make it easier to drain. Not so much because it'll lessen the knock sensor signal, which it may, but because you really need to take whatever is screwed into that threaded hole out anyway and stick something in to clear any debris that happens to be on the inside of the block to get all the water to drain out. If you put a tee in there, debris will gather behind it and the smaller passage through the tee will certainly clog up. Then you won't get all the water out and are likely to end up with a cracked block.

The best solution is to buy a deep 6-point socket that fits the knock sensor. Also, the knock sensor wire comes off super easy if you squeeze the connector in the right place. Then it's a piece of cake to remove and install the knock sensor. Just be careful not to over-tighten the knock sensor with a socket wrench.

[BrianW]

OK. Thanks for that feedback. Wasn't aware of the reinforcement within the block. Definitely don't want to mess with that. I have had the boat for a few years now but purchased it used - the hex on the knock sensor was a bit worn from prior owner. So I think I'll just keep doing it as I have and when fully worn get a couple of new knock sensors and a nice 6-point socket for them. Thanks for your thoughts!