3500 swap questions

Yes I know, look at the picture, look at the size of the inside pipe not the threads.

And bszopi yes I am using the stock knock sensor (just a replacement one for it).

How many times am I going to have to say this?

It's a 3/8" NPT thread. All I see is you placing a ruler beside the threads, I don't see any "inside pipe" in that picture, besieds, it's a sensor, NOT a pipe, so there will be no pipe ID to measure.

You know, it's not like I havent drilled and tapped for a CTS before, I've only had to do this operation several times, I also use a lot of pipe fittings and adaptors.

[PCGUY112887]

*sigh*

I'll say it again, the size of NPT tap is determined ny the INSIDE PIPE DIAMETER, NOT the thread diameter.

If you were to find a pipe that would thread into there, it would be 3/8" inside diameter.

Yes I know, look at the picture, look at the size of the inside pipe not the threads.

And bszopi yes I am using the stock knock sensor (just a replacement one for it).

[bszopi]

You need to use a knock sensor that matches the PCM you are using. Otherwise, the filter isn't correct and you will get either false knock or you won't pick up knock when it occurs.

*sigh*

I'll say it again, the size of NPT tap is determined ny the INSIDE PIPE DIAMETER, NOT the thread diameter.

If you were to find a pipe that would thread into there, it would be 3/8" inside diameter.

[PCGUY112887]

You sure about 3/8"? The smaller, 2 wire 3500 sensor looks maybe 3/8" on the ruler, but the larger 3 wire looks more like 1/2".

Granted this is on a wooden ruler... and I don't really know how this would be measured (from edge of the threads, or inside the threads).

As far as taking back apart, how could I drill and tap a head, sending aluminum everywhere while the head is on the block? I would fill the engine with aluminum.

*sigh*

Pipe theard is measured by inside diameter of the pipe itself, not the threads.

Yes, it is for sure 3/8" NPT thread.

The shavings, should be minimal, especially if you put grease on the drill bit and tap, to grab and hold onto the shavings. Besides, the shavings will only go into the cooling system, and although it's not ideal, to get anything in there, it won't really hurt anything., would most likely fall to teh bottom of the block.

I drilled and tapped the T-stat housing on my 3100 LIM with it in the engine, granted I had the T-stat out, and was able to vacuum most ofthe shavings out, but know that I missed a few and never had a problem with the engine afterwards.

[Superdave]

yep, just using 1 KS..

i think it's the original 3.1 sensor for my car as well..

[PCGUY112887]

Ah OK then, my 96 explains my 3 wire then.

Now the issue is just getting it in there, either with a tap (which still seems like it would get aluminum into the engine) or an adapter... either way I gotta figure out the proper sizes of each of these. Then I'll just have to extend the sensor wires I guess.

Superdave, I guess you only have 1 knock sensor correct? I realized the 3500 has a second knock sensor on the rear of the engine, I just unscrewed it...

[IsaacHayes]

94-95 3100's have a 2 wire ECT for PCM, and a one wire for gauges.

[PCGUY112887]

Thanks superdave, I feel better about my sensor now. I thought it had to go all the way in.

Bought a sensor for nothing , oh well it's an important one a new sensor is better.

[Superdave]

that's how far mine's in.

[PCGUY112887]

You sure about 3/8"? The smaller, 2 wire 3500 sensor looks maybe 3/8" on the ruler, but the larger 3 wire looks more like 1/2".

Granted this is on a wooden ruler... and I don't really know how this would be measured (from edge of the threads, or inside the threads).

As far as taking back apart, how could I drill and tap a head, sending aluminum everywhere while the head is on the block? I would fill the engine with aluminum.

Take what back apart? I though this sensor was installed in the rear head, which in any install I've looked at is pretty wide open, at least when the crossover was removed. :-?

[PCGUY112887]

I would tap it, but it's already installed. I am not taking all of this stuff back off again. I will end up ripping my new GM gaskets since you gotta RTV em in the corners of the orange channel.

If it were me, I'd drill and tap the head for the 3 wire size. 3/8" NPT BTW, for the 3 wire sensor, I haven't found out what the newer (3500) sensor thread is, but from pictures it looks like a NPS (National Pipe Straight). I'll have to pull mine out of the head find out.

Hard to tell from the pic, but that KS looks to be ok.

Really can't see shit in that cam sensor pic. A lot of the time due to heat cysles the cam sensor, or any other sensor of similar design for that matter will get stuck in the block, pry, pull, plead, curse, and it may come out in one piece.