3500 swap questions

[bszopi]

Would it even be possible to rivet it to the block?

[Guest]

Would it even be possible to rivet it to the block?

Anything's possible!

But I'm gonna bet it's bolted in.

[PCGUY112887]

Well please enlighten me then. I have undone the bolt but for the life of me I can't get it out. The RTV you see in the pic is actually all cut, it still just lays over the edge of the sensor.

Bad picture time (it's dark outside, focus doesn't like darkness). See the little round thing to the very right of the red wire? It seems like that is holding it in... but no torx or standard or metric hex will fit into it (it's round hah). It may be actually just holding the plate onto the sensor it's self, but DAMN this thing is stuck in there! Now that I have a good light on it, it doesn't look like a rivit, but it acts like one.



I know how stupid I look for not being able to get this out, but it really is THAT stuck!

Here is the knock sensor I mentioned earlier, this is as far as I can get it to thread in.



And here is my invesigation into the coolant temp sensor issue. From what I understood prior to me going outside tonight, I thought older engines (like my 96 3100) had a 2 wire coolant temp sensor, then a 1 wire coolant temp sensor somewhere else for the dash. Well it turns out mine had only 1 in it, a 3 wire in the neck of the lower intake by the tstat. The 3500 has 1 sensor in the head, and it's a 2 wire.



I would like to just use the 3 wire in my 3500 if I can, but as noted before and in the pic above there is a size difference. Would there be any problem if I got an adapter to convert the smaller size into the larger size? Would it read any less accurate if the actual probe was outside of the head a bit more?

Anyone know the NPT sizes of these so I could look up an adapter on mcmaster for it?

[Guest]

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.

[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.

[Guest]

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]

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.

[Superdave]

that's how far mine's in.

[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.

[IsaacHayes]

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

[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...

[Superdave]

yep, just using 1 KS..

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

[Guest]

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.

[PCGUY112887]

[Guest]

*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.