Tapping the brass block plugs for temp sensor
Who has tapped the threaded allen head block plugs for a temp sensor?
I need to mount a temp switch for the fan, in addition to the computer and gauge sensors in the heads.
I dont have an allen head wrench big enough to remove it, so I was just going to drill and tap it on the block.
Is it thick enough in the center to get a good 3/8" NPT tread in it?
Gary
I need to mount a temp switch for the fan, in addition to the computer and gauge sensors in the heads.
I dont have an allen head wrench big enough to remove it, so I was just going to drill and tap it on the block.
Is it thick enough in the center to get a good 3/8" NPT tread in it?
Gary
Take a bolt with the proper sized head and use that as an allen wrench. I welded a nut on the other end to get a socket on it, but you could just as easily put two jam nuts or vice grip on there. I wouldn't try working it on the block. You may not have enough depth for the tap.
Here is a picture of mine adapted to a Datsun sensor. I soldered the three left most pieces together so it doesn't leak and goes back in with a standard wrench. If I remember correctly, I tapped it with a 1/2 NPT, then used the 1/2 to 3/8 adapter (second from left). I think I had to do it that way because the bolt head was bigger than a 3/8 tap.
Here is a picture of mine adapted to a Datsun sensor. I soldered the three left most pieces together so it doesn't leak and goes back in with a standard wrench. If I remember correctly, I tapped it with a 1/2 NPT, then used the 1/2 to 3/8 adapter (second from left). I think I had to do it that way because the bolt head was bigger than a 3/8 tap.
An upside down bolt...........
Genius!!!!!!!!!!!!!!!!!!!
I didn't want to spend $100 on a wrench set I would only use once.
Genius!!!!!!!!!!!!!!!!!!!
I didn't want to spend $100 on a wrench set I would only use once.
Take a bolt with the proper sized head and use that as an allen wrench. I welded a nut on the other end to get a socket on it, but you could just as easily put two jam nuts or vice grip on there. I wouldn't try working it on the block. You may not have enough depth for the tap.
Here is a picture of mine adapted to a Datsun sensor. I soldered the three left most pieces together so it doesn't leak and goes back in with a standard wrench. If I remember correctly, I tapped it with a 1/2 NPT, then used the 1/2 to 3/8 adapter (second from left). I think I had to do it that way because the bolt head was bigger than a 3/8 tap.

Here is a picture of mine adapted to a Datsun sensor. I soldered the three left most pieces together so it doesn't leak and goes back in with a standard wrench. If I remember correctly, I tapped it with a 1/2 NPT, then used the 1/2 to 3/8 adapter (second from left). I think I had to do it that way because the bolt head was bigger than a 3/8 tap.

On the passenger side of the block, the even side if you please, just in front of the crank sensor is a smaller plug that also goes to a water jacket. I, well kinda forced my temp switch sender into that one. It felt pretty tight going in but with a little pipe thread compound I've had no issues with leaks, and it and the fan works great.
Why go through all the trouble!! The passenger side rear already has what you need. You don't even have to rethread anything...VDO makes a metric temp sensor costs all of $10. Save yourself tons of headache
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Front drivers side head is used for comupter temp sensor.
Rear passenger side head is used for the temp gauge sensor.
Then I still need a place for the fan on/off temp switch.
Rear passenger side head is used for the temp gauge sensor.
Then I still need a place for the fan on/off temp switch.
If anybody knows of a source for fan on-off temp switches that fit in the stock heads, I would like to know about them. Painless offers a relay kit that includes a metric switch, but they don't sell just the switch. At least I couldn't find it anywhere. somthing that comes on around 200° or more to trigger the high speed fan would be perfect.
I have read a number of posts that say to lathe down and rethread a 3/8 NPT switch, but don't feel like buying a die for this one time thing.
I have read a number of posts that say to lathe down and rethread a 3/8 NPT switch, but don't feel like buying a die for this one time thing.
Yeah, I realize that, but I'm not sure where the setpoints are or if it's even functional in my reprogrammed computer.
So I figured I already had the temp switch, the engine is out, and plug accessable. Better to tap it now if I need it later.
So I figured I already had the temp switch, the engine is out, and plug accessable. Better to tap it now if I need it later.





