In my autometer instructions it says to "use teflon sealing compound on pipe threads."

Now a few questions if i may. After reading quite a few posts it seams that some people use teflon tape like that used in plumbing. i have some left over from a 4am run to ralphs a while back.

Will this teflon tape do the job and do it well? or should i try to find what others have used on here. i believe it was permatex teflon something or other.

And here comes the doozy... These are NOT mechanical gauges. these ARE electrical gauges. So I have 1 wire coming of of both my water temp and my oil pressure gauges.

After much reading, some people recommend against using teflon since it will keep the sender from having a proper ground against the block. So how do I go about installing these right s they function as designed?

Thanks

I use Permatex form-a-gaske on the pipe threads myself.
I've read here several times that teflon tape might prevent a good ground connection BUT I believe that the pipe threads cut through the tape just fine.

permatex form-a-gasket eh? Will that allow the sending unit to have a ground?

Where would I pick it up. Just walked to autozone and they didn't have any.

Thanks Dean. And thanks for all the help before when I rewired the car!

Maybe, just maybe it's not called "form-a-gasket anymore.
I need to run out to my shop and see what it says.
Anyway it's the black sticky Permatex stuff.

I've never had a problem with the sender getting a ground through anything on the threads myself.

There are "sensor safe" sealing products out there, especially with the preponderance of EFI. Connections on these sensors are much more critical on EFI systems than anything you might run.

Good point Steve for those that might be running later model EFI systems in their old Chevelles.
Never thought about the grounds on newer cars being more critical but with todays modern computers it makes sense.

Back out in the shop now;
The stuff is called Permatex #2 gasket sealer, works great on pipe threads and thermostat housing gaskets as well as othe gaskets.

How much would you recommend I put on. Put a few dabs on and spread it around with my thumb? A crapload? or a tiny dot and not rubbed in.

You don't need a lot, very little all the way around.

Ok.

Now how tight should I make these bolts?

And it appears I will have to use the adapter for the water temp. So it will be the sending unit threaded inside the adapter threaded inside the intake.

So should I use the sealer inside the adapter as well as outside the adapter?

Thanks for answering my silly questions.

Jim these are not your typical bolts. A regular bolt has the threads cut straight but the threads on plumbing connections are threaded with a taper. They do this on purpose so that the threads get tighter and seal up. But it also means that if you put an Ape-level of torque on it it will get expanded a bit. Over time it will have to be screwed in further and further and you can run out of threads to seal.

You will want to use the sealer on all of the outside threads and it does not take much. I often put a small blob on one side and then press/work it down into the threads once around with my finger. No more than a 1/4" band works fine. I also often have more than I need so it oozes out. To make it look purty wipe off any excess ;-)

Old plumbers wives rule = Nothing on the first two threads.

Thanks guys, I'm off to go do this.

Update:

Uh oh. Well it looks like my electric sending unit does not fit! I took the old oil pressure sending unit out and when i went to go put my new electric one from AutoMeter in it doesn't clear the Performer RPM inatke Manifold.

What do i do? this is holding up everything now. is there somewhere else I can put it? And then get a plug for the old location?

FYI It's on a 350.

I found 2 possible locations after reading some threads.

One is above the oil filter:
http://datapusher.org/oilsend2.jpghttp://datapusher.org/chevelle/oilsend1.jpg

and one is in front of the block (would prefer not to use this one):
http://datapusher.org/chevelle/oilsend2.jpg

What about getting a 90* extension or just a normal extension. I assume I would get it at home depot's plumbing section? Would any fitting work, or should I look for a specific kind?

Also, if I use the one above the oil pump, I have noi idea what I would use to get that plug out.

Oh, oil pressure :hurray:
For some reason I thought we were talking "water temperature" :o
(probably because that was what I was working on)

I doubt that you would ever get that plug above the oil filter out without heating the block around it with an Oxy-Acetylene torch.

I just had to do this myself today to get the pipe plug out of the driver's side head for a temperature sending unit.
It was a 1/2" pipe plug that I removed with a 3/8" drive on a LONG 3/4 drive breaker bar.

That plug in front is 1/8" pipe size.
You can use a short 1/8" nipple and a 90* ell on it.

BTW you can also just put a fitting on the engine and run a line to the rather large Autometer oil pressure sensor mounted "remotely". This is what I did on my 396 because with headers and clutch linkage and my hand size I was not going to be able to get that sucker into the hole by the oil filter.

I made up a shim of sorts using 1/8" of plexiglass with a slot cut out to accept the ridge around the sensor. Then a simple pipe clamp from the hardware store and two screws mounting to the firewall.

Well I ended up doing some running around. i first got a small double ended nipple witha hex nut on it. it urned out to be too small and the 90 elbow wouldn't clear the manifold either so I put my original oil pressure line abck in and went back to the store.

A little aside here, it is way to hot to be working on a car and driving back and forth to the hardware store.

Back to business. I ended up getting a 1 1/2" double sided nipple. Unfortunately it didn't have a hex nu on it so i threaded it in as far as I could get it in by hand and then put the 90* elbow on.

This is where I get worried. When tightening it up, the nipple would just spin and pretty much went all the way to the bottom of the threads on the block. So i know the nipple is in the block as far as it will go (for the most part) and the elbow, well not sure how tight that is because I didn't want to keep turning it because it would just spin the nipple and not tighten the elbow :-(

Hopefully it all works out. Well back to soldering dash connections. Weeeeeee. Soldering in a hot car in the baking heat. Awesome!

Another advantage to the Permatex stuff - Doesn't matter if the pipe nipple is auctally tight or not, it won't leak.
The indian head shellac stuff in the bottle with a dabber works also.
(as long as you don't rotate the nipple after it sets up in both cases)

Just for the record........."Sensor Safe" means that the chemical compounds in the sealer will not damage oxygen sensors.:)