Oil pressure sensor extension

[johnbeck]

The threads on my old aluminum sensor extension are beat up. It threads into the block 4 full circles. The new steel(S Drake) will only go 2 circles. I ran a tap into the 302 block just to ensure clean threads- no change. My best guess is the new extension doesn't have enough of an initial taper on the half inch long male nipple. The female works fine. Any thoughts? (I know I've opened myself up to some entertaining commits in an effort to be descriptive!) Two threads on an extension isn't enough. S Drake customer service suggested running a die- I don't know if my die could change 1/2 inch of thread length available to match that portion of taper going into the block. I just want the D... 20 dollar part to work without returning, reordering and wasting another half a day. Help.

 

[c0astie31]

It almost seems like your thread and pitch are wrong.

 

[Steve83]

Try laying the old Aluminum threads against the new steel ones. They should nest perfectly.

Personally, I prefer a Ford part.



But common hardware-store plumbing works well, too.

.

 

[ntsqd]

I prefer to not use those things at all. I remote mount the pressure sender somewhere else and run a dead soft 1/8" copper tube between the adapter fitting in the port on the block and the adapter fitting screwed onto the sender. Sometimes I tag a tab onto the sender's adapter fitting for mounting, sometimes I wrap an Adel clamp around the sender's adapter fitting.

I always, always, always put at least one loop in the tubing to allow for vibration. In the pic below (taken to show the strangeness of the steering shaft - which is on the list to correct) you can see the adapter in the block and the tube. The sensor just above the coil bucket is the oil pressure kill switch for the electric fuel pump. Hidden behind the shock tower is the oil pressure sender mounted on the same 'T' as the kill switch.

 

[johnbeck]

Thanks all. I prefer Ford myself but the dealer says he can't go farther back than 1980 to find part numbers.( Last month I returned a new Dorman piece of junk timing chain cover and paid twice as much for a Ford Racing cover-I'm happy as can be). Thanks ntsqd, the extension is pretty simple and bullet proof- I'll try another manufacturer. Thanks again all.

 

[ntsqd]

I've never seen one break, but the idea of a heavy mass (a gauge type sender) cantilevered out in space just doesn't seem like a good idea. Mostly I go remote because of the need for other oil pressure sensors or switches.

 

[Crush]

Later model fords use a small pressure sender that doesnt require the extension. My 94 5.8 has one on it

 

[SteveL]

That's what I run on both broncos. The one that threads in directly to the block. They have a few versions of it an only 1 works with our gauge. I think they are discontinued. I was able to find a few on ebay and bought em. I can look up the part number if you want.

 

[Ourobos]

That newer smaller piece is not a sender.. It's a switch.. Anything over 5 psi and it'll send your gauge to a happy medium.. Not very accurate at all FYI

 

[SteveL]

With the smaller one I think the wrong or later one pegs the gauge. The one thar works is a ps-17. Like I said above I think they are discontinued and hard to find now.

 

[Steve83]

The mass of the sender is nothing compared to the strength of the factory connector, or plumbing pipe.


The later 6psi switch only sends the gauge to the middle if there's a resistor in the circuit, as shown in this TSB:



Without that, it pegs high.


I had forgotten about this; IDK if it shows the Bronco configuration:

 

[sykanr0ng]

Is this what you are looking for?:

http://shop.broncograveyard.com/Oil-Pressure-Sending-Unit-Extension/productinfo/10150/

 

[Tiko433]

When I got my truck it had a home made copper tube for a extension . I suspected it was not factory but it worked and let it roll. But it always made be neverouse. I was working on fuel pump and did not know but bent the tube. Stated it up , oil every where. The tube cracked . I went to remove it broke off in the block. Luckiy a "EZ out" got it out with any problem. I replaced it with a stock tube , works as should and feel a lot better about it.

 

[ntsqd]

The mass of the sender is nothing compared to the strength of the factory connector, or plumbing pipe.

Add in vibration induced fatigue and it is something to consider. I have seen steel extensions and I have seen aluminum extensions. For different reasons neither gives me a warm and fuzzy feeling. Like I first posted, I've never seen one break, but if one was to break it would be on my truck and it would happen in BFE. I prefer to not tempt fate with something easily fixed. Not to mention that I seem to frequently need more than one sensor or switch or combo of each.
And yes, the copper tube can also be fatigued and fail. That is almost always the fault of someone or multiple someone's working on or around it and not being careful. In ~40 years of working on engines in everything from swathers to race cars I have never seen a copper tube fail simply from use.

 

[Steve83]

Ford considered the vibration when they designed the connector. It can handle a couple of senders hanging out there, as that last diagram shows.

 

[SteveL]

I just checked ebay. There are some of the ps-17 senders on there. That's what I have on both broncos without the extension tube and run the stock cluster. Also running centech harness and hei dizzy but that shouldn't matter. To install I think it takes a 21mm socket. I just remember it was metric cause I had to go buy one. My larger standards wouldn't work.

 

[ntsqd]

They didn't consider my use of the vehicle in their calculations. I'm sure it would be fine for a street car (even though I wouldn't do it), but not off road as I drive on occasion. Really doesn't matter though, if it doesn't look like a good solution to me then it's not going to happen.

 

[englewoodcowboy]

It sounds to me like the threads didn't get cut right or the die they used was worn. I would pick up a 1/4" Pipe tap and die or borrow one from a plumber and chase the threads. Shouldn't have to do that with a new piece but it would probably be a lot faster than sending back and waiting for a replacement.

 

[Slowleak]

My sender extension is broken off in the block so I have been researching options hoping I can find a small sender. I did find a chart somewhere showing that a 1/4" NPT fitting should turn 3.1 turns before it is finger tight.

I have two Borg-Warner S334 senders that are new. Looking at them I can see that one is threaded with much more taper than the other. Must be some kinda Chinese math involved.....