Oil Pressure Sensor - Weird Tapered Thread Size?

[cunning plan]

Another question for the fantastic EaryBay techies. opcorn:

So I was cleaning the oil galleries, including the oil pressure relief valves in preparation to start rebuilding the engine. However, I noticed that when I went to put the oil pressure sensor back in, the thread at the top of the hole was massive:

The sensor will lift in and out without resistance this far:

Only here will a thread start to 'catch' ready for tightening:

As I was measuring to try and get an idea what was going on, I noticed that the pressure sender seems to have a 'taper' to the thread.

Here it is 9.87 at the bottom of the thread:

And 10.07 at the top of the thread:

Is this correct? Is the oil pressure sender thread supposed to be tapered?

:sign0009:

 

[Bundy]

As far as I'm aware they are all tapered...that's why you have to be careful not to over-tighten as they can crack the case at the thread...or just strip the thread!!
Cheers
Al

 

[cunning plan]

Perfect, thank you for confirmation! I was worried I was going to have to drill and retap the port, which meant more work! :roll:

 

[atafonso]

The thread on the case is galled. Originally it's a m10x1.0 same as brake pipe nipples. The sensor thread is tappered, generally 1/8"npt.
When fitting the sensor you should use a litlle ptfe tape and just snug the sensor, not really tightening. It will not leak that way.
Now you have to fix th thread on your case or it will leak/pull the sensor.
Buy an m10x1.0 thread insert with the apropriate tap, use red loctite to fit the insert on the case. Never will have problems again
Abel

 

[cunning plan]

The thread on the case is galled. Originally it's a m10x1.0 same as brake pipe nipples. The sensor thread is tappered, generally 1/8"npt.
When fitting the sensor you should use a litlle ptfe tape and just snug the sensor, not really tightening. It will not leak that way

Thanks.

Now you have to fix th thread on your case or it will leak/pull the sensor.
Buy an m10x1.0 thread insert with the apropriate tap, use red loctite to fit the insert on the case. Never will have problems again
Abel

Wait, why do I have to fix the thread in my case?

If the thread in the case is M10 and the sensor goes from an M9 to M10, the sensor dropping in that far before 'catching' the thread is correct?

 

[atafonso]

The sensor does not go from m9 to m10, in fact i have never seen an m9 thread.
The hole is probably enlarged by the tapered 1/8"npt sensor. Some are slightly larger and longer than others, if somebody screwed in too much one of these, chances are the hole is enlarged.
If the sensor bottoms out, try using one from a Golf which is an m10x1.0 not tapered with a copper washer. If the surface on the case is not very flat, you can correct slightly using a flat file. But it can only correct slightly, if filed skewed it won't seal.
Abel

 

[rlepecha]

The sensor does not go from m9 to m10, in fact i have never seen an m9 thread.
The hole is probably enlarged by the tapered 1/8"npt sensor. Some are slightly larger and longer than others, if somebody screwed in too much one of these, chances are the hole is enlarged.
If the sensor bottoms out, try using one from a Golf which is an m10x1.0 not tapered with a copper washer. If the surface on the case is not very flat, you can correct slightly using a flat file. But it can only correct slightly, if filed skewed it won't seal.
Abel

Or use the equivalent dowty seal rather than a copper washer, allows for a slightly less perfect sealing surface.

The other option would be to buy an M10x1.0 straight to 1/8 NPT, or M10 Taper and bond that adaptor or tee straight into the case.

Sent from my Swift 2 using Tapatalk

 

[cunning plan]

The thread on the case is galled. Originally it's a m10x1.0 same as brake pipe nipples. The sensor thread is tappered, generally 1/8"npt.
When fitting the sensor you should use a litlle ptfe tape and just snug the sensor, not really tightening. It will not leak that way.
Now you have to fix th thread on your case or it will leak/pull the sensor.
Buy an m10x1.0 thread insert with the apropriate tap, use red loctite to fit the insert on the case. Never will have problems again
Abel

The hole is probably enlarged by the tapered 1/8"npt sensor. Some are slightly larger and longer than others, if somebody screwed in too much one of these, chances are the hole is enlarged.

Sorry Abel, I had to re-read this a few times (my fault) to understand what you meant, however, I now do! arty0021:

I think we have a solution:

If the sensor bottoms out, try using one from a Golf which is an m10x1.0 not tapered

Or use the equivalent dowty seal rather than a copper washer, allows for a slightly less perfect sealing surface.

So, a clean up with a file, then a Golf sensor which is un-tapered M10x1.0 and a dowty seal.

Thank you gents! arty0047:

 

[atafonso]

Forgive my rubbish english

 

[cunning plan]

Forgive my rubbish english

More likely my rubbish understanding :lol: arty0047: