Pressure gauge replacement

[hangarb7]

OK, so I guess I do not need some kind of 'proper' aircraft gauge. A lot of gauges say non-TSO but the Stewart Warner gauges all appear to be automotive style.

[Robert Lees]

I might well be wrong, but TSO did not exist in 1940-1950, so you could fit what was available from whatever was available.

I'm willing to be corrected.
Rob

[astjp2]

I might well be wrong, but TSO did not exist in 1940-1950, so you could fit what was available from whatever was available.

I'm willing to be corrected.
Rob

The Shinn Wheels were TSO'd in 1939...but not everything was

[Edwin Otha]

Components only need to conform to a TSO, which is a minimum requirement, when directed to be, by the Administrator.

EO

[Scott]

TSO is required for some specific components when used for some specific purposes. Example primary avionics, instruments used for IFR.

The requirement for parts for certified aircraft is usually proof that it comes from the manufacturer, or
PMA (parts manufacturing authorisation), or STC or
if the manufacturer sourced parts from non-aircraft manufacturer, the same source or equivalent

The last one gives you some wiggle room (depending on local opinions). Transport Canada defines a "commercial part" as follows ( i believe the FAA has a similar thread):

• That is not specifically designed or produced for use as an aeronautical product;
• (ii) That is made to a specification or catalogue description and marked under an identification scheme of the maker; and
• (iii) Whose failure does not adversely affect the continued safe flight and take-off and landing of the aircraft

So... if you can continue flying if the oil pressure gauge fails, at least long enough to land safely, an automotive gauge with a part number is fine (the addition of an orifice at the engine fitting, even though the manufacturer didn't put one in, makes good sense and fortifies the compliance with paragraph iii )

[N96337]

Try AC23-27. As long as it's just like the original, you can substitute parts for older non supported aircraft.
John

[3Dreaming]

Try AC23-27. As long as it's just like the original, you can substitute parts for older non supported aircraft.
John

The way I read it there is more to than just being like the original.

https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_23-27.pdf

[Hank Jarrett]

Going for the "Original" U.S.Gauge instruments is really only a priority for those of us doing restorations where we go totally NUTS to get as much as possible back to factory. There is really NO REASON you have to go back to the original even for an AirVenture award winning restoration. USE WHAT WORKS SAFELY unless you are doing a museum level restoration. Just because those like me go to ridiculous "BAT S**T CRAZY" lengths to find EXACTLY what was used at the factory doesn't mean we ALL need to.

That said, if you DO have an original, even if not working, DON'T TRASH IT!!! There are still those of us out here who will spend down right stupid money to make them work again. For the oil gauges, if you want to "look" close without hunting down a pair of U.S. Gauge parts change BOTH temp and pressure. Almost all new gauges have the needle bearing at the bottom of the face instead of slightly up. Two matching needles don't attract the eye, even when too low. One high and one low sticks out. If you are just semi-crazy you can even have the face re-marked to look original. I have seen a couple of Scott gauges that even fooled me till I saw the displaced needle pivots.

Hank

Decide how crazy you are and ROLL ON!