Oil switch vs Sending Unit thread size

[tashakes]

I am in the process of replacing the idiot light with the oil pressure gauge. I ordered the correct sending unit and removed the switch from the back of the engine. When I tried to install the new sending unit it does not fit. The thread size is different on the new unit about 2.3 mm larger (or roughly 3/32). Bottom line is it does not fit. I thought it was supposed to be a like-for-like replacement. I would not think that cars factory equipped either way would use a different thread size. Please show me the way....

TIA

 

[Hemikiller]

Threads are the same regardless of which sender was installed.

1973 FORD MUSTANG 5.8L 351cid V8 Oil Pressure Sender / Switch | RockAuto

RockAuto ships auto parts and body parts from over 300 manufacturers to customers' doors worldwide, all at warehouse prices. Easy to use parts catalog.

www.rockauto.com

 

[Stanglover]

When I did my gauge upgrade, I kept the idiot lights installed in Rocketman's fabulous tach conversion as well as a new mechanical oil gauge. I used a T adaptor so I could use both the light sensor as well as the mechanical oil gauge.

 

[tashakes]

When I did my gauge upgrade, I kept the idiot lights installed in Rocketman's fabulous tach conversion as well as a new mechanical oil gauge. I used a T adaptor so I could use both the light sensor as well as the mechanical oil gauge.

Great idea on the “T” to keep the light and add the gauge. Will look for that. I already removed the light cluster and the ammeter to have them modified by Rocketman.

Threads are the same regardless of which sender was installed.

1973 FORD MUSTANG 5.8L 351cid V8 Oil Pressure Sender / Switch | RockAuto

RockAuto ships auto parts and body parts from over 300 manufacturers to customers' doors worldwide, all at warehouse prices. Easy to use parts catalog.

www.rockauto.com

Thanks for this. I will purchase the Motorcraft one to be safe. The one I got from Advanced Auto Parts may have been the wrong part number. https://shop.advanceautoparts.com/p/carquest-premium-engine-oil-pressure-switch-sac4542/12444750-P

 

[Stanglover]

Great idea on the “T” to keep the light and add the gauge. Will look for that. I already removed the light cluster and the ammeter to have them modified by Rocketman.



Thanks for this. I will purchase the Motorcraft one to be safe. The one I got from Advanced Auto Parts may have been the wrong part number. https://shop.advanceautoparts.com/p/carquest-premium-engine-oil-pressure-switch-sac4542/12444750-P

If you decide to go with a mechanical oil gauge, I have quite a few detail pics that might help. Finding a place to run the oil tube was a bit of a challenge. Also I made a mistake in not adding a loop in the line, but it's not been a problem so far. Let me know if you need more info.

 

[secluff]

Hello Tia,
As Hemikiller posted, the threads are the same for both sending units. The warning light and gauge sending units are 1/4"-18 pipe thread (NPT). Both thread directly into the block with no adapters.
Many here will attest to me hawking Motorcraft quite often. I like using the manufactures service parts when available. The sending unit for the light (Ford part# D4AZ-9278-A, Motorcraft SW-1311) and the gauge (Ford part# E4ZZ-9278-A, Motorcraft SW-1547-B) are still available from Ford. The link Hemikiller posted to Rock Auto is a great site. I've used it many times, and it offers Ford/Motorcraft parts. As is the norm now, shipping costs always enter into decisions when purchasing online products. Rock Auto still comes out a little under the retail price of $28.18 from the dealer for the SW-1547-B sending unit when adding shipping to the selling price.
If you decide to use a different brand from a parts house, specify their top-of-the-line product.

 

[tashakes]

If you decide to go with a mechanical oil gauge, I have quite a few detail pics that might help. Finding a place to run the oil tube was a bit of a challenge. Also I made a mistake in not adding a loop in the line, but it's not been a problem so far. Let me know if you need more info.

Thanks, I’m going to go electronic for now with the factory center gauges. Appreciate the offer.

 

[Stanglover]

Thanks, I’m going to go electronic for now with the factory center gauges. Appreciate the offer.

No problem. Electric are definitely easier.

 

[351c1971]

NPT and SAE threads from China were never very good.

 

[tashakes]

To close this out, I received the Motorcraft sender and fitted it with a "tee" with the factory switch, fit like a glove. So lesson learned, bought original from Rock Auto and will probably stick to that in the future. Now patiently waiting for my voltmeter and idiot light tach conversions from Rocketman to complete the job. Thanks all for the help.