Thread: The 4BD1 Part Numbers Reference

Originally Posted by Red90

Or just buy the plug and play sender that I provided the part number for. It is a perfect fit for the engine.

Not sure what you are on about a reamer. The female side of NPT is parallel. The tapered threads are on the male side. You just drill and tap. Of course M16 to 1/8 NPT adapters are simple to find.

I can assure you that the correct hole for an NPT male thread is tapered and this is why reamers specific to the task are made and sold. "To secure the best results the hole should be reamed before tapping with a reamer having a taper of 3/4" per foot." Source -Machinery's Handbook Twentieth Edition Page 1450.

Tap drill sizes - 1/8" NPT with reamer 21/64" without reamer 8.4 mm.
1/4" NPT with reamer 27/64" without reamer 7/16"
Source - Guide to world Screw Threads P.A.Sidders Page 305.

If you have a source for adaptors Metric Conduit to NPT do tell because I have never been able to find one.

ATM-2268: Adapter Bushing - 1/8 NPT female x M16 X 1.5 male | Auto Meter | eGauges.com

R7964: Adapter Bushing - 1/8 NPT female x M16 X 1.5 male , by ISSPRO - eGauges.com

Of course using the correct M16 sender provides a much better results.

Originally Posted by Red90

ATM-2268: Adapter Bushing - 1/8 NPT female x M16 X 1.5 male | Auto Meter | eGauges.com

R7964: Adapter Bushing - 1/8 NPT female x M16 X 1.5 male , by ISSPRO - eGauges.com

Of course using the correct M16 sender provides a much better results.

Well, I will be making a Metric male/1/4" NPT female to fit a Chicago Airguide sender and gauge to my Isuzu. I will also be putting one in the sump plug and the trans drain plug.

Those adaptors you quote must be specific to those gauge sellers. I can't find any at the usual engineering & fittings suppliers.

As to the Cockpit gauge reference. The Vision series gauges are much better.

The problem with using an adapter is normally the sensor tip ends up barely sticking into the thermostat housing. This gives a low reading. Using the one I quote puts the tip dead center in the coolant flow.

Originally Posted by Red90

The problem with using an adapter is normally the sensor tip ends up barely sticking into the thermostat housing. This gives a low reading. Using the one I quote puts the tip dead center in the coolant flow.

John, looking at that housing and the position of the sensor I doubt if there would be any variation in temp at any point across it?

It is the heat loss to the housing that causes the low readings. When you have the choice, you might as well do things as best as possible. When the perfect sender is easy to find and cheap, why use something else?

What’s the correct Aussy word? Bodgy. No need for a bodgy job.

Does anyone know the thread of the oil pressure switch on the 4BD1? Is it 16mm x 1.5 also? I want to fit an oil pressure gauge and retain the warning light.