Thread Question

richardpope50 · Post by **richardpope50** » Thu Apr 11, 2013 5:26 pm

Does anyone know what thread size this air temperature sender is? It's for a Megasquirt ECU and is approximately 16.7mm outside dia.

Follow up question ... Any idea where I can get one nut and two washers so i can fix it in my air intake?

Thanks.

DaveEFI · Post by **DaveEFI** » Thu Apr 11, 2013 5:44 pm

M18 x 1.5 is the common one.

Most common way to mount it is to get a threaded bung (Ebay, etc) and weld or glue that to the housing.

Where you actually situate the ATS is open to debate.

conrod · Post by **conrod** » Thu Apr 11, 2013 8:54 pm

Pretty sure those air temp. sensors in your pic have a tapered pipe thread (3/8 NPT I think?) meaning you cannot get a nut to suit:(

mgbv8 · Post by **mgbv8** » Thu Apr 11, 2013 9:07 pm

conrod wrote:Pretty sure those air temp. sensors in your pic have a tapered pipe thread (3/8 NPT I think?) meaning you cannot get a nut to suit:(

You will find 3/8" npt nuts on ebay.

All npt, bspt and bspp fittings will have a nut available for it.

DaveEFI · Post by **DaveEFI** » Thu Apr 11, 2013 11:04 pm

Think the answer is it depends on the sensor you use.. I know mine is 18mm as I have the tap I used for it on my home made ally trunking, and it's the only one approaching that size I possess.

But 14mm appears to be another common size.

http://cgi.ebay.co.uk/200911963744

kiwicar · Post by **kiwicar** » Fri Apr 12, 2013 9:54 am

Hi
I have one of those, it is 3/8 NPT I just mounted a piece of 10mm ally inside the manifold and tapped that, the tap came from china for about £10 and was with me in under a week, they are very pricey from the UK!
Best regards
Mike

richardpope50 · Post by **richardpope50** » Sat Apr 13, 2013 8:35 am

Thanks all and I see that 3/8 NPT is 17.145mm so near enough my measurements so I'll try and get a nut and washer.

The only place I can mount it is in the (Hotwire) rubber inlet hose (immediately after the air filter) to the plenum so I think I'll go for a nut and washer connection. Otherwise it would have to be a tap directly into the plenum casing and that's not easy as my bonnet is so close. It won't fit into my air filter either.

If that does not work a new hose is not the end of the world.

richardpope50 · Post by **richardpope50** » Sat Apr 13, 2013 9:04 am

Finding one is not easy! Can't find a nut anywhere (apart from USA) so anyone any ideas, please.

(It does seem that they are used for electrical junction boxes, though.)

stevieturbo · Post by **stevieturbo** » Sat Apr 13, 2013 10:11 pm

American NPT would be a taper thread surely ? So not likely to get a nut ?

Just buy a tap and tap the hole, or a chunk of metal or whatever you need to screw it into.

certainly any electrical product within Europe should be metric, M16, M20 and M25 being most common.

DaveEFI · Post by **DaveEFI** » Sat Apr 13, 2013 10:47 pm

richardpope50 wrote:Finding one is not easy! Can't find a nut anywhere (apart from USA) so anyone any ideas, please.

(It does seem that they are used for electrical junction boxes, though.)

Most usual electrical size was 3/4" now 20mm - but that is miles too big. I dunno what the actual thread size is or indeed type - that is what the conduit boxes are called. There's probably a wider range of nuts available from a decent plumber's merchant, if it is BSP.

How about cutting the trunking hose and inserting one of the tubes with a threaded bung from Ebay? That's more or less what I did - but to replace the AFM.

stevieturbo · Post by **stevieturbo** » Sat Apr 13, 2013 10:50 pm

Or just buy a sensor with a more standard thread size ?

richardpope50 · Post by **richardpope50** » Sun Apr 14, 2013 9:27 am

Thanks for suggestions but seems an expensive nut all ways round.