GM temp sensor to F block bushing adapter

[Jacob Bridges]

Hello all,

I have a 2 barrel FiTech EFI system to install; it uses a GM type temperature sensor. I am desmogged and would like to use one of the two temperature sensor ports in the block.

I have an OEM temp sensor bushing that I’m considering retapping the threads to fit the GM sensor but am worried about it holding up.

Does anyone know of a source for a bushing made for this conversion?

How have those of you who have done efi conversions handled this?

Thanks!

1974 FJ40 with original F155

 

[rkymtnflyfisher]

I have an old bushing from Autometer that I used for my temp sender, screwed into the 2F head, threaded for the Autometer sender unit.

Those threads may be the same as you are needing.

Any clue what thread size and pitch you’re dealing with?

 

[lcwizard]

Specter Off Road

 

[Jacob Bridges]

@lcwizard good idea I’ll google them! I had only tried searching on sor.com before posting here...

Do you happen to have a part or page number? I did not find any conversion bushings, only oem, which I bought to test fit the new sensor.

@rkymtnflyfisher thanks for the tip. The oem bushing just arrived from sor tonight. I’ll take it around the parts stores and try to find a match. I haven’t measured the threads yet.

Thanks!

 

[jembourbe]

I used an adapter when I did my FI conversion. I'll look for the info and post if I find it.

 

[lcwizard]

@lcwizard good idea I’ll google them! I had only tried searching on sor.com before posting here...

Do you happen to have a part or page number? I did not find any conversion bushings, only oem, which I bought to test fit the new sensor.

@rkymtnflyfisher thanks for the tip. The oem bushing just arrived from sor tonight. I’ll take it around the parts stores and try to find a match. I haven’t measured the threads yet.

Thanks!

part# 330-950A

the parts are under the V-8 conversion area, page 330 except I think theirs goes the opposite way. ... an oem temp sensor to a gm block.

 

[lcwizard]

I've always used the ports on the thermostat housing with no issues or special conversion adapters. I don't ever recall
any issues. I've done salvaged GM, Howell, Affordable and Holley. Worse case was I swapped thermostat housings for
one on an F motor to obtain the port. Most of my FI conversions have been to FJ60s which already have the extra ports

The other option is calling British Metrics. They have some odd metric to npt adapters

BSPT x NPT Adapter 316SS

 

[Downey]

The threaded hole in the Landcruiser head is the same as 1/2" NPT

 

[jembourbe]

OK, so don't buy the sor part no. 052-15 union -- it won't fit the GM sensor (assuming the GM sensor is 3/8 NPT thread).

What you need is a 1/2 BSPT to 3/8 NPT adapter. Like this one from 2005. (Although some say a 1/2 NPT to 3/8 NPT also works)

 

[Downey]

^^^^^10-4

 

[Jacob Bridges]

@lcwizard I had seen the SOR adapter and had a "Eureka!" moment before I realized it adapted to a GM block and had my bubble burst.

Also, my '74 F155 thermostat housing (I believe is original) doesn't have any temp sensor ports on it, only coolant in and out.

@jembourbe I bought that OEM union as well just to test it without pulling the one out of my head.

For anyone who finds this thread in the future, British Metrics sells the 1/2 BSPT to 3/8 NPT bushing here for $10.55
1/2 BSPT Reducer Bush | Brass Reducing Bushing | British Metrics

The only problem is, shipping is a minimum $12 and they have a minimum $25 order. So after throwing in some random BSPT fittings, I thought I might be able to use someday I stopped and realized I was about to spend $40 to get a simple bushing.

I had tried to avoid the myriad options available from China through eBay and Amazon but ultimately decided I would save myself $35, wait patiently for it to come in the mail, and hope the $5 Chinese bushing does what it needs to.

I assume it will work, if not I'll then go back to British Metrics and my simple bushing will have cost me $45... in which case I'll buy three of them and hang onto them until another mudder needs them.

My Weber 38 setup is running great right now but I still can't wait to see what EFI does to my '40.

Thank you all for your input!

-Jake