Hole thread on clamshell Cyl head?

9D280 · 28 May 2013, 14:12

Ok, any of you anoraks know the thread on the 1/4" hole beside the top spark plug on the Clamshell Cyl head?

It's the screw for the temp guage sender.

I'm guessing UNF or UNC, but I'd rather not find out the hard way I got it wrong & Belgium cut a metric thread!

Having proved my NMEA upgrade works electrically, I am now fitting the sensors in a less "lashed up" manner. Temp under a cable clip where it is currently wedged is of limited use!

Cheers.

Turbodiesel · 28 May 2013, 19:56

I think from memory (and its been a while) its a bit like a self tapping screw that holds it in. I might be totally wrong though!

9D280 · 28 May 2013, 22:24

Hmmm Maybe the thread in mine is the result of a previous fitting?

If so it does rather make life easier......

Thanks.

9D280 · 31 May 2013, 08:24

Postscript:

Well, I got a chance to mount the sensor last night. After cleaning out the hole I found it was tapped M6! Whether this was a factory thread or added by a previous owner I'll never know.

I fashioned a stud from an M6 offcut, and found that the spark plug makes a perfect lockwasher - the nut to hold the sensor in has to be at the correct angle to let the plug past the flats!

If anyone's interested let me know & I'll post a photo. When I get the pressure transducer fitted properly (just waiting for the hose connector) I'll do a "how to get a Clamshell to talk to an NMEA plotter" thread.