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Rover 4.6 Knock sensor boss thread

Posted: Thu May 17, 2018 1:31 pm
by AndyB400
Does anyone know the thread of the knock sensor bosses on the side of a 4.6 block? I was planning on buying a couple of LYR100740 studs but they've now been discontinued and no one seems to have stock. I've found some in the states but with shipping I reckon I could make them cheaper. I'm having trouble working out the thread size though. I'm pretty sure its not metric and it looks finer than UNC. I think its 1/2 so I'm going to try and get hold a 1/2 UNF and try that.

Re: Rover 4.6 Knock sensor boss thread

Posted: Thu May 17, 2018 9:31 pm
by stevieturbo
I had some knock sensors ages ago...I think I recall them being M10 ? Although metric would seem a bit out of place.

Can you measure the sensor ?

Re: Rover 4.6 Knock sensor boss thread

Posted: Fri May 18, 2018 1:00 am
by garrycol
A lot on these engines is metric and as these are a late addition in the engine build life so maybe they are metric but then maybe not - lol.

I agree that most places seem to not have any buy try these - seem to have some https://ukarauto.com/fasteners/11759-la ... 00740.html

When I was building my engine I got the studs from a LR wrecker (here in Aust) - they had quite a lot I guess from engines that had died and gone to heaven. So give your LR dismantlers a go.

Garry

Re: Rover 4.6 Knock sensor boss thread

Posted: Fri May 18, 2018 8:45 pm
by stevieturbo
The knock sensors I had....no idea where they came from had a male thread sticking out. Not a hole.

Exactly what do you have ?

And at a push you can helicoil an existing M10 down to M8. It's not a perfect install, but more than adequate for a knock sensor.

Re: Rover 4.6 Knock sensor boss thread

Posted: Fri May 18, 2018 11:33 pm
by garrycol
On the 4.0/4.6 with genuine knock sensors - the fat end of the stud in the pic in the link above screws into the hole in the side of the block so becomes a stud sticking out. The knock sensor then just fits over the the stud up around the section that is not threaded and held in place with a nut and washer on the end.

Garry

Re: Rover 4.6 Knock sensor boss thread

Posted: Mon May 21, 2018 4:46 am
by minorv8
I just looked at my spare block and it has two threaded holes just above the freeze plug. If this is the correct location the thread is most likely M12x1,25. I had a M12x1,5 bolt and it just catches on the threads but obviously won´t go any deeper.

Re: Rover 4.6 Knock sensor boss thread

Posted: Fri May 25, 2018 10:24 pm
by AndyB400
It’s looking like M12 x 1.25, definitely 1.25 pitch. I haven’t got a tap that fine, so I’ll grab some bolts tomorrow to confirm.

Re: Rover 4.6 Knock sensor boss thread

Posted: Thu May 31, 2018 12:07 pm
by AndyB400
Just to confirm it is M12 x 1.25. I’ve got some bolt now, so next job is to get them turned down on the lathe

Re: Rover 4.6 Knock sensor boss thread

Posted: Fri Jun 01, 2018 12:51 am
by garrycol
As i said above - why not just get some from a LR wrecker.

Re: Rover 4.6 Knock sensor boss thread

Posted: Sat Jun 09, 2018 11:49 am
by AndyB400
I did try but it’s such a small item they weren’t interested. Anyway, it was a £1 a bolt and not long on the lathe to make them.