Mo

The threaded boss on ScoobySports uppipe is apparently 12mm x 1.25pitch

What does this mean in english, what size compression fitting do I need?

Thanks for any light you can shed.

Mo

OK I think the penny has dropped, does this mean I'm looking for a M12 compression fitting?

Dave T-S

Mo

It's 12mm thread overall diameter, and 1.25mm distance between each thread.

Not sure what you mean by compression fitting. Do you want to fit the up pipe to an earlier model than a MY01 that doesn't have the EGT probe and blank off the hole? If so, just fill the boss with weld, or cut down a bolt to fit so the head fits flush on the face of the boss.

If you do buy any M12 bolts, make sure they actually give you 1.25mm pitch, as this is relatively rare - most M12 bolts are 1.5 or even 1.75mm pitch.

[Edited by Dave T-S - 6/21/2002 1:37:31 PM]

David_Wallis

Dave, Just out of interest what do you do for a living... you seem very up on thread cutting and taps / dies and machining...

David

Dave T-S

David

I work in insurance - but me dad was a toolmaker/instrument maker/watchmaker and spent a lot of time "helping" him as a kid so that's where I got it from

Also spent a bit of time restoring TR sports cars in the past.....

David_Wallis

ahh.. I see... Just curious, as there are not many people apart from machinists and engineers that understand thread pitch's the spanner fits so the bolts got to...

Just being curious..

David

Dave T-S

And i'm ambidextrous (read old) - can do Imperial, Unified or Metric

Mo

Hi Dave,

thanks for that but I'm still at a loss. I'm fitting it to a MY94 but I do have an EGT probe that needs to be fitted into the uppipe. General consensus seems that you fit the probe with an 1/8th BSPP compression ftting however the SS uppipe is tapped as above. RS and a number of local firms do not make a compression fitting to fit this thread

What to do???

Andy Forrest has fitted this uppipe lets hope he sees this thread.

Dave T-S

If you already have the up pipe, weld up the boss, and then get it drilled and tapped with a 1/8 BSP thread (I presume this is for an aftermarket EGT gauge?).

Get whoever welds it to do it with stainless rod, not mild steel, so it doesn't rust and seize the EGT probe in.

If you haven't got the up pipe yet, talk to SS, H&S *may* make you up a pipe with the correct thread boss welded on in the first place.

[Edited by Dave T-S - 6/21/2002 5:11:18 PM]