Turbo to exhaust manifold stud/nut

[ashm]

Evening all,
Having waited most of the summer for the last two nuts I need to reassemble the Elan, I wondered if anyone else could help.
There are 5 studs and nuts which fasten the hot side of the turbo to the exhaust manifold. Is anyone in a position to measure the diameter and pitch of the stud threads?
I would measure them myself but am in the middle of a house move so most of my tools are packed away goodness knows where.

Thanks,
Adam

[Jeemy]

Call South West Lotus, they manufacture their own parts as these are impossible to get from Lotus - when I tried I was told a 6-month waiting list at least as Lotus had not paid the supplier. They only charge a few pence per item and even if you work out the stud spec, there are other factors in the threading which make it simpler as far as I am concerned to buy a provable working part from somebody like them, and not wait for a Lotus part.

[ashm]

Ooh, thanks. Will call them!
Adam

[Brit-Car-Nut]

Just as a wish to clarify. --- Sorry Jeemy. I know you were just passing on what you were told.

The statement regarding Lotus and payment to their suppliers is absolute rubbish. I know for a fact that Lotus does not owe anything to Isuzu (the only supplier) and the A100E6382S nuts are on Isuzu back order. It behooves us all to try to avoid making statements that have not been proven and might embarass or otherwise harm those spoken about.

The A100E6167S studs are currently readily available at Lotus DEalers and Isuzu have backordered the nuts for what could be forever.

Unfortunately, I recently spoke with a parts broker in Japan regarding things like sumps and other engine parts and I was TOLD that Isuzu is not continuing production of any parts specific to the Impulse. I DON'T know this to be absolutely true and a lot of parts are used on other vehicles, so it may not be a dire as you would assume.

I did find a few of the nuts in the US and will endeavor to ID the design, material and see if I can source an exact replacement. There is something special about the nuts, so I would be cautious about someone having them "made" as temper, treatment and locking charastics are all in play.

[Jeemy]

It may well be rubbish, what I was told. What does not alter is the fact that a lot of these nuts are a 6-month order plus. Bearing in mind I still have a set of 9 on order from March, when they will eventually arrive on these shores seems to be a movable feast, or even a fast.

Steve at SJ told me to be very cautious ordering anything "to fit" because the nuts have complex threads, whether collapsible or not, I am not sure, that means a replacement that looks similar and specs similar, may not perform.

Which is why I still recommend South West Lotus for these items. They have supplies of these items that they are using and selling with confidence.

It would be good if we could establish what exactly is special about the nuts, as it is not rocket science, just one of a few possible proven options. The studs as long as rated for the torque, are an easier buy. I have the SWL nuts on my turbo and manifold and all seems to my untrained eye, to be well.

On a side note, Allon White do not have stock of these, but told me that they were the direct supplier to a few of the people I was buying from, i.e. Lotus > Allon > a lot of the people we use right now.

So they would be my first port of call, and if in quick need, South West Lotus directly after.

[ashm]

Interesting.
I spoke to SWL today and have two of their nuts on the way.
Apparently they also come with washers, as unlike the standard parts they are not flanged nuts.
Will see what they're like when they arrive!
Thanks all,
Adam

[ashm]

Went home today and measured a stud and nut.
The studs are M10x1.5mm at the exhaust manifold end and M10x1.25mm at the turbo end. The nuts are obviously M10x1.25mm, and appear to be some variant of the Trilock type, quite similar to this.
Adam

[Brit-Car-Nut]

And I thought only MG liked to use Fine/Coarse studs in their engineering. Thanks for the dimensions.

[GeoffSmith]

The studs are M10x1.5mm at the exhaust manifold end and M10x1.25mm at the turbo end.

Same as the wastegate manifold bolts if my memory serves me correct.

[Simon_P]

And I thought only MG liked to use Fine/Coarse studs in their engineering. Thanks for the dimensions.

Coarse into a casting - fine into a nut. Standard practice -