Alunox exhaust manifold - Did you retain the locking plates?

[tomcattom]

For those that have fitted the Alunox manifold to their Esprits, did you retain the original locking plates on the studs at either end? I had a bit of a look on the forums but can seem to find any close-up photos on anyone's project threads to give me a steer.

The nuts Alunox supplied for the turbo end have a flange and a serrated face so the locking plates there can't/don't look like they need be reused with those nuts.

On the head end the supplied nuts appear to have some kind of locking tab built into them so again would suggest the locking plates aren't required. That said I had aerotight nuts and the locking plates on the old manifold, which seems overkill.

A couple of the old locking plate tabs got damaged during removal, so just trying to work out if I really need them and if so I'll add them to my upcoming order of parts.

 

[910Esprit]

I didn't.    I originally used the flanged nuts, but they still managed to 'back off'  I had sufficient spare thread on the studs to use a narrow 8mm nut as a lock nut, so that's what I did.  I've had no problems since.   However, it would seem locking plates are probably the best approach

[Chillidoggy]

I used the hi temp aerospace K-nuts with no locking plates. No problems since the install, and after many thousand miles. I’ve just reused them again since the engine rebuild. Not cheap, but they work well. Make sure your cylinder head port faces are in good condition, and use the steel shim gaskets, not the composite ones.

Demon Tweeks supplied the nuts.

[910Esprit]

1 hour ago, Chillidoggy said:

use the steel shim gaskets, not the composite ones.

100% agree.  If the composite ones leak, they are instant toast.  The SS laminated ones are much more durable and easier to use

[Chillidoggy]

The steel shim gaskets are the Lotus specified for the S4s.

I think the composite ones were for earlier engines, but I’m not sure. Alunox supplied me with a set of composites when I bought my exhaust manifold, but when I pointed out they were incorrect, they refused to exchange them for the steel ones. Hey ho!

[tomcattom]

My Alunox manifold came with the composite gaskets. Not got the old one off yet to know what, if anything, is currently in there. I'll add the metal shim gaskets to my growing list of bits to order, along with some better nuts.

[Barrykearley]

Fitted the S4 with the “correct” ones.

fitted the S4s with the composite alunox supplied ones.

more important is without doubt decent studs and nuts

[snowrx]

I used a copper-plated deformed-top flanged nut over Nord-lock washers on mine, no locking tabs.  Has held up so far, but not a lot of miles TBH.  I did not trust the provided serrated nuts to hold on the Stainless flanges.

[CarBuff]

When we helped fit the Alunox header to Jenna's '83 turbo, we used the nuts supplied, no locking plates. Don't remember the gaskets...

 

I know we fitted the metal ones to our stock manifold on our '88.

 

Interestingly, the '83 didn't have locking plates on the original manifold hardware!

[Jacques]

I used hi-temp. K-nuts. No need for anything else and they won't move unless worked on. As they are a bit smaller, it also leaves a bit more room for working on them, if the manifold have to be removed some day. Very good solution.

Kind regards,

Jacques

[tomcattom]

Thanks for the input everyone. I've ordered some K-nuts since that seems to be the popular choice.

[Jacques]

You certainly won't regret the hi-temp ones. And take a set for between the manifold and the turbo as well. The normal ones are darker and not so hi-temp. resistant. It's the light grey that are. But they are clearly described on pages from those who sell them.

Linky:

https://www.demon-tweeks.com/dk/demon-tweeks-metric-hi-temp-aerospace-locknut-k-nut-243561/

or:

https://www.facebook.com/MerlinMotorsport/posts/2780024175350292?comment_id=2787105147975528

or:

https://www.motorsportpartsaustralia.com.au/product/1-4-unf-6-point-hi-temp-k-nut/

for the over seas guys.

Anyway, surely worth using. Enough commercial advertising

Kind regards,

Jacques

[ragingfool35]

i did but also used split locking exhaust nuts

[MrDangerUS]

What hex size are the nuts?

Thanks

[drdoom]

High strength locking nuts can be a headache if, when loosening the assembly, their grip is such that the stud is withdrawn from the cylinder head. 

[Jacques]

No, I put them on the shelf, never to use them again. I did though, install the high temp version (silver light greyish color), of K-nuts. Self locking. And I used 1200 celsius special thread paste. This last and it's been some years now. Works well. And they are a size smaller, so easier to do and undo in the event you need to do that. A lot easier actually.

Just my two pence on the matter.

Kind regards,

Jacques