NYLOC nut types

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baybell
Posts: 7
Joined: 04 Sep 2019 15:13
Location: Swansea, UK

NYLOC nut types

Post by baybell »

Hi there,
I am planning on replacing the head and base gaskets after the summer (all are weeping a small amount) and just starting to collect all the necessary parts. So far this forum has given me all the guidance and recommendations including using new NYLOC cylinder head stud nuts (and rocker stud nuts) which brings me to my question: according to the parts manual the nuts are:

Cylinder head stud NYLOC nuts (Pt No. 47.03.22) 8 x 10.4 VT.324
Rocker stud NYLOC nuts (Pt 47.03.20) 7 x 8.8 VT.322

I recognise the grade 8.8 but not 10.4 (only 10.9). Perhaps I am confusing the numbers as I am no fastener expert?
Does anyone know what ‘VT.324 / VT.322’ means as indicated in parts manual description?

That said, what NYLOC nut types would you recommend using:
Cylinder head: Replace with 8mm grade 10 Zinc plated type T or P (thin or thick)?
Rocker stud: Replace with 7mm grade 8 Zinc plated type T or P?

Many thanks

- 1978 350 Sport
harrymuffin
Posts: 292
Joined: 07 Apr 2014 16:06
Location: west midlands

Re: NYLOC nut types

Post by harrymuffin »

8.8, 10.9 12.4 signify the tensile strength of the bolt. These nomenclature are regarded as high tenssile as you can get lowere tensile strength bolts for applications where strength is not required. Stainless Steel bolts are generally rated below 8.8 so not recommended replacing where 8.8 bolts are fitted, disc bolts etc. The head studs aalthough not marked would be greater thaan 8,8 probably 10.9 and ideally zink plated nylocs should be used, same for the rocker nuts but not nylocs because the nuts are self locking against the rocker top. Use the thicker nuts as there are more threads so less likely to strip is an animal without a torque wrench does then up. I have a detailed chart which includes english and america nuts and bolts but no japanese somewhere, but instinct and familiarity takes over eventually. Buy them from a engineers emporium or ebay, cheapest in the long run or even Toolstation and buy them by the hundred if you do not have access to a zinc platers having sstripped the bike and then can't get all the fastners and brackets replated.
mbmm350s
Posts: 666
Joined: 22 Jun 2018 10:18
Location: Reading UK
Location: Berkshire UK

Re: NYLOC nut types

Post by mbmm350s »

Hi,
Cylinder head stud NYLOC nuts (Pt No. 47.03.22) 8 x 10.4 VT.324
Rocker stud NYLOC nuts (Pt 47.03.20) 7 x 8.8 VT.322
The 8.8 for the M7 is not the grade but the height of the nut, so 10.4 is also the height,
I think the VT refers to a generic supplier part or drawing number .

Today M7 is not preferred so only can be found from a specialist supplier, the M8 are easily available in DIN982 Bright Zinc Plated
grade 10.9 in 100s quantity they are 5-6p each, I use Orbital fasteners as I am in their free delivery van drop zone.
These are also used elsewhere on Morinis, notably disks and engine bolts , so its worth having a decent quantity to hand.

For the M7 unless damaged I would re use if you can't find a supplier, I have used Wentins fasteners in the past, NLM used to have stock.
For the head nuts, the special extra thick washers as Harry says must be used.

For the nit pickers out there, original yellow insert variant, probably made by Bulloneria LOBO, can be found from Ferrari specialists, where it seems these things matter, priced at 100x the industrial price of the more usual blue insert, blue now being standard for metric coarse at least in the UK.
Cheers
Mark
baybell
Posts: 7
Joined: 04 Sep 2019 15:13
Location: Swansea, UK

Re: NYLOC nut types

Post by baybell »

Thanks for the information guys, really helpful.

My only query is on the rocker nuts - If I've read your post correct Harry then you say the 7mm rocker nuts are not Nyloc - but I seem to have them installed, perhaps a previous owner upgrade?

Thanks again.

- Darren
Rockers.jpeg
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mbmm350s
Posts: 666
Joined: 22 Jun 2018 10:18
Location: Reading UK
Location: Berkshire UK

Re: NYLOC nut types

Post by mbmm350s »

Hi,

What you have installed is correct, the trunnion block stud nuts are M7 thick nyloc.
The adjusters are full nuts M6

By the way the upper face on both blocks is marked A (Anteriore) for upper because the blocks are asymetric,
I can see one A but not the other but its probably the photo isnt showing it, but worth double checking.
Cheers
Mark
baybell
Posts: 7
Joined: 04 Sep 2019 15:13
Location: Swansea, UK

Re: NYLOC nut types

Post by baybell »

Thanks Mark, thats clear on the block post studs, I misread Harry's post.

Yes, both blocks are marked A but installed opposite - would this be right or OK? Can't seem to figure this out from the Blue Book?

Thanks
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mbmm350s
Posts: 666
Joined: 22 Jun 2018 10:18
Location: Reading UK
Location: Berkshire UK

Re: NYLOC nut types

Post by mbmm350s »

Yes, both blocks are marked A but installed opposite - would this be right or OK? Can't seem to figure this out from the Blue Book?
That is Ok, so long as the A is uppermost, I couldn't see it properly in the first picture!
Mark
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