Shouldered vs. plain studs?

[aaronjb]

One for the engineering genii (geniuses?) in here..

I want to replace the manifold studs when the turbo manifold goes back on, and it seems a nightmare to find 'shouldered' studs of the right length (i.e. longer than stock), but easy to find 'plain' studs that are threaded all the way down..

Now my question is - if I use plain studs that are long enough to seat on the back of the threaded hole in the head, will that cause a problem vs. shouldered studs that seat the plain 'shoulder' against the face of the head?

Either that or does anyone have a handy supplier of studs?  s:) s:)  (IIRC they're M8x1.25, 25mm long end and about half that on the short end)

[markiii]

I can;t see a real issue using ones that are threaded along their whole length tbh, but I would also prefer shouldered ones

last lot I got from TommYD who located a batch

no idea where he got them from

would these do?

 m http://cgi.ebay.co.uk/MANIFOLD-STUDS-M8 ... 286.c0.m14 m

[aaronjb]

Man I must have been suffering from massive eBay FAIL when I was looking earlier!  s:oops: :oops: s:oops:  (Assuming they're x1.25, not x1.5 of course)

I'll go stand in the corner with a pointy hat on   s:oops: :oops: s:oops:  Thanks!

[Tem]

I can;t see a real issue using ones that are threaded along their whole length tbh, but I would also prefer shouldered ones

Many say the shoulder is there just to make sure ppl thread it deep enough without touching the bottom. I can't think of any other reason myself, so I've taken their word for it. Especially with aftermarket headers, where the shoulder isn't big enough to stop the stud undoing itself anyway. Not sure if it does with the stock manifold.

[aaronjb]

Reading what you said there Tem prompted me to think - I suppose threading it to the bottom of the hole is bad if the stud expands faster than the host metal, you could conceivably 'punch through' if the metal is thin there, or crack the head.. I hadn't thought of that possibility earlier  s:) s:)

Pretty sure those 45mm studs Mark pointed out are long enough, so I'll grab a set of those for when I re-fit the TS header.

[markiii]

can you order me a couple of sets as well please bud

[aaronjb]

Yup - will do  s:) s:)