RB26 single turbo exhaust mani studs

[iruvyouskyrine]

Hi all,

Converting to single turbo on my RB26 and utilising an existing single turbo manifold from my RB25 that has both RB25 and 26 stud pattern.
However, RB20/25/30 is all M10 exhaust manifold studs and RB26 is M8 which leads to lots of slop on the exhaust manifold when fitting to the head.

Is it common to change to M10 exhaust studs when going single turbo RB26? Or even use some kind of stepped stud? Or people are happy to have some slop when installing the manifold.

Have searched as i thought it may be a common problem however finding no info online about it at all.

any help appreciated, thanks.

[GTSBoy]

You could make some 10mm OD x 1mm wall spacers from 304L tube. Just cut them slightly shorter than the flange plate is thick and they won't get in the way of anything and won't impede torquing it up and will dial out all the slop. You'd probably only need to do 2 to control it, 3 or 4 to spread them out fairly evenly across the whole length, or all of them for completeness.

[iruvyouskyrine]

That is an excellent idea! Simple, effective and cheap. Thanks mate.

[KiwiRS4T]

5 hours ago, iruvyouskyrine said:

Hi all,

Converting to single turbo on my RB26 and utilising an existing single turbo manifold from my RB25 that has both RB25 and 26 stud pattern.
However, RB20/25/30 is all M10 exhaust manifold studs and RB26 is M8 which leads to lots of slop on the exhaust manifold when fitting to the head.

Is it common to change to M10 exhaust studs when going single turbo RB26? Or even use some kind of stepped stud? Or people are happy to have some slop when installing the manifold.

Have searched as i thought it may be a common problem however finding no info online about it at all.

any help appreciated, thanks.

I think people commonly go for a Sinco or 6boost manifold when going single but spacers will work for you.

[Duncan]

Bolts hold something in place using friction (tightness), they don't locate them. Spacers might help you assemble it in place but properly torqued nuts on the studs will hold the manifold in place regardless of the size of the hole vs size of the stud

[Ben C34]

I would do a combo of the suggestions.

2 spacers just for assembling to get manifold  in  the right spot, made longer so you pull them out after the rest of the studs are tightened.

I don't like the idea of exhaust manifolds not being able to grow, many oem manifolds will use 2 round holes in the center then slots for the rest of the holes.