How is the exhaust manifold connected to the head?

[FinGTI-R]

I blew an exhaust gasket and when i started to replace it I notided the stud threads in the head were gone. :? Also the exhaust manifold was in the head with allen head bolts, not with studs and nuts!

Now the head is re-thread but I dont know how to connect the manifold to it. I have new studs already, but when I ordered nuts from Nissan I got wrong ones with reverse thread! Also the holes in the manifold are much bigger than 10 mm, maybe 14 - 16 mm. How the hell I'm ever going to get the exhaust manifold connected back to the head?? Do I have to machine some sort of special nuts? Can someone pls post a pic how the manifold is originally connected or pics of the nuts?

 

[Bart GTI-R]

Hi there mate, If you need some special studs and nuts making up this company will sort you out.

www.inoxgrp.co.uk
They specialise for motorbikes but they make any sort of bolt, nut, stud etc..
hope that helps

 

[neil240z]

as you have stated yourself the head comes with studs factory and its always wise to replace the studs instead of using bolts, have you just ran a tap down the threads or have they been increased in size so the original studs will not fit?

The exhaust maniflold also has polo mint style washers and probably M10 nuts but could be wrong, do you live in the UK? a quality hardware shop should be able to supply the correct studs and nuts you need to match the studs and if you dont have the polo mint washers they can be easily obtained from someone on here.

its a fairly simple task really, if you could post a pic up of your head that will help.

regards

Neil

 

[ashills]

the studs and nuts are fine thread and arent readily avaliable
i have a supply of better quality flange lock nuts for the manifold to head if anyone needs some

 

[FinGTI-R]

The old threads were bored out and helicoils were inserted by a machine shop. The size of thread is M10.

Here is a pic of the manifold (not mine, but all are the same):

Those holes are not M10, more like M14 - M16? So there's a lot of extra space there. Something missing?

I haven't got a f*king clue what a polo mint style washer is. :lol: Maybe thats the part I'm meaning, I haven't ever seen the original studs and bolts! Some previous stupid owner used allen bolts... I can get them machined by my brother if needed. Any pics of them?

Oh, and I live in Finland.

BTW has anyone got experienses of nordlock washers? I'm thinking of using those also.

 

[neil240z]

im convinced the holes in that manifold have been drilled somewhat bigger!

you may need another exhaust manifold, there is no way the standard holes are M14/M16 and thats why there is so much space/play.

the polo washers are there to keep an even amount of pressure on the manifold, if no one as solved this by lunch tomorrow i will take a pic of my manifold, remove a nut and polo washer.

Neil

 

[MORF114]

the holes in the exhaust manifold are 2 different sizes the two middle ones which are more of a bitch to get to than the others are smaller than the other 6 as the pic shows.


Dont think there would be anything wrong with using nordlock washers probably better than the std ones as they will lock better with regards to engine vibrations.

 

[FinGTI-R]

The holes in the exhaust manifold are infact in three sizes, middle ones below are 11 -12 mm, top middle ones 14 mm and 4 holes in the sides are 16 mm. I measured them today. I think I'll use thick 30 mm washers (are these polo washers??), nordlock washers and nuts, that should do it!