Exhaust Manifold Nuts

Post Mon Sep 25, 2006 11:56 am

The copper ones for the gasket - 8 or 10mm?

Post Mon Sep 25, 2006 1:41 pm

M8 I believe

Post Mon Sep 25, 2006 9:39 pm

correct......Although i will be replacing mine with Stainless nuts......

Post Mon Sep 25, 2006 10:35 pm

You'll be surprised at how quickly stainless nuts rust on the exhaust!

At least I was!

Post Mon Sep 25, 2006 10:41 pm

You'll be surprised at how quickly stainless nuts rust on the exhaust!

Strange.....must of been some shit monkey metal ones.....

I only use A4 grade(316) with "copaslip" (Copper + Lead) to stop seizure of the nuts and corrosion of the studs.

Post Mon Sep 25, 2006 10:42 pm

I always replace the exhaust nuts with brass nuts and copper washers from my local allfast shop.about 10p each

Post Mon Sep 25, 2006 10:46 pm

I get all my stainless fixings from work for free !!!!

Post Mon Sep 25, 2006 10:53 pm

It will depend what grade stainless you use, and if it is martensitic or austenitic...

the 316 (austenitic) shouldn't 'rust' that is if i remember my material days properly

Post Mon Sep 25, 2006 11:57 pm

stainless is propper crap for nuts.
when i ran the exhaust fabricators, the ammount of problems u get with the stainless nuts. they are soft. all that exposure to high temperatures kills them. the minute u take them off they round off and ruin the thread. the best thing you want is mild steel studs with brass nuts. trust me im a doctor

Post Mon Sep 25, 2006 11:58 pm

e30cossie right on

Post Wed Sep 27, 2006 9:35 pm

tonyppe wrote:stainless is propper crap for nuts.
the ammount of problems u get with the stainless nuts. they are soft. all that exposure to high temperatures kills them. the minute u take them off they round off and ruin the thread. the best thing you want is mild steel studs with brass nuts. trust me im a doctor

I will have to disagree, the above mentioned things will happen if you dont know how to treat or use stainless (A2/4) fittngs correctly.

Trust me, I am a Fitter in the food and Pharmaceutical industry, and 99.99% of all the fittings i use are Stainless Steel (A4).

I do come across what you have decribed.....after some monkey boy has had a go and i have then got to put it right.....

Post Wed Sep 27, 2006 10:46 pm

we must be seeing a different grade of stainless then, or it may have somethign to do with the stainless studs or nuts and another aloy of metal being used reacting together with the high heat temperatures. because EVERY time (100% of toyota MR2s mess up when removing the dowpipe from the cat or turbo)
there was once when i managed to get 2 of the three nuts off ok, i did this by undoing it about half a turn, and then doing it back up and then undoing it a little more and then doing it bck up again, and keep doing it until it was off. i never put them back on tho. no way!

Post Wed Sep 27, 2006 11:24 pm

Stainless steel fixings will bind/seize up. when using stainless, keep all threads clean, this will reduce friction between the faces. If the fixings will be removed later, try and use some "copaslip" stuff, this will stop any binding of the threads.

The best way to get of stainless fixings that could be a twat is to use some light oil, like 3 in 1 or some diesel, and clean any exposed thread with a wire brush.

I use stainless fixings on exhuast systems to stop the problems with fucked nuts or bolts due to rusting.

Post Wed Sep 27, 2006 11:38 pm

I think in the food industry everything has to be stainless because it is easy to clean.my turbo manifold gets red hot and copper slip would last about 30 seconds.does the manifold on your foodmixer etc glow red?

Post Wed Sep 27, 2006 11:45 pm

The "Copaslip" i use has a working temp range of -40Ãƒ”šÃ‚°C to 1100Ãƒ”šÃ‚°C. Even when cutting stainless with a Plasma cutter, its not removed, only execss drips off. It is a twat to remove, try and use Loctite on a thread that has had "Copaslip" on it.....

Post Thu Sep 28, 2006 10:50 am

1100C ?? that is mad! what the hell can be liquid state at -40C to minus 1100C? i bet not much hotter than that and it becomes flammable?
i hate mr2s for the one reason that every time the nuts go wrong. i can remember being happy that they were un-doing then all of a sudden they would get tight and no matter what i did they would eventually snap off. i have put copper slip on before i was un doing, and ive tried using wd-40 type grease too. never had any derv to try but that sounds like a good idea.. i never used a wire brush on them either. if it was dirty i would wipe it off with my hand and glove.. may be that wasnt good enough.