Tiger Super Six
|
 posted on 15/6/11 at 08:54 PM |
|
|
Can you use normal bolts for exhaust headers?
As per the title really. I know there are normally studs with copper nuts but are normal cap head bolts ok and would it be ok to mix and match?
Thanks,
Mark
Mark
Tiger Avon
|
|
|
|
|
AdrianH
|
| posted on 15/6/11 at 09:23 PM |
|
|
I have! Stainless ones, though I would doubt it would make much difference.
Adrian
Why do I have to make the tools to finish the job? More time then money.
|
|
|
designer
|
| posted on 15/6/11 at 11:04 PM |
|
|
Copper is used to stop seizing.
|
|
|
norfolkluego
|
| posted on 15/6/11 at 11:06 PM |
|
|
quote:
Originally posted by AdrianH
I have! Stainless ones, though I would doubt it would make much difference.
Adrian
Same here, just one normal stud on each end to help locate it and the rest just bolts, much cheaper than studs all round.
[Edited on 15/6/11 by norfolkluego]
|
|
|
blakep82
|
| posted on 15/6/11 at 11:13 PM |
|
|
i was going to, but wasn't keen on screwing them into, and back out of a ali cylinder head, so someone suggested getting a length of stainless
threaded bar/studding or whatever its called, and cutting it up into the right size pieces. the whole lot should cost about the same as 1
'proper' stud.
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
|
|
|
indykid
|
| posted on 16/6/11 at 12:20 AM |
|
|
quote:
Originally posted by blakep82
i was going to, but wasn't keen on screwing them into, and back out of a ali cylinder head, so someone suggested getting a length of stainless
threaded bar/studding or whatever its called, and cutting it up into the right size pieces. the whole lot should cost about the same as 1
'proper' stud.
Stainless in an ali head would be inadvisable. Galvanic corrosion will either eat the threads, or lock the two together solid.
You can always cut down long set screws if you want high tensile studs, or even socket caps if you want really meaty studs.
|
|
|
blakep82
|
| posted on 16/6/11 at 12:37 AM |
|
|
ooh i thought they were just the job because they don't corrode? didn't think of galvanic corrosion, would have thought steel would have
been more of a problem though?
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
|
|
|
Grimsdale
|
| posted on 16/6/11 at 07:24 AM |
|
|
Have a look at a galvanic series graph like this: http://www.corrosionist.com/Corros1.gif
The further the metals are apart (in mV), the greater the risk of galvanic corrosion. So yes, indykid is quite right.
|
|
|
flibble
|
| posted on 16/6/11 at 07:37 AM |
|
|
Damn, i knew I shouldn't have use all those gold and platinum bolts! 
|
|
|
Peteff
|
| posted on 16/6/11 at 08:09 AM |
|
|
I've just fitted a new exhaust front to back on the car and it had stainless studs and nuts between the manifold and front pipe. All three of
them snapped like carrots and were impossible to drill out, I had to replace the manifold.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
|
|
|
Tiger Super Six
|
| posted on 16/6/11 at 08:18 AM |
|
|
Cheers for the reply - so if I use normal 8.8 steel capheads and put some thread lock on to stop corrosion?
Mark
Tiger Avon
|
|
|
Davey D
|
| posted on 16/6/11 at 09:16 AM |
|
|
id have thought that if you use thread lock on an exhaust manifold when it gets upto temp it will just burn away?
|
|
|
indykid
|
| posted on 16/6/11 at 09:21 AM |
|
|
if they're zinc plated steel, there's even less chance of galvanic corrosion
|
|
|
Neville Jones
|
| posted on 16/6/11 at 09:40 AM |
|
|
quote:
Originally posted by indykid
if they're zinc plated steel, there's even less chance of galvanic corrosion
Zinc plated, or galvanised, with long brass nuts, or stainless nuts, would be the normal accepted practice.
Cheers,
Nev.
|
|
|
wicket
|
| posted on 16/6/11 at 09:58 AM |
|
|
Never had a problem with std steel studs, brass nuts and copper ease on the threads.
I think the 'copper' nuts are steel with a flash of copper.
[Edited on 16/6/11 by wicket]
|
|
|
Strontium Dog
|
| posted on 16/6/11 at 10:04 AM |
|
|
quote:
Originally posted by Peteff
I've just fitted a new exhaust front to back on the car and it had stainless studs and nuts between the manifold and front pipe. All three of
them snapped like carrots and were impossible to drill out, I had to replace the manifold.
Hi Pete, what engine is the manifold for and do you still have it? I might be interested in it if you want rid of it!
|
|
|
Strontium Dog
|
| posted on 16/6/11 at 10:16 AM |
|
|
I have found that using bronze nuts is the best thing for high temp situations especially on turbo's etc! They always come undone and my
preference is for steel studs but A286 stainless is suitable if you want to go that route!
|
|
|
Greenie
|
| posted on 16/6/11 at 10:51 AM |
|
|
Why not just use what is recommended by the engine manufacturer, at the end of the day they are the experts.......
|
|
|
Strontium Dog
|
| posted on 16/6/11 at 10:56 AM |
|
|
quote:
Originally posted by Greenie
Why not just use what is recommended by the engine manufacturer, at the end of the day they are the experts.......
And unfortunately are working to a budget! They will not be using the best solution, but the cheapest they can get away with!
|
|
|
deezee
|
| posted on 16/6/11 at 11:10 AM |
|
|
quote:
Originally posted by indykid
Stainless in an ali head would be inadvisable. Galvanic corrosion will either eat the threads, or lock the two together solid.
You can always cut down long set screws if you want high tensile studs, or even socket caps if you want really meaty studs.
Galvanic corrosion requires more than just two metals in contact! Usually road salt and water need to be added. So unless your exhaust never goes
hot enough to dry the outside of the engine, and your using it in winter, you don't need to worry about this.
Stainless bolts will be fine, mild steel bolts will be fine. Its really nothing to worry about.
|
|
|
indykid
|
| posted on 16/6/11 at 11:20 AM |
|
|
quote:
Originally posted by deezee
quote:
Originally posted by indykid
Stainless in an ali head would be inadvisable. Galvanic corrosion will either eat the threads, or lock the two together solid.
You can always cut down long set screws if you want high tensile studs, or even socket caps if you want really meaty studs.
Galvanic corrosion requires more than just two metals in contact! Usually road salt and water need to be added. So unless your exhaust never goes
hot enough to dry the outside of the engine, and your using it in winter, you don't need to worry about this.
Stainless bolts will be fine, mild steel bolts will be fine. Its really nothing to worry about.
I'm aware of that, but from experience, I've had stainless studs corroded absolutely solid into alloy heads. They got drilled out and
helicoiled in the end.
What happens if you ever wash the engine or drive the car in the wet through a puddle?
The caveat's there. I won't say I told you so if you ever come a cropper, so carry on.
|
|
|
flak monkey
|
| posted on 16/6/11 at 11:34 AM |
|
|
Normal BZP studs with copper washers and brass nuts is the correct way to do it. People on ebay even sell kits of studs and it would cost less than
£10 to do it properly, so why bodge it?
Stainless is a bad idea in an aluminium head, its ok if its somewhere you can use loctite which will stop any corrosion forming, but you can't
do that on exhaust studs.
Sera
http://www.motosera.com
|
|
|
mcerd1
|
| posted on 16/6/11 at 12:25 PM |
|
|
quote:
Originally posted by flak monkey
Normal BZP studs with copper washers and brass nuts is the correct way to do it. People on ebay even sell kits of studs and it would cost less than
£10 to do it properly, so why bodge it?
exactly my thoughts 
from my own experience the zinc plate yellow passivated bolts/studs always seem to survive best
ford used them on most of the sierra / granada bits and most of them came off 'fairly' easily despite 20+ years of rot
(I wish they'd kept using them the ones on my focus are total c%^£ )
also when it comes to stainless not all bolts are the same (look at the table in Grimsdale's post) 304 stainless is nowhere near as good as
316... (but both have issues with aluminium)
as far as stainless bolts are concerend the heads should be marked: A2=304, A4=316
[Edited on 16/6/2011 by mcerd1]
-
|
|
|
