Exhaust studs.

[Cato]

The GSX engine build is coming on and I need to order some new exhaust studs. With them being M8 there are plenty of options/supply available, so I'm hoping to improve on the standard mild steel in terms of corrosion and heat effects. Anyone have any recommendations for suitable material going into a cast alloy head? Stainless, titanium and various types of coating on the steel seem to be the main options, along with bare steel, copper coated and brass for the nuts.

 

[colnerov]

Hi, Stick with mild steel studs rather than stainless or Titanium because they are closer on the Galvanic scale, for the same reason use Copper coated nuts or Brass. the further apart they are the worse the corrosion.



Colin

 

[Cato]

Useful info, thanks.

 

[frank horton]

I would have used st/steel until the above info...so for me brass on brass...

 

[GSR]

Ive always gone with the same material on stud and nut so that they expand and contract at the same rate of change in temperature

 

[grim_d]

Stainless/titanium should be fine if you install them with a nickel based anti-seize compound, same applies to mild steel however.

Copper nuts.

Personally I'd stick with mild steel studs.

 

[Pete.]

Stainless exhaust studs rot away in ally motorbike heads if they ar used through winters, and a great many Bandit owners have discovered.

 

[Cato]

OK so it's a case of sticking with the original set up.

used through winters

I doubt this bike will see the outside in winter unless the roof falls in.

 

[roofman]

I always take the studs out and use bolts or cap heads after running a sharp tap down the holes..better for in-out maintenance and never fall foul of studs failing in future.

 

[8ob]

In years gone by any threads into ali were coarse, the studs would have a fine thread one end coarse the other. Certainly less issues with studs back then, dont know why they went away from this practice

Bob

 

[Cato]

In years gone by any threads into ali were coarse, the studs would have a fine thread one end coarse the other. Certainly less issues with studs back then, dont know why they went away from this practice

Bob

Cost I imagine, same as most of the other "why did/didn't they" questions on machinery. Save 0.01p per thing and not care what happens in the workshop (or out of warranty).

 

[Cato]

I always take the studs out and use bolts or cap heads after running a sharp tap down the holes..better for in-out maintenance and never fall foul of studs failing in future.

Bolts always look wrong to me on headers and manifolds, plus it's easier to hang them on the studs and get everything lined up.

 

[123hotchef]

In years gone by any threads into ali were coarse, the studs would have a fine thread one end coarse the other. Certainly less issues with studs back then, dont know why they went away from this practice

Bob

Thats how the Mitsi's I have are too with copper nuts

 

[Pete.]

Modern ally castings are well able to hold fine threads. The head bolts on my turbo motorbike were 12mm x 1.25mm pitch and tightened to 75 foot pounds. I heard of people pulling them up to 100 foot pounds but I didn't have the guts to attempt that. Wasn't necessary either since the engine is still together 14 years later and clocked an official 238mph last year.

 

[roofman]

Bolts always look wrong to me on headers and manifolds, plus it's easier to hang them on the studs and get everything lined up.

set of headless bolts 1st to hang them

 

[roofman]

Modern ally castings are well able to hold fine threads. The head bolts on my turbo motorbike were 12mm x 1.25mm pitch and tightened to 75 foot pounds. I heard of people pulling them up to 100 foot pounds but I didn't have the guts to attempt that. Wasn't necessary either since the engine is still together 14 years later and clocked an official 238mph last year.

More info on this turbo bike

 

[dobbslc]

clocked an official 238mph last year.

Though the Dartford tunnel

 

[tom2207]

I run steel studs and double brass nuts and a brass washer on my BMWs and never have any bother.

 

[Pete.]

More info on this turbo bike

Not gonna hijack this thread I'll post some pics someday soon.

 

[Cato]

Not gonna hijack this thread I'll post some pics someday soon.

Hijack away because a discussion about exhaust studs vs a discussion about a 200 mph + turbo'd bike doesn't take too much thinking about.