Stainless steel head studs -- Pros V Cons?? Just trying to remove the head from my 85 XJ6 Sovereign. It has been sitting for the last 4 years. Previous owner could not start it --- pulled 40 litres of water out of the tanks, 81000 Km in great condition. Head gasket let go after 150 kms --- not suprising.

As it is super stuck, tried vibrating the studs with a hammer drill (sacrificial nuts) , suspending the car by the head, I think now it is time to remove the studs. Never had to do this before as I always had got them off, plus I was 15 years younger.

So -- stainless steel studs --- or original replacement ones ??. Stainless are nearly half the price , are they a better choice ??? What do you think??

 

As far as I know regular stainless has less strength than steel. I've heard of a military grade stainless alloy that is slightly stronger than grade 8.8 steel but I doubt you can find Jaguar studs made from that material.


Why does this happen...is it from corrosion or electrolysis? If its corrosion then stainless may help the issue. If its electrolysis then stainless wont help much.

 

Thanks for that ---I would suspect electrolysis , rather than corrosion. Coolant was great , just been sitting. Once I get them out I will check them and replave then as necessary with originals .

Thanks

 

Is it crucial to repalce head studs if im taking off the head? Curious as im replacing the head and gasket on my 84 Sovereign with 250,000 kms? Or will i be ok if i keep the originals in?

 

I have only ever used OE studs, on the 6 and 12 cylinder engines studs or OE studs.

YES, I looked into the stainless a very long time ago, and simply dismissed it in a heart beat.

The coolants today are very good, but the design of these engines is the issue. The coolant travels up the stud cavity in the head, and if the coolant maintenence is sloppy the gunk will form in that cavity, stopping the head from sliding off as designed, the big washer and "fancy" dome nut stop it escaping, and you thought the chrome dome nuts were there for looks, haha.

I always replace the head studs when doing this job, I simply do not want to go back there for another 30 years, and it invades my drinking time if I get it wrong.

At the age of any of these engines now, I would not even think of not replacing those studs, and the core plugs in the block whilst they are accessable.

 

The UK-based supplier, David Manners, now lists a set of high-tensile stainless steel headstuds. It looks like the stainless grade is not high in order to get the high-tensile property. Maybe worth a look or ask them. Got to be better than ordinary steel, surely ?

Head Stud Sets | David Manners Group

 

Don't know allot about Jaguars, yet, but metal is something different. Stainless is for corrosion resistance only. Stronger grades of stainless have more carbon content. Hence,.. less corrosion resistance.
Stick with good quality carbon steel. Cad plate or case hardened fasteners might be a good better option if available. Certainly rolled threads, as opposed to cut are stronger.

Jim