Corroded studs. Wow!

(Eric Feron) #1

Just for the record and for fun, here is the condition in which I found the block studs.
I am quite surprised to see so much material missing above the lower threads…

(69 FHC ) #2

It’s not unusual to see even worse that that.

Those can still be used however. Clean them up with a wire brush, cut the threaded ends off above the corrosion and you can shape them to be pretty useful punches, levers, pry bars or whatever. Their career as head studs, however, is over.

(Eric Feron) #3

Are the replacement ones zinc plated to slow / eliminate corrosion?

(Rob Reilly) #4

Does anybody make them from titanium?

(Paul Wigton) #5

For a price, Im sure it can be done…:wink:

(Rodney ) #6

If you use the correct antifreeze mixture or waterless coolant the new ones will see you out.

(David Jauch) #7

Would plating crack or chip when stretching the bolt? I don’t think so but do I know. Titanium is far weaker and you could pay for a few rebuilds and a lot of antifreeze before they pay off… or a different kind of block!
Or maybe tubes as sleeves that thread into the base for 1-2 threads, the head stud inside. The sleeves could be plated! And a copper seal at the top, or thread it there as well!
They‘ll last you out so no bother.

(Rob Reilly) #8

Titanium 6Al-4V Grade 5 yield strength 128,000 psi
Steel bolt Grade 5 yield strength 92,000 psi

(Foggyoo) #9

Could one build up the corroded area with welding?

(69 FHC ) #10

New studs aren’t that expensive. I’d say trying to repair used corroded studs would be penny wise and pound foolish.

(AndyBlakey) #11

Couldn’t agree more, don’t reuse old studs when they are in the state shown in the pictures.
The studs are cursed frequently on the XJ list but they really don’t corrode if the coolant is maintained properly. They do corrode when the cooling system is filled with tap water, lemon tea, gin and tonic or whatever other unsuitable liquid is to hand at the time. Also when the coolant is left to get too old and its anti-corrosion additives breakdown.
Unfortunately many of our cars have a history of poor maintainance at the hands of previous owners and this sets up problems that come back to haunt us years later.
New steel studs will be fine. Use a good quality coolant at full winter concentration - even if you live in a climate where freezing isn’t likely, and renew it every few years.



(john) #12

and be careful where you get studs as i have purchased new ones that i would not use for an engine.

(MGCJAG S2 2+2) #13

You can get Stainless studs


Stainless head studs, DON’T even think about it. Having worked on automotive issues in 56 countries I can affirm stainless, of any grade is not ductile enough, and when used on the XK engine results in broken studs.

(MGCJAG S2 2+2) #15

Hi…this is what i was refering to…for info only…im not making any recommendations

(Matt Furness) #16

I wouldn’t stray far from the original steel specification if I were a spare parts supplier. The original studs would have been selected for their strength and their fatigue life characteristics as part of the design of the bolted assembly. These properties are quite specific to the steel specification. I don’t know what a “semi stainless steel” actually is but I hope the suppliers had some decent engineering input to their material,selection,…

(tony) #17

I painted the exposed studs with red 2 part epoxy, then smeared them with copperslip,

have tested both these products ( and many others) for anti-corrosion properties by coating bare metal and leaving it outside for years in the wet & salty air

figured it couldnt hurt

(Matt Furness) #18

A reasonable paint system may do the trick. But these studs are fully immersed in hot liquid so I suspect the best solution is the best solution!!! Which is a 50/50 mix of the stuff that chemical engineers and chemists have designed to stop,corrosion in engines with known combinations of metals with different electrochemical potentials…this is a specialist field in itself so you would have to assume that the corrosion inhibitors present in anti freeze is suitable for the task …provided it is kept up to specification…

(MGCJAG S2 2+2) #19

Just for info a friend has quite a few ex miitary xk engines blue colour…when dismantling he found that they had stainless head studs…the engines provided to the British military had quite a few modifications straight from the factory due to the harsh enviroment the engines would be used in

(Matt Furness) #20

Yep. If they were sanctioned from the factory for military use then they would have had to comply with a particular set of circumstances applicable to military use. Possibly different criteria to civilian use…I dunno what these would be exactly but I suspect long life would not be high on the list…and the availability of a 50/50 mix of antifreeze/anticorrosion additive in the event of a loss of coolant considered not likely…so a “horses for courses” thing…