I’ve had all my exhaust manifold flange nuts loosten within weeks of tightening them every time. I’ve used the red loctite each time I’ve retightened them. Currently I am still using the original brass nuts with the split lock washers that XK’s sent me. Should I switch to grade 8 hardware?
How do people keep their exhaust together?
Joel
The Loctite is useless: too hot.
The name escapes me—someone will remember it (NordLocks!! Thanks, Erica!) but there is a nut “system” that utilizes a serrated washer, corresponding with a serrated surface of the nut.
Stover (pinch) nuts work, too.
I had the same problem for years, I’d leave a trail of brass nuts that had just dropped off the car. Even red loctite can’t help here because the extreme heat melts it. I tossed out the split washers and switched to Nord Lock washers a couple years ago and recently tried snugging them up. It wasn’t necessary as they hadn’t come loose.
Great information on Nord Lock products. Even though I have been a mechanical engineer for 40+ years, designing machinery, I had never heard of them.
I think that people may have trouble is that they are using brass nuts when they should have been using bronze ones. The latter are much stronger at temperature and should not relax. After all Jaguar OEM nuts do not come loose. In my 30 years with Jaguars I have never had these nuts come loose.
A couple of heat cycles expand them a bit, Run the car for awhile let cool down then retighten. Not a 5 minute warm up but an hour drive or so…
GTJOEY1314
Mine may be bronze, not sure. They’re whatever the usuals sell.
I did an experiment.
On one branch I used Nordlocks with SS nuts and a lot of anti-sieze. Has not come loose.
On the other branch split washers, with double-locked brass (i think, not bronze).
They did come a bit loose.
My manifolds have new studs as well
As is so often the case, this forum makes me go learn!
me too.
have a specialist fastener supplier near me, and afaic they said the brass/bronze nuts were for “exhaust manifold” applications.
I will ask them next time I am over there, one problem being that most of the staff seem a bit hateful of fasteners, and you have to ask the right questions
see them get wound up if you specify a fastener but not head time…“what head type…pan, flat, cheesehead etc etc etc” …its a bit like Monty Python
Thank you everyone for your responses. I will buy some nord lock washers today.
Joel
Anyone seen this on the intake as well? Or is there not enough heat generated to make this happen?
Never seen the need there: standard nuts and lock washers work fine.
Joel,
One of the best sources I’ve found (and use regularly) is McMaster-Carr. They carry the fully line of NORD (Swedish) lock washers: https://www.mcmaster.com/#standard-washers/=1bdg4bl. Everything I’ve purchased has been of the utmost quality – no junk. Hope this helps,
Happy Motoring,
DIck
'74 OTS
'99 XJR
1947 Stinson 108-1 “Voyager”
Joel,
Forgot to mention they’re also called Wedge-Lock washers.
Dick
I see that Nord Lock washers come in steel and stainless steel, as well as narrow and broad.
Which are the ones to get?
Peder