View Full Version : TR 4-cyl exhaust manifold to cylinder head nuts

11-01-2012, 08:36 AM
Some discussion here yesterday concerning the "tall" nuts which secure the exhaust manifold to the cylinder head. Some say steel nuts on copper plated steel studs, others say always copper/bronze nuts, yet other say steel nuts originally but later changed to bronze.

Any comments?



11-01-2012, 09:18 AM
Well, the part number for the nuts was the same from TR2 through TR4, so I don't think they changed. My belief is that they were always tall steel nuts; the occasional tall brass nuts are aftermarket (sold for a Chevy V8 as I recall).

Not sure about the copper plating, but I've never noticed any evidence of it. I use a copper-based anti-seize though, so maybe I wouldn't have noticed plating even if it were there.

As a side comment, it has been my experience that adding a heavy flat washer (aka "setup" washer) to the two outermost studs (the ones without the bridge piece) helps to keep the joint sealed. The lockwashers need to be replaced pretty much every time a nut is removed (apparently the heat cycling makes them lose tension). And a 'swivel' socket makes it easier to retorque the nuts occasionally, which will also help keep the joint sealed.

Geo Hahn
11-01-2012, 11:09 AM
Always hard to form an opinion unless you've seen several possibly original TRs... too easy to think 'Well, mine is correct'.

My TR3A hade the tall steel except for a couple of ordinary nuts. I tried to replace the latter with tall steel and was unable to find any -- suggesting to me that the tall steel were original. In the end I replaced the short nuts with some tall brass cut down to the length of the tall steel -- you'd have to be pretty nosy to see they are different.

My TR4 is pretty much an original car but had the short steel nuts there. However, I have determined that the head had been drastically repaired/rebuilt -- possibly at the factory -- so those nuts are not necessarily as original.

11-01-2012, 02:15 PM
Tall steel nuts on copper plated studs - just like the ones on the red 3A next to yours :smile:

Ps I haven't given up on my argument on the choke linkage either!

11-02-2012, 07:54 AM
The replacement studs I purchased for my 4A years back were copper colored. High temp copper anti-sieze is a must when assembling.