Cylinder head dome nuts

[Heuer]

I need to repaint the cylinder head with a new coat of Bradite Old Gold whilst it is still on the car. What is the consensus - can I just remove the 14 dome nuts (in the correct order), do the work and re-torque the head or would I be better removing a couple at a time, painting that area and re-torquing? The engine was rebuilt about 900 miles ago and I don't really want to replace the head gasket or drain the coolant unless I need to for such a trivial job.

Thoughts?

[vacbag]

David, as you say such a trivial job. Do not make it a big job, I suggest masking tape.

Steve.

[christopher storey]

David : I do this quite often and I just use a small brush round the d washers etc and a larger brush for the rest of it. I do not bother masking since even if you do get a spot on a nut it is very easy to wipe off with a thinners rag

[osgii]

His question is interesting. Is it possible to remove the head nuts without having to flush or change the gasket?
Instinctively I would flush before removing the nuts. I mean, even if the gasket is still in place, will it retain the coolant if the nuts are not "pressing" the two pieces together?

[PeterCrespin]

If you want to undo the nuts, do one at a time. As others have said, for a trivial job I'd just use brush around things (after taking the plugs out and blowing the muck off with compressed air). Maybe use a combination of 1" and 1/4" brushes

[abowie]

If I had to remove the head nuts I would take one off at a time, retorque it and then move on to the next one.
The question of whether I would check the torque on each one individually first and then retighten them to that torque if it differed from spec is not one I have an answer to.
Personally if it was just about painting the head I'd mask the nuts.

[AussieEtype]

Not being a "concourse" advocate I would say that some people have a little too much time on their hands

Garry

[Simon Bolton]

Ooooo...below the belt but tend to agree. Can't quite see Peter weilding something as delicate as a 1/4 "brush!
Afraid to admit that I used masking tape.
Simon

[christopher storey]

The question of advisability of taking off cylinder head nuts depends very much on what engine you have. With the short stud blocks fitted up to about 1967/8 there is not much chance of harm provided you do it when the engine is cold , drain the coolant to below block deck level, and only do it one at a time. The long stud blocks are a much more hazardous proposition as I know to my cost, because a. the studs rot and can break ; b. more insidiously, the studs often unscrew rather than the nut unscrewing, as a result of which water and assorted crud flows into the recess in which the stud is anchored, and by reason of hydraulic lock it is then often impossible to reseat the stud without taking out an adjacent core plug, and then only with difficulty. Thus with the long stud engines, easily recognised by the 5 core plugs on the exhaust side , I would unscrew a dome nut only as a last resort

[Heuer]

It is possible to do it using masking tape, a selection of brushes and care however on the 3.8 the plug lead carrier sits in the middle and is secured by two of the dome nuts. So at the very least the third and sixth nuts on the right hand side need to be removed to do a decent job. My interest is in how many dome nuts can be released at one time without warping the head? For example to remove the 3.8 engine to replace the clutch requires the fitting of an engine lifting plate (Churchill Tool No J8 ) to four of the head studs - so four can be released at one time without damage, one assumes as there are no warnings in the Workshop Manual. Later cars had the lifting eyes of course.

[christopher storey]

David : my experience with alloy heads is limited to Jaguar, Daimler V8 , Rover 4 cyl and 8 cyl , triumph 2 litre and oddly enough Vauxhall so is not particularly extensive, but it suggests that provided the engine is cold there is little chance of warpage . Daimler, for instance, allows the removal of rocker shafts which are held down by the head bolts themselves (saloons rather than SP250 which have studs and nuts ) . If one thinks about it, the XK heads were specifically made with unstressed heating to 100 degs C in mind for the purposes of valve guide replacement . With a short stud block I do not foresee a problem , ( as long as one takes steps to prevent any coolant ingress ) but with the later long stud blocks things are different , not because of the risk of warpage but for the reasons I have already set out

[PeterCrespin]

It is possible to do it using masking tape, a selection of brushes and care however on the 3.8 the plug lead carrier sits in the middle and is secured by two of the dome nuts. So at the very least the third and sixth nuts on the right hand side need to be removed to do a decent job.

The HT lead conduit was a feature of all 6-cyl E-types AFAIK. My two 70s still feature it.

Almost every XK engine should also have either alloy bridge pieces or steel lifting brackets for attaching a hoist without undoing any nuts.

As for the rest, I agree with Chris's last post.

Pete.

[Heuer]

Keep up Pete! The early 3.8's did not have the lifting eyes and required the use of the special Churchill tool which required the removal of four dome nuts and the plate then attached to the studs:

[PeterCrespin]

Sehr interessant Herr Ober...

At what VINs did the lifting eyes come in? I've forgotten your FHC VIN (Keep up David - modify your signature!) :-)

[Heuer]

Pete

The engine eyes were installed from August 1964 (engine numbers RA.7323/4) and at the same time the spark plug cables had to be lengthened, for the second time*, to accommodate them.

* cables were first lengthened in March 1962 because they were re-routed over the front of the engine rather than the side.

[Vegard]

Not being a "concourse" advocate I would say that some people have a little too much time on their hands

Garry

[Heuer]

Job done and no gaskets were hurt! Head is now the correct shade of gold.