Sq 4 rocker oil line leaks..

[bob cottam]

Hi All, further to my recent post about oil pressure in my re-built `58 square, I re-torqued the head as per recommendations the other day, and whilst the rockerboxes were off I started the engine up just for a look see.... Imagine my disappointment when I saw that both of the rocker transfer pipes between the rocker pedestals were oozing oil at each end from under the retaining plates- meaning that all four joints have failed.

Whilst the engine is cold, its just a slow but significant leak at each joint which, I would expect gets much worse when the oil is hot.

Maybe this is where some of my oil pressure is going?- it certainly can`t help...

The joints were fitted with small rubber `o` rings which came with the bike, I bought new ones from Drags, but they sent fibre washers?? which I did not like the look of so I rejected them.... the `o` rings seemed fine on assembly, so I put them back and now wish I had not!

I am now faced with the dilemma- if I undo the four sleeve nuts on the centremost head studs to fix the rocker leaks-will it compromise the cylinder head joint...…. any thoughts on this one....

[simon.holyfield]

If my experience is anything to go by, neither rubber nor fibre will last long in that heat. Whilst my Mk1 is not the same as far as rocker oil distribution is concerned, it now has copper sealing washers in the head.

[paul.jameson]

This joint and pipe is one of the problems on the Mk II. The original O ring seals are good for one use until disturbed and fibre washers may well perform similarly. It is possible (just) to fit 1/8" BSP unions with olive connections into the rocker blocks and use an 1/8" copper pipe between them. This works well but is very tight to achieve. David Jones used to do the mod as standard on the engines he rebuilt and I had zero problems with his work on my first Healey or my Mk II. So I have replicated his method on the current Healey project and on two other Mk II engines, one of which has now done a respectable mileage. I can take some photos and post them if anyone is interested but be warned that the clearances are small and you will need access to both lathe and milling machine.

[paul.jameson]

P.S. as the the cylinder head joint issue, you will cause no problems at all if you do the work on the pipes at the same time as you do a total re-torque of the head as you would after say 50 or 500 miles.

[bob cottam]

Thanks for the replies All. I would like to have confidence in whatever solution I go for, and maybe slightly thicker section Viton o rings would be good, but its all a risk if access is denied by the standard elliptical plates. I am minded to replace these with suitable washers and come up with a more serviceable set up that can be maintained if need be without disturbing the head joint fastenings....
Some photos would be nice Paul next time you are in there.... I take it that the rocker blocks are each tapped suitably to receive a male to female brass union, and then new copper lines made up with corresponding nuts/olives fitted?

I can feel a "Serviceability Improvement Modification Project" coming on!
Bob Cottam

[paul.jameson]

As requested Bob.

Modified oil line:

Modification to rocker cover:

[GuyWalton]

Im just about to start my mk 1 sq 4 restoration , bikes on the bench , this is a great help for the likes of myself .

[bob cottam]

Hi Paul, thanks for the photo`s. I take it the elliptical plates (redundant?) are disposed of and washers used instead.

Looking at the pics, it looks like a delicate job to drill/tap the rocker blocks to accept the unions-not too much room/meat to screw into there!

[GuyWalton]

Stripped mine today head off and frame stripped ready for paint , took all day but its ready , the mark 1 is different so cant do that fix .

[bob cottam]

I looked a little more closely at the rocker oil line mod today. I have obtained four suitable brass fittings with a 1/8BSP male thread. Diametrically, 1/8 BSP seems the optimum thread to use, as the existing counterbores in the rocker blocks look as if they are very close to the tapping size for this thread in any case. The amount of (vertical)meat available in the rocker block itself is minimal so I assume drilling down into the hollow rocker shaft itself is necessary to get the depth of thread required ………….??Anyone else done this mod who can confirm my observations?