Tag Archives: lubrication

HP valve to Cylinder Joint & Lubrication

From Experience two other issues to consider

While these are not drawing errors, they have emerged over the first 3 seasons with the engine, and should be considered by builders.

HP Valve Chest to Cylinder Joint

In the BOOK the designer suggests using Araldite? as a jointing/sealing material… its not a solution, particularly for this joint.

The joint between the HP Valve Chest and the HP cylinder is problematic, as the sealing faces are very thin, and the two components are only secured by 4 bolts, which are hard to tighten and not well positioned to ensure a steam tight joint.

My first attempt was using “SteamSeal” jointing compound  – this failed quite quickly.

The second attempt was using “Heldite” jointing compound – this failed within a few hours.

My last attempt was using “Oakenstrong” gasket paper, I had resisted this, not wanting to affect the overall block dimensions. However, rebuilding with gasket paper and jointing compound (Heldite) does seem to have cured this problem.

Lubrication of “small ends”

I spent a long time chasing a knock that appeared to come from the LP small end. Rebushing the piston rod and a new pin did not cure this, and it was clear that the pin was suffering.

This was finally cured by increasing the size of the Lubtech pump units feeding these bearings and slide ways. A “black” one (0.1cc/stroke) silenced the knock instantly.

I am sure that a better builder than me might make the sideway fits better, but the lubrication points at the bottom of the piston rods have to lubricate the “small end” and the slide-ways, and so need a heavy oil flow to ensure that both bearings are supplied on each cylinder, as I think the oil preferentially flows to the slide-ways, starving the bush at the lower end of the piston rod.