Blue rocker arms

[Juha Vane]

Bought al-rocker arm assemblies and some of the exhaust rocker arms are
blue. The set screws was blocking the oiling and probably part got hot.
Now I'm wondering if I can use these arms or are they too "soft" after running so
hot that they turned blue? Tried to photograph the colour, but they show very
similar in photo.

[Vic Skirmants]

If they are blue, there must be some terrible galling in the shaft bore. I have seen them seize on the shaft from lack of oil, but never turned blue.

[Juha Vane]

There is no galling on the shafts, not so much wear either. They disassembled
without any effort and turned freely on the shafts.
I believe the shafts can be used if I turn them 1/2-turn. There is a blue spot on the
blue rocker shaft, but no galling. The shims are blue where they normally are shiny.
I just can't get it visible in photos. All other parts in blue rocker are black, spring,
adjustment screw and shims where they are not shiny. I'm worried if they are too "soft".

The rockers have the oil holes that was supposed to be closed, still open if it make
any difference.

[Juha Vane]

Bought these parts from a disassembled 912 engine, mainly for the block.
Have no info about it's history.
It can of course be possible that the engine did not run for a long time without
rocker arm oiling and it was taken apart in the "last" moment.
Could this explain why the shafts are not galled?

[Tim Berardelli]

If you are talking about the area near the tips being blue-that is a normal result of the heat treating the rockers received. The "oiling holes" on the exhaust rockers were supposed to be shut at the 300 mile service-about 98% weren't -long term probably a very good omission !

[Juha Vane]

Some of the rockers are completely blue, not just the tip. They have been so
hot that colour has changed. Perhaps I use them to make a grinding jig to grind
minimal amount from the tips to make valve adjustment accurate.
The rockers are expensive, at least to me.

Should I plug the outside “oiling holes” or not?

[WilliamVaughan]

Blue? How about blue-ish grey? Blue-ish grey would be iron phosphate conversion coating. I really doubt you could toast a set of rocker arms with such uniformity as to turn them all heat-treat blue (oxide).