Freelander 1 TD4 Injector Washers - to anneal or not to anneal?

That is the question !
What is the current thinking and what process if yes.

Cherry red and cool slowly in air?

Many thanks

Buy some new ones? they're not exactly pricey.

I meant new ones before fitting.

I've never bothered, not sure why you'd need to TBH - it's not a procedure in any WSM for any of the manufacturers I've worked for.

The theory is that it softens the copper and reportedly makes them more able to fit to any irregularity in a used injector mounting hole and seat.

I know that some washers are harder than others, I have ordered a good make Bosch, but just wondered what folks do.

Many thanks

Shouldn't they be already prepared for use?

I've only ever annealed old washers, if I need to reuse in an emergency. New washers should be sufficiently soft to use out the packet.

andyfreelandy said:

The theory is that it softens the copper and reportedly makes them more able to fit to any irregularity in a used injector mounting hole and seat.

I know that some washers are harder than others, I have ordered a good make Bosch, but just wondered what folks do.

Many thanks

Click to expand...

If the seat is irregular, then it needs recutting. The injector securing bolt torque spread over the surface of the washer will not somehow force it into any irregularities to create an effective seal, annealed or not.

OK thanks all.

andyfreelandy said:

OK thanks all.

Click to expand...

To anneal copper you should heat to a DULL cherry red and quench immediately in COLD water.

Copper work hardens and becomes brittle. So for sheet copper work where you bend and shape it, thereby deforming beyond the elastic limit of the material, the annealing process is invaluable to prevent cracks and re-establish elasticity of the metal. The shear, tension and compressive stresses induced in the procedure are relieved. Stress and strain are related by Hooke's Law. The strain is the problem (extension of the material compared to original length). Within linear elasticity, the part will return to its prior form. Beyond that, you anneal.

So injector washers? After torquing the injector, to my thinking, the washers have had one cycle of straining. BUT, the number of strain cycles from heating and cooling is high. Hmmm, think a bit more... the torque tightening is retained between injector changes so the compression load into the washer stays largely constant and most likely within linear elastic limits. So, I suggest that the number of large strain cycles and the amount of strain is low, like once.

So you don't really need to anneal the copper washers, but if you do, it won't hurt them. Torque correctly is the most important.

I wish I could have summarised more succinctly.