October 15th, 2007

Working on it

Minor update

I think the head gasket problem is sorted now - I drove to work this morning and it's running OK. A few days back on public transport served to remind me how much more convenient (and quicker and cheaper!) it still is to travel by car. I did several things differently the second time I refitted the head, so I'm not sure which ones were most significant:
  • I had the head skimmed (cost: £25). The guy who did it said it was about 0.008" out of true at the lowest point before, and the surface finish was quite rough.
  • I replaced the studs, then I trial-fitted the head with no gasket and checked there was thread still showing so the nuts definitely weren't going to bottom out.
  • I used a Payen head gasket - very slightly more expensive than the standard one and reputedly more reliable.
  • I greased the surface of the head and block. Not sure if this has any effect other than making it easier to remove the gasket again later but it was one of the things recommended to me.
  • I oiled the threads on the studs. This increases the amount of tension you get for a given torque compared to doing it dry.
  • I torqued the nuts down to 44 lb/ft instead of the factory-specified 40.

Afterwards I changed the oil and filter, and flushed out the cooling system. This time before refitting the sump plug I tried annealing the copper washer (heat it till it glows red, then quench it) - I'm hoping that will allow it to seal better and stop it dripping. The way I flushed the block was to connect a hosepipe up to the heater outlet. It took several minutes for the water coming out to go clear, and that was after I'd already filled and drained the system twice. I think there's probably still a lot of rust stuck in the water jacket, but it's cooling fine so I'm not too worried about it.

I think I forgot to mention a couple of weeks ago that I did some work on the clutch linkage mechanism, including replacing the link rod because it was rather worn. The relay shaft is sticking a bit, so when I press the clutch and brake, then let go of the clutch while still braking, the clutch pedal doesn't come all the way back up (the brake pedal pivots on the clutch shaft). I suspect the clutch shaft needs replacing along with various bushes, but that can wait until I have the gearbox out. My new box has made it as far as Leamington Spa (near Birmingham) and I suspect I'll probably be collecting it when I go down to Walsall for Novacon at the beginning of next month.