Another head gasket failure!

[HJ2]

Top job!

[Brit-Car-Nut]

looking good. I hope everything continues smoothly.

[Fetnas]

So I bit the bullet so to speak and opened the vent chamber under the cam cover. I wasn't convinced my cleaning strategy had removed all the gunk as I could still see muck in the opening to the chamber. Annoyingly the caustic nature of the POR15 degreaser did oxidize the surface of the aluminium, so it's no longer bright, but that's mainly cosmetic. I gave it a good wipe down with a non scratch scourer to make sure there was no loose oxide that migh get into the oil.

cam cover opened.JPG

Once opened, I could see that there is no mesh inside the chamber as had been suggested, and that the only main area with gunk was around the inlet, and it was very sticky stuff. Another couple of hours of careful cleaning got it spotless. I then drilled out the rivets to take some stainless M4 machine screws I had, and tapped the holes. There was 1 location at the timing belt end of the spark plug wells where there is only about 3mm of aluminium thickness to play with so I left that one alone, I think 11 fixings should be fine.

Cam cover cleanedDSC_0075.JPG

Finally I put some silicon gasket where the original had been, put the plate back in place and installed the screws with blue locktite and tightened them up to 2Nm. The aluminium of the cover is quite soft and I was worried about stripping out the threads, and the threads I cut certainly weren't the best I could have done.

Cam cover closed.JPG

Then the cover went back on with a new gasket, although the old gasket was probably reusable. I'm currently getting more pipes and brackets zinc plated whilst I've got access, assembly should recommence next weekend.

[Fetnas]

Here's another slightly unusual question, what is the size of the inverted flare nut at the bottom of the dip stick tube?

In my efforts to de-rust and zinc electroplate as many of the rusty bits of pipe, I had the dip stick tube plated. The de-rusting process involved acid to eat away any old plating and rust. It appears that the nut has a high zinc content or another metal that doesn't like Hydrochloric acid which ate into the peaks of the thread and eroded them down to the point where it no longer engages the female thread on the side of the block!

This is rather frustrating as all that's left to finish putting it back together is a couple of coolant hoses, half the heat shields, refill fluids, install the power stearing belt and change the fuel filter. So close, but this stuff up of mine really threatens progress! I tried building the tread up with teflon tape, but that didn't help, the amount needed to make a difference would make the nut almost impossible to install with the limited spanner swinging room in that area!

If I can find a replacement nut, the plan is to cut the tube to get the old off and install a new nut, then solder a sleeve over the cut to join it back together. I've look around the net for a new nut, but am struggling to find something similar, and being a metric native, I'm finding the imperial fitting system a real pain in the arse to navigate!

So, does anyone know what this nut is or have ideas on how to restore this thread?

[Fetnas]

So for those that might be interested, the thread queried above is M16 fine pitch 1.5. I ended up rebuilding the thread with JB weld and a thread file. Thankfully it's not a critical seal area, so I'm pretty sure that's good enough.

In other news, all the parts are now back in, including the dip stick tube. I've also changed the fuel filer which was the original now 28 year old filter! It still had the green witness paint on it from original assembly! That has to improve things! I've put new 10W50 fully synthetic oil in the engine and primed the oil system with the plugs out and the inerita switch tripped! It took a bit of cranking to get oil pressure back, but having removed the oil cooler hard lines, there was quite a bit of air in the system that needed purging. I then reset the inertia switch and let the fuel pump run when the key was turned to ignition, but the engine was still off. I did that a couple of time until I could hear the pump tone change as it was working harder with the air out of the line. Checked the fuel system for leaks, and thankfully there were none.

At this point I put the battery on charge whilst I finished putting the heat shields back in, that is a challenging job, made trickier with the custom AC bracket and modern compressor my dad managed to squeeze into this area. Once that was done, it was time to clean up and test me resolve.

I turned the key, and with very little cranking, she sprung to life! Yay. The idle did drop down until it stalled, but I started it again and she ran fine. The top end is still sounding a bit tappety, I'm hoping that is mainly due to the lifters needing to pump up that last bit after they were stripped down and cleaned. They were all filled prior to being installed in the buckets, I'm guessing it's the air in the buckets that needs to be purged before they'll run quite.

I still need to check and adjust the ignition timing and probably the idle speed as I'm pretty sure the new fuel filter, regulator and injectors will delivering more fuel than the previous set up. I'm not sure how to adjust the CO potentiometer without a gas analyser, I suspect trying to buy one would cost more than upgrading to a closed loop set up, something I'm very keen on doing.

This has been a pretty epic job, with quite a bit of project creep along the way, but all the hard work is now done. Now to drive it before the next round rust elimination is required.

Thanks for the help and advice along the way from the forum, the breadth of knowledge here is truly amazing and greatly appreciated.