Ta.

Ignorance is bliss OB.. :| Either my micrometer is knackered, or I'm looking at replacing valves + valve guides now.

Cheers Ferryman, will peruse.

Where do I find the overhaul manual?

Heads disassembled and cleaning commencing. Hopefully they will be sufficiently cleaned by Monday to go to the machine shop.

I did a quick petrol-in-upturned heads test. On the good head, valves held it pretty well. On the bad one, no real surprises that the blowing cylinder leaked away fairly quickly. One other cylinder on the bad head also leaked away a little quicker than I'd like.

With the valves out, they all look pretty good. Will need to see how they look once cleaned up, but valve stem seals/stems appear to not be excessively worn - they all passed the 'pop' test on removal.

How much are reconditioned heads going for these days, then? As I will be > 200 quid for skimming on these before I do anything else.

Ferryman wrote:

At first sight it looks like these heads had a very different combustion per cylinder, for sure leaking gaskets or maybe a failing valleygasket too.
In the bigger circle, is that a trace of detonation? How is the pistonhead in that cylinder? The smaller circle, is that a damaged inletvalve?
The other bank has a more equal combustion so to see with brownish inletvalves.
I should give these heads a good service, skimmed for sure and the valves grinded, then a pressuretest.

Big circle is on the cylinder with the exhaust leak to atmosphere.

Re equal combustion, does the gems ecu have the smarts to adjust fueling on a per bank basis? If so it would probably have been running this bank out of kilter due to the misfire/blow.

Will have a closer look at the heads later.

Everyone here seems very trigger happy about skimming. Surely if an engineers straight edge shows they aren't warped, skimming is an unnecessary expense (ignoring other damage that might give reason to do it)? I'll check them later, but I'm quietly hopeful that they won't be, there were no cooling issues with this engine, just the blown head gasket, which I reckon is down to old age - the gaskets were genuine LR, so most likely on there from new. 150k miles on them seems reasonable.

Yeah there's a big gap in the gasket at that point. Haven't really done a lot of cleaning of the surfaces but as best I can see all the raised up bits on the head/block around that point are solely on the outer edge. If it were cooked, and I've not seen a cooked one so this is just an semi-educated guess, there would be damage all the way from the edge of the cylinder to the outside world.

Photo of the two heads off:

There is some damage on the edge of both the head and the block, around the point where it was blowing:

Another angle on the same damage:

I think this damage is someones botched attempt at sealing up the leaking head gasket with some kind of hardening metal putty.

I'm hoping it will chip off and won't require the heads to be skimmed, given it's really only on the edge of the head/block.
I've not yet checked the heads for trueness.

Looks like doing both heads was the right plan, too. The second head gasket is showing signs of degradation too, and I think between the two heads, probably 4 or 5 cylinders were either blowing or well on the way to thinking about it.

Heads off then.

Devils advocate here then; Gilbert is that a tacit suggestion that I should swap out the heater core for an oem replacement since I'm in there? :)

Original list.. urrm..

• Started demangling the radio wiring, but not finished. Got an aerial converter for when the head unit goes back in.
• Dash is out, and now that I've drained the coolant for the head gasket change, I can disconnect the heater matrix, get the whole unit out and get the flaps running smoothly. Will do the o-rings before it goes back in.
• All backlight bulbs sorted.
• LPG kit is here, but not done anything with it. Head gaskets first.
• Boot unlock button cleaned up and is less sticky.
• Cruise control probably still doesn't work, but I've fixed/checked most of it. It's just the last vacuum pipe that heads off towards the cabin that needs replacing now.
• Heated windscreen is definitely knackered. Open circuit on at least one half of it.

I'll probably make more progress on it once I get a suitable socket for the head bolts.

Hangs head.

Not really confused, just going off on tangents.

Mine is steeped in oil and the wheel arch liner is missing?

No prizes for guessing who. I guess he didn't fancy an engine rebuild.

I was hoping to get out today for a new socket, but didn't get time. Mate came round just before lunch and had me working on his astra all day. Discs/pads at the rear, handbrake cable, front droplinks, oil change and fuel filter. Surprise surprise, the droplinks were the hard bit. Droplinks are always a PITA.

Ah right ok, I presume my 12mm was sufficiently splined to do the business on those then? Didn't seem to take you long.

Ah right ok, I presume my 12mm was sufficiently splined to do the business on those then? Didn't seem to take you long.

Right. I'll pick up a 16mm six sided impact socket then. I was using one, but it cracked on the second bolt I tried.

What was the 12mm comment about?

Ferryman wrote:

For headbolts I have a 16mm air-impact socket, not that I use the airgun but they are stronger and don't slip off the head that easy when not holding the torquewrench exact vertical on the head.

Are you saying the head bolts are metric 16mm, not imperial?

Made a bit of progress today with help from Gordon. Got stuck on the head bolts though as they seem to be imperial, 5/8? Will need to get a hex socket for them.

One of the downpipes disconnected, but the other (predictably steering rack side) is being difficult.

Not exactly the cleanest innards I've ever cast my eyes over. And I liked how one of the rocker covers was barely attached. Surprised more oil didn't find its way out

Orangebean.. got links/part numbers for the foam and the pots?
I might as well do mine.