I always had problems with this engine. Nothing too bad but it tended to overheat a bit and members of this forum used descriptions such as "gutless".

Sometimes it would blow a bit of steam out the exhaust. Sometimes a lot. Like filling an entire intersection. It also leaked a lot of oil, tended to go through water, and produced a lot of caramel milkshake under the oil filler.

However I tested for exhaust gases in coolant once and found nothing, and also get 180psi in all cylinders. It ran ok I thought and apart from the occasional smoke screen I was happy.

I knew something was up but never got around to messing with it, thinking I would just replace the entire engine instead. Well after three years of this I had a bit of a think about it and decided the head bolts should be checked.

Well what to you know #8 was completely loose! I pulled right out and found it was broken off...!
So I guess this will be a royal pain to fix right? I have another running a12 that is a bit rough and has 140psi dry compression and 180 wet across all cylinders, so I could swap them, but maybe I should get a fresh engine.

So how hard is it to extract a broken head bolt?

Merry Xmas!

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Not difficult to fix. Just drill the bolt out and use an easy-out to remove it.

That A12 with 140 dry, 180 wet will smoke like a son of a gun.

Ok I might just give that a go. I am amazed that I don't have compression down in cylinders 3 or 4!

I'm not surprised. A-series has really good combustion chamber sealing and it means the cylinder head is very flat. They probably prepped the head very well when it was put together. Head gaskets normally only let go when a) the head overheats or b) improper prep

Rather than an easy-out, try a left-hand drill bit, it may come right out. If you do use an easy-out, only turn it by hand and do not force it or it can crack the boss.

I'd actually recomend against an easy out unless you've got no other choice, people have had all sorts of major headaches with them. I've never managed to get one to grip. Others have had them snap and leave hardened steel in the hole that you can't drill by hand.

THere's a few ways to go at it. If there's some bolt left above the block deck you could try cutting a slot with the hack saw to undo it with a screw driver.

Another way to do it is to centre punch and drill it out. Start with a small drill and slowly work up.

Yet another way is to weld a bolt to it (without damaging the block deck) and unscrew it with that.