Practically Classics Forum

I'd recommend - strongly - that you have the head pressure tested and refaced before refitting. Any aluminium head that's overheated to that extent and failed its HG as a result is sure to have warped. Most specialists charge between £40 and twice that to skim and pressure test a head and it's money well spent as you'd have to do the whole job again if you inadvertently refitted a warped head, which would give trouble almost immediately after you set out on the first test drive.
You may not see any warp, even if you test the face of the head on a sheet of glass, but it takes very little to wreck your hard work.

And if you do decide to do the job "by the book" (though I agree with Rob about keeping the camshaft fastened down assuming that the valves can be left alone), then we used to use a cover from a scrap engine with the sections between the camshaft bearings cut out so that the clearances could be checked with the camshaft held, which is why the tool was available. Just as good as the special tool, cheaper too, but I guess fewer O series cars are in scrapyards these days.

@Topaz: I'm in sunny Derbyshire, born and bred, little place called Staveley. Top detective work there.

@JPB: I'm getting conflicting advice on whether or not to test the head. Personally, I think I'd feel happier to have the head tested so I know it's good before putting it on the car, even with the extra expense it will incur. Popular opinion does seem to be that it'll be fine to just drop the head back on providing the block is flat and everything is cleaned and gapped accordingly on reassembly. I do always try and find the cheapest route, but not at the expense of doing the job right so I may end up going against popular opinion and get the head tested anyway, I think it'll make me feel better about things.

Do you have a decent quality large-ish sheet of glass spare?

DON'T use greenhouse glass.

If so, cover it in some fine grinding paste and "rub" the head over it. The glass should be easily within the tolerances of "flatness" that you need, and if you do this then the grinding paste will clean/flatten the places where the head touches the glass and will not touch any low spots. If the head is perfectly flat, then the grinding paste will show witness marks all over the mating surface, proving that it is flat, If the head has "low" spots then these will show up as un-touched.

Glass can bend slightly, so place the glass also on the flattest surface you can find, perhaps with a flat/even piece of cloth underneath, or even another piece of glass.

Obviously, clean all the grinding paste off when you've done it, but this shouldn't be difficult - it won't tend to stray too far into places that you don't want it. I've done this loads of times, (mostly with bike heads) and in fact it works best with ally heads.

HTH?

Top tip, but I haven't got a sheet of glass to use. I have been told there's a local garage that can test and skim (if needed) the head for £50 all in so once I'm done stripping it down I think I'm going to do that as it's easiest.

Bit more done today before work. I have removed the rocker cover and had a moment of panic because the valves all reset with a thunk and then the camshaft rotated as I lifted the rocker cover free. I applied my thinking head and realised it isn't actually a problem as I do still have reference points and information and the valves have to come out for cleaning and new stem seals anyway.



The sprocket on the camshaft has to be removed and turned around at some point as it's the wrong way, but I'm leaving it as it is for now so I can reset everything to the same point it was when the head was removed. I'll definitely be getting the head tested and skimmed if necessary, I'd rather spend a little more and not have the risk, expense and hassle of having to redo the head again shortly after rebuilding the engine.

My brother showed me what was what on the engine, it's surprising how much easier it is to understand the various components with them in front of you than it is through reading manuals and blogs, a lot of the engine parts make more sense to me in their application now. So the cam follower/bucket things (see how technical I've got) were removed with the aid of a magnet and numbered accordingly so they can be put back on the correct valves. The shims were kept with their respective buckets.


There's no signs of rust, serious pitting, scores, cracks or other damage, they all look in reasonably good order and I don't think they need replacing just cleaning.


With the camshaft split from the head some wear was apparent. There's tiny little speckles of something on the cam lobes, not sure what they are but it will all get cleaned off.


It would seem they've been there long enough to cause some scoring, but I'm guessing this isn't serious enough to affect things detrimentally.


We did do battle with the wax stat today but that's going to take some time to remove as it's Radwelded in place. We've got some movement on it, but not a great deal so I'll just continue soak it and work at it until it comes out. Managed to get the thermostat housing to rotate a little but that too seems stubborn about coming out of the head. I'm sure with some experience I could do this job a lot faster, but I don't need to so I see no point rushing things at this juncture.

Have you tried tipping boiling water over the "radweld" to see if that melts it enough to get the stat out?

yes, we just now tried that. It unseized the top half which promptly snapped when we attempted removal so now the bottom half is stuck in the thermostat housing. In better news, the housing is starting to come free so with more boiling water it might eventually come out which will be a good thing.

Engine rebuild shopping list:
Timing belt - bought £3
Gasket set - bought £15
Core plug/s - bought £20
Head test and skim if necessary - £40+
Waxstat - £10-15
Water pump - £8-15
Spark Plug/s - £2 each, £8-10 for a full set
Battery - £15 second hand
Points - £2-8 (prices are all over for these)
Air filter - £2-6

Total cost for rebuild: £117-147

The head is taking longer than I'd like to sort and I'm not being held up by something you might expect, which is frustrating me to no end. Valves are ready to be removed, all the various bits are dismantled and organised ready for cleaning before reassembly. Water channels can be got at to clean them out and the block has been checked and found to be, unsurprisingly, nice and flat.

The core plug set I ordered arrived, I've got a full gasket set and my new rebound straps have also arrived, so I'm not really waiting on parts. No, the thing holding me up is the waxstat. When I removed the old waxstat from the HL it was a bit stiff but eventually came free, was found to be not working and replaced with a new one. Unfortunately, the waxstat in the HLS is caked in what we're assuming is Radweld which in turn has sealed it in place and when an attempt was made to remove it, the top of the waxstat sheared from the bottom.



I have tried penetrating fluid, boiling water (as previously mentioned), hammers (aka, Universal Adjustment Tool), various tools, swearing... nothing is helping. So now I've resorted to slowly cutting and filing through the thick wall of the waxstat so as not to damage the thermostat housing so it can be removed and a new one put in because even before an attempt to remove the waxstat was made it was clear that it was jammed up and not working at all. Hopefully it will come unstuck all at once like the top half did and I can then clean out the thermostat housing and waterways.


Managed to unseat the cam from the rocker cover and found that the sprocket I thought was on the wrong way around wasn't. The reason for the alignment dimple only being visible on the outer face is that the camshaft seal was leaking badly and the inner face of the sprocket was so badly crusted with oil worn smooth by the guide that the dimple was impossible to find. Happily, Dad and I had guessed correctly when aligning everything for this job and the pistons are all where they need to be in their bores.


The work on the HLS engine and work in general have kept me from sorting out the HL suspension. I really need to get on task with finding a local friendly garage with a BFO hydraulic press to get those pivot shafts out for me because I sincerely doubt I have the means to do it at home having given it a damned good try three times now.

Progress, of a sort. A little while ago Dad showed me how to remove core plugs as this is a thing I'd never done before. Quite simple, providing that one of the core plugs you're trying to remove hasn't rotted a big hole through it which has then been gummed up with silicone which also has holes in it. I made a handy tutorial... probably.



So with the core plugs out of the block it was evident the water ones needed replacing as they're pretty crusty and both had holes in. The oil plug was in good order, but you'd expect that. I have a full set so I might as well replace them all.


With those out I could flush the head a bit more easily and broggle some of the horrible crusty stuff out. Quite a lot of detritus came out and I'm much happier with the flow of water through the head and the fact it no longer smells rancid.




Today Dad bought a new JCB drill and we decided to make an attempt on the stubborn waxstat that was firmly wedged into the housing. We ended up resorting to using a hole saw in the drill to remove the waxstat as it was the only way to free it from the housing. Whatever had been put through this engine it had welded the two components firmly together and it was no wonder we couldn't budge it with regular tools.





Next up is to purchase a suitable valve spring compressor (about £25) as the one we have is for a different engine - bought it for a Mk3 Ford Fiesta 1.1 if memory serves - so I can get the head ready for testing prior to refitting.

Then I need to back flush the radiator, remove and clean up the heater box, flush out the block as much as possible and drain the old oil, probably removing the core plugs in the block at the same time. Bolt the engine back together with the new gaskets and seals, fire it up and see what happens I guess.

All this will then happen again because once I have the HLS roadworthy the HL is getting the head stripped down primarily to renew the worn valve stem seals.

Looks like you are making good progress. I like working on engines, it is very satisfying when things are going your way (and immensely irritating when they aren't)
If the rad is full of the same crud as your engine was I would strongly suggest taking it for a re-core as there is no way you will be able to get all the grot out of the small galleries. I hate to say it but the heater matrix will almost certainly be as bad and need to come out. I have no idea how much of a job that is on a princess but on a modern car they seem to start with the heater then build the rest of the car around it :S.