Block cleaning

[Hugo]

I've got my block stripped right down now - core plugs out, the lot. Not quite sure what to do with it. What is the beast way to get all the crud out of the waterways? Blast it with a pressure washer? Or is chemical treatment better? And how about the head, when I get onto that?
The bores, amazingly, are as good as new - my much-chewed fingernals can't detect anything resembling a wear ridge. The rest of the engine is just nicely worn; bearings are just starting to go through to the backing material in places, some wear marks on the pistons - it looks like an engine that has done a lot of miles but has not been mis-treated.

[Hugo]

Just one more thing - I haven't managed to get that screw-in core plug out of the right side of the block. I don't think it's going to come out without heat, & that will probably distort the block. Has anybody succeeded in getting one of these out? And why is it there?

[JagWaugh]

Just one more thing - I haven't managed to get that screw-in core plug out of the right side of the block. I don't think it's going to come out without heat, & that will probably distort the block. Has anybody succeeded in getting one of these out? And why is it there?

A big one, something like 1-1/4"? Those are for an optional block heater. I'd leave it in - I've looked for a 220VAC block heater with the correct thread in the past and not had any luck.

I would take the block to an engine shop and have them tank it. But I'd want to know that they actually had a tank, otherwise I wouldn't see the point of paying someone to just moisten the deposits with a pressure washer.

[Hugo]

It's a 15/16" spanner size but the plug is much bigger. I can't see it going anywhere in a hurry. I've just spent half an hour getting covered in shite blasting it all out with a petrol-driven pressure washer. All coming out clean water now so I think I'll leave it at that. Maybe flush it all through when it's back together & running.

[mgcjag]

Hi Hugo....dont forget the crank...remove the plugs to clean

[Hugo]

Yes they're next - I guess they act as a centrifugal filter. And the plugs in the block for the oil galleries will have to come out I guess?

[christopher storey]

Hugo : 1. You'll NEVER get the plug in heater plug out

2. 40+ years on ( and not inhibited ) the crud in the b block will be so hard that the only real answer is chemical cleaning ; pressure washing will merely get the superficial stuff out. Incidentally, I should have said in an earlier post that it is important to take off that square plate at the rear of the block and check it for integrity, as they often go quite thin

3.The head, being alloy, is rather more sensitive to corrosion than the block , and if it has had plain water in, it is unfortunately common for the water passages to be badly eaten away . This can easily be seen , however, with the head upside down : the water passages where they meet the gasket should be of perfect oblong section ( i.e. the edges should not be eaten away) . I would not personally advocate chemical cleaning of the head except perhaps with citric acid solution- the powder can be bought from pharmacies

Do not despair if they are not in good nick : an aluminium welding specialist should be able to repair them

4.It is not essential to remove the oil gallery plugs on the side of the block but I cannot see that it will do any harm

5. Conversely, it is ABSOLUTELY ESSENTIAL to remove the crank journal plugs. These can be a real swine to remove and often need to be drilled out unless you are lucky. The engineering shop will not love you for getting them to do this job, but it is often better to let them get them out, but replace them yourself so that you can see that no short cut has been taken . Your eyes will water at the cost of replacements

[Hugo]

Thank you - most helpful advice. I gave up on the heater plug at an early stage! Just been knocking up an extended 7/16" tap to clean out the stud threads - that one behind the heater plug was the one that scared me - if I lose the tap in there I'll never get it out! I've welded an extension on now so it should be ok.
That plate on the back of the block is absolutely sound, much to my surprise. Not even a trace of pitting. Given that one of the core plugs rusted through a long time ago, that is odd (it has had water dribbling down the side of the block for a very long time by the look of it).
Likewise, those passages in the head are clean and have sharp edges (they are partially blocked with crud but you can push that out with your finger).
So far this is going too well for my liking. Crankshaft is next - sounds like fun - it looks like such a simple job - those are often the ones that catch you out!

[Series1 Stu]

I would not personally advocate chemical cleaning of the head except perhaps with citric acid solution- the powder can be bought from pharmacies

I agree Christopher, citric acid is the basic ingredient in kettle and steam iron descaler. It is quite benign but is great for eating the scale (calcium carbonate), which is alkaline. Alternatively, you could use vinegar, if you have plenty to hand. It's justst as effective.
S
Regards

[cactusman]

What ever you clean the head with do NOT use anything alkaline or it will attack the aluminium. So no sodium carbonate or sodium hydroxide (sodium hydroxide would be disastrous). So if using some proprietary cleaner look very carefully at the ingredients....

[Series1 Stu]

[Hugo]

........... 5. Conversely, it is ABSOLUTELY ESSENTIAL to remove the crank journal plugs. These can be a real swine to remove and often need to be drilled out unless you are lucky. The engineering shop will not love you for getting them to do this job, but it is often better to let them get them out, but replace them yourself so that you can see that no short cut has been taken . Your eyes will water at the cost of replacements

I'm so glad you warned me about those little buggers so I was prepared for the battle! I got five out of six out by a rather strange process - I ground down a 1/2" hex key (I had a 12mm or a 9/16", so I ground the 9/16" down) and attacked them with a 3/4" drive commercial air impact gun. That just rounded them off internally without much of a struggle, but then I was able to bash a 5 point Torx driver in the hole & drive it with the 3/4" impact gun, and blow me down four out of five unscrewed.
Why are they so tight in there? - they're not even tapered as far as I can see. Can't even see any trace of Loctite on them.
And you are of course correct - it is ABSOLUTELY essential to get in there to clean the crud out. The chambers were all half full of compacted sludge. I had poked a wire in there previously and concluded they were pretty clean, but I was completely wrong.
Off to drill out number six now!