Section 1: Removal of the Heads (Continued)
The removal of the nuts continued without incident - I used heat for the top row and just the socket for the ones that live behind the rocker cover. The process speeded up but every new nut brought another wave of nausea as you constantly think ‘will this be the one that snaps??’
I had removed 6 of the 8 from the left hand head and was left with one behind the rocker cover and one above it. Just trying the socket would not shift these so had to use heat.
Due to the proximity of the springs (valve springs......not sure yet) I had read that you can alter their properties if they are heated too much. Therefore I used a heat shield (Patent Pending) made from a tube of stainless steel to cover the spring and stop them absorbing heat from the propane torch.
This nut took more heating than had previously been required - my theory being that as you remove nuts then the remaining ones are placed under further tension.......or it could have been that my arms were getting tired.
This nut finally gave up the struggle and came off cleanly so I was left with one of the central ones on the top row. I went straight at it with heat, lots and lots of heat.......and it wouldn’t turn a mm.
Had a brew......and heated it again, a lot.......and it didn’t budge but did start to spring back against tension.......I got extremely scared.
I have read lots of accounts of people removing heads and all goes well until the last nut so I did the cowardly thing and had more coffee. I had a complete arsenal of breaker bars of increasing lengths at my disposal but I was just too chicken to try them.
So, I spun the engine round and started on the other side whilst awaiting divine (or otherwise) intervention.
The right hand head (labelled from the rear looking forward, I believe) went unbelievably smoothly, and in about a quarter of the time.
As my confidence had grown with each nut I had begun to get a ‘feel’ for when to stop and tighten back up or when to apply just that extra bit of pressure to release the tension, make the stud ‘ting’ and be closer to removing the nut.
I was a lot more liberal with heat application on the right hand head - I heated each of the nuts in turn. Top ones for 2 mins, lower ones for about a minute.
Within half an hour all 8 nuts were off
So, there are no mechanical fixings holding this head on, just years of corrosion and gunge and old sealant and probably some black magic. In my excitement I grabbed the coolant outlet in an attempt to wiggle the head off......and burnt my hand.
Armed myself with a couple of rags and gave the head a push and a pull
A small crevice appeared between the head and the block and the remaining coolant poured onto my feet.
There was just enough of a gap to see that as the head inches forward that it was dragging the cylinder liners with it - they are easy to see as they are large diameter metal cylinders that seat themselves into a recess in the head, 2 each side.
You don’t want the cylinders to come out when you remove the head as this will leave the pistons on that side of the engine without any support and they will clang down onto the studs, possibly damaging the piston (which are expensive) or snapping a stud.......which would just be extremely unfortunate.
So, a little care required - the cylinder liners have small tabs on each side just behind where they sit in the head. I used a wide bladed screwdriver to lever the cylinder back into the engine and out of the head recess. I put a steel ruler flat against the head face to avoid any damage to the lip as I levered against it.
If needed, you could cut the thick black water jacket seal that runs round the perimeter of the head to give yourself more access to the tabs on the cylinder. I didn’t have to as I have sufficient clearance to get the screwdriver in.
A bit more wiggling required to get the head over the threaded parts of the studs
Next thing you know, the head is off!
Once it is out of the way you have clear access to the pushrod tubes - the 4 silver cylinders at the base of the engine. These can just be pulled away. I took this opportunity to clean the oil and grime from underneath the head of each tube then stuffed a rag into the hole.
Each pushrod tube has two seals, one at the head, one at the base, both are cream in colour. I removed them all as I took out the pushrod tubes and discarded them as I shall be fitting new ones once we rebuild the engine.
So, the right hand head is off and I’m left with just a single nut holding the left hand head on.......time for a brew.
My hope was that by ignoring the situation for a while then the previously heated nut would have cooled, contracted and hopefully broken the corrosion that was stopping it moving. Spun the engine back round and tried the last remaining nut cold......it turned.....a tiny amount. I sweated.......a huge amount.
Tightened, loosened, tightened, loosened, felt sick etc.....then it finally gave up and off it came.
More wiggling produced nothing- this head didn’t want to move so it was given a little lateral persuasion with a big hammer, a block of wood and some nervous taps from a below average sized man
This gave just enough of a gap to use the screwdriver levering technique and the head came off leaving the cylinders behind.
As the head came off then it dislodged the cylinders from the recess that they sit in at the engine block end - therefore they were loose and prone to drop out. They could be easily pushed home
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