Piston Problems 
When stripping down the engine I broke a couple of rings on the first piston. I got a set of rings (Sparex) to fit on the number one piston with the idea of measuring all the gaps etc and comparing against my other three pistons to decide whether they need replacing or not.
Unfortunately I've come up against a number of issues...

First question: How should the number four oil ring be fitted?
The originals are all a sandwich of two thin rings and one wiggly one.
The Sparex one has three thin rings!

Second question: Why is there a lug in the fifth ring groove? It stops the ring fitting - it's not possible to compress it enough to fit into the liner.

Third issue: one of my pistons is not the same as the other three!
Number one piston has the lower oil ring groove, the other three are the original type.

Final problem: The top groove appears to be wider than the ring, with a thinner and deeper groove at its centre. When in this inner groove the ring compresses right down so should fit into the liner, however when loosening the compressing tool to slide the piston down it jumps up out of the inner groove and sits on the lip. The ring then is sat on this larger diameter part and can't be compressed enough to push down into the liner.

I've sliced one finger tip open already so am calling it a night now!

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Getting on 
I finally got myself sorted and took my head off to a workshop and had it done. It's back with new guides, valves, and a couple of inserts on the two really bad seats.

This afternoon I put all the springs on and then stood in the garage talking to my dad for about an hour, and making a list of all the bits and bobs I have to sort out before rebuilding the engine.
Need to get on and get stuff ordered now and get the garage clear so I can bring the tractor in. It's going to get cold in there soon :s

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Right, the valves are out and everything cleaned. It's looking like it's going to be an expensive trip to a reconditioning workshop for my head :(

The exhaust valves are very badly recessed and a couple of the valve stems are very sloppy in their guides. The exhausts are far worse than the inlets which surprisingly seem to have very little wear. Again it's cylinder 1 and cylinder 4 that are the worst as expected, the exhaust valve seats are heavily pitted and have deep steps before even attempting any grinding. It would be daft to grind the valves in and put the engine back together in that state as the manual specifically says that it needs inserts and new seats cutting.

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Opening the engine 
Well still no photos I'm afraid, I really must remember to take some next time the sun comes out!

I've finally opened the engine and seen the extent of the carbon deposits. Cylinder 1 is worst, number 4 is bad, with 2 and 3 fairly clean (in comparison!). There is a good 5mm thick layer of hard coke covering everything in cylinder 1, I've not removed any of the valves from the head yet to see what state they're in but the cylinder liners are visually fine, there is no deep scoring and all the piston rings on number 1 are intact. I guess it is just even wear all over and probably a poor seal around the valves.

There's a lot of cleaning to do to remove all the black sludge from the sump etc so there's plenty of jobs to keep me busy until I pluck up the courage to pull the pistons out.

In other news I got my seat pan back from my dad's friend with the big hole patched up. I've ground back the welds, filled all the biggest gaps with epoxy and given it a first coat of primer. Just need to decide how I'm going to fit it back onto the seat hinge now. It was riveted rather than welded but I may find some small nuts and bolts I haven't decided yet.

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Steering again 
I finally got around to acquiring a replacement steering casting to replace the cracked and crumbling original. I bought it off J. P. Bell of Scunthorpe. His shed is an Aladdin's cave with tractor parts from floor to ceiling so I'm sure I'll be visiting him again!

I removed the steering shaft from the "new" casting and just like on mine the top bearing immediately disintegrated scattering rusty rollers everywhere. I suppose this is because the bearing relies entirely upon being kept well greased, there is no way for oil to work up to it. Luckily my original lower bearing was in good condition so the pair of lower sets of rollers gave me a complete set of parts. I used the "new" steering shaft as my old one was bent and the threaded part pretty smashed in from removing the totally rusted on steering wheel.

The casting is in fine condition however the dashboard fixing bolts were sheared off at the rear which took some effort to knock out. Also the rusted remains of the four pins which secure the serial number plate were wedged in their holes. Three knocked out with minimal effort but one was stuck fast. I ended up removing a fair amount of metal from the inside of the casting around the hole before it finally came free. I filled this crater with steel epoxy and re-drilled the hole before finally giving the whole thing a coating of primer.

The steering column is now fully rebuilt and back on the tractor so I can finally move the tractor without the fun and games of front wheels that point in different directions!

No photos for now unfortunately because the old "broken" camera that I use to take pics out tractoring has finally given up the ghost completely. I'll have to remember to take some photos with my good camera next time I'm out there before I get my hands dirty.

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