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This page is an illustrated story about overhauling a New Major. It will gradually be fine-tuned into a cohesive article.
Henrietta has developed a loud squeaking noise and a heavy knock and it is all my fault! Under a bit of pressure, I took her out without changing the engine oil for about a year. Not that she gets that much work but here in lies the cause of the problem.
Henrietta is a petrol/paraffin (kerosene) fueled tractor. Unless these engines are working very hard and hot fuel tends to bleed past the pistons and dilute the oil. So this has to be changed at frequent intervals to avoid problems. I was rushed. I did not do it before the season started and now I must suffer the consequences. Just hope I have not completely ruined her as parts for these models could be a bit difficult.
Photos:
This is the vapouriser on the petrol/paraffin engines. Rather a large lump of metal. Can be subject to heat cracking and metal crystallisation. Virtually impossible to get a new one.
The porting on the head is different too.
The valves go in at an angle rather than straight down like the diesel. Note no rotator caps on the exhaust valves and the lock-tabs instead of spring washers on the nuts and studs.
The head is off! A bit carbon-y but not too bad considering it has been on for over 50 years as far as I know.
The petrol/paraffin engine has combustion chambers in the head, rather than the ones in the piston like the diesel version.
She also has flat topped pistons. Unlike the petrol version, the bore size is the same as the diesel so if she needs liners, diesel ones will fit.
On checking, the liners are still within specs after 50 years so we will give them a polish and fit a new set of rings. No sign of a seized piston either.
The next job will be to remove the sump. I am going to approach this job with the view to removing the engine so I intend to take the side frames, radiator, front block and axle off in one piece. This is how we used to do this, it is quite simple and reduces the lifting involved as it will run out on the front wheels.
Take all the bolts out from the frame and the engine front plate mounting. Don't forget the drag link on the other side.
Support the engine with a jack under the clutch housing. Remove the radius rod pivot pin from the sump and raise the jack. The radius rod should drop clear of the sump allowing the axle and frame to be pushed forward.
Gently does it. Everything slides out easily. Note I am on my own with no help so it has to be easy.
With the front end out of the way, I made sure the engine was well supported as I intend to strip it out to lighten it as much as possible before lifting it out.
The early engines did not have marks on the flywheel for timing. Just a pointer and a notch on the front pulley. The first job is to remove the starting handle dog and the front pulley. I put the tractor in gear with the brakes on and the wheels blocked then use a large flat punch and big hammer to free off the starter handle dog. Once this has been removed a couple of levers and a tap or two and the front pulley comes off. Next its the timing cover. Early engines did not have any dowels to hold the timing cover or front plate in position. these came with the engine modifications around 1955 when it was found that front end loaders caused movement on the engine mounting plate and the gaskets would fail.
With the timing cover removed the timing marks on the gears can be found. Note the early model three bolt fixing cam shaft gears.
Timing marks crankshaft gear to large gear.
Auxiliary drive shaft to cam shaft timing marks. Also note the split pin and castellated nut on the auxiliary drive shaft. Later models had a Nylocks nut.
With the timing gears out of the way I release the lock-tabs on all the front plate retaining bolts. Be careful with these as they are different lengths and threads depending on where they go. I am afraid that I have done so many of these that I can afford to throw them all in a can and clean them, then remember where they go back. (Sad is it not?) Note the position of the oil pressure relief valve on the early engine. Later models had this incorporated in the oil pump.
Once the front plate has been removed I take the sump off. Now I find Henrietta's problem. Number ! big end has seized. The bearing is a complete right-off and the crank is scored. Oh Dear.
Another view of the damage. I have never seen piston rings like this in all my experience either.
So now I call on Harriet Ferguson and her loader to take the strain. The engine comes out and the clutch sees the light of day. As far as I know this has done 50 years too! I can be reasonably certain of this as I knew where the tractor came from when I bought her. She had been owned by one family until I got her in 1974 and I certainly have never worked on her.
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