Diesel Repair Thrills
Weather-wise, today was just about perfect: Clear skies, slight breeze and not too hot. I love late summer / early autumn. I spent a fair bit of time outside, and what better way to enjoy the outdoors than driving earth moving machinery!
I did some road building on the old digger, which went well - including a spot where I had to fill in a hole that was too big to reach across. The solution was to carefully slide into the bottom, then fill it in by digging dirt down from the edges and work my up. This operation required careful planning so as not to literally dig myself into a hole.
This afternoon I did some work on the old Massey Furgesson 200 dozer that I bought (what a fool!). It's got may problems, but one problem is that diesel always poured out of one of the injectors, and I was pretty sure it was not firing on that one (so it was only running on 2 out of 3, and consequently way down on power).
I only had a vague idea how the injectors worked, but that didn't stop me pulling it apart on the work bench. That done, it was fairly clear how it worked and also what was wrong. Some ham-fisted numpty had assembled it roughly, or in the wrong order, so that some metal had been shaved off an internal locator pawl and ended up sandwitched in the mating surface which is all that holds in the diesel at full injector pressure. Hence diesel was just pouring out rather than going into the cylinder. To make matters worse, they had screwed the top screw (injector pressure regulator) all the way down thus preventing it ever opening anyway. I didn't understand this latter bit, but more on that in a moment.
Now officially, you should sent injectors to a fully qualified and tooled diesel workshop for overhaul; furthermore, you can't set the injection pressure screw to the correct pressure without a full test rig. But hey, this is a 40 year old tractor. Time for some farmer-brown repair.
I managed to scrape the offending metal off the mating surfaces with a small screwdriver and a hobby knife, so they fitted cleanly again. This is an obvious no-no - they should be re-machined, or probably thrown away. I then reassembled (more carefully than the last person!), and finished by screwing the top screw down all the way, as it had been, not realising this was the pressure regulator adjustment.
Of couse, when I reassembled and restarted, the engine fired up on the other two cylinders, and promptly blew the fuel pipe off the pump because the regulator was screwed right in and there was nowhere else for the diesel to go on that injector.
Realising the error, I looked up on the internet and learned that you can't set the regulator screw without a test rig. So, I measured how far the other two were screwed in, and set the repaired one the same. Classic farmer-brown thinking. I even managed to pop the swage back onto the burst fuel pipe with a paper towel and some vice grips.
This time, it fired up on all three cylinders, for the first time ever in the time I've had it - and what a sweet sound! Now I know that it was DEFINITLY only running on two before. It's very satisfying to ffix an old machine with a few hand tools and a bit of ingenuity.
The engine sounded much more eager on three cylinders, and I really wanted to try it out, but unfortunatley last time it was moving, one of the blade pins fell out and the blade was left dangling, plus the hydraulics are full of air and not working after I changed the oil. So it's not going to do any work for a while yet.
I did some road building on the old digger, which went well - including a spot where I had to fill in a hole that was too big to reach across. The solution was to carefully slide into the bottom, then fill it in by digging dirt down from the edges and work my up. This operation required careful planning so as not to literally dig myself into a hole.
This afternoon I did some work on the old Massey Furgesson 200 dozer that I bought (what a fool!). It's got may problems, but one problem is that diesel always poured out of one of the injectors, and I was pretty sure it was not firing on that one (so it was only running on 2 out of 3, and consequently way down on power).
I only had a vague idea how the injectors worked, but that didn't stop me pulling it apart on the work bench. That done, it was fairly clear how it worked and also what was wrong. Some ham-fisted numpty had assembled it roughly, or in the wrong order, so that some metal had been shaved off an internal locator pawl and ended up sandwitched in the mating surface which is all that holds in the diesel at full injector pressure. Hence diesel was just pouring out rather than going into the cylinder. To make matters worse, they had screwed the top screw (injector pressure regulator) all the way down thus preventing it ever opening anyway. I didn't understand this latter bit, but more on that in a moment.
Now officially, you should sent injectors to a fully qualified and tooled diesel workshop for overhaul; furthermore, you can't set the injection pressure screw to the correct pressure without a full test rig. But hey, this is a 40 year old tractor. Time for some farmer-brown repair.
I managed to scrape the offending metal off the mating surfaces with a small screwdriver and a hobby knife, so they fitted cleanly again. This is an obvious no-no - they should be re-machined, or probably thrown away. I then reassembled (more carefully than the last person!), and finished by screwing the top screw down all the way, as it had been, not realising this was the pressure regulator adjustment.
Of couse, when I reassembled and restarted, the engine fired up on the other two cylinders, and promptly blew the fuel pipe off the pump because the regulator was screwed right in and there was nowhere else for the diesel to go on that injector.
Realising the error, I looked up on the internet and learned that you can't set the regulator screw without a test rig. So, I measured how far the other two were screwed in, and set the repaired one the same. Classic farmer-brown thinking. I even managed to pop the swage back onto the burst fuel pipe with a paper towel and some vice grips.
This time, it fired up on all three cylinders, for the first time ever in the time I've had it - and what a sweet sound! Now I know that it was DEFINITLY only running on two before. It's very satisfying to ffix an old machine with a few hand tools and a bit of ingenuity.
The engine sounded much more eager on three cylinders, and I really wanted to try it out, but unfortunatley last time it was moving, one of the blade pins fell out and the blade was left dangling, plus the hydraulics are full of air and not working after I changed the oil. So it's not going to do any work for a while yet.