So have a 6466T Deere 644E loader, rather going from top to bottom on the machine and well its a little persnickety to start up when its cold, 28 degrees, it'll crank for 3 seconds before one cyl starts to pick up, then picking up one more and one more. I'll pause cranking at 5 or 6 seconds, let it heat soak for a few seconds then crank again, usually about 10 seconds of cranking before it lights off with 4 or 5 and runs until 6 comes in. when its running it purrs like a kitten, okay a really big happy kitten, huff of smoke if you give it the throttle like a typical engine coming on power. The machine has 25000 hours and the inspector that looked it over suspects its been rebuilt. I haven't seen a lot of threads of folks diving in to adjust valves, seems to be an easy enough job, pull the hood, air cleaner, muffler, air cleaner mount, breather and valve cover and you're in like flynn. JD like everyone else lists the timing spots and plugs and lines and which valves to adjust when.. Usually I'll do one cyl at a time, crank it over until its just around tdc and adjust that one, move back to the next, repeat. Do folks do it by the hourmeter or just if its running rough? I know adjusting the kubota valves cured a lot of smoke and vibration at all settings.
If that's really 25,000 hours, even if it was rebuilt it's high hours again now probably. Run the valves and while you're in there take the injectors for testing, spray pattern and pop setting.
I know this doesn't answer your question about Valves, but.. If its hitting on one cyl. at a time, you might be looking to hi up?? The inj. pump delivers fuel to the cylinders. you might just have a fuel bleed back problem?? not supplying fuel TO the cylinders.. if it has a hand pump bolted to the inj. pump, you could try to pump it BEFORE and DURING the cranking cycle.. ofcourse this will take 2 people. and see what that does before opening the valve cover. just a thought..
What's a good number of hours to get from this type of engine? I like the idea on getting the injectors tested, I've had stuff done by Boston injection a long while back, bet they're still in business. If its 40 or above, it lights right off in about 2-3 seconds max. When its cold the white smoke does show up pretty quick. I know when I changed the fuel filter you could pump and pump and hear the air running through the injection pump and dribbling back into the tank? Once the gurgling stopped it seemed to start up just fine. I can check it when its quiet and listen for air. No glow plugs so its a high compression engine? how do you test compression? Dummy injector?
With the amount of hours you could be looking at a number of things or a combination of all. Slow starting is a sign of being out of time, which could be faulty valve adjustment. Or at 28 degrees it could be that the rings and liners are worn and you have low compression. If the injector nozzles are worn or dirty you could be suffering from a weak or faulty spray pattern. I would start trouble shooting by eliminating some of these questions.
Hmm, there's a check valve I think in the fitting where the return line to tank connects, sometimes they get stuck open or the spring gets tangled up, might check that just for giggles. provides back pressure to keep the injection pump filled.
I had a 644E with my dad, and have been around a few more. When that engine starts, it should run up to about 1200-1400 rpm before coming back to idle. Why they do this is because there is a magnet in a plug at the end of the rack in the fuel pump. The object is to hold the rack in "full fuel" position to provide extra fuel for better cold starts. Also, some(not all) of the pumps with this feature have starting notches in the plungers to provide advanced timing as well. If it doesn't run up to a pretty good rpm before returning to idle when it starts, possibly someone may have removed the magnet. You could try holding the accelerator down fully when you are trying to start it and see if that helps at all.
Besides the other good advice on here: To me adjusting valves is like changing the oil. It is something you do on a set schedule so that you know it is done. Eventually they will wear until they are either sloppy and hammering or valves are being held open and you don't want either of those things to ever happen. So if you are not sure about it, and you are having symptoms that could be due to valve adjustment, just do it because you know it needs it one way or the other. Other things, like replacing injectors, opening up injection pump, etc. you want to have a more definite diagnosis before throwing money and/or opening up things that may not need it.
I'll say the first start sounded like it was going to go to the moon! but yep, then settled into a nice idle! We're used to that now
I'd guess that a compression test while you're having the injectors tested is in order. Not saying that you won't benefit from an overhead, but what you're describing sounds more like high hour injectors or engine. How's the blowby when cold and hot?
If the engine has half as many hours, you are talking about something that is normal for that temperature. If those are original hours you are lucky the things starts at all. As the temperature drops you lose compression which is ignition temperature. The fuel pump will likely have lost some top end firing pressure and the injectors may be dribbling or opening a little low. Generally that will make the engine start a little better with a little more black smoke. More than likely the valves will only be a little loose. All the maintenance tips above are good advice. It depends on your ability to pay for them and your tolerance for the machine being down. Basically the motor is just getting a little old and showing its age. I've looked at enough of them to say that is more common than not.
Others can correct me on this but my starting procedure is a little different than most. I do not believe in stopping the starter once committed to starting. Giving time for heat to soak in doesn't do any good. The iron is all stone cold and will stay that way from what little heat is being generated. Rather, the inside of the cylinders is warming up from the compression and any ineffectual firing that may be happening. Stop cranking and you have lost that into the deeper iron and water jackets along with whatever was in your battery used for that cycle. Once it begins to fire noticeably on one or more cylinders, your starter time limit (run the starter for only x number of seconds) no longer really applies. The engine is helping the starter along now and starter amps just went way down. So you can hold the starter on longer than would normally be allowed with a cold dead engine. Additionally some people seem hair triggered to release the starter when the engine starts to pick up any speed. Starters have a throwout mechanism so if the engine really takes off the starter will disengage or overrun. The motor continues to spin but this does not hurt anything. So when the engine is starting to pick up speed leave the starter switch engaged as long as it takes for the engine to really take off on its own. This way if it is a bit of a false start the starter can keep helping it along. That is my take on starting reluctant diesels. Of course, if it is too cold, start aids busted, no starting fluid available, etc. and you know it is not going to start at all then don't bother. That is true starter abuse. But 3 seconds to begin firing is a pretty short crank cycle in my book. If you go 15 seconds or more and see thick white smoke out the stack and no firing is occurring, then stop and investigate why.
When adjusting valve lash, I always adjust the intake valve when the exhaust on the same cylinder is wide open, and adjust the exhaust valve when the intake valve on the same cylinder is wide open. I don't worry about timing marks or whether it's on the exhaust or compression stroke. I've done it that way on dozens of makes and models and hundreds of engines, gasoline, diesel and natural gas, and never had a problem with the exception of a Mack with a Dynatard cam. About 90% of the time, valves are found to be tighter than specs if off at all. This is because of valve seat recession.