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HBrianW

Ud 525

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Good day all, I have a UD 525 engine I am attempting to put back into service as a small sawmill power plant. After many drawbacks I now have it running on gas and diesel, but it smokes from the rear exhaust pipe when running on diesel. Found a carbon obstruction between the head and "low compression" valve, and cleared that, but it still does the same. Runs perfect on gas, and doesn't really run that bad on diesel but it has the white smoke/smell of diesel when set to run there. So...what is my best direction from here? I do not have many custom tools, but have been an auto tech for 30+ years, how to test for compression or for a bad injector nozzle? Any likely or popular problems? Thanx for any input.

Brian, Deer Island Oregon

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You may have a damaged starting valve. Check it by removing that spark plug and see if you have any compression leaking out while running in diesel mode.

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Zactly. Spring pressure is only 25 lbs so they tend to stick kinda easy.

There are more items in waiting but first things first.

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Thanx guys, "starting valve" is what I refer to as "low compression" valve, had one held open but had cleared it; rechecked, all are closed. Really thought I had it when I found that, but oh well. Gonna determine which cylinder it is this weekend, will write in here again if/when I get somewhere with it. Understanding the obvious (cleanliness, organization, etc.) of it, is there anything technical about removing an injector nozzle for inspection/teardown/cleaning? I have confidence in doing it, but not in getting repair parts when needed. My manual doesn't have the best info, and lousy pics. Thank you for any help.

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Injectors are easy to take apart other than setting the break pressure when putting it back together. Parts are entirely different matter. The copper rings can be annealed soft again if needed, but in the recent past I was told they were available at IH.

You are probably aware, but that engine is a 6 cylinder version of the D350 in the 9 series tractors. Binderbooks.com has the injection pump service and parts books in good quality for a decent price.

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Well, I found I have 2 smoky cylinders, #'s 4 and 6. 4 will clear up some if I let it idle for 15 minutes or so, 6 will hit and miss, mostly miss. It does still add poweer to the engine, as I hear an rpm drop when I open the nozzle bleeder. I dis/re-assembled the #6 injector (went well I thought), no change. The problem is much worse when I try to run the rpm up, with it even starting to "pop" out the exhaust pipe. Both cylinders smoke plenty when at higher speed. I'm beginning to think I may have a sticking valve, but it runs so well on gas.

I do not know if it makes a difference, or if I made my own problem by doing it but I have installed an electric fuel pump to bypass the unuseable mechanical one. I used the body of the old pump and blocked off the fuels capability to get anywhere except for one hole that goes into the body of the injector pump; I found no use for that passage but felt it better to leave it open.

Another set back, all okay. Thanx on the info on Binder Books, there's one a little ways away I better go visit. I guess I better read up on that pump. I'll monkey with this thing again, get a note back if I do get it figured out. I will look here for comments as well, please do write with any advise you can share.

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Which pump do you have? Plain, "A" or "IH"?

The little hole basically supplied pressure to open the scavenger pump valve. It serves no purpose in your case but if not an "IH" (that means a B pump in the books) then the primary pump also serves to empty the main injection pump leaky bits that drain into the case. It must be dealt with.

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Well, I got some numbers from the tag, top line says International (logo) Harvester; second line Chicago Illinois USA; third line has a"B" in a stamping area, then the next stamping no270; after that Is what I believe to be a "1" (it may be a deep scratch) 64R91; 4th and last line in a stamping area Serial 3234. By "stamping area" I mean a space on the tag that is apparently meant for a number to be stamped there. There is also a large IH logo on the cast top section of the pump unit.

To add to my previous post, I should say I left the port for that orifice open and connected to my fuel return line; figured if any came out it could run back to the tank, and I could see no way pressurized fuel should have gotten there. But my figuring has been wrong before, lol. Are these numbers indicative of which unit it is?

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You definitely have a B pump. Should not be an issue.

Part number is 6 digits, starting with 270, so 270164R91 makes sense. Yes it tells you how the pump is configured. The governor weights, springs and plunger are all detailed by that. You also do the various adjustments according to it as well.

270164R91 is listed for the UD525/UD554 under special applications and is set up for 1395 RPM, 5% regulation.

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Thanx for your help! I believe the smoking is a cylinder issue, but any info is greatly appreciated. Hope to have better news soon.

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Swap the injectors around.

FYI, primary pump pressure is acceptable anywhere from 30 to 70 psi. 40 is plenty for anything but all out for the dyno and even that is questionable.

It is interesting that both 4 and 6 are on the same plunger. That may be significant.

Also, run some Marvel Mystery Oil through it as soon as you can. Dump it directly into a fuel filter if you can, or fill the sediment bowl etc. Sticky distributor valves can be a problem.

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Had the fuel pressure @ 50 psi, the gauge reads that as minimum "okay". Took the #6 plug out as it ran on diesel, no puff or pull at all. Swapped the #6 and #5 (known good) and #6 cleaned right up! #5 doesn't smoke as much as #6 did, but it does still miss. Will run some MM oil thru next run.

So, can I just get some new injector components and put them in? Figuring on the valve and seat pieces, and the spring anyway providing they are available. Or do they need machined? I can lap them, but could send them to a shop as well.

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50 is plenty. Later on IH dropped the pressure to about 40 or so, probably to extend life span of the gears.

Central Fuel can do injectors, I would maybe pull it apart for inspection. (Just note the setting on the pressure tension nut.) Injector valves do corrode and can be icky. Otherwise the nozzle orifice may be crappy or the pre-cup may be badly eroded. Parts are very hard to find, Central has them still.

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gentlemen;

i have a UD 525 and also am killing every mosquito within a mile of my Galion 118. When I start it it will start easily on gas. When i try to switch it to diesel, it will not switch to diesel, but did when I last started it almost a year ago. I let a novice mechanic try to work on it but he only took the top nozzle off the injectors and had them cleaned. I feel like something in stuck or sticking.

I may be engaging the diesel lever incorrectly anyway since I thought that I was to throw it all the way down to change over to diesel. However when I throw the lever down approx. 1/3, the diesel starts being injected as indicated by the terrible smoke. When I lower the lever down 2/3 it runs better but still must have the gas running in order to stay running at all. When I lower the lever down all of the way, the motor will sputter a few times then die unless I bring the lever back up. Am I doing the wrong thing by lowering the lever down all the way or is that for killing the engine anyway??

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It sounds like the starting valves may not be closing when switching to diesel. That would result in compression too low for the engine to run on diesel.

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I want to be be perfectly honest, I am not a mechanic, so how do I unstick the starting valves??? I did put Marvel mystery oil with the diesel to hopefully unstick everything. I also sprayed all fittings on the gas side of the starting valve cross shaft levers/compression release mechanisms with wd40.... So what else could I do??

When I had the mechanic look at the motor, we tried to remove the injector nozzles but we didn't have the correct tool to remove the injectors (part number 1 020 284 r91) but took off the top nozzles. We were able to get one injector out (#6) and it was as clean as could be!!! I was told that if one injector is clean most likely they all are.

Is there any manual that I could purchase that describes how to start the motor, maybe I'm doing something wrong to begin with!!!

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Thing is, the starting valves don't have much spring pressure. They are rated new at 25 lbs. Doesn't take much to have a valve get sticky. They will smoke like a fogger.

I have had luck in the past by removing spark plugs and working the exposed valve stem with skinny needle nose through the plug hole. Not real easy to do.

Also have tapped on top of the valves to get them to pop loose. Easy does it.

Also, you can kinda block the spark pug hole with your thumb etc shoot some PB Blaster etc into the spark plug holes. Aim high in general and you can hit the valve stem and guide directly. As a plus if it holds liquid you will know that the valve is closing okay.

You can buy an operators manual from Binderbooks.com. They may not have your exact setup, but get one for a UD525 or a UD16 and it will be close. Even a TD9 manual would be helpful. There are rules about not leaving the starting valves open. Hopefully they are not warped.

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Thing is, the starting valves don't have much spring pressure. They are rated new at 25 lbs. Doesn't take much to have a valve get sticky. They will smoke like a fogger.

I have had luck in the past by removing spark plugs and working the exposed valve stem with skinny needle nose through the plug hole. Not real easy to do.

Also have tapped on top of the valves to get them to pop loose. Easy does it.

Also, you can kinda block the spark pug hole with your thumb etc shoot some PB Blaster etc into the spark plug holes. Aim high in general and you can hit the valve stem and guide directly. As a plus if it holds liquid you will know that the valve is closing okay.

You can buy an operators manual from Binderbooks.com. They may not have your exact setup, but get one for a UD525 or a UD16 and it will be close. Even a TD9 manual would be helpful. There are rules about not leaving the starting valves open. Hopefully they are not warped.

Each plunger has a reverse check valve that was the main culprit that caused the plunger not to work. Had to lap the reverse check needle.

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Gentlemen:

I sprayed all of the outside levers to include the compression release, the fuel advance levers and pivot attachments, the starting mechanism with wd-40 and let it set overnight. Went back the next day and damned if everything started working!!!! The grader is running "so good"!!!!! I went ahead and found a copy on eBay for the"International UD-525 Power Unit" which is great for any new owner of this motor so think you so much for that tip!!!!

My next problem is to get the brakes fixed. How hard is it to get to the brake drums on the Galion 118. I think the wheels are pressed on a tapered shaft so if they are pressed on they must then be pressed to come off. Is this right or wrong??

Thanks again for all of your help. Will I need to go to a different forum to ask about the brakes??

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Woohoo!!

Brakes are a question for the construction forum. That is where the heavy equipment people mostly hang out.

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