Good morning folks. I can get my hands on a older D8H for the price of scrap.( I don't know the age or where I can find the serial #) The cat appears in good shape but the story is that it lost oil pressure. The old girl has been sitting for 20+ years and never moved. The farmer that owned it had gotten a heart attack and never gotten around to fixing it. The old guy has died a number of years ago .Now the family are in the process of selling the equipment and land. Back to the cat, The under carriage shows very little wear on sprockets chains idlers or rollers,..90 % good. It has a power shift and winch,..all levers are loose. All oil levels are good, no coolant visible in the rad, no cracks in the block that I can see. the engine is loose,..I can turn it by hand pulling the fan around. The exhaust stack of both engine and pub are open to the world and I wonder where that rain water goes that disappeared down their tubes for the last 20 years. The pub engine could be seized(water on the pistons) as the hand crank is missing and I had no means of turning it. oil level is good and not a trace of water in it. My questions What could be the most likely cause of the sudden loss of oil pressure? Would it be worth buying.(transport to my place would be $1500) scrap value is around $1000. Thanks.
The most important question in my mind: what do you want to do with this beast? and what experience do you have going for you? I'd investigate a little more where the coolant went and where the rain went. The rain may have had a drain in the piping or turbo so it never reached the cylinders. The coolant could have leaked out too, but I'd find out where the drain is on the engine block and see what's in there, and how much is left in the bottom of the radiator. Then fill with water to see where it leaks, then drain again obviously.
I have a half section bush to clear, that's why I thought of buying it and fixing it .But on a my farm a cheap dozer always comes in handy. I am pretty handy fixing equipment of any kind, done that all my life. A number years ago I rebuild a D7 for a neighbour so that might qualify me to tear into this one. I might take another trip out there but it is over 100 km one way.
s/n locations...
if started up in the winter with heavy oil, it could have twisted off the oil pump shaft-it is about 3ft long. the serial# split between low horse and high horse is at about 10700. what part of northern alberta are you in? i'm in the peace country. does it have front mount hydraulics or side-mount? 6 roller or 7 roller track frames? in my opinion, depending on the price landed in your yard, even if it doesn't run it would be worth it for parts as long as you are not in a hurry to recover your investment. last year I paid $500 for a worn front idler. my 46a still runs good but it could use a final drive re-bearing and re-seal and my undercarriage is almost done
They story did not say if it happened in summer or winter. The cylinders are mounted to the side of the hard nose. I did not count the rollers. Is it normal to have no rain cap on the exhaust stacks of these things? I am near Peace river.
You must be prepared for a full motor rebuild ,20 years sitting could be other problems to . Plan for the worst and hope for the best . Its a big enough risk buying and old dozer going , let alone not .
Yes I realize that. All I ever did was buy old equipment and fix it so it works again. I just try to figure out if it is worth buying this thing knowing that buying cat parts is like buying diamonds
Undercarrage is about 40-50 grand so if it has good undercarrage you have value there just for parts
I don't remember if the shaft breaks off or the key/pin comes out, but this is a known problem. There is an update, either late H or K. You can figure out if this is the problem by removing the pan. Probably a lower end rebuild at a minimum.
I never recall seeing an 8H with hand crank pony, they were all electric start. Not saying they didn't exist, just curious.
Yes the pony is electric start but it also appears to have a hand crank adaptor.
I know a number of years ago I rebuild a neighbours D7 (he had just bought)that had very low 2-3 Psi oil pressure. Turned out the splines on the pump shaft were gone causing the shaft to spin in the coupler and the PO had spot welded the shaft to the bushing which was bound to fail but it lasted long enough to find a victim that would buy the wore out hunk of iron. I wonder if the D8 uses the same oil pump drive set up as a D7.
mine has the hand crank adapter as well as the electric starter. some of those machines had a viscous fan hub, so unless it is bolted solid like mine, you likely wouldn't be able to roll it over by the fan blades. did you actually see the crank pulley move or perhaps the belts were slipping? by hydraulics I meant is the pump driven off the crank pulley( tank, pump, and valve all as one unit- sticks out in front of the lower grill area) or is the tank mounted to the RH side fender beside the seat with the pump mounted to the rh rear of the engine just below the floor plate?
correct me if i'm wrong, but I think the d7 of the same vintage is pretty much the same but only a 4 cyl instead of a 6
Yes saw the crank pulley roll over when pulled the fan blades. Yes I think there's a pump up front driven by the crank. I thought there was pump on the right rear side of the engine as well, might be driven by the flywheel maybe,..not sure though, can't recall seeing a tank beside the seat either. I only looked around this cat for about a half hour and I don't posses a photographic memory. I should've taken some pics.. but alas.
Here is what I see for a 46A D8H oil pump set up:
when I rebuilt mine many years ago that 4M358 shaft had about a 20 degree twist at the splines. it must have tried to pump some thick oil in cold weather. when starting old cat engines, I always spin the engine over on decompression until i'm ready to fire it then stop it, and let the oil pressure gauge go back to zero. then spin it over again and watch the oil pressure gauge come back up- then you know the pump drive is all good. the problem is, that in cold weather, with a cold machine, the mechanical gauge takes a long time to come back down, so it could have zero oil pressure and you would not know it until major damage is done. I use this procedure even in the summer- its just a good habit
Every D8H I've worked on had twisted splines on the oil pump drives. It's just something you replace every time you rebuild one of those motors. Ask me how I know. Rain caps on the stacks were something that people put on after they got a new machine. Around here you mostly saw coffee cans on top of the stacks. You tell the rookies as the first time they would start the engine the can would go flying. All the low power H's I've worked on were converted to electric start. I've never heard of a high power having anything but an electric start. By the same token, I've never seen a high horse engine that had a compression release. Doesn't mean that they aren't around. Most of the low horse machines I've seen and worked on did not have a muffler. If it had a muffler, it was mounted vertical. Vertical mufflers took the place of spark arresters in the woods, they didn't quiet anything down. All the high horse machines that I've seen and worked on had a muffler mounted horizontal. Mufflers started out being mounted under the engine hood. Factory mods put the muffler on top of the hood. Low horse machines have the big bulge out the front of the hard nose underneath the radiator. Makes changing fan belts are real pain. Back in the day, I rebuilt those engines out of frame with machine work, new jugs, rebuild the heads and remove and install for around $7,500. I doubt anyone could touch one now for less than $30,000.
That still does not answer the question of where all that water goes that rained down the smoke stacks all those years? Is there a drain hole in the elbow leading into the turbo? After all, The engine is stil loose,...don't know about the pub though
If water was going in the engine it would not be loose. The rings would have rusted to the jugs by now.
That's what I thought too.
Even if all the rods had broken clean and the crank could move free, the water would have seeped into the pan, floated the oil out, then rusted out the pan and drained. So if your oil level is correct, then the water had to have drained out somewhere. The cylinders could still be rusty just from condensation, and all manner of things could be wrong with it. At least the open pipe doesn't seem to be the worst thing in this case.
Out of curiosity,you say you had seen the crank pulley rotate when you turned the blades. I assume you had the decompression lever over to achieve this,other wise I would think it an impossible task. As others say,the pump drive on these D342 engines are a poor idea and always buggered when you see them. I would like the sump off and check the oil pump and debris gauze that you will find in there. You may also find some water marks on the 4 and 5 crank journals where water could have found it's way in. A new pump,drive shaft and filter gauze basket fitted to the sump,plus a good in situ clean up of the main and big end journals,could very easily see this machine fit to start after measuring the valve lash. Could be a good buy. As for the tracks been around 90% good.They possibly are,but they could also be dry type and rusted.Seals in idlers and rollers may be good,maybe brittle and dry. Pictures would give a better idea. Best regards
. Thanks, At this point commenting on this cat is no longer relevant. The owner changed his mind about the price, he now wants 6 grand as is and he has already sold the C frame and blade to a cousin. Apparently one final drive pinion or bull gear has some broken teeth as well. At this point I think it is getting too costly to try to get this thing back on the road.
Thanks for the update. Fate has played it's hand in your favour I reakon