Bobcat 863 high oil consumption question

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bttpe

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My 863 with 970 hours has high oil consumption. I'm guessing one gallon every 2-3 hours. The air filter was very black and soot covered. It smokes heavy black smoke during start up. The machine runs strong and has no other issues. My research suggests either a head gasket or a bad turbo. We will pull the turbo first and from what I've read any slop in the bearings would be indicative of failure. I have both a diesel compression test kit and a leak down test kit. Will either of those point out the head gasket.
 

foton

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If the engine starts easily and is strong with right at 1000 hrs on machine I doubt you have a compression issue. look at the turbo.first. but let me state this a compression test of the engine would be good numbers to have as a future reference, and a well it is not this.
 
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bttpe

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Thanks foton. I appreciate the response. I'll do a compression test before pulling the turbo. I'll post the results soon.
 

Tazza

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Start with the turbo. Remove the hose from the turbo to the intake manifold, if there is excessive oil in it, your turbo is bad. Turbo play is one thing, a failed seal may not always have shaft play, it usually does, but it doesn't have to be the case,

Don't leave it too long, if the turbo is bad, there is a chance it can get bad enough to run away on you.

Compression isn't a big deal, if it starts and runs well, it means you have good compression to burn your fuel charge.
 
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bttpe

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Yes I think this happened all at once. A good friend of mine bought it new and obviously seldom used it. When we bought it he ran it through Bobcat Service because an oil drip. They replaced a seal in the oil dipstick. Going back a year I used it one weekend and found it low on oil (wouldn't show on dipstick). Bobcat, he and I all though that the seal was the issue. He doesn't ever recall it using oil. I've maybe put 10 hours on it and am on my sixth gallon of oil.
 
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bttpe

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Update! We changed out the turbo. I don't think it was bad. Lots of carbon on the exhaust side but clean on the intake side and no play in the turbo wheel. Ran it one hour afterwards and still the same issue. It used about one gallon of oil. There is oil blowing out of the dipstick and we may see some from the head gasket area although there is lots of oil everywhere at the moment. We will do a compression test and leak down and I'll report again.
 

Tazza

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As you have changed the turbo and still have issues, i suspect cylinder issues, pressure out of the dipstick hole, i think your getting blow by and your oil is being burnt.

A compression test will tell you something, but if your starting easily, i'd like to think your cylinders are ok, if you're getting hard starts, takes a bit of cranking, i'd suspect cylinder;ring issues
 

laurencen

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oil seals on the valves will eat the oil but not pressure the crank case, my guess is the oil rings on pistons either damaged ot stuck with carbon
 

foton

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about when the poroblem started did someone use starting fluid to get it to run? maybe cracked rings.
 
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bttpe

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The original owner is a friend of mine. After talking with him I don't think he used ether to start it. He kept the battery charged, oil changed etc. It mostly sat for long periods of time. We haven't attempted to free up the rings other than running it hard for short periods. Still no compression test or leakdown test. Hopefully will do that next week Oct 10th. We aren't opposed to pulling the head ourselves, but dragging our feet.
 
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bttpe

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Broke two glow plugs during removal to compression test. The two cylinders we could do both have 425 psi +. We are deciding if we try to drill and tap ourselves or just pull the head and take to machine shop. I hate pulling the head without completing the compression or leak down test. argggggg
 

foton

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yeah that is a tuff call but I think I would pull the head to avoid the chance of metal from the drill and retapping process left in the cylinder. But it will let you see the top of the pistons and that could give you a idea on the two cylinders that you can not test yet.
 

Tazza

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Your best bet is to pull the head off, you have a far better chance of success. It can be done without pulling the head, if you can pull an injector, roll it over to TDC and use compressed air to push any metal particles back out the glow plug hole. This works especially well when you chase a thread, it blows the chips out.

Just throw a new head gasket at it, you can then do your tests. If you oil the block and head surface, you can re-use the head gasket, as long as you clean it off properly before you do final assembly.
 
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bttpe

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I attempted to do a compression test and broke off two glow plugs when trying to remove. In the process of removing them we lost one of the electrodes down into the cylinder and had to pull the head. Pulled the head and found a blown head gasket. See pictures. I though Duetz used 3 layer metal head gaskets. This one isn't. As I have said before I know the original owner all my life. He swears the head was never touched. He couldn't confirm if Bobcat touched it without him knowing. When we purchased it they ran it through their shop and said that an oring on the dipstick caused the oil loss (1 gallon/hour). Some shenanigans somewhere. We damaged the sealing point for the glow plugs in two holes. For now I'm going to plug them with bolts and crush washers. I just want to verify that this solves the problem. I'll buy or repair the head later if this solves the original problem.
 

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bttpe

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Will follow up when it's back together and report how it's going. Again, I really appreciate you guys who take time to help us. We just wouldn't have the money to run it through a shop.
 

Tazza

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I believe all the Deutz engines we build run composite head gaskets, so i wouldn't be surprised that a composite one came off, glad you found the issue though.

If you seal off the glow plug holes, please remember you really want to seal the entire hole and even have some sticking out the end, every bit of space you take up with the plug or bolt, takes up compression room, even altering this slightly will effect combustion. I suggest you get new glow plugs and seal them the best you can. You may be able to re-cut eh sealing face with a long end mill that will cut the shoulder for you.
 
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bttpe

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It's finally back together. We've had it started and running and good compression on all four cylinders 420 psi +/- 5 psi. Using bolts on the two damaged cylinders. It does make it hard to start so we've added a small magnetic block heater in an attempt to get it to spin the motor faster. Now that it has run we have epoxied one of the glow plugs in place where we damaged the hole. That needs to sit for several days so that I'm confident in cure. I believe that we will pull the valve cover and double check valve clearance per the work shop manual and see if that helps. It was a "good" starting machine before so we hope to get back to that. Saving our money for a remanufactured head in the future.
 

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