D8N motor overhaul

[JD 63]

Hi
I have a 1988/89 D8N which is using a lot of oil around a gallon on a 8-10 hr day it has 17500 hrs, I use it on the farm to move some dirt to fill in a low spot usually a 100-300 hrs per yr. When I bought it the undercarriage gone through with new tracks put on and the trans and final drives has been worked on.
So my question is I was going to buy a in frame kit and do it myself on the farm
Is there and trick or things a person should watch for while it apart or is this a bad idea

 

[BillG]

How much is leakage vs burning. Is it past the rings or turbo if burning. At 300 hours per year on a 35 year old machine and one gallon per day it"s hard to justify for the money, but it is yours.

 

[Delmer]

How much blow by, and how does it start and run?

 

[Mbar]

Have counter bores checked. You may find they are beyond the cuttable limit in frame and have to pull motor. Interstate mcbee makes great parts for a aftermarket option. Definitely weight options. A gallon a day is not bad for a machine used that little. Some Lucas may go a long way.

 

[chidog]

That high time, it needs to come out. Seals need to be changed, front end needs to come apart.
What condition is the cam shaft?
Consider the fuel pump needing an overhaul.
There can be some block problems too, lifter bores, cylinder upper and lower areas.
Leaky gasketed areas. Its just not an inframe deal I would think.

How are you at precision measurements?

 

[Bluox]

What kind of motor oil are you using and how often do you change it?
Just for a reality check call your local Cat dealer up and price a recon engine and their rebuild kits should be 3 different ones or so and availability.
Have your serial number, should be a 11N or a 70V when you call.
Bad Bob

 

[skyking1]

If it was still pulling OK I would keep putting oil in it.

 

[R.D.G013]

I would be with skyking1, if its pulling and running ok just put oil in it, for the few hrs U do/yr, if it was doing 1500/yr maybe a different story. May be do oil samples to see what the internals are doing as in bearing wear etc, like if its got Hi levels of bearing metals then may be time to look at crankshaft bearings before it does one.

 

[nicky 68a]

I don’t consider a gallon a day too much on a D8 that age.
Most of that gallon may just be leaks?
Regular servicing and keep it on the same oil brand may be what it wants.
If it’s working ok,just leave it well alone I reakon.

 

[chidog]

A gallon a day? True not bad when I know of some airplanes that did that in a hour and sometimes drank more.

 

[Bluox]

Pull and check your air cleaners .
Pull top off precleaner and check that.
If you don't change oil often enough a restricted air cleaner will pull oil through the turbo seals.
Adding new oil to old oil is not the same as a oil change.
Check engine breather tube is not plugged or buried in dirt.
Bad Bob

 

[JD 63]

Here’s a picture of the 9TC D8 3 shank ripper

 

[JD 63]

Thank you for all your responses.
The motor on the top side is very clean and it’s amazing how quick it starts and runs very well, no sighs of a miss or sputter at idle or under load.
I haven’t pulled the belly pan off since I bought it 6 yrs ago, but I would think if it was down there it would show signs of oil on the ground.
I have change final drive oils and check the plugs and checked hyd oil for fillings and engine filter and haven’t found anything to warrant a concern
I will check out all your suggestions, it maybe as simple as a plugged breather tube.
If it turns out to just being a worn engine, at what point would you consider the oil usage to be excessive 2-3 gallon a day. ?
If it turns out to be a engine rebuild or a swap, would the machines value go up enough to justify that expense, I’m up in Alberta Canada
Unfortunately I have no knowledge if anything had been done to the engine, I just have the work orders for trans and final drives and under carriage
Thanks Jd 63

 

[Delmer]

One gallon of oil used per one hundred gallons of fuel used is one standard I've heard for NEW engines. If your new engine uses oil at 1% of fuel, that manufacturer doesn't consider it a problem.

Another thing to try is to keep the oil at the lower level on the dipstick, some engines use more oil at the higher mark than the lower mark.

Do you run oil samples on it? SOS from Cat is cheap, hopefully it doesn't show anything, but it might show something to make you speed up the process.

 

[JD 63]

Okay I could try keeping the oil level a bit lower and see what that does.
also one of the previous responses asked me what oil I used, I used a 15w40 which I use in all my other equipment on the farm.

 

[Bluox]

Okay I could try keeping the oil level a bit lower and see what that does.
also one of the previous responses asked me what oil I used, I used a 15w40 which I use in all my other equipment on the farm.

Which oil do you use and how often do you change it?
Have you checked the air filters?
Have you checked the prefilter?
Have you checked the breather tube?
Bad Bob

 

[JD 63]

I use a John deere plus 15w40 which is supposed to have more additives than just 15w40 and every 150 hrs

 

[Bluox]

Cat calls 0.034 gallons per hour normal motor oil usage.
So that would be about 1 quart per day.
So if you aren't leaking you have a problem.
The list I gave you have all been simple causes for high oil consumption.
Bad Bob