Slobbery Deere, blowby question

[fast_st]

So my favorite big project, Deere 644e with a 6466T engine, well it keeps slobbering on the rear axle from the the crankcase breather, I looked on both sides of the engine for a Detroit diesel sticker but nope, it says Deere. Its a steady fog of blowby, and an oil drip now and again too. Not sure what the standard is.

Companies like Reliance seem to sell engine overhaul kits, the clock reads 29000 + hours and I have no service history on how many hours are on the engine itself. It starts and runs decent, a tiny bit of oil from the turbo. I'm leaning toward a rebuild on the engine, new pistons, rings, sleeves etc. Seems like the correct path is to pull the pan and check the crank, get some good measurements with a micrometer and then order up a rebuild kit. Kits seem to run under 2k for the most part then I'd also like to overhaul the rear main seal and have the cyl head checked. Guessing it might be 5k overall, does it sound like I'm in the ballpark?

 

[Tinkerer]

Hard for me to say because the head work could make a big difference in the overall cost.
Don't forget to measure the camshaft lobes. New bearings for it are mandatory IMHO.

 

[Nige]

Blowby.? You need these boys ............

 

[mg2361]

I would replace that turbo as well since a turbo can also be a source of blowby. Just for your info the Deere spec for blowby measured with a water manometer is 2" of water at full rpm full load.

 

[56wrench]

you never said, but it depends also on how much work you do yourself and what kind of shape the block is in( liner counterbores) etc. also, maybe your rods will need new top bushings and the lower ends checked. the main question is how many hours does it need to last? that will determine how much its worth spending. if its actually 29000hrs on that engine there may be a lot of worn-out parts. so, you have to determine- full actual rebuild or patch job

 

[Tyler d4c]

I had a6466 head done a few years ago new seats guides and valves it was about 600 if I remember right.

 

[fast_st]

Hard for me to say because the head work could make a big difference in the overall cost.
Don't forget to measure the camshaft lobes. New bearings for it are mandatory IMHO.

Cam bearings cheap insurance?

 

[fast_st]

Blowby.? You need these boys ............

too much go go gas? they seem to know what they want to get done!!

 

[fast_st]

I would replace that turbo as well since a turbo can also be a source of blowby. Just for your info the Deere spec for blowby measured with a water manometer is 2" of water at full rpm full load.

got a couple questions, is that plug the breather and measure blowby or 2 inches of water up top someplace like say the oil fill cap? water is easy to work with. I've resealed a couple turbos for the ford navistar engines, its really just a under $50 kit for all the rings and seals vs a rebuilt turbo, I'd think if the compressor and turbine wheels are in good shape, can do the rest on the bench in an hour.

 

[Tinkerer]

Cam bearings cheap insurance?

Absolutely. It just doesn't make sense to me to put new bearings on a crankshaft and new piston pins (or con rod bushings) and then lose some oil pressure because of worn camshaft bearings. If you do remove the cam bearings be sure to mark the position and direction (front or rear) as soon as each one comes out. It is critical that the oil holes in them line up with the oil supply holes in the block.

 

[Nige]

On something like this, provided the coin was available and justified in terms of what the engine is going to be expected to do after the intervention, my motto would be "do it once, do it right". You're going in twirling wrenches you might as well do all the little incidentals (like cam bearings and cam gear train bearings) as well while you're in there.

 

[fast_st]

Absolutely. It just doesn't make sense to me to put new bearings on a crankshaft and new piston pins (or con rod bushings) and then lose some oil pressure because of worn camshaft bearings. If you do remove the cam bearings be sure to mark the position and direction (front or rear) as soon as each one comes out. It is critical that the oil holes in them line up with the oil supply holes in the block.

Yeah, have had auto experience with that, where someone put bearings in wrong and caused all sorts of fun damage! This machine gets run maybe 100 hours a year and still gets an annual oil change but my goal is keeping its value up so a full kit is within reason as then we'll have a known quantity for not only the driveline but for the engine as well. Axles, seals and center pins and a slew of other things were done a few years back.

 

[mg2361]

is that plug the breather and measure blowby or 2 inches of water up top someplace like say the oil fill cap?

Leave the breather open and place the water monometer over the dipstick tube. Here is a picture of my homemade one that hangs on the back of my tool box (sorry it is upside down). You fill the manometer with dyed water (I use food coloring dye) to the "0" and when the engine is hot, full throttle full load you add the the numbers above and below the "0" to get your inches of water.

 

[fast_st]

Keen, so dipstick toob! I'll give it a test Sunday, nothing that fancy though as its a one shot test!

 

[terex herder]

A friend just knocked apart a 8.1L Deere with way to much blowby on 14,000 hours. Started good at 25F, good power. 5 of 6 top rings were broken.

 

[Nige]

A friend just knocked apart a 8.1L Deere with way to much blowby on 14,000 hours. Started good at 25F, good power. 5 of 6 top rings were broken.

Similarities with the Doosan in the YouTube video then..........pretty much every top ring fell apart on that one also.

 

[highwayghost]

my motto would be "do it once, do it right".

Man..... I wish more thought like that!! I am SO tired of cleaning up messes!

 

[old-iron-habit]

I always say, "Any job, big or small, do it right or not at all." Unfortunately although I always consider it, I don't always practice what I preach. The machine is not always worth it.

 

[Birken Vogt]

Sure you can do it right on something new and shiny but if the whole machine is old and decrepit then it is nice to know the ways to do it quick and dirty to just get by until it throws a rod and gets sent to the junk pile.

Like if you have an engine with a bad lifter, scratch in a lobe but cleans up OK and the rest of the lobe looks all right, got blowby and a bunch of hours, and the rest of the machine is rough but still works, just clean up the lobe and throw a new lifter on and let it run the rest of its life before something non-economic happens to kill it.

 

[mg2361]

A friend just knocked apart a 8.1L Deere with way to much blowby on 14,000 hours. Started good at 25F, good power. 5 of 6 top rings were broken.

A millennium ago I had an old JD450 dozer with a hard start complaint when cold and even though the compression test was all within spec every top ring was busted. Since then I only use compression tests to find hard failures like broken valves or holes in pistons. I use a leak down tester most of the time if I suspect cylinder issues.