M7030 Blow-by (HELP)

[PoorPlowboy]

Hey Art, could you define 'running cold' for us who are new to diesels? I have yet to start it up when it is very cold out. How long should the engine warm up in various temps. before moving? Is there a chart for this anywhere? Thanks!

Running cold just means that you frequently crank the tractor to do small jobs and turn it off before the engine has had time to reach operating temperature. It takes a bit of a load on a diesel tractor for it to reach operating temp.

On my Perkins engines, it takes them almost 45 minutes at idling to reach operating temp. I'd bet that it takes a 'bota a good while idling to reach it as well. I simply give them a couple of minutes to get the oil circulating well and go to work and they'll reach op temp within 5 minutes.

The only "good" thing about cold run glazed cylinders is that you can usually get them back in good running condition with a cylinder hone by cross hatching the sleeves without any other machine work required.

 

[art]

It would be a rare diesel to get to operating temps at an idle. You can hone the glaze off though.

 

[5030]

As stated, diesels aren't meant to idle. Bad things happen, oil gets contaminated quick, bores glaze, the engine loads up with unburnt fuel...

Diesels are meant to run at operating temperature, 180 or better engine coolant temperature, especially the new emissions compliant ones. In reality, you want to see a 200 plus coolant temperature.

Idling a diesel in cold weather should be as brief as possible to get the oil in the tractor transmission and hudraulic oil circulating and if it's going to idle for a protracted amount of time, the engine needs to be bumped above the base idle to better than 1000 rpm.

because of the engine mass, there is no way you could get a diesel to operating temperature (in cold weather) except by blocking the radiator off..... Why big triucks have winterfronts.

 

[Sackett876]

From what I understand this tractor was bought new and worked in the Orange Groves in Fla...until we got about it about 10 yrs ago, since it has only been run a few times a year, but every time or most every time it was run for a few hours at a time, bush-hogging, disking, ect. Just from listening to you guys I really like the sound of the head gasket...Here is why,, 3 yrs ago it leaked very little when warmed up and under a load,,,drop to idle for few seconds it'd stop,,,next yr a little worse,, but could still use it,,,last yr leaked worse,, but still drop to idle it'd stop,,,, could use it adding say a gallon an hour,,,,now this yr when warms up it leaks (pours out under load) idle still leaking,,,can't run it at all,,,way too dangerous!!! So why does the head gasket make sense,,,because of how it would leak under load,,more oil pumped,,,idle stop,,less oil pumped....then it has gotten worse....any way I'll know tomorrow as I'm taking the head off so I can LOOK IN THERE and then I'll make a report here for advise,,,or to say too someone you were right!!!! I've got my fingers crossed for the head gasket guy!!!!
Tell me more about the cylinder glazed?? please

 

[suzy]

Thanks guys for relieving anxiety about running cold. In the winter it will have the block heater working for it. I have yet to see its little glow plug light go on. My son also said to move the loader a bit while warming up to get oil moving around.

 

[Sackett876]

It's not likely but you could find the head gasket blew and instead of leaking to a cooling water port it's leaking to an oil passage port.

CrazyAl,
You are not crazy!!!! You were right!!!! Almost,,,it was the head gasket...here was the problem,,,,I took the head off today,,,there is a "line-up tit" on the block that alines the head on the short block...on the head gasket there are brass/copper rings around all the oil port holes,,,oldly enough (as the head has never been off) when the factory put the head on(3145.7 hours ago) the brass ring was bumped loose from the head gasket and was stuck on the line-up tit...as time has gone on the brass ring wore on the head gasket and rubbed a hole into the head gasket!!!!!!!!!!!!!The head looked great,,,,,the cylinders are excellent,,,,slick as a baby's butt!!!!!!!!!!!!!went to the Kubota place and ordered me a new head gasket and valve cover gasket.....for a total price of $215.00 I'm gonna have the tractor working!!!!!!!after 3 trips to real mechanics...So once again I'll say thanks to you CrazyAl.....
Shawn...

 

[PoorPlowboy]

Woah now. $215 for only a head gasket and valve cover gasket? That is certifiably insane! The last engine I rebuilt was only $115 for every seal and gasket on the whole 3 cyl diesel. It wasnt a Kubota, though.

 

[5030]

CrazyAl,
You are not crazy!!!! You were right!!!! Almost,,,it was the head gasket...here was the problem,,,,I took the head off today,,,there is a "line-up tit" on the block that alines the head on the short block...on the head gasket there are brass/copper rings around all the oil port holes,,,oldly enough (as the head has never been off) when the factory put the head on(3145.7 hours ago) the brass ring was bumped loose from the head gasket and was stuck on the line-up tit...as time has gone on the brass ring wore on the head gasket and rubbed a hole into the head gasket!!!!!!!!!!!!!The head looked great,,,,,the cylinders are excellent,,,,slick as a baby's butt!!!!!!!!!!!!!went to the Kubota place and ordered me a new head gasket and valve cover gasket.....for a total price of $215.00 I'm gonna have the tractor working!!!!!!!after 3 trips to real mechanics...So once again I'll say thanks to you CrazyAl.....
Shawn...

That is a good deal. Kubota parts are expensive, just look at a can of Kubota touch up paint sometime and we all know how much SUDT costs, one reason why I run Chevron Synthetic instead. 15 gallons of SUDT puts a serious dent in my bottom line......

The brass rings are designed to compress when you torque the head down (don't forget to torque the head progressively and in the proper order when installing the new head gasket....) and seal the combustion chamber and passages from cross cotamination.

The line up 'tit' as you refer to it should actually be a locating dowel pin, no 'tit' at all and there should be more than one.

 

[Sackett876]

That is a good deal. Kubota parts are expensive, just look at a can of Kubota touch up paint sometime and we all know how much SUDT costs, one reason why I run Chevron Synthetic instead. 15 gallons of SUDT puts a serious dent in my bottom line......

The brass rings are designed to compress when you torque the head down (don't forget to torque the head progressively and in the proper order when installing the new head gasket....) and seal the combustion chamber and passages from cross cotamination.

The line up 'tit' as you refer to it should actually be a locating dowel pin, no 'tit' at all and there should be more than one.

I thought that should have been at least 2 line up pins, but there is only one,,,it was/is located on the left rear corner of the block????

You said the proper order??? Is that from the middle out to the ends??? That's how we did 25 yrs on Mack Trucks??? and the cross contamination,,,with "blue glue"?

 

[Sackett876]

Woah now. $215 for only a head gasket and valve cover gasket? That is certifiably insane! The last engine I rebuilt was only $115 for every seal and gasket on the whole 3 cyl diesel. It wasnt a Kubota, though.

Hey I thought that it was a little high,,,,but when we thought that we were looking at a re-build,,,,man 215.00 looks GREAT!!!!

 

[PoorPlowboy]

Hey I thought that it was a little high,,,,but when we thought that we were looking at a re-build,,,,man 215.00 looks GREAT!!!!

I think Kubota Corp. Accounting Dept. realizes this. :laughing:

Just be careful setting the cyl head down on to that gold plated jewel as not to bend the compression rings or such. That's one part I would definitely hate to buy twice for one job.

 

[5030]

I thought that should have been at least 2 line up pins, but there is only one,,,it was/is located on the left rear corner of the block????

You said the proper order??? Is that from the middle out to the ends??? That's how we did 25 yrs on Mack Trucks??? and the cross contamination,,,with "blue glue"?

No blue glue on a head gasket. Valve cover maybe. Gasket shellac or nothing at all.

The deck and head underside needs to be clean and flat. You need to remove any residue and/or carbon prior.

I'd be investing in a shop manual. I have no idea of the tightening sequence, the starting torque, the finish torque or if the head bolts are dry torque or wet torque. Only the shop manual (or a dealer knows). They may also be one time use.

Mack trucks don't count.

 

[MHarryE]

The shop manual purchase is a good investment. You cannot always go by old practices. As an example the Perkins 4.4 liter Tier 2 engine has a significantly different tightening torque pattern than the 4.0 liter Tier 1 engine. If you use the Tier 1 pattern, you will quickly blow a Tier 2 head gasket, and they aren't cheap. In fact you would be pleased to pay only $215 for the special head gasket needed to withstand cold start combustion chamber pressures whcih, hard as it is to believe, are higher than those the engine sees under full torque.