HST Filter

[chuck172]

According to the maintenance schedule, on a Dk 40, the first HST filter change is at 50 hours. When is the second, 200 or 250 hours?

 

[murphy1244]

My book says 200 hours.

 

[chuck172]

The way I read the book, it says replace the filter at the first fifty hours, then every 200 hours after that. To me that's 250, 450, 650 etc.
Like the engine oil, change at 50, then every 100 hours. So it would be 150, 250, 350 etc.
I could be over complicating things again though! I don't know what's wrong with me, seems like the most simple things can get so involved.

 

[VictorW]

The way I read the book, it says replace the filter at the first fifty hours, then every 200 hours after that. To me that's 250, 450, 650 etc.
Like the engine oil, change at 50, then every 100 hours. So it would be 150, 250, 350 etc.
I could be over complicating things again though! I don't know what's wrong with me, seems like the most simple things can get so involved.

That how I read it too. I did my second at a one hundred mark so they continue to be at something-hundred. It would also be ok if it was something-hundredfifty.

 

[chuck172]

Yeah I did my second oil change at the 100 hour mark too. But the Hst and Hyd. filters are real expensive.

 

[VictorW]

Yeah I did my second oil change at the 100 hour mark too. But the Hst and Hyd. filters are real expensive.

After reading my post, it didn't come out right. :ashamed: I had done the initial engine oil and filter along with the trans oil and filter at 50 hours. Then did engine oil again at 100 hours and then the trans filters at 200 hours with the trans oil at the 400 hours mark as per manual. Now everything I do is at the something even hundred mark. Maybe just easier for me to look for a hundred hour mark than something with fifty at the end.

 

[kco]

The way I read the book, it says replace the filter at the first fifty hours, then every 200 hours after that. To me that's 250, 450, 650 etc.
Like the engine oil, change at 50, then every 100 hours. So it would be 150, 250, 350 etc.
I could be over complicating things again though! I don't know what's wrong with me, seems like the most simple things can get so involved.

This is the schedule I follow for my DK35.

 

[cat fever]

I think I have decided to just change my engine oil every fall. Transmission/hyd every other fall. I do not put enough hours on per year to do either more often. Filters with every change.

 

[ksbrdmkr]

To add to the confusion is the different Tach/clock times that DK/DKSE have. In my opinion for the DKSE one could easily add 50% more time to the maintenance intervals to match the earlier DK models.

 

[chuck172]

can you refresh my memory on the different tach/clock times? I do remember reading something about this before. It does seem like my hours are flying by.

 

[IslandTractor]

can you refresh my memory on the different tach/clock times? I do remember reading something about this before. It does seem like my hours are flying by.

I think he was referring to the fact that engine hour measurement is based on assumed running for an hour at full PTO speed. Many tasks are done at lower RPM so technically the engine has been running for more hours than the hour meter documents.

I don't think it is a big deal and don't bother to make corrections as the factory recommended service intervals are very conservative. No big deal to change oil at 60 or 70 or even 100 real world operating hours instead of at 50 hrs at PTO speed.

The 50 meter hour figure correlates to total number of engine revolutions rather than real world operating time. Imagine a car that goes 60 mph for 50 hrs, that means changing oil every 3000 miles. Most every auto company today recommends 5000 miles between oil changes and even longer when using synthetic oil as many folks do. Going over the 50hr at full PTO speed is therefore not likely to cause any problem at all and certainly running at less than full PTO speed for an equivalent number of engine revolutions won't. Just check the oil every ten hours or so and change when convenient after the hour meter hits 50.

 

[ksbrdmkr]

An engine tach records time equal to a clock only when running at a certain rpm while clock time is recorded as straight clock time. On the engine tach when running at a low rpm it may take up to twice as long to record a hour.

 

[taw1126]

On the engine tach when running at a low rpm it may take up to twice as long to record a hour.

This is my "learn something new" for today. I thought the meter was simply tracking clock hours regardless of speed. Is the tracking proportionate...like 2 hours operating at half of rated rpm = 1 hour on the meter? Or it tracks every hour over some threshold rpm?

 

[ksbrdmkr]

It is my understanding that the DK 45SE changed from using a "tack" time recording to a straight clock time "hobbs" time. On some light aircraft one has to record both times, the "tachometer" time for the aircraft maintenance and the "hobbs" time for rental charges. The tachometer is based on the engine rpm.