too high oil pressure?

[coolbus]

I just changed the oil in my 8V-71, now the guage reads about 30 lbs at idle. I don't know what it was B4, but I think around 12lbs?

I only put in 5 gallons, as I read that some folks prefer to keep it a little low on the stick. It looks to be about 1/2 inch below the 'full' mark.

I have not driven it since the oil change. High idle yeilds about 45lbs. Is there some problem? Too high pressure? Could the sender have crapped out right at the time of oil change? 

Thanks

Mark

[prevost82]

When I fire up my 8v92TA it runs up to 80 psi cold, then settles down to around 30 until it gets up to temp, then idle's at 12. Running down the road it increases 10 psi for 10 MPH eg, 50MPH=50psi / 70MPH=70psi in high gear.
Ron

[niles500]

Koooooooolbus - anything above 10 psi at idle and 50 psi at full load is acceptable - don't fret it - FWIW

[HighTechRedneck]

Ditto on the pressure comments.  On running the oil a little low, I know some do it to reduce oil consumption.  Personally I wouldn't do it.  The manufacturer set the oil level based on engine needs under various conditions and the oil also plays a role in engine cooling.  Also, just like in a car where the top quart is the safety margin, the top gallon is the safety margin in your DD.  If you choose to run it low, must check it very frequently and don't let it get any lower on the stick.  And always keep a couple extra gallons (at least) on board.

Just my opinion, take it for what it is worth.

[Stan]

Coolbus: You should verify that your dipstick is correct. The usual oil capacity of a 8V71 is over seven gallons so you would appear to be more than two gallons low with five gallons. I know this wasn't part of your question but just offering friendly advice.

[jjrbus]

How do we determin the right amount of oil? I think I have read there are different size oilpans for DD's for different applications. I do not even know I have the right oil pan! The service manual only provides spec's for the oil not amount.The DD manual I have does not specify the amount of oil. Or am I missing something?
I do not use the add or full marks on my dipstick. If I run it up to full, it goes somewhere fast, I don't know where, seems to be all over the engine, the ground, the toad. It will quickly drop to about 1/4 inch over the empty mark and then takes about one quart every 500 miles to maintain that level.
My bus is 28 years old, The motor may be older. Is this the original dipstick? Is it even the right one for this motor?
The dipstick for my transmission is 2 dipsticks brazed together! I bought my coach from a charter company who maintained there coaches very well. So I have always just assumed that everything was right.

[RJ]

FYI -

According to DD, the correct "full" mark on the dipstick should be 1" below the interface between the block and the oil pan.

IIRC, this info came from a fellow who works at DD's rebuilding facility and was posted on the Yahell Detroit Diesel group.

FWIW & HTH. . .

[DrivingMissLazy]

FYI -

According to DD, the correct "full" mark on the dipstick should be 1" below the interface between the block and the oil pan.

IIRC, this info came from a fellow who works at DD's rebuilding facility and was posted on the Yahell Detroit Diesel group.

FWIW & HTH. . .

Yes Russ, that information has been posted in various locations before. One nut indicated that the best was to determine the proper level is to hold the dipstick outside the fill tube and down to the oil pan. Then mark on the dipstick where the pan meets the block. Full level should then be marked one inch below this line.
Richard

[Don4107]

What about those of us who have a Detroit tipped on its side?

Don 4107

[Dallas]

What about those of us who have a Detroit tipped on its side?

Don 4107

Don, The V-drive engines have a different oil pan and dip stick than the T-drives.
The full mark is the same in both cases.

Dallas

[jjrbus]

Thanks for the info.
I took a quick, non engineering, not technical look at mine, that is approximately where it is. I could have done a more technical inspection but there is oil everyplace and I did not want to get filthy

[gus]

In my 50+ yrs of experience most engines will throw out the top qts/gal of oil in short order then settle down. My 671 is no exception. I once had an airplane that would throw out the first two qts in 20 min then settle down for hours on the rest. Same thing for a number of my vehicles.

This is no old wives tale!

[Cary and Don]

We have found that if we fill to the full mark and the engine is cold, it will be over full once it gets warm.  If it is half way between fill and full cold, it will be full when warm.  We check every 200 to 300 miles, just for safety and we always carry a five of oil.

Don and Cary
4107

[Sojourner]

DD 2-cycle engine has extra oil flow rate than 4-cycle. Wrist pin & piston & skirt is get heated twice the times while 4-cycle one. So greater oil flow is spraying at bottom of piston assy as well wrist pin to keep it cool.
DD design 2-cycle to have larger variation of oil psi from cold to warm up temperature.

FWIW the following is only my thinking..... DD 2-cycle can have even bigger oil pump to maintain reasonable oil pressure like 4-cycle so that when oil is thinner (heated) viscosity while spraying at wrist pin & piston & skirt via connection rod & bearing but is way beyond the needed of cooling & rotating parts lubed???

Either cycle engine have oil pressure relief valve.

FWIW

Sojourn for Christ, jerry

[HighTechRedneck]

FWIW the following is only my thinking..... DD 2-cycle can have even bigger oil pump to maintain reasonable oil pressure like 4-cycle so that when oil is thinner (heated) viscosity while spraying at wrist pin & piston & skirt via connection rod & bearing but is way beyond the needed of cooling & rotating parts lubed???

Either cycle engine have oil pressure relief valve.

FWIW

Sojourn for Christ, jerry

Might work.  I know it makes me nervous to see the low oil pressure at idle when warmed up even though the manual says it is normal.

As a side note, I remember in the good old days of shade tree mechanics, a high capacity oil pump was sometimes used to extend the life of a high mileage car engine.  When used like that though it was only a delay of the inevitable, increased the risk of spinning a bearing and oil leaks would get worse.  But sometimes it was the only way to get another year down the road.