20 psi oil pressure on mep 002a

[hedgehog69]

Fired up unit...runs good, but oil pressure dropped to 20 psi. I will check tomorrow with a cold start to see where it runs at cold. Also need to get another manual printed so I can troubleshoot the possibilites. I just did an engine swap with a new engine...it runs 35 psi. Just wondering ..if thae 20 psi is correct....what kind of life expectancy can I expect from the engine? I have another fresh rebuild I can swap in.

 

[Carl_in_NH]

Need to know what your cold and warm pressures are - and what oil you're running in it - to make a meaningful comment.

Is it dropping right away, or only after warming up?

 

[hedgehog69]

Need to know what your cold and warm pressures are - and what oil you're running in it - to make a meaningful comment.

Is it dropping right away, or only after warming up?

I am using Castrol 15w-40 diesel oil. As I said...I will get cold oil pressure tomorrow and will time the drop to 20psi

 

[mistaken1]

The low oil pressure cutout switch is set at 14-15 lbs.

What does the manual say:

From TM 5-6115-584-12 MEP-002A Maintenance Manual - Change 6 - Page 2-3 :

e. Check oil pressure on engine mounted gauge.
pressure should be at least 20 psi minimum.

Same manual page 2-5

i. During operating of the Generator Set observe the following.
(1) Check % rated current meter.
(2) Check fuel level gauge periodically.
(3) Oil pressure gauge located on engine should indicate 20 psi minimum.

Same manual table 3-2

Normal indication: 20 to 45 psig at rated RPM.

Same manual page 4-37

a. Test. Attach a pressure gauge of known accuracy between
flexible oil line and unit pressure gauge. Operate unit for 1/2 hour
and check that both gauges read the same. At rated RPM the
normal oil pressure is 20 to 45 PSI which is dependent on air
and engine temperature, grads of oil, and wear tolerance of
engine. If the unit pressure gauge is in error by more than 5
Ibs, replace.

 

[hedgehog69]

I got a bit windy with my question...I think. What I am really wanting to find out is at what oil pressure does a person make he decision about replacing or rebuilding the the engine. I will have access to my manual tomorrow. If 20 psi is the minimum pressure to be considered 'normal', pressure can only decrease with more use.

Thanks for the info so far!!

 

[Bill W]

According to Operators TM5-6115-585-12 ( table 3-2 w/change 8 ) dated 1977, Normal is 25psi and minimum is 15psi.
Now another manual I have ( dated 1988 ) states oil pressure should not go below 20psi. I personaly feel that since these are low rpm constant speed engines ( with solid lifters ) that 12-15psi (hot) would be the no go/rebuild point for me.

 

[hedgehog69]

According to Operators TM5-6115-585-12 ( table 3-2 w/change 8 ) dated 1977, Normal is 25psi and minimum is 15psi.
Now another manual I have ( dated 1988 ) states oil pressure should not go below 20psi. I personaly feel that since these are low rpm constant speed engines ( with solid lifters ) that 12-15psi (hot) would be the no go/rebuild point for me.

I did get back to a cold start last week. Initial start up pressure was great...45-50...according to the guage. New Castrol 15w-40 in the crankcase. It took about 15 minutes to drop down to about 22.5 psi. I shut it off for a bit and came back. Fired it up and only got about 15. I am thinking engine swap.
But....before I do that...I am going to swap the guage out...just to be sure it isn't a guage issue.

 

[PeterD]

Swapping the sender (this is an electronic sender/gauge combo, right?) is a good idea. You should also test with a known good fully mechanical gauge to confirm the reading as well.

 

[Speddmon]

Peter,

it's strictly a mechanical gauge, and I was going to suggest the gauge swap, but the OP already stated he was going to do that.

My personal feeling, if you have the availability of a fresh engine to use, I would continue using the old one until the pressure starts to drop off even more. The low pressure switch is there to protect the engine, you shouldn't destroy it just from use. Why swap out a perfectly good running engine just for something to do. You will have just as much rebuild work if it's making 20 PSI as you would if it's making 14-15 PSI.