Low oil pressure

[James Farmer]

I recently did a an inframe on my 450 dozer. 188d engine. New sleaves pistons and rod and main bearings. Camshaft bearings too. I replaced the oil pump. The oil pressure is 25lbs when cold. When it gets warmer it drops to 5lbs.

 

[AllDodge]

Were the journals measured?
Have you checked pressure with another gauge?

 

[Tinkerer]

Welcome to HEF, James !
If you get the same pressure with a new a gauge. I would guess the you installed std bearings on a crankshaft that has one , or all the journals reground for .010 or more undersize.

 

[kshansen]

Welcome to HEF, James !
If you get the same pressure with a new a gauge. I would guess the you installed std bearings on a crankshaft that has one , or all the journals reground for .010 or more undersize.

That is one good possibility.

One question is "Why engine was inframed?"

I know that might sound like a dumb question but knowing the full story might help point someone in the right direction.

 

[James Farmer]

I am using a manual gauge. I tried another one with same results. The old bearings said standard. The reason I inframed it. The engine was smoking badly. I should have plastic gauged the crank and new bearings.

 

[Tinkerer]

If all of the main rod bearing caps are torqued down properly I would suspect an oil pump problem. Relief valve is the first thing that I would check. Also for air leaks in the oil pump piping. You did clean the screen right ? No rags in it ?
It happens.

 

[James Farmer]

Everything is good in that area. Had the pan off and checked the o ring on the pump. I suspect the crank. Going pull it back down and check it over again. The cam was worn. But it didn't look that bad. The crank is worn too. I should have replaced them anyway. Thanks for your time. I just thought I missed so simple.

 

[DMiller]

Said put cam bearings in? Most gauges take a reading off a cam journal feed so may be seeing a restricted port or a rolled bearing. Anything done to Rocker Arm shaft? Is it possibly loose or a cup plug unseated at one end?

 

[td25c]

Where did the oil pressure run before the overhaul ?

 

[Tinkerer]

Why did you replace the oil pump ?
Best to check out that new one before going crazy taking everything else apart.

 

[kshansen]

Where did the oil pressure run before the overhaul ?

That question is part of what I wanted to know when asked "Why it was Rebulit"!

Don't recall if I ever got into a 188D to see the pump, I think I did as I rebuilt a couple many many years back but before just tossing a new pump at any engine I would open it up and check clearances and for visual wear.

I'd tend to trust a used pump that I knew had been running at 60 psi with warm oil before a new pump that could have been assembled with low quality parts by someone just learning the job at the factory.

 

[James Farmer]

The gauge was not working before. I replaced the cam bearings. I made sure the holes lined up.

 

[James Farmer]

The old oil pump had a lot of scarring and wear. I figured I want this engine to last so I replaced it.

 

[AllDodge]

Maybe I missed it but did you try connecting another gauge?

 

[Tinkerer]

Did you by any chance check the bearing journal sizes on the new camshaft or slide the new bearings over them before installing them ?
Outside chance you have a mismatch on one or all of the bearings.
Curious to know about the pump relief valve yet.

 

[RZucker]

The gauge was not working before. I replaced the cam bearings. I made sure the holes lined up.

This is a "dead in the water" issue. Not knowing the previous oil pressure readings makes it really hard to say it's "this or that".

 

[td25c]

Operating equipment without a working oil gage .

As the President would say ….. LOL!

Hopefully its simple like the new oil pump is at fault .

 

[James Farmer]

Read my text before you. I did not run this machine with an oil pressure gauge that wasn't working. I pulled the engine because it was smoking. I inframed it.

 

[Tinkerer]

Oil pressure ? From the service manual. This ---->

 

[kshansen]

Read my text before you. I did not run this machine with an oil pressure gauge that wasn't working. I pulled the engine because it was smoking. I inframed it.

We might be misunderstanding here. I believe td25c asked about the oil pressure before the in-frame to get an idea of how the original gauge was working. You then replied:
The gauge was not working before. which would give one the idea that the engine had been run, if only for a few seconds, with gauge not showing any pressure. I'm sure many here would feel that if an engine is running no matter how badly it is always a good idea to do some basic checks before tearing down. Simple things like oil pressure and checking for air bubbles in the radiator would point to things that need to be checked while engine is apart.

Everyone needs to understand that any replies are only made to the information we can read here! While forums like this can be very helpful it is very difficult to diagnose things by text messages alone. Things that one would notice in seconds if there in person can take several days of back and forth texting to ask the right question and get the right answer.