1991 RT/TT - First Failure in 230K / 17 years

[cbatters]

Originally Posted by Drweldin

Clint,
Can you elaborate on the bypass valve, and how that works...?

Oil pump has built in spring loaded valve that acts as a pressure regulator for the oil. Once oil pressure gets up to ~90-100 PSI it opens and diverts excess oil back to oil pan. With a healthy pump and engine, you will have max pressure by ~4000 RPM on a warm engine. In the graph shown earlier, you wll see engine RPM contine to rise to 6000 while the oil pressure remains the same after ~4000 RPM.

Note: This valve also helps limit maximum pressure on cold start


Clint

[cbatters]

Originally Posted by OhioSpyderman

Clint,

Here's what I found..

MB631712 Hose Steering Oil RESEVIOR

The other two lines are labeled as RETURN and SUCTION, but unfortunately CAPS shows "**NO DATA**" for both of these parts...

Sorry, I tried.

Bob.

Thanks for trying.

[Drweldin]

Originally Posted by cbatters

Oil pump has built in spring loaded valve that acts as a pressure regulator for the oil. Once oil pressure gets up to ~90-100 PSI it opens and diverts excess oil back to oil pan. With a healthy pump and engine, you will have max pressure by ~4000 RPM on a warm engine. In the graph shown earlier, you wll see engine RPM contine to rise to 6000 while the oil pressure remains the same after ~4000 RPM.

Note: This valve also helps limit maximum pressure on cold start


Clint

Thanks

[cbatters]

Originally Posted by cbehnken

rev it out to about 6K. If the oil pressure starts DROPPING instead of going up it is the pump. Same thing happened to my old NA with much less miles.

When you rebuild be sure to open up the oil pump. You'll be amazed at the wear the gear has cut into the pump case.

Looking forward to pics

I'll get some pics posted shortly.

1050 miles and it is beginning to make some all too familiar sounds. Oil pressure has not been right since I put it together and #4 is running way too loose.

I have a short block on the way but may need to get another 1000-2000 out of this engine so I am going to check bearing and replace the oil pump. Anxious to see what kind of wear there is on the pump and how much improvement I get in oil pressure by replacing the pump.

VERY interessted in pictures of failed pumps and cases where oil pressure improved with replacing JUST the oil pump. (Historically there are lots of posts where pressure improved when changing bearings and pump but I don't recall any threads where the only component chjanged was the pump.





Clint

[OhioSpyderman]

Sorry to hear that you may not make your target mileage

Unfortunately for you (and fortunately for us), you are providing us with some very helpful info.

Still wish I was closer so I could give you a hand....

"Stay the course"

Bob.

[Hannibalzero]

Originally Posted by cbatters

I'll get some pics posted shortly.

1050 miles and it is beginning to make some all too familiar sounds. Oil pressure has not been right since I put it together and #4 is running way too loose.

I have a short block on the way but may need to get another 1000-2000 out of this engine so I am going to check bearing and replace the oil pump. Anxious to see what kind of wear there is on the pump and how much improvement I get in oil pressure by replacing the pump.

VERY interessted in pictures of failed pumps and cases where oil pressure improved with replacing JUST the oil pump. (Historically there are lots of posts where pressure improved when changing bearings and pump but I don't recall any threads where the only component chjanged was the pump.

Clint

Just curious, but if you have that second shortblock on its way, why try to nurse along the current engine by installing a new oil pump? (Maybe I read that wrong?) It seems like the best move would be move would be to install the new engine ASAP (and maybe check the clearances on its bearings and pump gear while you are at it). From the sounds of things, I don't know if I'd trust bearing #4.

[cbatters]

Originally Posted by Hannibalzero

Just curious, but if you have that second shortblock on its way, why try to nurse along the current engine by installing a new oil pump? (Maybe I read that wrong?) It seems like the best move would be move would be to install the new engine ASAP (and maybe check the clearances on its bearings and pump gear while you are at it). From the sounds of things, I don't know if I'd trust bearing #4.

Daily driver so I am either driving it or wasting $50/day on a rental. I am also stubborn and want to know what is possible in terms of options for rod bearing damage.