B6000 oil pressure

[wisc6000]

Last year I put rings, rod bearings and did a valve job on my B6000. After ~50 hours I'm now seeing oil pressure around 30 psi. Oh oh, IIRC it always ran around 40-50. When I fire it up cold it'll show 80 as it's on the relief valve but drops precipitously when it heats up. Water runs at 180-190. I changed the oil and it's still 30 when hot.

Any ideas?

 

[85Hokie]

30 when hot....that aint bad at all!!!
I run 15w-40 in mine - 55 psi cold and when good-and-hot.....15!

 

[D2Cat]

When you were working on it did you replace the cam plug? If not that could be you cause to lower oil pressure.

 

[wisc6000]

^ Yes on the cam plug and that's the reason I went into it. I machined steel plugs for both ends and pressed them in. A little arc weld zap to insure they were not coming out.

I'm concerned with the 30 psi and around 15 psi at hot idle when for the last forty years it always had mondo pressure.

 

[85Hokie]

^ Yes on the cam plug and that's the reason I went into it. I machined steel plugs for both ends and pressed them in. A little arc weld zap to insure they were not coming out.

I'm concerned with the 30 psi and around 15 psi at hot idle when for the last forty years it always had mondo pressure.

Did you change oil types? or weights of oils?

 

[North Idaho Wolfman]

I would be pulling the oil pan and checking rod bearings, sounds like you have one going out.

 

[wisc6000]

Yeah I'm thinking rod also. I fed it new shells when it was down and the original ones looked ok other than a lot of imbedded crap due to the poor excuse of a rock strainer called an oil filter screen.
Oil is the same as usual, 15/40 Delvac or Rotella.

 

[200mph]

Didn’t see any mention where the crank bearings were replaced. If checking rod bearings, it might be wise to check crank bearings. What condition is the oil pump in?

Is the oil pump pickup screen clean and leak free to the housing (sucking air)?

 

[JerryMT]

Last year I put rings, rod bearings and did a valve job on my B6000. After ~50 hours I'm now seeing oil pressure around 30 psi. Oh oh, IIRC it always ran around 40-50. When I fire it up cold it'll show 80 as it's on the relief valve but drops precipitously when it heats up. Water runs at 180-190. I changed the oil and it's still 30 when hot.

Any ideas?

You said you replaced the rod bearings. Did you replace the main bearings also? The mains usually have pretty large journals so wear at that location can have a big effect on oil pressure. What about the oil pump,? They wear also. Could the relief valve be partially stuck open?

 

[wisc6000]

Didn't replace the mains. I pulled a couple caps and they looked fine. Other than some embedded dirt like the rods did.

Pickup screen is clean as it comes out with every oil change. It seals to the case via o rings which are good.

Dunno about the relief valve other than when cold it bleeds off pressure at 80 psi.

 

[JerryMT]

Didn't replace the mains. I pulled a couple caps and they looked fine. Other than some embedded dirt like the rods did.

Pickup screen is clean as it comes out with every oil change. It seals to the case via o rings which are good.

Dunno about the relief valve other than when cold it bleeds off pressure at 80 psi.

You can't tell journal clearance by looking. Use some Plastigauge to see if the mains are within spec.