High Oil Pressure on 3B, suggestions?

Joined
Jan 10, 2005
Messages
149
Location
Mt Vernon, IN and Monterey, CA
Here are the basics:
- 3B from an 85 BJ70 (Canadian 12V) - this engine/tranny sat in a barn in Iowa/Ill for 20 years, but after getting it going I see compression tests at 420PSI across the 4 cylinders.
- Turbo from a Ketih42 kit
- I sourced an oil filter bracket to flip the orientation so that the filter points down so that it didn't point up (weird in my book) and interfere with the exhaust manifold/turbo
- I've run it a few times with no issues, but I didn't have gauges installed yet. I just plumbed in a Dakota Digital instrument cluster (absolutely love it!) and it comes with it's paired oil pressure sensor. I was excited to see all of the gauge/instrument cluster functions working, but the oil pressure is pegged at 80psi (who knows above that?).
- am running 15-40 oil, cruiser is in southern Indiana, cold, but it's in the pole barn/garage which we keep ~60 F during the day

Thoughts?
- I am concerned about the oil cooler valve on the filter bracket. I don't have an oil cooler on my 85 3B, is the valve blocking normal function?
- Is there actually an oil pressure relief valve? My search found the oil cooler valve as mentioned above.
- are my oil passages internal to the engine blocked by gunk/sludge from sitting? Solutions? I am thinking of draining oil, changing filter (and inspecting it), putting in some 0-20 oil, maybe a strong slug of Marvel Mystery Oil to try and flush passages, then change oil again...
- any other suggestions, or alarms going off about my planned next steps?

Thanks for sharing your experience/wisdom!
 
Joined
Sep 12, 2020
Messages
139
Location
Victoria BC Canada
My 3B in my 78 bj40 does have an oil pressure relief valve on the left side of the timing cover directly beside the oil pump. My analog oil pressure routinely is around 80-90 psi when cold, under load. At idle, when the engine is warm, the oil pressure runs around 20-30psi. I use 10-40 rotella motor oil; and having recently rebuilt the engine I had the block (and all oil channels) pressure cleaned. There are no obstructions in any part of the system. My oil/filter change interval is about every 3 months.
 
Last edited:
Joined
Jan 10, 2005
Messages
149
Location
Mt Vernon, IN and Monterey, CA
I'm feeling much better about my oil pressure. I had a very helpful phone conversation with Dakota Digital about the scale/limit of the analog gauge. T gauge goes to 80psi, my worry was that it seemed to be pegged to the right so I didn't know what my reading was. I learned two things on that call: 1) if the reading from the sender goes above 100psi, an EEE is displayed to show out of range; and 2) I was able to set the display to show a digital Oil Pressure reading. Armed with that info, I found I was getting 89-90psi on cold start/idle and I came down to under 40 after warming up.

Also, I pulled the Oil Pressure relief valve from near the oil pump (US passenger-side, front, just above the oil pan) and the valve slides easily - pulled it right out using a small magnet, way way less that 80psi of pressure, more like 1-2psi. In my original search on an oil pressure relief valve I found this thread and was wrong about the 3B not having one: "Proper" 3B oil pressure indicator function - https://forum.ih8mud.com/threads/proper-3b-oil-pressure-indicator-function.250566/#post-3850397

Thanks OTBT
 

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