oil pressure erratic- any ideas?
05-06-2008, 07:39 PM
#1
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oil pressure erratic- any ideas?
What would cause the engine oil pressure to drop 20 lbs ( 70 to 50) at mid range rpm at random? The engine oil temp was the same. I noticed this after an oil and filter change, Napa Gold 1742, tried another filter (same type) and had the same results. The engine is a 572 cu in, supercharged, intercooled, with thermostatic oil cooler. The gages were checked (swaped with the other engine), it is the engine. Any ideas? Thanks John B
05-06-2008, 07:58 PM
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You said you switched the gauges, are they mechanical? If not, what about the senders? I would recommend hooking up a mechanical gauge to make sure where the problem lies.
05-06-2008, 08:00 PM
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Maybe try to isolate the engines from the wiring. Try splicing in a temporary 6' lead at the oil pressure senders and switch the port and stb OP wires. You could also and switch the port and stb OP wires at the gauges. This is an easy place to start.
05-06-2008, 08:48 PM
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I swapped both senders then swapped both gages and the problem stayed with the engine. This is a weird one. I called Sterling and Mike was unable to come up with anything. The other motor has the same filter with out any pressure issues.
The pressure stays at 70 +- until the motor was run for 15 minutes. Then after a run to 4000 it drops to 50+-. After sitting for a while it goes back to 70. It seems like a valve in the cooler or some bypass is switching?
Thanks for the ideas
The pressure stays at 70 +- until the motor was run for 15 minutes. Then after a run to 4000 it drops to 50+-. After sitting for a while it goes back to 70. It seems like a valve in the cooler or some bypass is switching?
Thanks for the ideas
05-06-2008, 09:46 PM
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I had a problem exactly like this a few years ago. Mine was caused by the ignition wires. I had a leaky wire running by the wire to the sender and it was driving it and me nuts. It could also be the connection between the sender and the gauge. Make sure that your ignition wires aren't touching the sender wire and see if that resolves it.
Rene
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05-07-2008, 07:13 AM
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I have had oil pump releif valves stick after oil changes for no apparent reason...but I would suggest getting a mechanical gauge and hook it up temparaly to take out the whole electric system and go from there..Rob
