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Oil pressure light behaviour

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I've been poked with a stick before on oil pressure and my approach to monitoring with what I percieved as a potential problem engine.

I don't think my phillosophy is 100% correct for all people on all ocassions, nor do I believe it's 100% wrong.

IMHO there is more than "one way to skin a cat" and the answers to questions/problems don't need to be mutually exclusive.


And just to let everybody in on a little secret, the reason manufacturers don't fit gauges to vehicles anymore?............Accountants

I'll get my coat

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10 hours ago, Lucky Phil said:

For general information to anyone reading this thread in the future this methodology is flawed and it's best to stick with the historically tried and tested oil pressure observations for troubleshooting. This LOP light on after the kill switch timing thing has way too many variables to be a troubleshooting tool. .....[cut]....


@Lucky PhilI didn't mean to have the all covering solution to potential oil pressure problems :-).  The methodology is flawed (and then you put it mildly), but so are a lot of methods. When running a test-center back in the past, the accreditation counsel always joked that at the end every sensor is temperature sensor, suggesting that temperature should always in the equation for correction. An incorrect pressure release valve is difficult to find with cold oil (in the workshop). A short blink of the LOP-light in a corner at low revs and the lack of delay in LOP light gave my workshop immediately the hint to first check the valve. I must say, I had never even heard or thought that the valve could be calibrated. Unfortunately, I had driven it to long at low pressure, so harm was done to the bearings of the crankshaft.

But I will order a new pressure sensor for the V11 '99. They turn out to be less than 10 Euro :-). 

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I wasn't going to post again, but, the PRV release pressure can be adjusted by shimming the spring to compress, making the valve lift at higher pressures.

With the HiCam engine my own experience was the OEM spring acuation wasn't all or nothing, it partially lifted, prior to full lift

When I conducted static tests on the valve I found the lift pressure with cold oil on the bench was higher than the pressure when I ran the valve in the engine.

My best guess why this occurs (and it's no more than that) was the valve cycling inside the running engine. The result was the running pressure in the engine was lower than the lift pressure obtained on the bench.

I also want to thank @Lucky Phil for all the time and help he generously gave me and the solution of installing the Griso spring into the PRV in the HiCam. Without it I'd still be groping around in the dark.

The aforementioned results were with the 4v/v engine and it's different to the 2v/v engine. I've never had the need to conduct any tests on a 2v/v engine as I've never experienced any problems with the 2v/v bikes. On both of mine the pressure is stable at approximately the PRV lift pressure of 60psi once the engine is up to temp and revs over 2ks.

No idea if that's any help or not but thought I'd add it just in case

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I like to thank all of you for your responses, sharing experiences and urge to rational methods. Very helpful and when it is about engines (particularly Guzzi), I just love to read it.

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