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09-11-2021, 09:40 PM
(This post was last modified: 09-11-2021, 09:41 PM by Rpm.)
Evening all. My first question. Does having a coil on the oil pipe to the gauge make any difference to the oil pressure, I know this may be obvious to some, but not to me.
The other question is how do you get to clean the oil pressure release valve, what a stupid place to put it.
My oil pressure appears a little high despite cleaning the oil jets with a micro bottle brush.
Regards Rob RPM
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Location: Darkest Bedfordshire
Q1: No
Q2: I wish I could get at mine but it's going to have to wait till the engine is out I think! Maybe it was put there precisely to stop people fiddling with it... What do you mean by "a little high" RPM? Could the recent drop in ambient temperature perhaps be the cause? Your oil will be like treacle on a cold November morning.
n.b. I have never quite managed to determine at what pressure the standard PRV should open.
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Q2: Rob, my understanding of the PRV is that as long as everything else is functioning correctly it does not affect the oil pressure - it is only there to offer an "escape route" if the oil cannot circulate freely. Once the oil is warm it shouldn't be able to increase the pressure.
The engine needs to be thoroughly warm before the pressure reaches normal (several miles for me at this time of year). If it's still high you must have a blockage somewhere else. If this is the case I have once cleared a blockage in the gallery by spinning the engine over on the starter with the jet cover-plugs out. Messy but effective!
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Location: Sherwood Forest
Car type: 1938 Talbot Ten Airline
I use a traditional oil - SAE40 in summer, SAE30 in winter - and it will usually take around ten miles before the oil is up to temperature and the pressure stabalises; once there I reckon on around 1psi per 10mph (a bit higher for a 3-bearing engine). I imagine using a multigrade oil will produce slightly lower readings until up to temperature, but probably similar figures once hot.
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09-11-2021, 10:20 PM
(This post was last modified: 09-11-2021, 10:26 PM by Rpm.)
Thanks, Chris and Pete. Thought that was the case re, the PRV. My oil pressure drops to around 4or 5 once warm, and rises to 10 when revved. my jets are clean but may try Peter's idea also. thought mat PRV not opening. My oil stick suggests it's a little overfilled.
Rob
Mike, my standard 3 bearing engine has Morris gold film 20/50 engine internals are very clean.
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Location: North Yorkshire
Your oil pump may have been uprated. My saloon has an uprated pump and the oil pressure is a few psi more than I would expect with a standard pump.
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My (pressure fed) engine clocks 100 psi on start-up with an A7 PRV... which leads me to surmise it won't be doing much at 10 psi.
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As Chris observes the setting is somewhat academic, but has anyone ever found a recommended setting for jet fed cars. If ever apart worth checkingit not rusted shut.
I wish everything on my inherited "modern" was so accessible! Seven owners do not know when they are well off!
The oil gauge can function as a clutch slip indicator....
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Location: Peak District, Derbyshire
Car type: 1929 Chummy, 1930 Chummy, 1930 Ulster Replica, 1934 Ruby
It's worth remembering that for eight years after its introduction, the only oil pressure indication one had was a button sticking out of the dash. For the oily-hypochondriact the difficulty lay in getting an accurate reading using a vernier caliper, especially when traversing a bumpy road. Of course. at night, the problem was solved by measuring, at the end of the journey, the extent of the oil stain on one's trousers.
