cd.thomson
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| posted on 20/5/10 at 12:24 PM |
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oil pressure again
Currently got 15w/30 in my engine but not entirely sure what that means.
Its a C20XE.
The oil pressure gauge shows 4.5bar of pressure when cold but during IVA yesterday once up to temperature it was reluctant to show any pressure at
idle. Once some revs were on the pressure rose to 1-2bar.
Whats the craic? Sticking release valve, wrong oil or are the numbers okay?
Craig
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adithorp
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| posted on 20/5/10 at 12:37 PM |
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Are you sure its 15/30? Thats an unusual spec'; 5/30 would be more likely. If thats what you've gt it's a failrly thin oil. how many
miles are on the engine? 15/40 or 10/40 might be better.
adrian
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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cd.thomson
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| posted on 20/5/10 at 12:46 PM |
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loads of miles on the engine, not been rebuilt - straight from the donor.
I'm tempted to drop the oil now its been for a run out anyway.
is 10/40 thicker? so itll give me higher readings?
Cheers adrian, you've helped me out a lot this last fortnight or so!
Craig
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flak monkey
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| posted on 20/5/10 at 12:53 PM |
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10/40 will be better yes.
Sera
http://www.motosera.com
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philw
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| posted on 20/5/10 at 01:07 PM |
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10/40 is the correct oil for these engines
Must try harder
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cd.thomson
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| posted on 20/5/10 at 01:12 PM |
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ace, is it cheaper to buy oil online these days or from halfords with my trade card?
Craig
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02GF74
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| posted on 20/5/10 at 01:38 PM |
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quote:
Originally posted by cd.thomson
ace, is it cheaper to buy oil online these days or from halfords with my trade card?
halfords, 5l semi-synthetic £ 21 (but you get free screwdriver set limited offer ... but when I last bought this stuff about 1 year it had the same
offer; go figure ...)
tesco, 4l semi-synthetic, £ 16.
ignoring the free scredriver, then Tesco is cheaper; both own brand, probably fllled from the same tap at the BP depot.
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philw
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| posted on 20/5/10 at 01:51 PM |
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Tescos is only 20p a litre cheaper, i need some oil and some screwdrivers so it's off to Halfords for me.
Must try harder
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Charlie_Zetec
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| posted on 20/5/10 at 02:32 PM |
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10/40 is the correct oil to use, but if it's got high miles then I'd go with a 15/40 - I ran it in my Mk2 Astra GTE that had almost been
to the moon and back, and it never missed a beat.
Artificial intelligence is no match for natural stupidity!
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britishtrident
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| posted on 20/5/10 at 03:16 PM |
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Symptoms are consistent with a bit of big end bearing wear.
Although it could go on long enough like this it would be worthwhile dropping the sump and sticking a set of big end shells in and remove and the
suction filter and wash it in celluose gunwash thinners.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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rost
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| posted on 20/5/10 at 03:24 PM |
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My dad's 4AGE runs at 2.5 bar when warm too, on 10W40. Never thought it to be on the low side, should I be worried?
Charlie don't surf!
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adithorp
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| posted on 20/5/10 at 03:25 PM |
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For information so that you know what the numbers are...
Oil used to be of a single grade (ie, 30 or 40 or 50 etc) The higher the number the thicker the oil (gear oil is 90's). So a 50's oil had
lots of protection but was so thick that in winter you couldn't turn the engine over. So you put in a thin oil for winter (say 20's) then
had to change back to 50's in spring because 20's was too thin when hot in summer. Lot's of hasstle but the oil only lasted
1500miles anyway.
Along came Shell (I think) with "multigrade" 20/50. That (simplistically) behaved like a 20 when cold and a 50 when hot, or at least that
was the theory. As oils have improved they are able to protect better for any given viscocity and now new cars are running on what would have been
rediculously thin grades 40 years ago. So modern engines are on 5w/30 from new.
adrian
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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britishtrident
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| posted on 20/5/10 at 03:38 PM |
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quote:
Originally posted by rost
My dad's 4AGE runs at 2.5 bar when warm too, on 10W40. Never thought it to be on the low side, should I be worried?
Oil pressure is only relative ---- it is easy to get a too bit obsessive about oil pressure it is only when you get significant change in oil
pressure it is time to investigate.
Oil flow rate to the bearings is generally much more important than pump delivery pressure as the bearings depend on oil flow for cooling. The
actual pressure that keeps the bearings from making metal to metal contact with the crankshaft is generated hydrodynamically within the bearing, this
pressure is many times higher than the pump pressure.
[Edited on 20/5/10 by britishtrident]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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britishtrident
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| posted on 20/5/10 at 03:39 PM |
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quote:
Originally posted by adithorp
For information so that you know what the numbers are...
Oil used to be of a single grade (ie, 30 or 40 or 50 etc) The higher the number the thicker the oil (gear oil is 90's). So a 50's oil had
lots of protection but was so thick that in winter you couldn't turn the engine over. So you put in a thin oil for winter (say 20's) then
had to change back to 50's in spring because 20's was too thin when hot in summer. Lot's of hasstle but the oil only lasted
1500miles anyway.
Along came Shell (I think) with "multigrade" 20/50. That (simplistically) behaved like a 20 when cold and a 50 when hot, or at least that
was the theory. As oils have improved they are able to protect better for any given viscocity and now new cars are running on what would have been
rediculously thin grades 40 years ago. So modern engines are on 5w/30 from new.
adrian
5w/20 is now the flavour of the month it is being forced on the manufacturers by the environmental lobby.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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NS Dev
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| posted on 20/5/10 at 03:45 PM |
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sounds like sticking relief valve to me
Even with knackered big ends they usually show a bar at hot idle.
Pull the valve out, give it a clean out and reassemble and see what happens then.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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cd.thomson
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| posted on 22/5/10 at 09:15 AM |
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thanks for all the replies everyone
Craig
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