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Post by anklesn on Aug 22, 2015 12:39:14 GMT
Hello just had a recored radiator put in as old one split. My mechanic has sorted out sticky choke and throttle and now has the car idling at 600rpm! Very sweat and gear change clunk now gone, box changes really smoothly, but I have noticed for the first time that the oil pressure is on low. Previous to this oil pressure very good but car was idling at 1200rpm. any suggestions welcome thx v much.
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Post by eightofthem (Andy) on Aug 22, 2015 16:16:56 GMT
V8 engines are notorious for low oil pressure at idle, and the gauges are also not the best, how are the other gauges reading?
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Post by anklesn on Aug 22, 2015 19:42:39 GMT
Hi Andy thx for your reply. Amp meter needle flicks between 0 and the first mark on the minus side. There is a new battery in. Temp gauge around normal dead centre. As I say since I bought the car the pressure has been fine this has only happen since the new rad and idle speed being brought down from a reducuously high 1200-1300. Thx
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Post by lagain on Aug 22, 2015 20:54:17 GMT
Does the oil light come on ?
My car also ticks over at about 600 RPM and when it is hot the green light comes on when stationary in traffic. When cold at 600 RPM the needle stays in the middle and no green light. So the problem is with the oil getting thin. The pressure is created by 2 gears that run at engine speed so at 600 RPM they are not turning very fast.
The advice from Rover was that if the oil pressure was OK once the car is moving there is no problem.
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Post by anklesn on Aug 22, 2015 21:29:34 GMT
Hi thx. No the oil light so far has not come on and whilst driving the pressure seems to move towards Low and back up a little when idling. When I mentioned it to my Mechanic he said he felt it was because the car is idling much lower than before. I am going to ask him to raise it a little to around 700 to ensure it does not roll back on hills which it does a tad on steep hills. Thx again
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Post by guidedog on Aug 23, 2015 9:28:40 GMT
The V8 block is generally low A rough guide is 10lb pressure to every 1000 revs. If you are ticking over at 500/600rpm the oil light will come on as the oil pressure switch is normally rated at 8lb's.
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Post by enigmas on Aug 23, 2015 10:06:17 GMT
What viscosity oil are you using? Idle at 600 rpm is probably too low, as once you select D the idle speed will drop further.
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Post by lagain on Aug 23, 2015 15:52:22 GMT
Hi thx. No the oil light so far has not come on and whilst driving the pressure seems to move towards Low and back up a little when idling. When I mentioned it to my Mechanic he said he felt it was because the car is idling much lower than before. I am going to ask him to raise it a little to around 700 to ensure it does not roll back on hills which it does a tad on steep hills. Thx again Do you know that if you put the gear lever into '2' the car will not roll backwards, then just knock it back into 'D' as you move off. I use Millers classic sport which is a semi synthetic 20/50, it is a bit disappointing that it does not stay 'in grade' when hot. I have used semi synthetic since my engine was rebuilt about 20 years ago. If an engine is used to a 20/50 mineral oil it is not a good idea to go to a semi synthetic as the cleaning agents in the semi syn. can cause problems. Before I had my engine rebuilt I had a high volume oil pump, which was just deeper gears and a spacer and helped with pressure at tick over - do people still use these ?
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Post by guidedog on Aug 23, 2015 16:05:52 GMT
Yes I upgraded. But I also installed a mechanical oil gauge which gives me a better reading. In drive I read 600revs oil light flickers, the oil transmitter breaks at 800revs. I don't like the light on but its something I will live with until October when I start a major engine upgrade.
Some owners have upgraded to post 76 SD1 blocks which already have the more efficient pump.
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Post by anklesn on Aug 23, 2015 21:01:00 GMT
I don't know what oil is in at present. I have bought some Penrite Lite, shall I just do an oil change and then adjust tickover to around 650 -700 and see if pressure goes back up. Thx again
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Post by petervdvelde on Aug 23, 2015 21:59:28 GMT
i have an MGB with a RV8 3.5 SD1 engine which i rebuild and this idles at approx 600 rpm and it under all circumstances shows a healthy oil pressure (middle of the scale). My Rover P5B idles at 700 RPM and when warm is just in the green area. The engine feels healthy and doesn't use much oil I agree with statements that oil pressure when idling can be low and that you don't need to worry and that the car still has lots of miles to go and as long as the oil light doesn't light up there is not much to worry about
Peter
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Post by anklesn on Aug 23, 2015 22:16:42 GMT
Thx all for some great info. I will report back once I've had idle increased. Thx again
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Post by enigmas on Aug 24, 2015 1:25:24 GMT
Take a look here: www.penriteoil.com.au/products-categs.php?id_categ=14&id_subcateg=69If you're concerned with the oil light 'winking' at idle, move to the next range of oil, i.e., Penrite Classic Medium 25W/70. You could also fit an accurate mechanical oil pressure gauge in the engine compartment to see what's really occuring during 'hot' idle. The end plate on the pump may be scored (this increases the pump gear end play...resurface the plate and refit with the thinnest gasket available or self made A4 computer printer paper)
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Post by johnwp5bcoupe on Aug 24, 2015 8:56:28 GMT
I converted to Penrite a couple of years ago Vince not the cheapest over here but I wont use anything else now
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Post by Deleted on Aug 24, 2015 9:27:33 GMT
I converted to Penrite a couple of years ago Vince not the cheapest over here but I wont use anything else now John, what grade do you use? The Comma I use is 20/50 and I think I burn a bit of oil on the overrun. I think I'll try Penrite next change. Perhaps I should try a 25/70 to add a bit of thickness at the top end of the viscosity when the engine is hot. Perhaps the 20/50 is too light.
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Post by enigmas on Aug 24, 2015 9:50:00 GMT
Penrite is the 'good ' stuff John. We're lucky over here as it's an Aussie company. I use it for my classic bikes & cars. I believe a lot of classic car owners have forgotten about the need for ZDDP for flat tappet engines like the Rover V8. Penrite prints this prominently on their oil containers.
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Post by johnwp5bcoupe on Aug 24, 2015 11:18:36 GMT
I converted to Penrite a couple of years ago Vince not the cheapest over here but I wont use anything else now John, what grade do you use? The Comma I use is 20/50 and I think I burn a bit of oil on the overrun. I think I'll try Penrite next change. Perhaps I should try a 25/70 to add a bit of thickness at the top end of the viscosity when the engine is hot. Perhaps the 20/50 is too light. I use the Classic Light 20/60 Richard and have had no problems
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