| Author | Message | ||
     Nigel A Ralph Unregistered guest Posted From: 85.202.191.203.dynamic.qld.chariot.net.au |
Hi all I know I seem to ask some obvious questions now and again but my knowledge of the basic fundamentals is a little bit lacking. I am learning however and I do enjoy getting a full explanation so I can understand the science behind it all. I don;t want to admit anything ,but... what would happen if the engine oil was a tad low and when it was topped up an extra 1 or 2 litres of oil was added. The situation was that my oil was low and I added some. When I checked to see if it was right, the dip stick still showed low, so I added more. When it finally registered at the appropriate mark I left it ,but the next day when I drove off I got a huge shock at the amount of blue exhaust smoke and returned it too the garage. When I rechecked the dipstick it showed a bit over a centimetre above the max mark so I had to drop some oil out of the sump. Have I done damage? Why the difference in oil level when adding oil, to after driving? (Message approved by david_gore) | ||
| Paul Yorke Frequent User Username: paul_yorke Post Number: 71 Registered: 6-2006 |
Hi Nigel, probably no lasting damage. The main problem with the V8 is that,in effect, you add the oil to the rocker gallery. There are only small drain holes that allow the oil back to the sump. The oil you pour in goes to the gallery but then can take about 10 minutes to drain down into the sump. Especially when it is all cold. This gives the lag between you adding the oil and the final reading on the dip stick. Pour it in very slowly and leave more time for it to settle. Regards, Paul. | ||
| Nigel A Ralph Unregistered guest Posted From: 128.202.191.203.dynamic.qld.chariot.net.au |
Thanks Paul My major concern was with the blue smoke that came out. I live below a hill which the car has to struggle up first thing in the morning. The oil on the dipstick is about 1.5 cm above the Max level. Should I drop a litre or two out of the sump? Does the extra oil damage anything? (Message approved by david_gore) | ||
| Paul Yorke Frequent User Username: paul_yorke Post Number: 72 Registered: 6-2006 |
Nigel, When you said, 'so I had to drop some out' I assumed that you had already drained the extra out and it was now to the level! Never leave excess oil in the engine and don't drive it with excess oil waiting for it to burn off. ( If you overfill at a service station , then need to drive somewhere to drain it, then that's OK ) Drain it out when it's cold. Drain about 3 litres out then add it back to the correct level. | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 1284 Registered: 4-2003 |
Nigel, Only your pride is damaged. As a remark or two, let me offer the following. York Motors in Sydney recommended that the level be maintained at half to three quarters between the marks when the SYs were new, and even shortened some dipstick tubes and adjusted the float level to show Full at that level. This was to reduce that occasional drip from the rear main bearing oil scroll. Following present practice and following the advice of Cal West, I replaced the scroll by a Silver Spirit etc PTFE lip seal and housing on our '72 around 1989, and it is happy with the oil level full now. It is utterly leak free. Although highly undesirable, an overfilled sump only causes danger as such if it seriously overfilled to maybe 6 litres or more above full. In that case, on extended heavy braking the oil surge can cause the forward pistons to crash into the oil possibly causing piston breakage. An overfilled sump will barely affect blue smoke unless the motor has very badly worn pistons or rings, something quite unusual in these cars. What affects blue smoke and oil consumption enormously is the state of the valve stem seals. Believe me, the original asbestos-rope-wax type is utterly useless after a few thousand miles. Standard practice these days is to follow the Crewe bulletin issued in the 1980s for all postwar V8 cars and fit the stem seals of SZ cars from chassis 6751 around 1983. These are available from Crewe outlets, but some like Introcar now offer an even more improved type for all postwar cars and for some prewar cars, and at a much more favourable price. These seals, in most cases, stop blue smoke dead, extend valve stem and guide life, cut coking of and wear of valves, and eliminate oil consumption completely. A certain club member in Victoria will be doing this upgrade to his Silver Shadow II soon, and let's hope that he does a write-up with pictures. The change does not require the cylinder head/s to be removed. | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 1285 Registered: 4-2003 |
ps The big cloud of blue smoke on starting after filling or topping-up the oil is typical when the valve stem seals are shot as most are. The volume of oil temporarily in the B-Bank rocker while it drains after filling causes a fair quantity to dribble straight down the valve stems and to burn on start-up. Also, an accurate engine oil level reading can only be made at least 10 minutes after the motor has been left standing after being hot. The reading on a cold motor will be maybe 1cm lower, and will fall very low upon starting the motor for a minute, stopping and immediately measuring even when hot as so much is hanging around the top of the motor. A cold motor completely filled to capacity will usually read <minimum> on the button for the first 10 minutes while running. The button measurement on the gauge on most cars is fairly accurate, but only when hot, engine idling and the car level and not moving. | ||
| Paul Yorke Frequent User Username: paul_yorke Post Number: 73 Registered: 6-2006 |
Nigel, I would only recommend using the oil gauge button as a check. It's nice to check every time you start the car. Don't rely on it when driving a car you haven't had long. Once you are familiar with the car and KNOW for certain that the gauge matches up with the dip stick level. it is a very good indicator of the oil level. But really it is just an extra check. If you always check it before starting the engine , you will know where is sits on the gauge. If it deviates from it's normal position, it is definitely time to dip the engine manually. Otherwise keep checking the oil with the dipstick as normal. If your garage is level. Do it there before running the engine that day. When checking and topping up engine oil, wait for the level to drop towards the minimum level on the dipstick. You may find that it drops from the max level by (say) 5mm very quickly , but will then stay there for ages. Topping it up frequently to the maximum will be a waste. Try letting it find it's own level between the marks. If it keeps dropping at the same fast rate to minimum, then keep it higher towards the Max level. The best one we had was a customer who added 15 litres to his engine and the gauge still said empty. At least he stopped at that point and phoned us to check. A faulty transmitter wasn't sending a feed to the gauge. He didn't even know that the dipstick was there. Almost as good as a customer that complained how slow and difficult it was to top up the oil, so had popped by for us to do. His face was a picture when I opened the filler cap instead of trying to pour it down the dipstick tube - like the automatic transmission! | ||
| Nigel A Ralph Unregistered guest Posted From: 126.201.191.203.dynamic.qld.chariot.net.au |
Thanks Paul and Hi Richard Many thanks for your input. Without wishing to pee in your pocket Richard, I would like to compliment you on your very precise and profound knowledge of these magnificent vehicles. I had thought that my dipstick was a little strange as it didn't have a lower mark and the end seemed a little rough. Is it possible that mine was one of the 'shortened'ones you refer to? It was delivered to an R McDonald of Beecroft in July 1974 by York Motors. The blue smoke only occurred after I overfilled the engine with oil. Does this then fit with "the state of the valve stem seals" or could it be possible that my car is one of the unusual ones with very badly worn pistons or rings. Logic would tell me that blue smoke would have been visible from day one if this was so! but although I have much of my car's history, I do not have all and it could well have had an abusive owner at some stage. If ordering the parts do I just ask for "stem seals for SZ cars?" The replacement of these seems a highly desirable course of action in any case. (Message approved by david_gore) | ||
| Nigel A Ralph Unregistered guest Posted From: 245.203.191.203.dynamic.qld.chariot.net.au |
Hi Richard and Paul I do use the button check very regularly and although showed OK before I overfilled the engine, the dipstick didn't register so I panicked a bit. Paul, I'm not as bad as topping up 15 litres or trying to fill it through the dip stick so you have made me feel very positive about my efforts. I will drop a few litres out this weekend and try to get the correct level. Richard, the stem seals sound an excellent investment. (Message approved by david_gore) | ||
| bob uk Unregistered guest Posted From: client-81-108-177-215.brig.adsl.tesco.net |
A common mistake that is made with lots of engines is to check the oil level just after the engine has been run and assume it should be on the max mark. The only time (on most engines that is )that the oil level should be on max is when the engine has sat still overnight on a level road. If the oil is checked just after the engine has stopped the oil up the top of the engine will cause the level to be below the max mark. It is quite possible for an engine to hold a 1/2 to 1 litre in the top end. Providing the oil level when cold is between 1/2 min/max and max then no oil is required. However if I am about to do a longest journey then I will put it on max cold. Also do remember that oil expands when it gets hot. A small amount of overfill(say 1 litre) will not causes damage only a mess and maybe blue smoke. Top end lubrication !? On my car the oil filler neck goes to lower down than b bank rocker box. The Shadow is not a fast oil filler and glug backs are common which allows oil to go up the breather pipe which then gets sucked into the engine and ---blue smoke. I see no value in the oil level gauge apart from making you not actually look at the engine. Mine works fine but I still check the old way. I had a Rover P4 with the same oil gauge and that worked as well. When ordering parts you must have the vin number and explain what you want and ask about any up dates------ which is why I get my parts from the local RR gurus --they know everything. Also if the car is not smoking ( bearing in mind that a slight trace of blue on pulling away is common but never should any blue be present when moving) then I would suggest that the valve seals are left until it gets worse or the engine is worked on for other reasons such as a decoke. The seals should be present in a top end gasket set. The original fibre ones are not available in any case. (Message approved by david_gore) |
