| Author | Message | ||
     Benoit Leus Prolific User Username: benoitleus Post Number: 260 Registered: 6-2009 |
My Shadow has always used some oil and it was always noticeable on start-up, especially if it had been standing. The valve stem seals have been replaced a couple of years ago. The car is used irregularly and mostly for very short journeys (not good, I know). I have now taken it to the Goodwood Revival, a 250mls, mostly motorway trip, cruising at 70-75mph. The weather was hot, but the car behaved impeccably. However, as it was getting dark, I saw exhaust smoke in the headlights of the car behind me, when I accelerated. On arrival, I checked the dipstick and found it right on the min level indicator, altough I had filled it up to the max before departing. I still use the same Castrol 20w50 I always use. I know this engine, at 120.000mls, is getting on a bit, but is this signalling a rebuild ? Benoit | ||
| Omar M. Shams Grand Master Username: omar Post Number: 788 Registered: 4-2009 |
Dear Benoit, what type of valve stem seals did you use the last time you replaced them? Did you use the rope ones or the green ones? If you used the rope ones - do them again. The green seals work very well. 120,000 miles is nothing for these engines unless there has been abuse in the past (which i doubt in your case). Thanks Omar | ||
| Robert Noel Reddington Grand Master Username: bob_uk Post Number: 1116 Registered: 5-2015 |
Add 500 ml of ATF to un gum rings. Check breather. 120k miles is not high miles. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 2064 Registered: 6-2009 |
I'm with Bob UK on the 120K miles is not high miles in any meaningful sense on a big V8 like the one in the Shadow. 120K should be "barely broken in," really. Also, be sure to check your flame trap and clean it thoroughly if necessary. I had an oil leak problem for years from the valve covers having gone so far as to replace the original gaskets, which did little to help. Little did I know how much pressure gets trapped if there is not free air flow through the flame trap to relieve it. If you have any noticeable oil leak at all you could be blowing a lot more out while moving and never even know it if your flame trap is completely clogged (or significantly clogged). Brian | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 1402 Registered: 5-2012 |
Benoit If the smoke on acceleration is visible only on a cold engine it could just be condensation in the exhaust pipe. i.e. water evaporating off as steam. What color is the smoke? white=steam, grey=oil, black= too rich a petrol mixture. If it is grey smoke and clearly visible on a hot engine on acceleration, I'd carry out a compression test on all cylinders to see if the piston rings/ cylinder bores are ok. Geoff | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 371 Registered: 4-2015 |
Benoit... Your concerns mimic those I expressed many months ago on my EPW Silver Dawn...exhaust smoke visible in headlights of cars to the rear at night coupled with oil consumption. Clearly (to me) that oil smoke that is being blown out the exhaust can come from only two sources...rings or valve seals...and my query at that time was as to a procedure to differentate between those two sources of oil into the combustion chamber. It has been my understanding that when the seals are bad, oil is drawn into the engine through those seals mostly under the suction created not when under acceration, but rather under throttle closed and decending a hill situations, and then blown out and visible upon subsequent acceleration. I wonder if this is similar to what you are noticing and if so, perhaps tends to lend credibility to the premise that it is the seals that are bad. | ||
| David Gore Moderator Username: david_gore Post Number: 2198 Registered: 4-2003 |
Another explanation - as you mentioned the car is normally used for short trips say 30 mins or less. Short trips where the engine spends only a short period of time at operating temperature are notorious for causing a build-up of water condensate in the sump [worse in cold climates]. If the engine burns some oil in normal use, the build-up of condensate can mask the loss of oil when using the dipstick to check the oil level. However, if the oil level is checked after a long trip such as you have done recently, the condensate will have evaporated leading to the low reading. This problem is one of the reasons why I suggest a car mainly used for short trips especially city driving should do a number of long trips of more than 2 hours duration at highway speeds together with regular checks of the engine oil level each year. | ||
| Patrick Ryan Grand Master Username: patrick_r Post Number: 498 Registered: 4-2016 |
Very interesting thread here gents. My car with 150,000 miles uses some oil, but would only require about 200mls once a month, and that is with regular driving both days every weekend. My car blows black smoke under lively acceleration, and can smell quite a bit rich from time to time. But I expect the richness on these carbs. I also expect the engine to use some oil at 44 years of age and 150k, but that useage I feel is quite normal. I use Penrite HPR30 20W/60 What I am interested in is the cleaning/servicing of the flame trap. Has this been covered on the forum in the past? | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 1403 Registered: 5-2012 |
Hi Patrick Keeping the flame trap clean on these cars is vital. Here is a great thread on the topic: http://au.rrforums.net/forum/messages/17001/16554.html Geoff | ||
| Benoit Leus Prolific User Username: benoitleus Post Number: 261 Registered: 6-2009 |
Gents, thanks for all your replies and help. The valve stem seals were replaced with blue ones from Introcar. I did the B-bank myself, the A-bank was done by a mechanic when he replaced the valves. I do not know the quality of his work. I cleaned out the flame trap +/- 2 years ago. I'll check it again this week. On start-up the smoke is clearly blue. I don't know what colour it is when accelerating, as I could only see it in the headlights of the cars behind me. It also smokes when hot (not on start-up). Would Penrite 20w60 reduce oil consumption compared to a 20w50 oil ? I'll try and do a compression check in the next few weeks. Benoit | ||
| Omar M. Shams Grand Master Username: omar Post Number: 793 Registered: 4-2009 |
Dear Benoit, I would be tempted to take a random seal out to see if the compound it was made from was a bad batch or perhaps if the mechanic didnt fit them all the way home. By taking one out you will have peace of mind with regards their condition and assurance that they have not lifted off their seats. Thanks Omar | ||
| Mark Aldridge Grand Master Username: mark_aldridge Post Number: 342 Registered: 10-2008 |
Benoit, would it be worth idling the engine for a few minutes, and then remove the sparkplugs and compare them. Any oiled plugs would identify the guilty cylinders ? Bob how long do you run the engine with ATF in the oil ? Mark | ||
| Jean-Pierre 'JP' Hilbert Prolific User Username: jphilbert Post Number: 152 Registered: 9-2013 |
Mark, I add 0,5 litre of ATF before each oil change, fill up the fuel tank and drive it for as long as that full fuel tank lasts, that is 300 miles, then drain the oil. My main objective of this exercise is to quieten the hydraulic lifters. This ATF trick is not specific to RR engines, works on any classic with hydraulic lifters. | ||
| Benoit Leus Prolific User Username: benoitleus Post Number: 263 Registered: 6-2009 |
Yesterday I cleaned the flame trap (it could do with a clean) and today I took the car out for a 130mls trip (it was a very hot day and traffic was terrible, so the oil will have been hot and thin). Oil consumption has improved somewhat, but still more than I'd like. I was quite surprised at the amount of oil dripping out from the flame trap and the tube when I took it out of the car. I'll try Bob's ATF idea and see if that improves matters. When changing the oil I'll use Penrite 20w60 instead of Castrol 20w50. If all that fails I'll follow Omar's advice and check the work done on the valve stem seals by the mechanic. Benoit | ||
| Robert Noel Reddington Grand Master Username: bob_uk Post Number: 1120 Registered: 5-2015 |
When warm 20/60 and 20/50 will be about the same thickness, so by all means change to 20/60 but don't expect a vast improvement. At least the engine is getting a shot of new oil often, its changing its own oil. I think given the amount of oil in the engine that 500ml of ATF could be left in until next oil change. If the smoke hasn't got better in 3k miles it the ATF is doing nothing. The ATF will get burnt any way and adding fresh oil will mean the ATF will be all but gone. ATF as Jean-Pierre said does make sticky high bollock wotsits better. The sweet spot for engine oil is 100c hot and 10 psi per 1000 rpm. so at 4500 rpm the pressure should be 45 psi. The RR V8 has a max pressure of 42 psi. Relief opens at 42 psi. At 100c heat 50 weight oil will be about 10 weight and 60 weight about 12 weight. To understand oil better go to Bob the oil guy on the web. | ||
| Mark Aldridge Grand Master Username: mark_aldridge Post Number: 344 Registered: 10-2008 |
Thanks Jean-Pierre and Bob, I presume the ATF has a detergent effect. Is this better than an engine flush additive prior to an oil change ? even on solid tappet engines ? Mark | ||
| Robert Noel Reddington Grand Master Username: bob_uk Post Number: 1122 Registered: 5-2015 |
I never use engine flush stuff after a diesel engine failure due to flushing oil. AFT is good as a release agent as well esp with acetone. Do not put acetone in engine though. Engine oil additives are like putting to many eggs in a cake one ends up with a mess. The oil makers oil recipe is not to be messed with. Also these engines require Zinc stuff in oil at 500 parts per million minimum or equivalent additive which is in the oil already so always take the advice of the oil maker as to suitability of your chosen oil, don't assume. Synthetic oil versus normal stuff. the difference is not as great as often stated by bar stool mechanics. Initially mineral and synthetic perform equally but as the miles build synthetic fairs better. By 6000 miles the mineral oil is worn out but the syn is still good to go. this is because 20/50 mineral starts off as 20 and viscosity improvers are added to give the 50 bit. These additives wear out and one ends up with 20 grade oil. Synthetic starts out as 50 and the additives give the 20 bit. So when syn wears it goes to 50 grade. Turbo charged engines MUST HAVE fully synthetic oil such as Mobil 1 because mineral will carbonize and block the oil ways in the turbo due to high temps. I use Castrol 20w/50 every 6000 miles. last oil change was 4 years ago. This is because I have a local agent who gives me a good price on Castrol stuff. Given that I don't use a lot I cant be bothered with cheaper oils. however for UK people Comma oils are good quality and cheaper than Castrol should one be a bit strapped for spondolics. Yes ATF can be used on solid lifter engines. My Jeep has a 4 litre straight six petrol engine with hyd. lifters and that has 500ml of ATF in in which stopped the idle rattle from the tappets. This engine is just as smooth as a RR engine. My Shadow is on LPG which is much kinder to engine oil. Note--- The colour of the oil is no indication as to its fitness. At university I was told that thicker oil is not good in engines and it causes problems rather than solve them. This tends to be counter intuitive to the lay men. Engine oil is part of the cooling system. | ||
| Larry Kavanagh Experienced User Username: shadow_11 Post Number: 15 Registered: 5-2016 |
I have been following this thread with interest. I noticed that my Silver Shadow 11 had been using slightly more oil than usual and I was topping up the level more frequently but there was no evidence of exhaust smoke. I removed the flame trap and discovered that it was slightly dirty but I could see through the gauze so it wasn't totally gummed up. I gave it a good clean and blow-through with compressed air and added 1/2 litre of ATF to the engine oil. First thing I noticed was oil pressure reading slightly improved. Having driven approx. 300 miles I notice that the engine has become appreciably more silent and the tappet noise that had been present beforehand has been virtually eliminated. Another thing I noticed since cleaning the flame trap is that the engine appears to start easier whereas beforehand it might cut out on initial start-up when cold and have to be restarted using more throttle. It's too early to say if my oil consumption has reduced but early indications are that it might have done. All in all I think flame trap cleaning and addition of ATF to the engine oil has been a very successful exercise based on my experience to date, in particular the tappets are noticeably quieter. It will be interesting to see what happens after I change the engine oil next week, I intend to use classic 20/50,just waiting on a filter to arrive by post. | ||
| Benoit Leus Prolific User Username: benoitleus Post Number: 266 Registered: 6-2009 |
After the car had been standing for 3 days I took out the spark plugs. I inserted a straw in each cylinder to check for oil. With 3 of the cylinders I picked up some oil. The A2 cylinder even proved to be my personal little oil well. This certainly explains some of the oil consumption, especially on start-up. Also I discovered a small drop of oil on the garage floor, the source of which I still have to locate. But the real eye opener was the state of some of the spark plugs. The spark plugs of the cylinders served by the left-hand carb were encrusted with a black carbon coating, especially the A2 plug. It's surprising the engine still idled so smoothly. The carbs have been adjusted in the past by a well known classic car specialist in the area. However, it's clear the left-hand carb mixture is way too rich an the right-hand carb mixture is slightly too weak. The inside of tailpipes also have a thick coating of black soot. This might explain some of the smoke on accelaration (which in daylight looks more grey/black than blue). And of course a lot of short distance driving will not have helped. So, I will now have to investigate the valve stem seals, the oil leak and find someone competent to adjust the carbs. Benoit | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 1410 Registered: 5-2012 |
Hi Benoit What I great time to teach yourself how to tune the carbs. However badly you do it, it's not going to be worse than it is now. Tuning carbs is not rocket science. It's just a case of balancing them first and then setting the mixture strength. A great tool for balancing the carbs is a Unisyn Carb balancer for around 30 bucks. There are many suppliers - here's one: https://www.summitracing.com/parts/edl-4025?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-edelbrock&gclid=Cj0KEQjwsO6-BRDRy8bsxfiV2bkBEiQAF8EzKGfqIacZoZb5bFeJC56XOahwiXQrvvvkz384hk1U27kaAiGI8P8HAQ Once you've balalanced the carbs just use the mixture screws to set the mixture. Geoff | ||
| Mark Aldridge Grand Master Username: mark_aldridge Post Number: 349 Registered: 10-2008 |
Benoit, is your shadow 1 or 2 ? If it is a 2, then check the carb floats are not sinking ! Had this problem on an early Spirit ( same carbs ) porous plastic float. Mark | ||
| Omar M. Shams Grand Master Username: omar Post Number: 807 Registered: 4-2009 |
Dear Mark, Benoit has a Shadow II. I also suffered two (no one) float problems. Both my floats (on two different SY-II cars) filled up with petrol. This is not an uncommon problem. Omar | ||
| Benoit Leus Prolific User Username: benoitleus Post Number: 269 Registered: 6-2009 |
Today I started on the job of replacing the valve stem seals on the A-bank of my '79 Shadow. In the past I had a mechanic do them (I did the B-bank myself). Well, I'm not surprised I have an oil consumption problem as the first valve stem seal I removed looked like this :  The inside is totally chewed up due to careless installation. I expect the other ones to look more or less the same. Benoit | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1673 Registered: 6-2006 |
Hi Benoit, You've probably noticed that the top of the valve guides have a sharp edge at the top where it is is chamfered to accept the string type seals. This edge should be ground off or turned inwards so the guide is not cut by the sharp edge when fitting or if they are knocked down too far. I think there are some photos on my Facebook page or my website so you can see more clearly what I mean. |
