peejay4A Posted July 21, 2014 Report Share Posted July 21, 2014 Gaps all in line? Quote Link to post Share on other sites
Peter Cobbold Posted July 21, 2014 Report Share Posted July 21, 2014 (edited) Check the plugs - pull in after cresting the smoking hill. Oil passing the rings should show up. Frankly at 1pint of oil or so in 10 miles its amazing the plugs still work. Plug reading: http://brianesser.com/technical-information/the-ultimate-guide-to-spark-plugs/ #2: http://www.dansmc.com/Spark_Plugs/2.html If the plugs are fine then dont drop anything 'til we've talked this over more. Peter Edited July 21, 2014 by Peter Cobbold Quote Link to post Share on other sites
Guest ntc Posted July 21, 2014 Report Share Posted July 21, 2014 Gaps all in line? Maybe but I would go for oil control ring's over lapped Quote Link to post Share on other sites
AlanT Posted July 21, 2014 Report Share Posted July 21, 2014 If we are to correct;y guess what is wrong with this, we need a lot more detailed reporting of exactly when and why the smoke is produced. Can you drive about and never make any smoke. If so what is the oil consumption then? If you drive in 3rd gear can you make smoke? Can you get any smoke in first gear? In other words is this related to revs or torque? Can you produce/stop smoke at will? If so exactly what are you doing? Does the oil burning continue at the same rate as the level in the sump falls? Or does it fall off as you get to half full. Are there any rumbling/rattling noises when you first start up after a period without running? Does adjusting the relief valve give a predicable effect? Is water consumption negligible. Are there bubbles or oil in the water? What make of pistons did you fit? Did they come with rings on them? If not where did you get the rings? Quote Link to post Share on other sites
Paul Down Posted July 21, 2014 Report Share Posted July 21, 2014 If the engine only appears to burn oil when going up hill is this a clue? Either it burns because the engine has to work harder or possibly because the oil level in the sump rises up at the back. Quote Link to post Share on other sites
Geko Posted July 22, 2014 Report Share Posted July 22, 2014 (edited) One clue could be that "blue" smoke coming from the rocker cover (i would rely more on my nose than on my eyes to ascertain if this is oil): It is either direct compression or blow-by gasses or both but either way it shows that oil is actually burnt(ed) in the combustion chamber, not outside. The most likely causes are loose valve guides or faulty oil rings. As there are no stop pegs in the ring groves, rings do move around and do line up every now and then even when staggered on assembly but this would only cause marginal oil drag in the combustion chamber but never result in a blue cloud as described. Faulty oil rings i.e. with weak tangential load could cause both oil being dragged in the combustion chambers on compression and burnt oil residues to mix with the blow-by gasses on power and exhaust especially when torque is called for. Also look at what type of valve guides have been installed, I recall that bronze guides are a bit particular to handle. The above also make the case for multiple faults, hence given the high oil "loss" I would look at issues occurring across all 6 cylinders, not just 1 or 2. Edited July 22, 2014 by Geko Quote Link to post Share on other sites
John L Posted July 22, 2014 Report Share Posted July 22, 2014 Is there not a restrictor in the rocker shaft, if its not there then there will be lots of oil at the rockers and will also lower the overall oil pressure, as there is no restriction. Could also be the second piston ring as these are tapered at the bore surface, they are usually marked top on them and sometimes fitted in the top ring position, and should act like a bore scraper to scrape the oil back down in its proper second position. Could also be the shells with too big a clearance, and the oil is flooding out and the rings cannot cope with the excess oil being flung about. Will be really interesting to know what the culprit is. John Quote Link to post Share on other sites
peejay4A Posted July 22, 2014 Report Share Posted July 22, 2014 ^^ What John said. Is the plug present in both ends of the rocker shaft? Quote Link to post Share on other sites
Peter Cobbold Posted July 22, 2014 Report Share Posted July 22, 2014 Post #1 : "I used from the top oil dip stick mark to the bottom mark in 5 - 10 miles." That has got to show up on plug(s)-surely ? Yet there's no mention of plugs needing changing. And after leaving to cool and topping up oil it runs fine at 50mph using hardly any oil. I doubt those symptoms reflect that much oil burning in the combustion chamber(s). Peter Quote Link to post Share on other sites
billy l Posted July 22, 2014 Report Share Posted July 22, 2014 I can't believe that much oil is being burnt in the combustion chamber without causing missfire and fouling the plugs, is the oil somehow getting into the exhaust flow by some weird thing going on? (porous head, crack in head,) But why only going up hill?. I would remove manifold and have a good look. Quote Link to post Share on other sites
Peter Cobbold Posted July 22, 2014 Report Share Posted July 22, 2014 (edited) I can't believe that much oil is being burnt in the combustion chamber without causing missfire and fouling the plugs, is the oil somehow getting into the exhaust flow by some weird thing going on? (porous head, crack in head,) But why only going up hill?. I would remove manifold and have a good look. +1 If a late-type gasket designed for recessed block was used on an early block the chambers would seal OK ( I guess) but the oilway may not. That could allow oil to escape and spread around in the gap across rear of the block/head joint.. Perhaps in level running at 50mph it drains into the pushrod holes. But at 70mph and uphill it escapes at the other side of the block onto the exhaust manifold. But oil should also appear in the rad, and coolant would escape too. Dunno. Puzzling. Would dealry like to see the plugs. Edited July 22, 2014 by Peter Cobbold Quote Link to post Share on other sites
Rob Salisbury Posted July 22, 2014 Report Share Posted July 22, 2014 +1 If a late-type gasket designed for recessed block was used on an early block the chambers would seal OK ( I guess) but the oilway may not. That could allow oil to escape and spread around in the gap across rear of the block/head joint.. Perhaps in level running at 50mph it drains into the pushrod holes. But at 70mph and uphill it escapes at the other side of the block onto the exhaust manifold. But oil should also appear in the rad, and coolant would escape too. Dunno. Puzzling. Would dealry like to see the plugs. Peter, have seen this experiment carried out first hand (a friend did this on a 2000 saloon), ...... coolant goes everywhere, a mechanical fountain!!, quite spectacular!! ..... how about the oil/fuel seals in the Pi distributor pedestal giving up under duress? after all you don't need a lot of oil in the petrol to give a good smokescreen Cheers Rob Quote Link to post Share on other sites
Peter Cobbold Posted July 22, 2014 Report Share Posted July 22, 2014 (edited) Peter, have seen this experiment carried out first hand (a friend did this on a 2000 saloon), ...... coolant goes everywhere, a mechanical fountain!!, quite spectacular!! ..... how about the oil/fuel seals in the Pi distributor pedestal giving up under duress? after all you don't need a lot of oil in the petrol to give a good smokescreen Cheers Rob Rob, Nothing convinces me more than an experiment - the more spectacular the better. !!! So you have ruled out gasket mismatch. Oil in petrol - but the oil would have to get into petrol up a pressure gradient. Can the oil pump be fitted to pressurise the MU pedestal with oil? I've never heard of that, but this is a weird engine so...? The reverse flow, petrol leaking on to the sump? Apart from exploding sumps I dont know what that would do to make oil smoke. The rocker vent tube is going to atmosphere I think, not back into the filter or manifold. Peter Edited July 22, 2014 by Peter Cobbold Quote Link to post Share on other sites
Rob Salisbury Posted July 22, 2014 Report Share Posted July 22, 2014 Peter, the normal vent from the rocker cover goes through a little flame trap and then into the air intake,manifold, plenum thing down stream of the air filter, so the engine eats it's own blow-by. Yes, 70psi oil against 100-108psi petrol is not going to win, so that wont work, although fuel thinned oil would give lower oil pressures .... still think it's the oil control rings, hope we get a blow by blow account of the strip down Rob Quote Link to post Share on other sites
Peter Cobbold Posted July 22, 2014 Report Share Posted July 22, 2014 Peter, the normal vent from the rocker cover goes through a little flame trap and then into the air intake,manifold, plenum thing down stream of the air filter, so the engine eats it's own blow-by. Yes, 70psi oil against 100-108psi petrol is not going to win, so that wont work, although fuel thinned oil would give lower oil pressures .... still think it's the oil control rings, hope we get a blow by blow account of the strip down Rob Rob Normally yes, but he has K&Ns and said the hose 'goes to air'. Cant make out why the OP hasn't inpected the plugs. Elementary first step on any engine inspection. Peter Quote Link to post Share on other sites
Andy Moltu Posted July 22, 2014 Report Share Posted July 22, 2014 +1 If a late-type gasket designed for recessed block was used on an early block the chambers would seal OK ( I guess) but the oilway may not. That could allow oil to escape and spread around in the gap across rear of the block/head joint.. Perhaps in level running at 50mph it drains into the pushrod holes. But at 70mph and uphill it escapes at the other side of the block onto the exhaust manifold. But oil should also appear in the rad, and coolant would escape too. Dunno. Puzzling. Would dealry like to see the plugs. Had this on a Spifire - when a gasket set had the wrong head gasket in - the coolant pours out so not the likely reason for the oil consumption. Quote Link to post Share on other sites
boxofbits Posted July 22, 2014 Report Share Posted July 22, 2014 Still not sure why you burn off enough oil to have negligible oil pressure on tickover, so I wouldn't take the dipstick theory as read. Does it purge all the oil eventually or just some of it? It will usually burn off excess only if overfilled. Quote Link to post Share on other sites
peejay4A Posted July 23, 2014 Report Share Posted July 23, 2014 ^^ The OP doesn't relate the low oil pressure to the amount of oil in the sump so the assumption is that it remains low whether oil is burnt or not. Or did I misunderstand? Quote Link to post Share on other sites
snowric Posted July 23, 2014 Report Share Posted July 23, 2014 Have you taken your rocker cover off yet to check in there? Pull the breather off first - is there loads of oil in there ? If so check plugs in rocker shaft as suggested and check oil feed rocker pedestal is securely fixed - a leak here or from the rocker shaft would deliver a load of oil to the engine, impact oil pressure and cause the breather to feed lots of new running in oil into the cylinders ! Good luck. Snowy Quote Link to post Share on other sites
Dave Burgess Posted July 23, 2014 Report Share Posted July 23, 2014 Peter NTC, and Andy M have almost certainly got your oil consumption problems identified with incorrectly fitted oil rings, with one addition. All rings have tapered edges, they should scrape down and glide up, if you've put the rings in upside down you will be pumping oil in the quantities you've described up the bore and out through the chimney. Head and sump off i'm afraid, can be done with engine in the car. You can then check all your potential OP problems at the same time. Dave B Quote Link to post Share on other sites
Wimbleball Posted July 23, 2014 Author Report Share Posted July 23, 2014 Hi In answer to a couple of questions: - I can drive about in 4th and 3rd without producing blue smoke, its if I give it lots of power I get the smoke. I took the rocker cover off, but it wasn't swimming in oil. Having said that I was not using lots of power going through the village so it may have had chance to drain back. Missfire: I had driven at 70mph on the motorway for about 18miles when I got to the bottom of Halden hill (near Exeter). It is quite a steep hill and I tried to keep at 70. About half way up the hill is when I produced a plume of blue smoke enough to cover a 3 lane road (and a lot of the opposite side as well). I did have a misfire, so much so that I dropped to 45mph and had to go into 3rd. When I go over the top and started to go down the other side the missfire cleared and the blue smoke lessened. The smoke kept coming for a greater or lesser extent depending on if I was using power. On the return trip I kept to 50 and hardly used any (about a 1/4 of the dip stick). When Ichanged the oil, to check I had not overfilled, I noticed I had assembled the spin on oil filter adaptor incorrectly. I had assembled it with the plunger pushing against the adaptor, not the block. That is now assembled correctly but has made no difference. Forgot to check the plugs in the end of the rocker shaft when I had the rocker cover off, but I bought a reconditioned rocker assembly from Rimmers so assumed it would be correct. I will check when I take off the rocker cover again. Even though the engine is burning oil it sound sweet, with no rattles as someone asked. Again, the plugs were sooty, not oily, but as I said before, I'm not powering through the village so they may have chance to clear. Quote Link to post Share on other sites
Andy Moltu Posted July 23, 2014 Report Share Posted July 23, 2014 If it's an oil control ring it may well run reasonably well unless the plugs foul up. Perhaps not as well as it might because the inlet charge will be contaminated. Compressions should be fine as the oil control rings contribute little, if anything to this, and so you won't get too much breathing via the rocker cover. How do you tell whether the oil control rings are assembled properly? - That depends on the manufacturer some have dots stamped into them to indicate top/bottom but come in a variety of forms sometimes with coloured markings to indicate which way up and how to assemble. Quote Link to post Share on other sites
Guest ntc Posted July 23, 2014 Report Share Posted July 23, 2014 The middle segmented ring has been fitted wrong and is over lapping. Quote Link to post Share on other sites
Peter Cobbold Posted July 23, 2014 Report Share Posted July 23, 2014 I agree now its rings. 1pint in 10 miles oil consumption was difficult to believe burning. Peter Quote Link to post Share on other sites
AlanT Posted July 23, 2014 Report Share Posted July 23, 2014 What you didn't say was where you got the pistons and rings. I bought pistons and the rings came fitted to them. If you bought these items separately can you tell use how you selected them and anything else you know about them. I find defective oil pumps produce a distinctive rattling when you first start, because they dont get the oil round quickly enough. Listen for this. Quote Link to post Share on other sites
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