Fen Posted October 21, 2016 Share Posted October 21, 2016 (edited) Hi Guys, i just thought id throw it out there and see if i may be able to move towards a solution. Car Background : She is an Azure blue 05 roadster non rev-up de motor, has done 62,000 miles with fantastic service history. Of the 40-odd various cars i have owned, by far the tidiest. list of mods include: full de-cat stainless exhaust (hence being able to notice smoke) plenum spacer air induction pipe and cone filter baffled oil catch can. Symptoms: a rather large amount of blueish smoke on start up, clears after 30 seconds or so. (park nose up, not too much, park on the flat, a fair bit, park nose down, quite a lot. front 2 plugs rather gunked up, mid 2 plugs a litte gunked and rear 2 plugs looking fine) drives and pulls faultlessly not missing a beat. after standing in traffic on tick over, puff of smoke when i set off, nowhere near as much as cold start. no smoke after a warm start has used 3l of oil in 1300 miles and decreasing. started about 2 months ago, steadily getting worse. spark plug holes are dry Recent service items (within 2000 miles) Fuchs Titan Pro S 5w30 oil K&N oil filter new iridium plugs new pcv valve (even though old one seemed to work with the suck/blow test) Todays work/findings with how the car seems to be smoking i was leaning towards it being a valve stem seal issue, so i took it upon myself to get an ebay borescope and dive in to check whats going on in the pots. I drove her to the garage last night, ( some spirited driving and no noticeable smoke either) to make sure that any liquid oil had been burnt off. left the car over night and dig in taking the coil packs and plugs out today. using my borescope i wanted to check see if any oil had migrated into the cylinders overnight. as expected i did find some oil in there. obviously not on top of pistons, because of being canted over for the V. all oil was seen on the outboard side of the bores. (photos attached). one thing that did surprise me is that all of the cylinders had wet pools of oil, to varying extents. the amount of oil seen relates to the condition of the plugs as above, forward 2 cylinders, quite a large amount of oil, lessening for the mid cylinders and even less in the rear, but both banks appearing pretty much equal. i did a cold compression test whilst i was there just for peace of mind ( i know it wont give me an idea oil consumption) the results were very consistent at 150psi per cylinder. My ponderings i am by no means a qualified mechanic, however i am an aircraft engineer and am relatively competent at undertaking most jobs on cars, even though it takes a while and many, many cups of tea. my reasons for thinking it is the valve stem seals is the fact that the car was laid to rest last night hot, no smoke, which would suggest to me that there would be no wet oil in there (burned off) and over night oil has seeped into the bores past the valves via potentially knackered valve seals. and the fact that this was not a sudden issue but had been worsening over the past few months. deteriorating rubber seems to do that kind of thing from my aircraft experience, until it finally decides to fall apart. i dont think oil could have crawled up past the pistons and rings over night because of two reasons 1, gravity and 2, i didnt park my car on its roof (or lack of). i have tried to explain the situation as best i can, and was hoping that some of you more knowledgeable Z-ers may be able to either correct me if im wrong or advise on the next course of action. i could just about justify the cost of of a valve stem seal replacement, definitely not a rebuild though, would rather take her off the road and do an LS1 corvette conversion over the nest couple of years, haha. Questions: if tackling the stem seals, would there be anything else to renew/ check whilst im in amongst the timing gear etc? to minimise cost was thinking of doing the job in car with heads on by using the Jim wolf technologies valve spring tool, does anybody have experience with these? have one for rent? once the timing covers etc etc are off what seals, gaskets etc would i need for camshafts etc, and where is the best place to source them? OEM valve seals or the uprated ferra ones? autodata says 6 hours to do the job, is this per bank? and is it realistic? is there anything i have missed? what happens if i have a bolt left over? haha anyways thanks for reading through this not too short post. I tried to give as much information as i can at the mo to accept some good advice I eagerly await your replies, thanks Fen Edited October 21, 2016 by Fen 1 Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted October 22, 2016 Share Posted October 22, 2016 (edited) Have you run compression and leak-down tests? to check if its ring related first, stem seals are usually most apparent on cold start, however its the same for worn piston rings, you would likly see smoke during overrun due to both conditions though, which make for hard diagnosis. Edited October 22, 2016 by Tricky-Ricky Quote Link to comment Share on other sites More sharing options...
Fen Posted October 22, 2016 Author Share Posted October 22, 2016 I run a cold compression test, all seemed good, didn't have equip for a leak down test. It's the oil that's appearing in the bores overnight that's the concern, a 10w40 oil is going in today just to see if there's any difference in smoke and consumption Quote Link to comment Share on other sites More sharing options...
Alpinaman Posted October 22, 2016 Share Posted October 22, 2016 Thats also a lot of oil to use.. The only other thing i can think of is if the crankcase breathing system is blocked in some way.. Im not particularly familiar with the engine myself..so not sure how it works on this engine,but oil due to crankcase pressure can be pushed into the manifold.. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted October 22, 2016 Share Posted October 22, 2016 The fact that it seems to be appearing on the top of the pistons over night would indicate the stem seals, however it would only happen on the cylinders with open valves, and also the drains on the follower buckets would have to be blocked to get any appreciable amount of oil, The idle/low load side of the PCV system (the one with the one way valve) tends to generate the most oil vapor, which is why most fit a catch can to stop the accumulation of oil pooling in the plenum, The high load side witch is unregulated, and operates via the intake vacuum at larger throttle openings is the one which is more important, but seldom gives trouble. Quote Link to comment Share on other sites More sharing options...
Fen Posted October 22, 2016 Author Share Posted October 22, 2016 i understand what you're saying, i have already been through the pcv system as you mentioned and have installed a baffled catch can in the idle/low side. just dont really know what tack to take, risk forking out to do the stem seals and potentially not cure the underlying problem Quote Link to comment Share on other sites More sharing options...
Fen Posted October 23, 2016 Author Share Posted October 23, 2016 Well, after some more investigation, it's looking more likely to be the oil control rings...not a happy bunny. So new question is, can I get new rings fitted for sub £1500? Or buy a low mileage engine out of a car at a breakers? Quote Link to comment Share on other sites More sharing options...
ZMANALEX Posted October 23, 2016 Share Posted October 23, 2016 If the rings have gone then you will more than likely find that the piston ring glands will be damaged as well, which will mean new pistons. So if you replace the pistons and rings and hone out the bores, fit new main bearings and big end bearings, together with a gasket set. etc etc etc.then you will be well North of £1500.00. You will have to strip the motor to fully assess the damage. 1 Quote Link to comment Share on other sites More sharing options...
Fen Posted October 24, 2016 Author Share Posted October 24, 2016 that's what i was worrying about i have a friend in the trade trying to find me a motor, i have found one with 61,000 of the shelf at a breakers for £1300 with a 30 day warranty. would much prefer to see it running first. its a real shame because the rest of my car is mint. if i could get the thing sorted for less than 2k, it will prevent me sticking some cats on it and rolling it to a dealers and exchange it out for something else.... had one offer of 5K, but it defeats the whole object of me getting the thing. if you hear of a motor or such out there i would be very grateful. i believe you are the go to guy for bits and advice, nice to make your acquaintance. Quote Link to comment Share on other sites More sharing options...
ZMANALEX Posted October 24, 2016 Share Posted October 24, 2016 Have you ruled out valve stem seals and/or valve guides ? Quote Link to comment Share on other sites More sharing options...
Fen Posted October 24, 2016 Author Share Posted October 24, 2016 (edited) not completely, although the symptoms are pretty much still the same as my original post, just varying in severity when she feels like it. today, masses of smoke on start up, not so much whilst driving about. i managed to get my borescope back into a couple of cylinders and managed to get it point upwards with a piece of string. looking at the valve faces they seem carbony but dry, i would expect to see them darker black if they were wet with oil. the latest oil consumption news as of saturday is about 220 miles over 2 weeks = 1.5l of oil. im trying a 10w40 in it see if it makes any difference. it seems to be getting notably worse every day but the car still drives fine and smooth tickover etc. would stem seals and guides equate to that much oil loss? bearing in mind, the car is bone dry underneath so no external leaks you don't happen to have any cats available do you? Edited October 24, 2016 by Fen Quote Link to comment Share on other sites More sharing options...
ZMANALEX Posted October 24, 2016 Share Posted October 24, 2016 1.5 litres of oil over 220 miles, I would definitely be expecting to see excess emissions whilst driving, especially with decats. Sorry, fresh out of pre owned DE cats at the moment. Quote Link to comment Share on other sites More sharing options...
Ewen@Clark Motorsport Posted October 25, 2016 Share Posted October 25, 2016 We have a pair of used CATS here if its of any use 1 Quote Link to comment Share on other sites More sharing options...
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