rulloyd Posted September 22 Report Share Posted September 22 Hi all Is this normal? I had a fuel problem (blocked needle valves) which I’m fixing. Took the carbs off today and around the manifold opening seems very oily. And into the carb bore both sides. Smells of petrol but definitely not just fuel. Many thanks for all advice! Rich Link to comment Share on other sites More sharing options...
Keith Nock Posted September 22 Report Share Posted September 22 I would have thought its probably the dashpot seals leaking on the carbs they perish after a few years . I need to get mine sorts this winter Link to comment Share on other sites More sharing options...
johny Posted September 22 Report Share Posted September 22 I think more likely the vent pipes from the rocker box - oily fumes from sump plus a bit of piston blow by? Might be worth checking how much puffs out and what the compression readings are like.... 1 Link to comment Share on other sites More sharing options...
Pete Lewis Posted September 22 Report Share Posted September 22 i would agree overfilled dashpots or if CDSE leaking o rings on the needle adjuster Pete Link to comment Share on other sites More sharing options...
rulloyd Posted September 23 Author Report Share Posted September 23 Thanks all. The engine was reconditioned a few years back (still very low mileage) and I changed the diaphragms at the same time. The carbs are CD150 not CDSE. i will have topped up the dash pots fairly recently but have driven the car since then so if any oil were to overflow into the carb bore it would have long gone I presume? I broke down quite recently (unrelated, blocked needle valves) and the engine has stood idle for a couple of weeks since then. I noticed the oil when I took the carbs off to change the needle valves (and floats as coincidentally one was leaking). The oil was trapped on the manifold side of the butterflies (both sides) so suggests it’s engine related? Could a relatively new engine force oil down the breather (and get thought the emission control valve?). I should have a look in the U bend of the pipe into the manifold I guess. I’ll also check the diaphragms. Can oil seep into the carb bore on a CD150 past the diaphragms? Otherwise where does excess oil go? Thanks again. Rich Link to comment Share on other sites More sharing options...
rulloyd Posted September 23 Author Report Share Posted September 23 What does this hole do? 😬 Link to comment Share on other sites More sharing options...
Pete Lewis Posted September 23 Report Share Posted September 23 that to me is the temperature compensator air bleed , if you have it on a base cds i would assume its a blind hole or some how a later body has been used the throttle discs dont look centralised and the screws are best on the intake side so if they drop out you trap them on the safe side also check the discs are fitted the right way round so the chamfered edge completely blocks any air flow/daylight oil from over filled dashpots will exit down the air piston and run out the two holes in its bottom. Pete 1 Link to comment Share on other sites More sharing options...
johny Posted September 23 Report Share Posted September 23 2 hours ago, rulloyd said: Could a relatively new engine force oil down the breather (and get thought the emission control valve?). I should have a look in the U bend of the pipe into the manifold I guess. I’ll also check the diaphragms. Can oil seep into the carb bore on a CD150 past the diaphragms? Otherwise where does excess oil go? Thanks again. Rich Its not a case of forcing oil down the breather but the manifold sucking oil rich vapour from the engine which on cooling lets the oil condense out and then run down into the manifold. Think theres a cover plate inside the rocker box to stop the larger droplets of oil being sucked into the vent pipe.... Link to comment Share on other sites More sharing options...
JohnD Posted September 23 Report Share Posted September 23 Some rocker covers have the cover plate extended to a small box, originally stuffed with wire wool. That can become solid with oil residue, and block the vent, or in this case making it unable to capture oil droplets. The other possibility is that crankcase pressure is too high, thanks to excess blow by. The extra flow carries more oil vapour into the inlet. Check compressions? A cure would be to divert the hose to a catch tank, but that only deals with the symptoms! John Link to comment Share on other sites More sharing options...
rulloyd Posted September 23 Author Report Share Posted September 23 2 hours ago, johny said: Its not a case of forcing oil down the breather but the manifold sucking oil rich vapour from the engine which on cooling lets the oil condense out and then run down into the manifold. Think theres a cover plate inside the rocker box to stop the larger droplets of oil being sucked into the vent pipe.... My car actually has an SAH cover (I bought it new nearly 40 years ago… ). I don’t think it has a cover plate as far as I recall. I also have a servo connected on the manifold side of the the breather pipe by the way. Rich Link to comment Share on other sites More sharing options...
rulloyd Posted September 23 Author Report Share Posted September 23 2 hours ago, JohnD said: Some rocker covers have the cover plate extended to a small box, originally stuffed with wire wool. That can become solid with oil residue, and block the vent, or in this case making it unable to capture oil droplets. The other possibility is that crankcase pressure is too high, thanks to excess blow by. The extra flow carries more oil vapour into the inlet. Check compressions? A cure would be to divert the hose to a catch tank, but that only deals with the symptoms! John Thanks John. The engine is reconditioned, low mileage and was rebored. I doubt there’s a compression issue (if there is I’ll be really annoyed!) but I’ll test it just the same 👍 Rich Link to comment Share on other sites More sharing options...
johny Posted September 24 Report Share Posted September 24 Have a look in the ECV and its pipework first to confirm this is the source and also that its not stuck open.... Link to comment Share on other sites More sharing options...
Pete Lewis Posted September 24 Report Share Posted September 24 check the dashpots ...always do the easy first and with a servo connected to the breather are you really getting a full vacuum to power the servo ?? you can buy flame trap to add to a plain breather they were used on many cars its there to stop crankcase fumes from fire bit like the davey lamp its simple gauze to stop flame back places like car builder solutions list them Pete Link to comment Share on other sites More sharing options...
johny Posted September 24 Report Share Posted September 24 Yes the WSM servo installation instructions recommends drilling a separate hole in the manifold approximately 2.5" along from the ECV connection👍 Link to comment Share on other sites More sharing options...
68vitesse Posted September 24 Report Share Posted September 24 10 hours ago, rulloyd said: My car actually has an SAH cover (I bought it new nearly 40 years ago… ). I don’t think it has a cover plate as far as I recall. I also have a servo connected on the manifold side of the the breather pipe by the way. My servo connection, MK1 2L Vitesse, done years ago never been a problem, on a recent MOT examiner remarked on the efficiency of the brakes. Regards Paul. Link to comment Share on other sites More sharing options...
JohnD Posted September 24 Report Share Posted September 24 (edited) 11 hours ago, rulloyd said: Thanks John. The engine is reconditioned, low mileage and was rebored. I doubt there’s a compression issue (if there is I’ll be really annoyed!) but I’ll test it just the same 👍 Rich Oh, ye of too much faith! The question is not how long ago it was rebuilt, but are the rings sealing adequately? Get out your compression gauge and settle your mind! Paul, a brake servo does not contribute to the "efficiency" of the braking system. It merely augments the pedal pressure, up to a point: Triumph's disc brakes, unassisted, are excellent. You should be complimented ( and were!) on your brakes, but the servo should not take the credit. John Edited September 24 by JohnD Link to comment Share on other sites More sharing options...
johny Posted September 24 Report Share Posted September 24 4 hours ago, 68vitesse said: My servo connection, MK1 2L Vitesse, done years ago never been a problem, on a recent MOT examiner remarked on the efficiency of the brakes. Regards Paul. yes that connection looks ok Paul as any oil should drain to the manifold and not the servo but even so the manuals the bible (well nearly always😁)... Link to comment Share on other sites More sharing options...
68vitesse Posted September 24 Report Share Posted September 24 4 hours ago, JohnD said: Paul, a brake servo does not contribute to the "efficiency" of the braking system. It merely augments the pedal pressure, up to a point: Triumph's disc brakes, unassisted, are excellent. You should be complimented ( and were!) on your brakes, but the servo should not take the credit. John Quite agree, I fitted the servo to reduce the effort needed on the pedal not to improve the brakes. The biggest improvement I made to the brakes was to file the green stuff pads in the bin. Regards Paul. Link to comment Share on other sites More sharing options...
johny Posted September 24 Report Share Posted September 24 Ha I managed to sell my slightly used green stuff pads on! With brake efficiency it depends on what is meant, to some people efficient brakes are those that need little human effort to pull up a car effectively and a servo certainly helps that... Link to comment Share on other sites More sharing options...
micklewis Posted September 24 Report Share Posted September 24 90% of the time its because people are not using 20/50 oil in there dashpots as triumph specified (dont feel bad lotus ,mg,ah,jag,bl and RR has the same issue) mick Link to comment Share on other sites More sharing options...
johny Posted September 24 Report Share Posted September 24 but what else are people using? Its so easy put it in your engine (20w/50) - put it in your dashpots🙃 Link to comment Share on other sites More sharing options...
micklewis Posted September 26 Report Share Posted September 26 On 24/09/2024 at 18:10, johny said: but what else are people using? Its so easy put it in your engine (20w/50) - put it in your dashpots🙃 any thing from wd40 , 3 in 1 ,antifreeze, 5w,10w beer and a variety of snake oils mick Link to comment Share on other sites More sharing options...
johny Posted September 26 Report Share Posted September 26 ha ha I think those are old myths! It might have been like that back in the days when these cars were everyday motors but now i think the worst will be the wrong grade of oil because its all thats on hand.... Link to comment Share on other sites More sharing options...
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