JohnG Posted March 13, 2015 Report Share Posted March 13, 2015 All Good morning The MOT went OK, but, there is a problem with high levels of hydrocarbons; 8079ppm, when the limit is 1200ppm What can I do to bring this under control? Is it a case of; - car to Manvers, or - MU to Neil or is there an easy fix, of which, I am unaware? My friendly, helpful, local garage is good and Pete cut his teeth on 6 cylinder cars in the 70's and 80's, but, they do not have the background capability to adjust the MU, if that is what is needed Thanks, as always Quote Link to post Share on other sites
Grabea Posted March 13, 2015 Report Share Posted March 13, 2015 Hi John, Please don't take this the wrong way but have you checked the cold start lever is in the fully off position? my other comment would be with that amount of unburnt fuel passing through the engine I would think it will wash off the bores pretty efficiently and lead to excess wear so I would address this issue sooner rather than later. I would have thought having Neil set up your MU would soon be repaid in fuel savings! Regards Graham Quote Link to post Share on other sites
TriumphV8 Posted March 13, 2015 Report Share Posted March 13, 2015 Hi John as I can see from the data you have a CR where normally the 150HP CP type is known to have that HC-problems due to the large cam overlap in TDC. If yours does that and that is the only problem what means the CO content is in limits and with that there is no need to check levers and resetup MU. I would look at the injectors if they spray properly and check valve clearance first. If that does not help I woul check if CO level is really in limts. Than ignition timing can be checked. Quote Link to post Share on other sites
Peter Cobbold Posted March 13, 2015 Report Share Posted March 13, 2015 It might be runnng rich due to a perforated diaphragm in the MU - try the 'tongue test': http://www.tr-register.co.uk/forums/index.php?showtopic=34963&st=0&p=261520&hl=tongue&&do=findComment&comment=261520 Peter Quote Link to post Share on other sites
peejay4A Posted March 13, 2015 Report Share Posted March 13, 2015 Do we have a reference point for "normal" HC emissions for PI cars, which mostly seem to run rich? Quote Link to post Share on other sites
JohnG Posted March 13, 2015 Author Report Share Posted March 13, 2015 (edited) Thanks all Graham I checked the cold start lever on the MU before I delivered her. My local, helpful, friendly garage also checked that the lever was closing correctly, in the hope of an easy resolution to the problem. No offence taken! Neil refurbished my MU last summer, so it is possible that it needs to be tweeked Andreas Neil supplied the injectors last summer and, to my untrained eye, the cones look to be good. Peter I will do the tongue test tomorrow morning If the diaphram appears to be in order, I think I will get her over to Clive Manvers, so that he can set her up as a unit, rather than fettle isolated parts. Edited March 13, 2015 by wjgco Quote Link to post Share on other sites
Nick Jones Posted March 13, 2015 Report Share Posted March 13, 2015 High CO is normally the result of rich running. High hydrocarbons is normally the result of a misfire or even high levels of petrol in the oil. First check would be throttle body balance. If this is out then you'll be having some cylinders running very rich at idle and maybe even some running very lean - and if either misfires - high HCs is the result. Nick Quote Link to post Share on other sites
Guest ntc Posted March 13, 2015 Report Share Posted March 13, 2015 Your car should be exempt from that test. Quote Link to post Share on other sites
jojim65 Posted March 13, 2015 Report Share Posted March 13, 2015 Hi, My apologies for slightly hijacking the thread but I'm interested in the emissions side of the TR6, I realise my 1970 CP is exempt (thankfully) but I wonder what you make of my figures. CO runs at about 4.6% at idle and HC 800ppm, Off idle CO is 1.2% and HC is 60ppm. These are best figures, the mere presence of a cloudy day or a different brand of petrol makes a difference... Thanks Jim Quote Link to post Share on other sites
Peter Cobbold Posted March 13, 2015 Report Share Posted March 13, 2015 The PI must be run rich, all the time. If not, it will pink when throttle is suddenly floored. Its all due to the lack of a 'acceleration charge', aka throttle pump. So reducing the CO or HC, which means leaning the mixture at t/over and cruise ( the MoT conditions dont cover full load), will result in rattling the pistons when going to wot. Peter 0'Leanspike . Quote Link to post Share on other sites
JohnG Posted March 13, 2015 Author Report Share Posted March 13, 2015 (edited) Nick As Peter says, the PI needs 'rich' at tickover My problem is that I seem to have a bit too much 'rich' The only evidence I can offer for rich or lean is the colour of the plugs They are an even dark brown (symptomatic of a slightly rich mixture) except for no 6, which would appear to be running richer (black deposits) Neil I wish Registered on or before 30/07/75; smoke test Registered on or after 01/08/75; emissions test My car was registered on 01/08/75 Hey ho Edited March 13, 2015 by wjgco Quote Link to post Share on other sites
Peter Cobbold Posted March 13, 2015 Report Share Posted March 13, 2015 (edited) John, One day out .... that must be infuriating. But I think it should be possible to lean the tickover just for the MoT without disturbing the settings of the MU. You need to remove the black plastic cover and insert a piece of shim stock, maybe 20thou to start with, between the MU piston and the rollers that push it in according to their position on the datum track: On this diagram the piston is # 49 and the roller # 18 : http://www.lucasinjection.com/LUCAS_BLOWUP.gif On here you see the datum track and a hint of the roller towards the left of end of the piston: http://vitessesteve.co.uk/LucasStuff/TR6PIN5.gif Many years ago TRAction had a brief article on doing this. It might be on the Technicalities CD. Insert the shim with fuel pump off, or the piston will be forced against the roller and datum track. The MoT garage may well be able to do it if you show them the diagrams. Remove it for the next 364 days. Peter Edited March 13, 2015 by Peter Cobbold Quote Link to post Share on other sites
Nick Jones Posted March 13, 2015 Report Share Posted March 13, 2015 Nick As Peter says, the PI needs 'rich' at tickover My problem is that I seem to have a bit too much 'rich' The only evidence I can offer for rich or lean is the colour of the plugs They are an even dark brown (symptomatic of a slightly rich mixture) except for no 6, which would appear to be running richer (black deposits) Neil Yes, But rich means high CO. What is your CO? AS not mentioned maybe that was not a fail point? High (very high in fact) HC without high CO = MISFIRE! Fuel passing clean through the engine without burning at all. Perhaps n0 6 gets no air at idle? Nick Quote Link to post Share on other sites
Ragtag Posted March 14, 2015 Report Share Posted March 14, 2015 As someone once said, 'I agree with Nick'! HC= unburnt fuel If your MOT garage is friendly, rather than messing with the MU, could you remove the air box/plenum and get them to re-measure? Quote Link to post Share on other sites
JohnG Posted March 14, 2015 Author Report Share Posted March 14, 2015 Nick Cold, the CO was a 'just fail', but, warm, an easy pass No missfire, she runs very smoothly and starts well, except when she has been standing for days I know what a missfire feels and sounds like, a missfire was the reason for the MU overhaul last summer I have no argument with the 'unburt fuel' line of thinking, just need to trim it back for the MOT Chris I will certainly remove the air filter for the next time Peter In the garage as I type, waiting for 1st coat paint to dry on garden boxes for SWMBO Once the 2nd coat is on, I will do the tongue test. Then, find somewhere to get some shim. I have a couple of weeks before I can get back for a retest Quote Link to post Share on other sites
JohnG Posted March 14, 2015 Author Report Share Posted March 14, 2015 (edited) OK Took her back to my local, helpful friendly garage and stuck the probe back up her pipes, this time with the plenum off, got the figure down form 8k to 3.8k, good, but not enough. I will get some shim and try Peters suggestion, with the MU Did the 'tongue test', the MU held vaccuum nicely, did it twice, just to be sure Peter, infuriating is one word I suppose, not the one I used though Edited March 14, 2015 by wjgco Quote Link to post Share on other sites
Peter Cobbold Posted March 14, 2015 Report Share Posted March 14, 2015 (edited) Once an engine goes richer than about 11:1 it will fail to burn all the fuel to completion ( H2O, CO2) even with a super spark and no misfires . http://planetcampbell.us/AFR_Emissions.jpg http://petrolsmell.com/wp-content/uploads/2012/07/SI_engine_emissions_lambda-253x300.jpg and HC soars, as does CO. Looking at that first curve AFR=10 gives HC=200ppm, So John's 1000ppm-plus means its running stinking rich. I reckon its may well be the diaphragm. Peter Just seen John's test below - its not the diaphragm. Edited March 14, 2015 by Peter Cobbold Quote Link to post Share on other sites
Peter Cobbold Posted March 14, 2015 Report Share Posted March 14, 2015 (edited) John Give the PRV a few thumps with the engine running. If the fuel psi is way too high that will make things run richer. Was this a problem a year ago at previous MoT? Also try diverting the rocker cover breather to a catch tank , in case the HC is oil burning. But you did that when the plenum was taken off... Peter Edited March 14, 2015 by Peter Cobbold Quote Link to post Share on other sites
JohnG Posted March 14, 2015 Author Report Share Posted March 14, 2015 John Give the PRV a few thumps with the engine running. If the fuel psi is way too high that will make things run richer Peter I like this idea, I'll try it tomorrow, before the family descends on us. Was this a problem a year ago at previous MoT? Peter Don't know, I bought her with the MOT. Mind you, I have my doubts about the people who worked on her during the PO's tenure, some of the things Manvers found would make your hair curl! Quote Link to post Share on other sites
Crawfie Posted March 14, 2015 Report Share Posted March 14, 2015 Mind you, I have my doubts about the people who worked on her during the PO's tenure, some of the things Manvers found would make your hair curl! John, I know all about that "hair curling" feeling with the things Stuart told me about my car !! Quote Link to post Share on other sites
Peter Cobbold Posted March 14, 2015 Report Share Posted March 14, 2015 (edited) John, I wonder of the HC is oil, not excess fuelling. So... Take a look at the first curves I posted above. You say your CO is now within limits, engine hot - so what AFR does it correspond to ? Now what would the HC be for that same AFR? If the HC is wildly out of proportion to the CO I think it points to oil making a lot of the HC. eg if your CO is 4% then the corresponding HC at same AFR ( 13) is around 100ppm - but you have over ten times that HC. Thats too big I think to be explained by fuel combustion. Removing the plenum reduced HC and that could be because blow-by with oil was no longer being burned. Inlet valve guides sloppy? Are any of the plugs at all oily? Peter Edited March 14, 2015 by Peter Cobbold Quote Link to post Share on other sites
JohnG Posted March 14, 2015 Author Report Share Posted March 14, 2015 (edited) Peter You are getting a bit ahead of me there, so, let me add to what I have reported, following the test this morning I am not burning oil, I don't think None of the usual smell or blue smoke No need to top up between oil changes (annual irrespective of miles driven and done 2 weeks ago) No plug fouling Easy starting; Run pump for about 30 secs, give it some 'choke', crank her over whilst tickling the throttle and, 9 times out of 10, bingo, up she comes, uneven for a few seconds until I blip the throttle and tweek the 'choke'. Inlet valve guides, now that's a totally different kettle of fish. I don't have the kit to check this, beyond my fingers, a vernier, a 0 - 1 mic and my Mk 1 eyeballs, but, again, oil in the mix from any source would mean reduced volume in the sump and, from what I can see and have experienced over the 9 months I have had her on the road, oil depletion is not an issue. However . . . . Pete (the old boy at my local helpful friendly garage) claims; - to be able to smell petrol (I tend to agree) - to be able to hear some uneveness in the tickover This, I would call . . . .rhythmic. She is not smooth on tickover, there is an almost soporific rhythm to the way she ticks over. I like it! Pete doesn't. He reckons there is over fuelling for sure. So; To Star Engineers on Monday, to get hold of some shim and then I will do my best not to wreck the good work Neil did on my MU last year! If this works, I will plan in a visit to Clive Manvers for a more permenant cure If it doesn't work,I will plan in a visit to Clive Manvers for a more permenant cure Edited March 14, 2015 by wjgco Quote Link to post Share on other sites
Peter Cobbold Posted March 14, 2015 Report Share Posted March 14, 2015 (edited) John, OK, that rhythmic hunting is typical of over rich mixture, I dont think oil would do that. Hope the shim works. Puzzling - the new MU should be fine.So next place to check is PRV, measure fuel pressure. Have you given the PRV a good thumping, pump on? Peter Edited March 14, 2015 by Peter Cobbold Quote Link to post Share on other sites
JohnG Posted March 14, 2015 Author Report Share Posted March 14, 2015 Peter From the help offered, the PRV would appear to be the next step, so, Mothers Day AM I will locate it and tap it. Apropo furthering the solution, I have a 160psi gauge; - what do I need to check the pressure? - where is the best place to check the pressure? If I can identify what I have, then at least I have a starting point Quote Link to post Share on other sites
snowric Posted March 14, 2015 Report Share Posted March 14, 2015 Failing exhaust valves is one possible cause of HC getting inot the exhaust so maybe a compression check after you have done everythign the others have suggested. The best place to check to pressure is at supply to the metering unit using a take-off point. Not something that you can get on a Mothers' Day but maybe sdomeone in your area has oen you can use. Snwoy Quote Link to post Share on other sites
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