Phil P Posted August 22, 2002 Share Posted August 22, 2002 Hi All, Was out for a blat last night & noticed that when I accelerate hard, the exhaust smokes a bit. It was dark, 1/2 hour into the blat & i noticed it as I gunned it from about 2k revs down a motorway on ramp - looked in the rear view mirror & saw it in the headlights of the car fast dissappearing behind me! Didn't look like a huge amount of smoke but was noticeable nonetheless. My question is, what can cause this? car is a 1600 xflow on twin dcoe 40s. Oil pressure is fine (2bar t/o, 4 bar running) & the last time i checked, the plugs were not oiled at all. The car hasn't been run for the last couple of weeks and prior to that had done a fair few short journeys of about 10mins or so. Could it be the carbs running rich? Thanks Phil Link to comment Share on other sites More sharing options...
Graham Sewell Posted August 22, 2002 Share Posted August 22, 2002 During hard acceleration, it will always run rich (almost by definition). The main question would be what colour was the smoke (white or black)? Black/blue(?) smoke would indicate oil, but white would be water vapour! Low tech luddite - xflow and proud! Link to comment Share on other sites More sharing options...
cdg Posted August 22, 2002 Share Posted August 22, 2002 It's probably oil smoke caused by slightly worn rings. If the car is still performing as it should be, I wouldn't be at all worried. You ought to see some "rebuilt" Lotus twincams smoke... Chris. Link to comment Share on other sites More sharing options...
I.Mupferit Posted August 22, 2002 Share Posted August 22, 2002 Just to clarify Grahams reply, if I may, generally speaking black indicates excessive fuel burn which often happens when you floor the throttle and the good ol' DCOEs tip a bucket load of fuel into the engine! Blue (the more worrying of the two) will indicate oil and could be caused either by piston rings or valve guides. Brent Link to comment Share on other sites More sharing options...
Graham Sewell Posted August 22, 2002 Share Posted August 22, 2002 Brent, Thanks for clarifying that, I wasn't too sure which way round black and blue went, unless it was bruising on the shoulders from the 4-point harnesses. Having said that, I would doubt that Phil had a chance to notice the colour as he was flooring it down a slip road - not the best time to watch your mirrors for a prolonged period Low tech luddite - xflow and proud! Edited by - Graham Sewell on 22 Aug 2002 13:53:35 Link to comment Share on other sites More sharing options...
Smegnoguk Posted August 23, 2002 Share Posted August 23, 2002 My 1600 Vx does exactly the same when I put my foot down hard from a standstill. I have only done about 4,000 miles so it isn't engine wear. It leaves people standing at bus stops in a bit of a haze! I decided that it must be petrol vapour or condensation in the exhaust turning to steam. However following replies to my recent question on Twin-choke Webbers, I wonder if it could be because the idle mixtures are too rich. Mind you I tend to agree with Brent Chiswick. Could be sheer volume of petrol going through the engine. My petrol consumption is apalling if I drive hard. You can almost see the petrol guage going down! 😳 Link to comment Share on other sites More sharing options...
JKJ Posted August 23, 2002 Share Posted August 23, 2002 My X-Flow is at 28,000 miles now, no rebuilds fast as hell,, and under normal running there is no excessive smoking from the exhaust. When I accelerate hard after a period of following slower taffic there is definate haze from the exhaust. It's what they do. Worry when the performance drops off. Link to comment Share on other sites More sharing options...
Phil P Posted August 27, 2002 Author Share Posted August 27, 2002 Thanks for all the replies guys. That certainly puts my mind at rest, but I'll try & find out what colour the smoke is. Maybe I'll go out for a blat tonight & get my brother to hang out of the passenger side facing backwards while I floor it to see if he can make out the colour Phil Link to comment Share on other sites More sharing options...
Graham Sewell Posted August 27, 2002 Share Posted August 27, 2002 Just make your brother aware of any lampposts at the apex of corners Low tech luddite - xflow and proud! Link to comment Share on other sites More sharing options...
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