kevinprice Posted March 8, 2004 Report Share Posted March 8, 2004 hi the sun shone this weekend in sussex, so thought i'd get the 6 out (73 PI). everytime i do this after a long break number one plug oils up and i only get 5/6th power. oil pressure is good , timing ok, lumetronic electronic, fuel seems ok, it appears that when i use the choke after a period of time in the garage,number one always does this. I have noticed that due to the original intake method, number 3 plug is perfect colour, 4 to 6 are progressively lean and 1 to 2 are progressively rich.a clean of the plug cures the problem and stays clear until i put the car back in the garage for more than a week. any clues please ?????? Quote Link to post Share on other sites
Guest Neil Russell Posted March 8, 2004 Report Share Posted March 8, 2004 Different colours on plug electrodes sounds like a combination of different fuel pressure / atomisation through your injectors and hence mixture, could also be worn shuttle unit giving different fuel amounts and / or butterflys not being in sinc allowing different amounts of air. Also HT leads / Dizzy cap not giving the same spark and hence an even or clean burn in each pot. Sounds like a full set up is needed to eliminate all of the usual fueling / ingnition issues Oil Fouling sounds like the valve guides on No 1 cylinder. It is probable that after a long lay up oil is finding its way down the guide from the top of the cylinder head onto the top of the piston. Do you get a lot of Blue smoke on initial start up after the car has been standing? Neil. Quote Link to post Share on other sites
kevinprice Posted March 8, 2004 Author Report Share Posted March 8, 2004 hi nigel the engine has recently been rebuilt, new valves and stem seals fitted, compression is good, fuel distributor has had new seals and new diaphragms,new injectors also fitted, air balance could be out as this was done by hand. the colour of plugs isnt major, i believe this is common due to the air filter design, ie inlet closest number one. thanks for comments any other ideas ??? Quote Link to post Share on other sites
Guest Neil Russell Posted March 8, 2004 Report Share Posted March 8, 2004 If you are getting oil fouling (not petrol fouling?) then the oil has to be coming from the oil supply. The only places it can come from are the rocker cover via the guides or past the rings from the cylinder block. If only one pot is affected then I would do a dry and wet compression test to eliminate rings. If rings are not the cause then It has to be guides. If you are only getting trouble after a long lay up then I would err towards the guides. Just because the engine is newly re-built doesn't mean that it could not be the fault?? All it takes is a scored guide on assembly or it pressed in slightly out of square or was it reamed slightly too large before assembly? food for thought? Only other option I can think of is if you have any emissions equipment, crank case ventilation etc near to no 1 intake port? and a blocked pressure relief valve etc. I think it is guides though? Neil. Neil. Quote Link to post Share on other sites
jonlar Posted March 8, 2004 Report Share Posted March 8, 2004 I have noticed that due to the original intake method, number 3 plug is perfect colour, 4 to 6 are progressively lean and 1 to 2 are progressively rich. This the opposite way round to normal. Personally I don't use the choke, I keep on cranking till it fires up, this also gives the oil a chance to get circulating. Quote Link to post Share on other sites
Richard Crawley Posted March 8, 2004 Report Share Posted March 8, 2004 You need to be certain weather it's oil or petrol fouling as the causes will be quite different & I am not sure from reading your post which it is. Otherwise, I agree with all said so far. Although, jonlar, I can never get mine to start without any choke - it used to years ago but perhaps I’m now running too much advance for the **** fuel available! Quote Link to post Share on other sites
jonlar Posted March 8, 2004 Report Share Posted March 8, 2004 Are you using any additives Richard, I'm on Castrol VM+. Quote Link to post Share on other sites
Bob Stubbs Posted March 8, 2004 Report Share Posted March 8, 2004 I agree with Jonlar. Normally its cylinders 5+6 that foul up. Are you counting from the radiator end (cyl 1) or bulkhead end (cyl 6)? If it is really 5+6 then I would have thought that most PI users suffer that problem. I'm just trying the modification of the plenum chamber on my car and am expanding it to try and get greater airflow to the rear cylinders. Apparently it will work but you could also get the same effect by ditching the plenum and fitting 3 K+N's fed with directed cool air from the front. Quote Link to post Share on other sites
Richard Crawley Posted March 8, 2004 Report Share Posted March 8, 2004 Are you using any additives Richard, I'm on Castrol VM+. Not so far, I've been rather sceptical of them, do they really compensate enough to be effective? Quote Link to post Share on other sites
kevinprice Posted March 9, 2004 Author Report Share Posted March 9, 2004 hi guys no its definitely number 1 near raidator end, it is fuel fouling, and only after a lay up of a week or more, and only if i use the choke to start. i think its butterfly set up thanks for all the comments Quote Link to post Share on other sites
Richard Crawley Posted March 9, 2004 Report Share Posted March 9, 2004 i think its butterfly set up Poor butterfly synchronization usually gives lumpy idling & poor pick up & should not cause the plug to foul unduly, a quick blast up the road should clear this anyway. Which throttle linkage do you have CP or CR? The CR set up is known to be inferior & rather difficult to set up properly & many convert to the CP series linkage. Have you checked you are getting a healthy spark at No.1 cylinder? try checking/changing the ignition lead/cap/plug etc. Have you checked the spray pattern on the injectors? I would always suspect these first even if they are recon. units. A duf injector is more likely to give the symptoms you describe, particularly at idle or small throttle openings. I've found that leaving my car for more than a week always causes initial spitting & farting but this usually clears with a few judicious blips of the throttle, although very occasionally it requires a bleed of one or more injector lines to cure it. I put this down to fuel evaporation/pressure loss in the injector lines & gumming up of the injector nozzles. I try to run my car once a week when laid up - in fact I’ve been out in the sun doing just that for the last 30 minutes! Quote Link to post Share on other sites
jonlar Posted March 9, 2004 Report Share Posted March 9, 2004 Are you using any additives Richard, I'm on Castrol VM+. Not so far, I've been rather sceptical of them, do they really compensate enough to be effective? I think VM+ is worth it for the octane boost. Quote Link to post Share on other sites
Richard Crawley Posted March 10, 2004 Report Share Posted March 10, 2004 I think VM+ is worth it for the octane boost. Thanks, will give it a try. Do octane boosting additives give an instant result or is it something you have to use over a few tankfulls before you notice it? Quote Link to post Share on other sites
jonlar Posted March 10, 2004 Report Share Posted March 10, 2004 From my personal experience, once thoroughly mixed and circulated throughout the system - instant, there are some who say the additives cause coloured gummy deposits, I believe this is due to the U/L **** petrol and its own additives, the colour of VM+ etc make it more visible, but I may be wrong! Quote Link to post Share on other sites
jean Posted March 10, 2004 Report Share Posted March 10, 2004 Speaking about additives, I think we should differ the additives just to prevent valve recession and those containing octane boosters. Octane boosters will give an instant result, if you can notice it, as they will increase the octane number, but not by much. 1 or 2. As soon as you stop adding it, it's back to normal. Many additives commercialized to fight valve recession do not contain octane boosters. In addition the chemical formula of additives may vary, and it's advisable not to mix them Jean Quote Link to post Share on other sites
kevinprice Posted March 18, 2004 Author Report Share Posted March 18, 2004 hi thanks for all the input, problem not solved but improved, firstly timing was slightly out, therefore engine running rich,once plug colours sorted and engine running correct,with butterfly on number 3 replaced due to wear a gap was allowing too much air. there is obviously some inherant design fault though, using the choke fully open will still cause fuel fouling of plugs. the suggestion of cranking over a few times with out choke avoids this. Quote Link to post Share on other sites
JohnC Posted March 18, 2004 Report Share Posted March 18, 2004 Kevin, I'm not sure it's a design fault - I know many members have disconnected the throttle part of the cold start control (leaving the mixture enrichment part connected), but mine's set as per the original design. I'm currently using the car every day, and it starts in about 2 seconds (thousandandonethousandandtwo brrrrm) with no accelerator whatsoever. I don't need full "choke", but then the morning temp is only in the teens © - what temp do you see at present? The thing about the TR engine is that lots of little things can contribute to a problem. Fix one, and the situation improves, but you're not there yet. You've checked your timing and your butterfly balance. Is there any leak in the vacuum supply to the PI Control Unit? Has anyone "tuned" your PI for you (I wouldn't trust mine to anyone without a fully set up calibration bench complete with 6 measuring cylinders, variable speed drive and vacuum supply...)? I'm sure others can add more, but you get the picture. John Quote Link to post Share on other sites
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