simon iregbu Posted December 27, 2004 Report Share Posted December 27, 2004 I have been trying to get my idle set-up for a couple of days now without a great deal of success. The problem is that that when I first start the car (with the choke pulled fully out) the idle speed is up around 2500rpm but it seems to be the only way that the car will start. Afetr I have coaxed it to start I have to push the choke in so that it will idle around 1500rpm. As the car warms up I can push the choke in and it will idlke around 800-1000rpm (any lower and it will struggle to idle smoothly. I have set the points gaps and the static timing as specified, I have replaced the MU with one from Prestige injection so I assume that this is calibrated. I have also replaced the thottle linkages with the underslung kit that Prestige also supplies (CR series), so that the butterflies open at the same time. I have adjusted the butterflies so that they are shut but I seem to be adjusting the air bleed screw to different settings depending upon whather the engine is cold or at temperature. From this information I would deduce that there is an air leak somewhere that negates the air bleed passage. Is there a procedure that I should follow to set up the ignition/idle/choke cable etc? Should the set up be carried out with the plenum chamber removed? Any other things that I should be doing? etc. Any help would be gratefully apprieciated as the car is now in the US and as they do not have the PI version over here there are no specialist to take it to (that I have been able to find in the Michigan area anyway). So I will be carrying this out myself. Simon Quote Link to post Share on other sites
Bob Stubbs Posted December 27, 2004 Report Share Posted December 27, 2004 Simon I'm not a great expert on the PI system either although my one has similar changes to yours (new MU; Throttle Linkage etc). However, from the description of your starting procedure it sounds just about spot-on to me. I find, I need full choke to start which then makes the engine rev to 2-3k depending on how you've set the throttle part of the choke cable. Almost immediately, you can shove the choke in by about half and then as it warms up, it idles smoothly at around 800 rpm (and that's the point at which I'd make final settings to the air bleed screw). If your set-up made the engine run rough after warm up or it was a dog to start from cold then maybe you'd have to look at other things (e.g air leakage; dodgy injectors; PRV setting) but as you've described it, it just sounds normal. For info, the only other "mod" I've done on mine is to increase the diameter of the plenum chamber to give more volume to allow cold air through to cylinders 5+6 - which often run rich compared to the others. Other than that sounds like just a normal PI set-up............ Quote Link to post Share on other sites
simon iregbu Posted December 27, 2004 Author Report Share Posted December 27, 2004 Bob Thank for your feedback, I thought that it was just me (maybe the two of us now). The only real problem that I have currently is that I wouls have thought that once the set-up has been made then you should not have to mess with the air bleed screw ?? Simon Quote Link to post Share on other sites
Bob Stubbs Posted December 28, 2004 Report Share Posted December 28, 2004 Simon There's always a bit of fiddling and fine tuning to do with the air bleed screw. I guess even the ambient air temperature or change of altitude or whatever would have an impact on the idle speed. No, I'm quite happy with how mine runs just now. Once you know the individual quirks to starting the thing it's no big deal. Quote Link to post Share on other sites
scotty Posted December 28, 2004 Report Share Posted December 28, 2004 Hi , before I took mine to bits for its resto I replaced all the injection bits , I did not connect the choke cable to the throttle mechanism just to the MU . this provides enough fuel to start and means that the engine bearings will not run at speed dry . Let the fuel pressure build up by turning on the ignition / fuel pump and by the time you have put on your belt and tuned the radio you should be able to start the car . It is quite common to not connect the throttle to the choke . Just tie that part of the cable out of the way or use a single cable choke to the MU . Simon once the bleed screw is set you shouldnt need to touch it again . Did you balance the butterflies with a carb balancer ? they are quite fussy . the stuff that Malcolm supplies is first class so you shouldnt have a problem . He is a really helpful guy and will give you loads of advise on the phone if you give him a bell , Quote Link to post Share on other sites
Richard Crawley Posted December 28, 2004 Report Share Posted December 28, 2004 The only real problem that I have currently is that I wouls have thought that once the set-up has been made then you should not have to mess with the air bleed screw Simon, you should not have to fiddle with the bleed screw like this, something is not quite right. I set a up new throttle system up on a new engine last February & apart from reducing the idle speed a couple of times as the engine freed up I have not had to touch it & it idles very, very smoothly. They can be laborious to set up but if the components are not unduly worn & you follow the procedure in the BL manual it's fairly straight forward. I don’t have a balancer but use a Rizla cigarette paper as a very fine feeler gauge, a trick I picked up years ago. This sets the butterflies as low as possible to ensure no air leaks (allowing the maximum adjustment range on the bleed screw) but not so low they actually snap shut when you release the throttle (not good for the throttle bodies & spindles. You have already replaced the linkage system, did this include the throttle spindles? It may be they, or the bodies themselves are worn & letting in too much air. My spindles were quite bad after only 80K miles but the bodies were OK so I totally rebuilt them & linkage system & it has transformed the engine idle & low speed running. The fag paper trick is also a good way of up setting points! Quote Link to post Share on other sites
simon iregbu Posted December 28, 2004 Author Report Share Posted December 28, 2004 Scotty, you said that you did not connect the fast idle part of the choke cable. Does (or did) your car idle at the 750-800 rpm range as it states, when warm? All of the spindles and linkages are new but the butterflies were the originals.When I rebuilt the intakes I checked for wear of the inside surface and can say that there was nothing of any significance. I do not have a carb balancer so I cannot check each of the manifiolds to ensure that the are set the same. I used a feeler gauge to check that they were similar. Richard, when you set up yours using the Rizla paper method did you leave a gap between the bottom of the butterfly and the intake body? I have tried to set this as per the manual which indicates that there should be no gap, then as you pointed out you should have maximum adjustment with the air bleed screw. You state that having the butterflies close completely is a bad thing, I presume for wear to the intake manifolds so does this mean that there should be a small gap. I would have thought that if this is the case then there will be air leakage passed the butterflies and the air bleed screw is less effective at reducing the idle speed. My air bleed screw is only open about 1/2 of a turn from closed, is this similar to yours? Simon Quote Link to post Share on other sites
scotty Posted December 28, 2004 Report Share Posted December 28, 2004 Scotty, you said that you did not connect the fast idle part of the choke cable. Does (or did) your car idle at the 750-800 rpm range as it states, when warm? Simon , short answer - Yes . The car ran beautfully . I think it was Malcolm who actually suggested it to me . As an aside Simon the door & boot floor panels I got from you last year are in place , painetd & look great . Richard - its the simple things that never cease to amaze me - thats a cracking idea . The only problem is having been off the "rollies" for 5 years the missis will be a bit suspicious if I go out buying more papers ! Quote Link to post Share on other sites
simon iregbu Posted December 28, 2004 Author Report Share Posted December 28, 2004 Scotty Glad to here that the panels that you got off me worked well for you, your contribution to my G/Box overhaul fund was much appreciated, Thanks . I will try removing the fast idle cable at the weekend and see how it starts. I will also check all the settings (again) and see if I can finally put this one behind me. Simon Quote Link to post Share on other sites
Richard Crawley Posted December 28, 2004 Report Share Posted December 28, 2004 Simon, I set the butterflies so the Rizla paper is just nipped but can still be pulled out, this gives the very minimum gap but ensures the butterflies do not continually hammer against the throttle body when they snap shut under return spring pressure. You can use a very fine feeler gauge but the thinnest I've got is still somewhat thicker than a fag paper & steel does not bend to the contour of the curved inlet so can be a bit hit & miss. I have the fast idle part of the choke cable connected & set as per the manual & I have not had any problems with it; it gives a faster idle on initial start up & stops it cutting out. I will check the position of my air bleed screw for you in daylight tommorow. My starting procedure is to turn on the ignition & wait 10 seconds for the fuel pressure to build up; crank the engine for 3-5 seconds with no choke to get the oil pressure up a little; & the injectors firing fuel instead of air, then crank the engine on around ½ choke (in summer - a little more now we are in winter). As soon as it catches, I give it a little throttle as this helps it fire up. If I leave it for more than a couple of days or so, it will never fire on all 6 but usually 3-5 cylinders have a go; it then spits & farts a bit with all 6 kicking in after a few seconds, encouraged by a few judicious prods of the throttle. I can push the choke right home after only 15 -20 seconds & it then idles smoothly at around 700-750 RPM, increasing to around 800 -850 RPM once it warms through. I have had the car since it was 3 years old & it ran the same then as does now with an all new engine & ancillaries. Scoty; I have not smoked for years either but my dear old dad taught me that trick working on motor bikes when I was about 15 & I am still using the supply of Rizlas I found in his bedside cupboard when he passed away 4 years ago. Quote Link to post Share on other sites
Richard Crawley Posted December 29, 2004 Report Share Posted December 29, 2004 Simon, I ran the TR up this morning & checked the air bleed screw position with the engine hot; screwing it right home just about stalled the engine, 800 RPM was achieved at just under half a turn so it’s similar to yours. What condition is your engine? A worn engine will produce erratic/poor manifold depression & hence, poor idle. Check the fuel distributor vacuum tube is clear & not leaking. Check you don’t have an ignition distributor problem; a worn unit, loose bob-weight springs or a worn spindle will also give erratic idle - fitting electronic ignition may help here. Try re-setting the ignition timing with the engine running using a strobe light, static settings can be a bit hit & miss; also, the timing marks should appear static under the strobe, if they dance around it’s almost certainly an ignition distributor problem. I also replaced the spindles on the original butterflies, but did you make sure they were all seating nicely against the throttle body after the screws were tightened? I had to swap them around a bit to get a good seal on each one & used a locking compound on the screws; wont do the piston much good if one came out! Quote Link to post Share on other sites
simon iregbu Posted December 29, 2004 Author Report Share Posted December 29, 2004 The engine was completely rebuilt with new hoses everywhere so I am pretty sure that this is not the problem side. I will look into the distibuter side of things and check that everything is okay and the check the timing with the engine running. Could you tell me what your timing is at idle, the repair manual I have only quotes the static (11deg BTDC) and no values for the idle (the carburetter version have 4deg ATDC). I have converted the to unleaded so I will have to account for this when I can get the car out on the road, or can I do this now ?(we had 8" if snow before Christmas and here in Michigan they salt the roads to keep them clear so I won't be driving on the road until spring, but I want to get everything ready between now and then). I know when I replaced the spindles that I made sure of them seating completely but I will check this out at the weekend as I have to get hold of a carb balancer. Thanks Quote Link to post Share on other sites
Richard Crawley Posted December 30, 2004 Report Share Posted December 30, 2004 Simon, The static setting of 11 degrees is correct for a CP series engine so, assuming you have the FULL CP series spec. (including the distributor which is different to a CR!) I would start from here. Use the 11 degree timing mark for both static & strobe setting at idle but increase the idle to around 900 or so RPM to give a steady idle but don’t go too far or you will bring in the auto advance mechanism. You will probably find your ‘so carefully set static timing’ is over advanced by a couple of degrees once you put the strobe on! With the strobe connected, you can also check how well (or not) the auto-advance mechanism is working (& hence how good or bad your bob weight springs are) at the relevant RPM settings given in the manual. Using low octane unleaded fuel, you may have to reduce the 11 degree initial advance; some say up to 5 degrees is necessary in order to prevent pre-ignition detonation on the **** fuel now available. Personally, & to my surprise, I have not had any problems & have found it to be quite happy running the original settings without any signs of detonation using premium unleaded fuel, without any octane booster! Weather or not my stage 2 engine tune helps here I don’t know but I had previously experienced pre-ignition detonation using 4* leaded on the standard engine so I was a little surprised by the apparent lack of problems. The 4 degrees ATDC on the carburettor car, along with a rather lean mixture, was, I believe, more to do with BL attempts to reduce exhaust emissions for the American market & if you have a true & uncorrupted CP engine, I would avoid running this sort of advance (retard!) as it will give the engine all the response characteristics of a sponge pudding! You can vary the ignition auto advance characteristics by using different bob weights & springs but this gets a bit involved & I think unnecessary for a road car, even one running a fairly serious tune. Quote Link to post Share on other sites
simon iregbu Posted December 30, 2004 Author Report Share Posted December 30, 2004 Richard The car is a CR version with no modifications to the engine to improve performance. I could not find any information about the timing difference for the CP to CR, is there one. Also what were the differences in the distributers? Is the later type more unreliable. Quote Link to post Share on other sites
Richard Crawley Posted December 30, 2004 Report Share Posted December 30, 2004 Simon, I have checked all my manuals/parts books this morning & it appears the CP & CR engines, apparently, both used a 22D6 Lucas distributor. The CR series appears to have a different part number but, unfortunately, I can’t find any information for the CR unit specifically so I can only assume it has essentially the same characteristics as the CP unit & so, uses the same ignition settings. This is certainly inferred in the Haynes manual but my original BL manual (circa 1973) merely states that the CP series distributor (part number 41219) was fitted up to commencement of the CR series, it gives no specific information for the CR unit at all. Sorry if I miss-led you, I was under the impression the CR unit was significantly different but this appears not to be the case. The 22D6 distributors (5 different types!) fitted to the US market carburettor engines, however, appear to have significantly different advance characteristics so are not really be suitable for the PI engine without modification. It may be worth checking your distributor part number to see exactly which one you have fitted. Presumably, all of the carburettor 6 cylinder Triumph saloons used a variant of this distributor so it’s possible it may have been swapped at some time in the past. Quote Link to post Share on other sites
Mike G Posted December 30, 2004 Report Share Posted December 30, 2004 Hi Simon, I have been running my’73 CR on unleaded since 1997. I have set the ignition timing at eight degrees BTC. As these engines were never designed to run on unleaded, the way I would suggest you do it would be to set it to eight degrees, then when the car has been run for a while, labour it slightly up an incline and check for pinking. If it doesn’t pink, then start to gradually advance the timing using the micrometer adjustment on the distributor until it does, then back off, until it is just timed out. Mike G Quote Link to post Share on other sites
simon iregbu Posted December 30, 2004 Author Report Share Posted December 30, 2004 Mike Is your 8 deg a static setting or at idle ? Quote Link to post Share on other sites
Mike G Posted December 30, 2004 Report Share Posted December 30, 2004 Simon The eight degrees is the static timing. Mike G Quote Link to post Share on other sites
Richard Crawley Posted December 30, 2004 Report Share Posted December 30, 2004 Mike Is your 8 deg a static setting or at idle ? Simon, the static & idle settings are the same as long as you dont increase the idle so far (i.e no more than 900 RPM) that it brings in the auto advance mechanism. Quote Link to post Share on other sites
simon iregbu Posted January 14, 2005 Author Report Share Posted January 14, 2005 I have set my timing to 8deg BTDC and have ran the car so that it is warm. I took the intake plenum off and found that the centre intake manifold was not closing compltely and hence I could not drop the idle done far enough. I have adjusted the butterflys so that the will close and it now is alot better (approx 900rpm idle), but still not quite right. The problem that I have is that all of the butterflys are slightly open. If I put me hand over the ends of each of the intakes they are all sucking air, albeit only a small amount. When I do this I can get the idle to drop sufficiently that I have to adjust the air bleed screw to bring the idle speed back up. Are there any tips/tricks to setting these up such that I can set them so there will be no air being drawn in via the inlet manifolds and I can then adjust the air bleed screw to set the idle. (Richard - I have yet to try the cigarette paper method to allow for a small gap at idle, I may try this once I know I can reduce the idle down to the 700rpm stated) Quote Link to post Share on other sites
JohnC Posted January 14, 2005 Report Share Posted January 14, 2005 Simon, One trick which worked for me a few years ago was to slack off the linkages to make sure the butterflies were snapping shut, and then loosen & re-tighten the two screws which secure each butterfly to its spindle. I guess (in my case) this allowed one or more butterflies to move slightly & seat better. Worth a try? John Quote Link to post Share on other sites
jonlar Posted January 15, 2005 Report Share Posted January 15, 2005 Has anyone tried doing what Roger Williams suggests to CR cars, either fitting CP type throttle bodies, or block the air inlet tubes nearest the head on CR type, using those nearest the butterflies (as with CP), and also fitting a second idle control screw to the throttle body at the rear (by No. 6 cylinder) which apparently greatly improves the air supply to 5 and 6? Quote Link to post Share on other sites
alexthegrt Posted April 30, 2007 Report Share Posted April 30, 2007 hi im not sure how to exactly post stuff so i hope someone sees this and reply's i have a TR6 and it has 1 too many problems. does anyone know where i can find a good manual with everything including wiring diagrams. i need a name and possibly a place. or if there is a downloadable one. thanks Quote Link to post Share on other sites
Jersey Royal Posted April 30, 2007 Report Share Posted April 30, 2007 (edited) hi im not sure how to exactly post stuff so i hope someone sees this and reply's i have a TR6 and it has 1 too many problems. does anyone know where i can find a good manual with everything including wiring diagrams. i need a name and possibly a place. or if there is a downloadable one. thanks Welcome to the forum Alex Not sure of downloadable book, however there was a cd manual on e bay. Or have a look in the Tr Register on line book section. On my six i use a Haynes Manual, and a Brooklands Repair Operation Manual (brown book), which i find very good. Depends on your mechanical Knowledge , although mine is limited i am learning all the time from the posts on this forum. Regards Guy Edited April 30, 2007 by Jersey Royal Quote Link to post Share on other sites
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