RobinTR6 Posted March 16, 2009 Report Share Posted March 16, 2009 MANY thanks to Richard the 'real ' Crawley Pilkie, Foster 461 NTC and the boys met at Stoneleigh. Swallowe dthe bullit and removed gearbox and replaced thrust bearing from the RHP type to Koyo type, new cross shaft and double bushes, new fork and pun. Clutch perfect now but lets see how it fares after a few thousand miles. Thrust bearing was tired and cross shaft bushes worn on one side so some movement , no other obvious wear problems. Anyway all back in and went out for a long spin in it yesterday. Anyway, on the test 70 miles the car was running rough at anything below 2k revs. I dont believe its petrol related ie MU , pump, tank as as soon as you push it it flies. Have checked points and plugs but it misfiring at low revs, rough running as well then seems to clear when you plant pedal to metal. The fact that is misfiring /backkfiring a bit is whats throwing me. I'll replace condenser and check injectors, any other ideas ?? (well at least I can drive itnow without binary clutch) Quote Link to post Share on other sites
alanwcoote Posted March 16, 2009 Report Share Posted March 16, 2009 I had the same problem last year,the butterflys were not opening at the same time due to worn throttle linkage. Adjusted it by eye which made big improvment and has since been done by pros who used a vacume and is spot on. Worth a look? Alan Quote Link to post Share on other sites
RobinTR6 Posted March 16, 2009 Author Report Share Posted March 16, 2009 I had the same problem last year,the butterflys were not opening at the same time due to worn throttle linkage. Adjusted it by eye which made big improvment and has since been done by pros who used a vacume and is spot on. Worth a look? Alan Alan thanks, sounds worth a try, will have a go this weekend Quote Link to post Share on other sites
Red 6 Posted March 22, 2009 Report Share Posted March 22, 2009 Alan thanks, sounds worth a try, will have a go this weekend I might be a bit late here but it sounds like the butterflies to me as well. The method is simple, all you need is a cheap gunsen carb balancer. The best way to do it is to start with each manifold in your hand so you can loosen the butterfly disc screws, snap the mechanism shut a few times to "centre" the butterflies, re assemble with screws tightened onto the engine and use the carb balancer to make sure all the butterflies open together. So in summary the idea is that: firstly, when the butterflies are shut no air passes through secondly, when idling air only passes through the air bleed valve (ie the butterflies are tight shut as per 1 above) thirdly, when the throttle opens, all butterflies open at the same time. (this is what the carb balancer does) This is a simple but very rewarding job. Its a bit fiddly the first time but anyone can do it. Finally before you do this just check that the static timing is correct, again another easy job which only requires a lightbuld and a few leads. Hope this helps, Quote Link to post Share on other sites
Guest ntc Posted March 22, 2009 Report Share Posted March 22, 2009 Hi Robin As Richard and I have said many times before the butterflies should not be totally shut. Richard I will no doubt elaborate on this for you. You are wasting your time if the throttle bodies have worn spindles and the linkages are also worn. If they are ok, by all means use a simple balancer to balance the engine above tick-over. Regards Neil ps Glad you got the clutch sorted. Quote Link to post Share on other sites
Red 6 Posted March 22, 2009 Report Share Posted March 22, 2009 Hi Robin As Richard and I have said many times before the butterflies should not be totally shut. Richard I will no doubt elaborate on this for you. You are wasting your time if the throttle bodies have worn spindles and the linkages are also worn. If they are ok, by all means use a simple balancer to balance the engine above tick-over. Regards Neil ps Glad you got the clutch sorted. I would like to hear more regarding why you think the butterflies should not be totally shut and will keep an eye out for the explanation. Quote Link to post Share on other sites
Mike C Posted March 23, 2009 Report Share Posted March 23, 2009 Red,I think the reason the butterflies should not shut completely is simply to maintain a nominal clearance and stop them jamming into the inlet manifold bodies.The Brown Book says the clearance should be less than 2 thou (.05mm).I would not try to do any of these adjustments with worn linkages. Quote Link to post Share on other sites
Red 6 Posted March 23, 2009 Report Share Posted March 23, 2009 Red,I think the reason the butterflies should not shut completely is simply to maintain a nominal clearance and stop them jamming into the inlet manifold bodies.The Brown Book says the clearance should be less than 2 thou (.05mm).I would not try to do any of these adjustments with worn linkages. Hi Mike, The brown book, I thought as much Its a good book everyone should have one but it is known that some parts are vague. The part you refer to is 19.20.05, paragraph 7. That section refers to throttle butterflies from engine no CR 1E ie the 125 bhp engine which has a slightly different linkage. However when consulting the official Lucas PI injection training manual the almost identical wording refers not to a CR setup but to a CP set up (tr5 and 150 TR6's) and for the origional manifold where there was no seperate air bleed. The 2thou gap was there to let the engine idle, without the gap no air could enter so no idle. This was one of the contributing factors in giving the PI system a bad name. Lucas realising the problem rushed out a retro fix to temporarily cure the problem until a proper engineered solution could be found. The solution can be seen on some origional early TR5's and consists of a rudimentary air bleed which involved the dealer drilling and tapping the No1 inlet manifold. A proper solution was of course found and implimented in the form of the bleed valve situated on No1 inlet manifold on later production, thus the need to bleed via the butterfies was indeed not needed. The design of butterflies in the PI are no different to design of the butterflies in a carburettor, it was the technology of the time, what Lucas did by introducing injectors was to enhance that technology. Thus with the exception of the early idling issue the butterflies should be closed. Now on the subject of worn linkages, and I will add worn spindles, which is just as common, you have two further problems: The worn linkage will in effect prevent all the butterflies from opening simultaneously giving rise to a misfire on acceleration, exactly the symptom on a car with twin carbs where the carbs are not balanced, and with worn spindles (obviously depending on how worn) the apparent inability to close (or seat) the buttterfies manifesting itself as an erratic idle or a fast idle, the test here being to shut the bleed valve completely and the engine will still run! So when setting up and tuning a car with worn components it is a case of do the best you can or do the job properly and start from scratch with new components (or better still a new design linkage) I will let the brown book have the last word 19.20.05 (up to engine CP77609E) paragraph 18 sic "As a check to ensure all the butterflies are fully closed hold a finger over the end of the air valve pipe so that the engine stalls" Its all in the book, just a bit muddled thats all. Quote Link to post Share on other sites
Mike C Posted March 23, 2009 Report Share Posted March 23, 2009 Red, Sorry if I' short but I have to leave for work.The Brown Book is vague, for example I admire the simple innocence of the hand deftly inserting the pin into the windscreen winder handle. Reading the paras you quoted I'd agree the butterflies and air valve have to be to be tight enough to stall the engine. I still believe that the procedure would be very hard to get right and keep right with worn linkages. Regards Quote Link to post Share on other sites
Red 6 Posted March 23, 2009 Report Share Posted March 23, 2009 Red, Sorry if I' short but I have to leave for work.The Brown Book is vague, for example I admire the simple innocence of the hand deftly inserting the pin into the windscreen winder handle. Reading the paras you quoted I'd agree the butterflies and air valve have to be to be tight enough to stall the engine. I still believe that the procedure would be very hard to get right and keep right with worn linkages. Regards Couldnt agree more and the windscreen winder is a classic regards, Red Quote Link to post Share on other sites
88V8 Posted March 23, 2009 Report Share Posted March 23, 2009 If you let them shut completely they'll wear a ridge into the throttle bodies which will then be scrap. There should be a fag paper clearance. The idle screw is for ease of use, it does not mean the butterflies should be bang shut. Ivor Quote Link to post Share on other sites
RobinTR6 Posted March 23, 2009 Author Report Share Posted March 23, 2009 If you let them shut completely they'll wear a ridge into the throttle bodies which will then be scrap. There should be a fag paper clearance. The idle screw is for ease of use, it does not mean the butterflies should be bang shut. Ivor Ivor and all, my manifolds are worn and no doubt spindles etc. Two points tho, this hasnt been an issue till now (well not bad enough to complain about), before the idle wasnt great but she went well so something has happened. AND when the choke is slightly on (excess fuel lever about 25%) she runs beautifully. Thankfully Harry lives nearby and thinks he can help so I will be chasing him down. I will post on the outcome. Quote Link to post Share on other sites
Guest ntc Posted March 23, 2009 Report Share Posted March 23, 2009 I would like to hear more regarding why you think the butterflies should not be totally shut and will keep an eye out for the explanation. I stopped reading the brown book many years ago Quote Link to post Share on other sites
davehop Posted March 23, 2009 Report Share Posted March 23, 2009 AND when the choke is slightly on (excess fuel lever about 25%) she runs beautifully. Thankfully Harry lives nearby and thinks he can help so I will be chasing him down. I will post on the outcome. hi Robin Please do post when you get it sorted - I'm experiencing very similar symptoms and will be glad to hear your solution. best Dave Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.