North London Mike Posted August 10, 2007 Report Share Posted August 10, 2007 Hi Guys Manvers tweaked LNK during her last visit and, whilst she is now running better than ever with plenty of 'sparkle', she has started to run on....... How to stop it ? Old wives tales abound, idle before switch off, blip the throttle before switch off, etc etc, Ian (4VC) Cornish was at the NLG meet last night and revealed that he had a similar problem and fitted a ‘run on valve’ which was only partly successful prior to a new manifold which did the trick Clive Manvers favours backing off the timing a notch on the dizzy (with a loss of ‘Sparkle’) restoring the pre- run on state of tune So, do I retain her extra performance with a miracle cure or de-tune her ? To be fair the advantage was only marginal but once you’ve had it………. Any help appreciated Quote Link to post Share on other sites
67_gt6 Posted August 10, 2007 Report Share Posted August 10, 2007 I wouldn't be happy knowing it was getting that hot in the chamber. The last time I was playing around with the timing I had a little run on after one of my adjustments, I backed it off a little on the vernier (ie about 1 degree, if that) which removed the run on with no noticeable performance hit. A full notch on the vernier is 4 degrees at the crank, it may well be that you only have to back off a quarter of that. Andy Quote Link to post Share on other sites
North London Mike Posted August 10, 2007 Author Report Share Posted August 10, 2007 I wouldn't be happy knowing it was getting that hot in the chamber. The last time I was playing around with the timing I had a little run on after one of my adjustments, I backed it off a little on the vernier (ie about 1 degree, if that) which removed the run on with no noticeable performance hit. A full notch on the vernier is 4 degrees at the crank, it may well be that you only have to back off a quarter of that. Andy Thanks Andy I'll give that a go and report................. Quote Link to post Share on other sites
smizgals Posted August 12, 2007 Report Share Posted August 12, 2007 Mike, Have you got electronic igntion? I fitted the MSD electronic ignition on my TR5 and had a persitant run-on. Anticipated in the kit was a diode to be fitted between the alternator and the charging light, for this situation. I measured a 3 volt leak from the alternator which was enough to keep the MSD box operating with the ignition switched off. Stan Quote Link to post Share on other sites
North London Mike Posted August 12, 2007 Author Report Share Posted August 12, 2007 Mike, Have you got electronic igntion? I fitted the MSD electronic ignition on my TR5 and had a persitant run-on. Anticipated in the kit was a diode to be fitted between the alternator and the charging light, for this situation. I measured a 3 volt leak from the alternator which was enough to keep the MSD box operating with the ignition switched off. Stan Hi Stan Yes , have electronic ignition but also had it before the run on problem. The cause is known, advance curve tuning !! Followed Andy's suggestion and retarded the ing. by 4 'minor' clicks on the vernier seems to have solved the problem. Now all I have to find out is did I over cook it.................. Andy said that a 'full' click on the vernier was worth 4 deg's at the crank. OK a couple of questions Whats a full click, the thing only clicks (doesn't it) and 4 clicks did it, but no way have I retared it 16 degrees at the crank !! Also I seem to remember that the full range of the vernier was only two full degree of advance or retard anyway (four in total if it was full over one way) However there seems to be a LOT of confusion regarding just how much adjustment is available on the vernier? Vernier's, fun for all the family........ Quote Link to post Share on other sites
littlejim Posted August 13, 2007 Report Share Posted August 13, 2007 Although it is now getting hard to remember when my 4a was running, yet alone running on, I stopped it happening by doing a by the book carby tune. had no idea what I was going to do if that didn't fix it. Quote Link to post Share on other sites
smizgals Posted August 13, 2007 Report Share Posted August 13, 2007 Hi Stan Yes , have electronic ignition but also had it before the run on problem. Mike, My response was incomplete. When I first installed the MSD there was no run on. Sometime later after fiddling under the dash around the ignition switch I caused a short and it was after that I got the run on. Am still baffled why? Stan Quote Link to post Share on other sites
North London Mike Posted August 13, 2007 Author Report Share Posted August 13, 2007 My response was incomplete. Stan Hi Stan So was mine! I should have also added that I backed off the tick over from 1000rpm down to 800rpm, it fluffs a little down to 650 and back, but generally runs and holds OK. previously at 1000rpm raced to 1200 and back and was firm at 1000 so in full cry as you shut down the ignition The full test will be the next cold start and run up to full temp (wish me luck) Quote Link to post Share on other sites
smizgals Posted August 13, 2007 Report Share Posted August 13, 2007 Mike, Concerning RPM, I measured mine recently and the rev. counter is showing 200 RPM more at tick over! Having compensated for that I get a much smoother tick over since. Good luck, Stan Quote Link to post Share on other sites
North London Mike Posted August 13, 2007 Author Report Share Posted August 13, 2007 Mike,Concerning RPM, I measured mine recently and the rev. counter is showing 200 RPM more at tick over! Having compensated for that I get a much smoother tick over since. Good luck, Stan Stan That's interesting isn't it, I assume you measured it with a timing light. If mine was also over reading it would make sense as 800 did seem a bit low for a warm(er) cam profile Anybody else got any feed back on rpm and tacho readings ? Quote Link to post Share on other sites
67_gt6 Posted August 13, 2007 Report Share Posted August 13, 2007 Hi Mike, if you look at the vernier adjustor you should see a scale on the left hand side near where the vacuum unit is. Each division on the scale is equal to 4 degrees on the crank so as you wind the adjustor in or out you should see the scale increase/decrease. Andy Quote Link to post Share on other sites
North London Mike Posted August 13, 2007 Author Report Share Posted August 13, 2007 Hi Mike, if you look at the vernier adjustor you should see a scale on the left hand side near where the vacuum unit is. Each division on the scale is equal to 4 degrees on the crank so as you wind the adjustor in or out you should see the scale increase/decrease. Andy Hi Andy MMmm, mine must be the budget item as all I can remember is the A&R arrows (Advance /Retard) and the knurled knob, no scale I'll pop out to the garage, have a look and report Quote Link to post Share on other sites
smizgals Posted August 14, 2007 Report Share Posted August 14, 2007 Stan That's interesting isn't it, I assume you measured it with a timing light. Mike, Fyi, I checked the RPM with one of those meters for cars that also does dwell angle etc. You connect it to the low tension cable from the dizzy. Stan Quote Link to post Share on other sites
ianc Posted August 15, 2007 Report Share Posted August 15, 2007 Mike, the anti-run on valve which I fitted back in 1998 is one of a family of such valves, each of which has a slightly different mounting plate and connection, so you would need to choose the right one for your car (if you decide it is worthwhile). Mine is mounted to a small bracket which is bolted onto the 4th (counting from the front) right head stud, and plumbed into the take-off in the bridge part of the inlet manifold (i.e. the tube linking the front and rear pairs of the manifold). The power is from the ignition circuit, so that the valve opens as soon as the ignition is switched "off". It is true that when my original (1962 SAH) exhaust manifold started to fall apart at the brazed joints, I had a lot of problems with running-on, but once I replaced it with a new manifold of the same pattern (SAH design, obtainable from Moss/Triumphtune), there was a vast improvement. The new manifold did not fit (centres for the front and rear studs were nearly 0.25" adrift) and it had to be adjusted in a hydraulic ram - that left the faces no longer aligned correctly, and it took me about 12 hours (and a lot of grinding wheels!) to get everything re-aligned. I was informed by my supplier that none of these manifolds fit correctly! Why did I fit it and not another type? Solely, because I wanted to retain the original SAH pattern on 4VC. I have noted the details of "my" valve, which is made by Tecalemit and has the following codes on the label attached to its body: TDA 684, 103/449, and it is 12V operation, of course. Ian Cornish Quote Link to post Share on other sites
North London Mike Posted August 15, 2007 Author Report Share Posted August 15, 2007 I have noted the details of "my" valve, which is made by Tecalemit and has the following codes on the label attached to its body: TDA 684, 103/449, and it is 12V operation, of course.Ian Cornish Hi Ian Thanks for the details which I have noted. However, I'm encouraged by my fiddling and hope I've solved the problem which was only a result of trying to match 4VC's performance after my test drive with you I'll let you know how successful I've been when I next see you Quote Link to post Share on other sites
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