spitfireguy Posted August 7, 2015 Author Share Posted August 7, 2015 Nick... I always appreciate how you hang in there with me on my stupid questions... really I do! I had red springs in the carbs, but bought brand new red springs to make sure the 4 1/2oz or whatever was more accurate, I also have brand new Yellow springs as well. I can't think of ANY place near me that would be able to do a dyno thing... We do have a repair shop called "Mr. Sports Car" and he is in my British Car Club, but his shop isn't much more than a lift and some tools. I DO plan on pulling a few club members aside this Sunday at the Autocross event, maybe their collective wisdom will help as well. The air filters I have are K&N cone style. I have the MGB round, venturi type things mounted on the carbs, and the air filters attach to that via large hose clamp. Last night I went for a long cruise... If I accelerate full throttle down, it's really gassy smelling. Accelerate half throttle and short shift, not so bad. Cruising down the highway, steady throttle at 4000 RPM, it stutters on and off. Based on the Minty Lamb charts would the AAR or AAF be better than my current AAM? It's really the 6-9 needle position that I need to worry about, right? Since I've messed around with these needles so many times, perhaps I'm going about it wrong. If you think a different needle should be tried.. I know this is a lot to ask, but after I insert the new needles, tell me the steps you would take.. maybe I'm missing something? Mike Link to comment Share on other sites More sharing options...
2.5piman Posted August 8, 2015 Share Posted August 8, 2015 Hello Mike, looking at your link for that distributor I'm put off by the fact that it says it will also fit some other cars. Yes of course it will fit but what is the advance curve, I see no mention of that? There are literally hundreds of 45D4 distributor curves. (Also very many different vacuum modules, both the original Lucas distributor and vacuum modules are stamped to identify them, e.g. 40870 and 6 14 8 respectively) P.S. I see that one is identified as 41427? Is that correct as per the workshop manual? You could try advancing and retarding the distributor six to eight degrees about the standard setting just as a trial at your 4000 rpm to see if it has any effect, it probably will upset the low down timing but it may give some feedback at higher speeds. If it does then that distributor is wrong. I also see that you have opened your plug gap. I have a book called Engine Technology for the Modern World by Roger Bywater which goes into very detailed description of all the aspects of engine deign and his view is that widening the spark gap from the original specification is detrimental as it takes more of the enrgy away from the phases after the initial spark and also increases plug wear. I'm not saying this has any bearing on your problem it's just an aside and contrary to the percieved opinion that widening the gap is better. Alec Link to comment Share on other sites More sharing options...
GT6 Nick Posted August 8, 2015 Share Posted August 8, 2015 Mike, have you considered fitting a wideband oxygen sensor so that you can see how the carburettors are really behaving? I fitted one of these http://www.innovatemotorsports.com/products/MTXL.php in my injected GT6, and am thinking about putting one in my Herald as well. It has twin HS4s like your Spittie - and to reassure you - once they're tuned, they stay in tune very well. I'm only thinking about fitting a wideband because I love to tinker and want to see what's going on down in the engine room! In your case, it would show whether the carbs are running rich or lean at various points in the rev and load cycle, allowing a better needle choice. Mine are AAQ, by the way. You'll also be able to see if they're providing some momentary enrichment when you put your foot down - the damper oil and spring have a bearing on that. Link to comment Share on other sites More sharing options...
Nick Jones Posted August 9, 2015 Share Posted August 9, 2015 Agree that the wideband O2 sensors are powerful tools. However, they do have their limitations. Misfires due to ignition problems or mixture extremes show as high levels of oxygen (charge passes through the engine unburned) and show as lean/very lean. Nick Link to comment Share on other sites More sharing options...
spitfireguy Posted August 10, 2015 Author Share Posted August 10, 2015 Alec, V8Nick and Nick: I know I've been concentrating on the Carbs, so much that I've kept the ignition discussion on the back burner. It finally dawned on me that as you all have suggested at one time or another that my distributor (and other parts of the ingnition) may be the culprit. I'm very much in agreement now. I have an older distributor, not sure if it's a 45D4 or not, but I'm going to rummage through my parts boxes until I find it and do some experimenting. I probably won't have anything to report back for a week or two, but again, I can't thank you enough for your ongoing suggestions and thoughts. I'm going to get this right, and I owe that to you guys. Thanks... OH.. the O2 sensor.. I'll look into that a bit too. Will do distributor first, then may fall back on O2 later. Thanks.. Mike Link to comment Share on other sites More sharing options...
GT6 Nick Posted August 10, 2015 Share Posted August 10, 2015 If we're talking about distributors, the biggest improvement I made to my car's running in years was replacing the points distributor with a programmable 1-2-3. It took a while to get the advance curves right, but a lot of the car's quirks, which I'd thought were down to poorly tuned or worn HS4s, turned out to be due to the distributor. The 1-2-3 was expensive, but worth it. And no, they haven't sponsored me! I'd had the original Lucas 25D4 reconditioned and recurved a few years ago - OK, maybe 15 years ago - so didn't want to admit that it was causing problems. That would mean I'd wasted money, dammit! The car had always had a slight flutter at moderate revs, and eventually developed an intermittent earthing problem with the baseplate (intermittent meaning 'only at the most inconvenient times possible'). I changed the baseplate and points, but the basic poor running didn't improve. The next step was taking the plunge and replacing the whole dizzy. But, as soon as I started the car with the 1-2-3 for the first time, I realised how many of the car's problems had been down to the ignition. Suddenly it didn't need any choke for a first start on a mild day, it just started and ran perfectly. Once I'd dialed in a basic set of curves and then fine-tuned them while driving, it ran better than it ever had in twenty-something years. I still carry the old dizzy in the boot in case the 1-2-3's silicon brain explodes, but I hope it doesn't. Refitting the Lucas dizzy would be a great leap backwards. Link to comment Share on other sites More sharing options...
spitfireguy Posted August 11, 2015 Author Share Posted August 11, 2015 V8 Nick: Sorry to be so stupid, but what is programmable 1-2-3? Is that the wideband sensor suggested earlier? Pulled my old distributor out and it is the US spec 45DE4.. with the black box electronic ignition.. neither of which I am using obviously. At the Autocross this past Sunday, I was talking with one of the old-timers in the club and once I added 'ignition and distributor' into the conversation, after talking tuning the carbs for a while, his eyes lit up and said yes and agreed you fellas have been guiding me down the right track. I've sent an inquiry to this guy: http://www.advanceddistributors.com/ Jeff is his name and once I mention him, several people say he knows his stuff. The go to guy here in the states for distributors. I believe I will work with him rebuilding my 45DE4 or whatever else he suggests after I hear back from him. on a side note.. Pertronix, Crane, or ? is best in your mind? Mike Link to comment Share on other sites More sharing options...
Nick Jones Posted August 11, 2015 Share Posted August 11, 2015 This is a 123-Tune http://www.123ignition.nl/products.php?id=50&lang=eng Distributor with fully 3D programmable curve. Do not confuse with the cheaper and inferior version with switchable curves. Nick Link to comment Share on other sites More sharing options...
2.5piman Posted August 11, 2015 Share Posted August 11, 2015 Hello Mike, hang on just a minute, it's all to easy, if costly, to jump into buying more equipment. Do try running the car with different timing settings as i suggested as this could give you a guide to whether the timing is the problem or not. For just a little time and at no cost can give you an indication if you are on the right track? Nick, I have no doubt that the programmable 123 can give good results, (as much as I hate electronics on old engines) but the blurb on their website is terribly optimistic and really misleading. It is very easy to adjust but very difficult to get right without doing it on a dynamometer.. Alec Link to comment Share on other sites More sharing options...
Nick Jones Posted August 11, 2015 Share Posted August 11, 2015 Agree on two counts. First, I'm not necessarily thinking it's a timing thing. Mike has said he's experimented with the timing without much effect. I was more suspicious that it was some kind of hardware malfunction. Second, the 123-Tune (or any mappable 3D system) is a powerful tool that comes into it's own on modified engines, especially heavily modified. The two main benefits are that it is much easier to actually change the settings as they can be altered on the fly - no monkeying with springs and weights (which will save you money at the RR), and also that you can do things with it that are not physically possible (or at least very difficult) with mechanical systems like have more advance at lower rpm than higher rpm which can really help low end torque with a wild cam. It is probably overkill on a mildly modified engine (though still benefits to be had for sure) and care is certainly needed when setting it up. A friend of mine killed a perfectly good Ford crossflow by dialling in too much advance at full throttle/rpm - melted two pistons. Definitely a rolling road is is very helpful tool in setting it up, especially the the high load areas, but with care and a smart assistant you can get a pretty damn good result by driving around. In Mike's place though, I'd be banging in a simple points distributor and swapping the coil/leads/plugs just to try and provoke a reaction. On the subject of plugs, I've mentioned before, here and elsewhere, that I've had great results with triple electrode plugs, Bosch W(R*)7DTC being the favourites, but the equivalent NGKs work ok too. Note that I've had trouble with NGKs failing due to flooding/severe overfuelling which seems to impair the ability of the insulator to insulate - newer plugs seem worse affected. Nick Link to comment Share on other sites More sharing options...
spitfireguy Posted August 12, 2015 Author Share Posted August 12, 2015 Nick and Alec: Thanks for the link and explaining the 1-2-3 ignition. I'm hesitant to throw more money at my problem, although truthfully, I have and am doing so now. Based on the reaction you both had with the TruSpark distributor, I switched my focus to studying up more about timing, distributors, etc. I have a 45DE4 in my parts boxes that presumably was on the engine at one time, but I can't remember. I believe the vacuum component is a 'retard' rather than an advance? None the less, I do want to know more about the distributor. I was able to get a bit better running at higher RPM's with my current TruSpark if I started with about 16 Degrees static. So, throwing more money at the problem, but with the idea of isolating the problem, I bought a 45D4 brand new from SpitBits yesterday. Standard points, etc. I'll be following Nick's lead by installing the distributor, NEW plug wires, NGK's and swapping in a coil of the previous mentioned changes prove no difference. This has been a long process, but I've learned a lot from you both, Alec and Nick, and appreciate you taking the time to stay with me here working this out. Mike Link to comment Share on other sites More sharing options...
DaveNotSoSideways Posted August 12, 2015 Share Posted August 12, 2015 Try BP6es plugs. I always ran BPRs after issues with petronix ignition and BPs causing an idle misfire. 5ES is too hot for modern non-leaded fuel and increased CR ratios. Link to comment Share on other sites More sharing options...
spitfireguy Posted August 24, 2015 Author Share Posted August 24, 2015 Bringing this to a close... I have solved this issue now. Alec, 2.5piman, V8Nick and especially Nick, I really appreciate all your advice and suggestions. I can't find a forum anywhere else that has straight-forward advice like here. I put in a new 45D4 distributor (41449) with points. This was what was needed all along, not really the HS4's, even though symptoms suggested so, it was the ignition all along. With the new distributor, my idle was smooth and even, acceleration was stronger, higher RPM's were attained with no stutter or hesitation. Next I added the Pertronix unit which made it even better, bagged the points and put them in the boot, replaced the coil. I'm on the right track now. BP6ES plugs are in the mail and will be installed this week. New plug wires were installed as well as an FYI. Summary, the TrueSpark electronic distributor I purchased from a US British Parts specialist was all wrong. 2.5piman sent me down the right road questioning the advance curve on this distributor. I spent many hours studying and learning about advance curves, etc. and knew I was chasing my tail working on the carbs rather than ignition. So to help anyone else that may be in the same boat, I do not recommend the TrueSpark distributor for a 1500 Spitfire. It's all wrong. Can't say THANK YOU enough to the forum regulars that have in the past, and have again with this issue helped me immensely. Thanks. Mike Omaha, NE Link to comment Share on other sites More sharing options...
Nick Jones Posted August 24, 2015 Share Posted August 24, 2015 Very pleased to hear you've solved it - and thanks for reporting back - otherwise we'd never know whether our suggestions were any good! Drive and enjoy! Nick Link to comment Share on other sites More sharing options...
2.5piman Posted August 25, 2015 Share Posted August 25, 2015 Hello Mike, well done, it's a great feeling when a troublsesome fault is cured, and I second Nick's remarks about letting us know. Alec Link to comment Share on other sites More sharing options...
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