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James Wilson Member 
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I'm thinking about fitting an electronic distributor as offered by: http://www.123ignition.nl/ Anyone have any experience with these, or comparable installations? Seems straightforward enough.... |
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Harkes Member 
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I have checked them out since i'm dutch and this is a dutch company and i was in need of a new dizzy as mine was leaking. They do not have a model for the Lotus 907 engine or the Esprit. It was recommended one could try, at your own risk, a standard of the shelf 123 dizzy for MGB or Mini I believe it was. Since the 123 dizzies are expensive i did not want to run the risk to see if it would work. The problem is the Lotus is a horizontal application and there is quite some oil pressure. I had a distributor made some years ago by Aldon Automotive esp. for the Lotus 907 and the darn leaked from day 1 and quite a bit. Next problem with the 123ignition is that they will NOT work with an MSD set up. Also, if you have a Pertronix Flamethrower coil like i have then check the Ohm levels. 123Ignition requires 1Ohm and i believe the Pertronix Flamethrower is 0.5ohm or so. Pertronix Ignitor can of course no longer be use when you opt for the 123 ignition. Having said all that, the 123Ignition IF they had a Lotus 907/Esprit model, is an awesome all in one distributor including electronic ignition and one can choose from 16 advance curves!!! And you can set STATIC timing easily as there is a built-in LED that will light up!!! Through JHPS it could be worthwhile to have a few made for the 907. For those who don't have pertronix ignitor, flamethrower and/or MSD and who are in need of a new distributor or want to go for electronic ignition this could be really interesting. Erik Harkes Netherlands Last edited on 11-15-2006 02:06 pm by Harkes |
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Jensen Healey Super Moderator 
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The 907 likes a very aggressive advance curve. The MGB distributor should be a direct fit but may or may not have the proper curve. IIRC 16 degrees advance at 2500 rpm. Even if you have an electronic dizzy the accuracy is limited by the timing belt flapping about. For performance you want a crank fired ignition. The remanufactured unit from the club store with a Pertronix in it should be excellent for street use. Kurt |
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Greg Fletcher Administrator 
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Kurt is quite right, the MG distributor looks like it fits, but the advance weights and springs are unique for the Lotus/Jensen Healey application. If you just stick that in, you could get it to idle and that's all. On the remanufactured distributors we sell, the spring sets are always replaced with new ones. These springs are custom made for us as the original parts are just about impossible to find now. It actually is a great deal considering all the work that goes into these- they look better than new and are better calibrated than the original Lucas units. These are available with or with the vacuum retard capsule, with traditional points or with the Pertronix Ignitor. Delta also sells an aftermarket unit that uses a vacuum capsule. |
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Judson Manning Member 
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Generally speaking, you can adapt any Lucas 23/25/45 series distributor to the 907. Early on, I ran a Mallory distributor designed for an MGB, that ran just fine. I did get Mallory to add an oil seal as it had a minor oil leak. I currently run a Lucas 45D vacuum magnetic from an Esprit that wires right up to my MSD - very smooth. Don't be scared by the advance curve. Hundreds of weight and spring combinations are out there so you can get exactly where you need to be for low RPM driving. Besides, once you put in new pistons, cams, carbs, the original advance curve has to be modified, and the only way to optimize it is to use a dynomometer - $$$$. My suggestion: Go with a rebuilt unit from JHPS; or if you want to go cheap, find a 'new' MGB distributor that has the features you want, and just swap the weights & springs from your 'old' JH distributor. |
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Mark Rosenbaum Member 
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For whatever it's worth to this discussion, the data I've come across indicates that a stock JH engine has the following centrifugal advance curve, regardless of carburetors used: Crank Crank RPM Advance 1000 0.0° 1200 2.0° 1400 4.4° 1600 6.8° 1800 9.0° 2000 11.4° 2200 13.6° 2400 16.0° 2500 17.0° ???? 22.0° mechanical limit with stock 11° centrifugal cam. Given the time frame in which things were developed, one must wonder whether these values were chosen for best performance, or for least emissions. |
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Art DeKneef Member
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I was at Delta this afternoon and saw a new distributor Jim has there to replace the original. I believe I saw Pertronix on the side of it. It had a small red electronic device inside. Sorry I don't have more info. He only had 5 and they were destined for Australia. But he'll get more. Art |
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Harkes Member
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Guys, i agree on using the JHPS dizzies or the one DMS is selling. But what i can conclude from what is said by Judson and others is that one can apparently use an general MGB dizzy which 123Ignition is actually selling! I'm still wary that it might leak, which is still why i personally would not go for the 123ignition dizzy. But what you guys seem to miss is that the 123Ignition dizzy has 16 advance curves one can tap into by using simply a screw driver!! This means no changing weights and springs! In other words the 123Ignition dizzy seems like a great alternative! Setting static timing with the built-in LED light make things easy, optimal tuning by having the choice of 16 advance curves, spark balancing and there is more. I chose a safer and cheaper route using an Esprit dizzy and built my own Pertronix ignitor in and will use it with my MSD and Pertronix coil. My advance curve may not be optimal for my engine but it will work fine. But if i didn't already have an MSD, Pertronix Ignitor and coil and if the 123Ignition MGB version dizzy would fit AND not leak oil then i would certainly buy that item as it replaces the MSD and top of it i can tune my 2.2L engine optimal with the 16 advance curves, spark balancing, static timing LED etc.. It would be cheaper and offers tuning for the amateur. It would be the next best thing well after crankfired ignition, hence my remark about the JHPS asking 123Ignition for an MGB version may be as Judson also did with his dizzy with extra oil seal added for the 907.. I would be really curious and interested in it. Erik Last edited on 11-16-2006 10:58 am by Harkes |
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Tom Thomson Member
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I've been thinking that I may not know all that I thought I knew about ignitions. What SPECIFIC benefits do I get from a "high performance" set-up. Tom 13753 |
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Judson Manning Member
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Tom, The benefits of a 'high performance' ignition system include: Quicker cold starting, increased fuel economy, better reliability, more power, and lower emissions. Without a 'high-performance' system, you simply increase your odds of the engine periodically misfiring when cold or when it's under severe load. To maximize reliability, use only the highest quality distributor cap, plugs, and plug wires with a distributor that has been properly refurbished. Adding a 'high-energy' coil (or better yet an MSD set-up) will hit the plugs with A LOT of juice to make sure they fire when the distributor tells them. Timing is the other half of the equation and left to the internals of the distributor. Basically you have a switch (either points, optical, or magnetic), and a series of springs, weights and vacuum capsule to adjust the point at which the switch operates. Springs and weights rarely wear out. Likewise, points really aren't so bad as long as they are adjusted periodically. However, this need is why Pertronix, et. al. replace the points with either a magnetic or optical pick-up which never requires maintenance. The stretch of the timing belt limits the accuracy. The ultimate in high-performance is something like the fully electronic crank-trigger system used on Yellow Dog. In order to generate all of Yellow Dog's 240hp, this system hits the spark PERFECTLY on every stroke. This system is probably worth 5% in HP over a typical MSD system and at least 10-15% in HP over a 'stock' system. For a stock or mildly warmed over 907, you might see 3-5% increase in performance using MSD or Crank Trigger, but the real benefit is reliability. Judson |
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Tom Thomson Member
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Judson: The reliabilty part I get; no points to burn etc. It's the starting, economy, power and emissions that have me wondering. These all seem to point to a "hotter" spark which must mean watts (or ergs or joules or calories or whatever label you choose). This, in turn, must mean amps since the voltage at the plug gap limits coil voltage (once the arc is established, at whatever level, the voltage can go no higher). Of course a higher secondary voltage will allow a wider plug gap providing (perhaps) a more effective spark. This sounds as though coil output voltage may not be a good reason to spend the money. Cynical maybe, but I use lots of salt with manufacturers claims. If I understand your comments on crank trigger systems, reliable timing provides a gain of 5 to 15 %. Does this assume some dist. shaft wobble, looseness in the drive dogs etc ? Is this gain thru the rpm range or at top? After I think I have mastered this much, I intend to worry about spark duration, slope of the curve and other such esoteric trivia. Thanks for the info Tom 13753 |
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Judson Manning Member
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Tom, The initial assumption is that the spark will fire every time, which simply is not the case. MSD type systems that reach +40K volts and have multiple sparks in their duration are trying to increase the odds of the spark firing. Of course when/if the spark does strike, it has to ignite the fuel. If the engine is cold and the fuel is poorly atomized, this may not happen (hence the 'multiple' sparks). A larger plug gap also increases these odds, but 'resistance' increases and more voltage & energy is required. Likewise with increased compression ratios, there is actually more 'resistance' and the spark needs more voltage to jump the gap. Doubly so if the plug gap is widened. Tripple that if the plug is also fouled with carbon. Once you understand/accept that 3-5% of the time your plugs are NOT firing (on a good day), that's when the choice to adapt a 'high-performance' system makes sense. Judson |
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Dan Eiland Member
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Happy Holidays to Everyone, I was going through some of the old posts about ignition systems looking for information about what others have done when they convert to the 2.2L. I found one post from Erik Harkes where he mentions running 15^ static advance and full advance of 28^ @ 3500 rpm. I do not know much about all this but can understand that due to the changes in stroke, compression, piston size, camshafts (104's), Carburation (dellorto 45 Trijets) and electronic ignition, that it makes sense that I would have to make changes in the ignition advance to make things work together properly. I am thinking of using my old distributor with the Pertronix LU142 installed along with the new 60,000 volt Flame-Thrower HV coil (3 ohm unit) and the Pertronix Second Strike Box. I notice a lot of people recommend the MSD 6A or AL units. Seems to me the boxes are about the same, so I don't know if there is an advantage using one over the other. I already have a new set of Magnicore 8.5mm wires so no need to purchase new ones. I am wondering if I need to make any changes to the advance cam in the distributor? The one in mine is marked 11^. Do I need to change mine to one that is stamped 15^? I could just grind off some metal from the end of mine but then I wouldn't know how much to grind or how to check it. I could just find another distributor that already has the 15^ cam and rob it to change mine. What are your thoughts? Dan Eiland |
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Harkes Member
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Hi Dan, happy holidays to you. About MSD: i am running MSD 6A not AL. The MSD delivers multiple sparks up to 3000 rpm. Past the 3000 rpm it goes back to one spark. So no extra gain there. Delta Motorsports now sells a new item from Pertronix called "second strike". This little box provides 2 sparks shortly after one another (adjustable!) but from 0 rpm to the very end of your rpm range. Really an improvement over the MSD. It works of course perfect with your current Pertronix Ignitor and coil. About advance curve: my 2.2L engine as you found on the board runs on 15 degr. static and 30 degr. max advance (not 28) @ 3500. The weights in my dizzy are stamped 9 degr. (original 2.0L dizzies are stamped 13 degr. i believe). with a high performance engine you need less mechanical advance then with your stock set up. 9 degr. is about right, but i think 7.5 would be the optimum for my engine. there is a formula, used as a rule of thumb: (max advance - static advance)/2 = mechanical advance in my case: ( 30 - 15 ) / 2 = 7.5 degrees mechanical advance. don't grind anything off your current weights. It is not only the weights that determine the advance curve, it is also the two springs! Bring your dizzy to a professional shop and get a new advance curve optimized for your 2.2L engine. good luck. erik Last edited on 12-27-2006 08:42 am by Harkes |
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Dan Eiland Member
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Erik, thanks for your response. Now you know why I admitted knowing nothing about this topic. Looks like I had this backwards. Appreciate your response and explaining what you have done. If I decide to purchase the parts to do this myself where would I look for parts for our distributors? I will wait until my engine is finished and back on the road before making a final decision as to which way to go on this. I am looking into the Electromotive system as well but it is running around $830 plus shipping and I would still need to have a machine shop do some work to make it fit. The pertronix system is much more affordable but then I will need to deal with adjusting the advance curve on my engine once it is up and running. If money were no object I would go for the Electromotive system, but cost has to be considered and it is a street car in the end which weighs in as well. Again thanks for your assistance and have a Happy, Safe and Prosporous New Year. |
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Harkes Member
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Hi Dan, i didn't know any of this either until i went through the whole process of a new engine and all :) Hope my info is a little bit of help to you. Gary Kemps taught me a lot but there is a whealth of information on this board and great people and i could not have done without. I discussed crank fired ignition (electromotive) with Gary as well and it is indeed the best ignition you can get for your engine, and indeed the most expensive. If i had the money i would go for this too, but i had to save somewhere. Besides the cost of it, the work necessary (fixing a bracket for the sensor, plugging the dizzy gap etc.) to make it all work is considerate. I might go for this in the future when budget allows. For the dizzy: I don't know a place in the US, but Greg Fletcher/JHPS offers dizzies on exchange basis. Send in your old one, have it rebuild and discuss with Greg that the shop builds you a new advance curve based on your engine details. I went to Aldon Automotive in the UK (as i'm based in the Netherlands). Good luck and please keep me posted. Happy New Year erik |
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Dan Eiland Member
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I am wondering how the experts figure all this out? How does one determine what is the best advance curve when building an engine (rebuilding in our case)? I was trying to find someone with the same, or close to, engine modifications I'm doing to find out what they did to modify their distributor advance. I just figured I could use what they did to have my distributor modified and it should work just fine for a street performance car. I've read a couple of on-line write-ups on this subject and it does seem possible to figure this out mathematically. I'm sure others on the list have already been there done this and could save others some time if nothing more in determining the advance set-up for their distributor so the engine is ready to go when the rebuild is complete. Yes, I know there will always be the fine tuning of the carbs and the timing, etc. etc...., but it seems to me the distributor could be set up ahead of time close enough for a street car. This seems similar to setting up a set of dellortos when you are rebuilding them and getting them as close to perfect before they are installed on the engine. Once they are installed they can be further tuned for perfection. Doesn't this also apply to the distributor? Can't I set up the distributor advance based on the numbers and then fine tune things once the engine is finished and running? Currently the stop in my distributor is stamped 11^. From what Erik is telling me it sounds like an 8^ stop would work much better for a modified engine with long duration cams. I found a place in the USA that can do the work and completely rebuild my distributor to like new or better for a very reasonable amount. I am thinking of having both my distributors done just to have a back-up. Would like to hear what others have done, besides Erik, who have gone with the 2.2L upgrade and 104 cams. I really appreciate Erik's feedback and find it very helpful. I also heard from Pete with Yellowdog and his input was just as helpful. I know there are more than two people out there who have done this upgrade. I would like to hear from others out there. Thanks in ADVANCE! |
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Harkes Member
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I'd certainly be interested to hear from others as well, both opinion's and dizzie advance curves. My dizzy is currently stamped 9 degr. for my 2.2L engine. thanks Dan, the 123ignition distributor has electronic ignition build-in but it hasn't got weights/springs inside but instead 16 advance curves which you can tap into to fine-tune (all electronics build in a classic distributor). The only thing is, i'm not certain they have a model that fits the JH/Lotus, but it seems they do. Just fyi. cheers erik |
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Harkes Member
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http://www.teglerizer.com/mgstuff/lucastuning.pdf this link contains a must read if you are to tune lucas distributor. |
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Jensen Healey Super Moderator
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Good information Erik! I may have met one of the previous owners of your car here in the San Francisco area. Was it ever owned by Jim Gagnon? Just a few thoughts on distributors for modified 907's. Since most of us simply use parts that Lotus included in various later iterations of the engine, then it would make sense to use a distributor from a later Lotus. Some of the Esprit guys are using a spring set from Mr. Gasket (#928) to re-curve their 45D distributors. They like the steeper curve which is more like the stock JH. I don't know if this is seat of the pants engineering or was actually developed by a tuner. The 9xx is not listed on the 123 website or http://www.starchak.ca/ because none of those 16 curves are right for the JH or Esprit. I have no doubt that Garry Kemp or other knowledgeable tuners can re-curve for more power but the laypersons like me should probably stick with a stock unit. Remember, you can check the basic curve with a timing light and a hand held tachometer. Cheers, Kurt |
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Dan Eiland Member
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With all this talk about distributor advance, I'm wondering if I keep my vacuum advance when using dellortos or do I remove it from the distributor? I have read it can't be used with dellortos. Should I purchase another 25D4 without the vacuum advance? From what I read on this subject it sounds like all these distributors are basically the same except for what is on the inside. I don't know why I couldn't just purchase a non-vacuum advance distributor already set up for my engine. All input welcome. |
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Harkes Member
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Hi Kurt, that is very interesting. I don't know exactly who the first owner was of my car. All i know is that it was meant to go to the US as it was a stromberg/US set-up. But i was told my car never reached the US but went to Switzerlands instead. I do have information on the previous Swiss owner. It could well be the car did go to the US before it went to Switzerland... My vin is 15175 Dan, you are right; you can't use the vacuum advance with Dellorto's. You need to blank it off. There should be some info on how to do this here on this board. However the cost of having it refurbished and new weights/advance curve is most likely as much as getting a new one. You can get a NEW dizzy for your JH/Lotus without the vacuum advance part and ready for your high performance 2.2L engine. Check with Delta and ask for the Pertronix Flame Thrower High Performance 45D Distributor for British Engines and discuss a proper advance curve for your car. It comes equipped with a Pertronix Ignitor II. Introductory price is $ 215.95 erik Last edited on 12-29-2006 09:05 am by Harkes |
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normv Member 
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My trusty Jensen Manual shows the following centrifugal advance curves, in crankshaft degrees for the 3 types of distributors. 45D.4 RPM Advance 550 0 1250 15 +/- 1 3550 18 +/- 1 25D.4 (early emission engine) 1000 0 1600 6.8 2200 13.6 2500 17 Max Note It list idle retard separately for stromberg cars as 3-5 at 6in of Hg and 5-7 at 10 in Hg prior to Eng. No 4803 This is the vacuum capsule on the side. This is vacuum retard NOT vacuum advance Dellorto (I guess this means the 23D.4 as it list this for non emission engines) BELOW 1000 No advance 1200 2 1400 4.4 1600 6.8 1800 9 2000 11.4 2200 13.6 2400 16 2500 17 Based on these figures if you were to use a 45D and simply remove the module and lock the base plate you could end up with a far to aggressive advance curve, this could be masked by reducing the static timing but I suggest you would loose performance , I have never tested this on a Dyno so I may be wrong and the engine may accept this, however I strongly suggest having 83% of your advance in by 1250 rpm is not ideal (assuming my trusty manuals figures are correct, it is a old Jensen parts & service book so I have no reason to disbelieve it) Last edited on 12-29-2006 01:39 pm by normv |
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Judson Manning Member
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The Lucas 45DM with Vacuum advance fits nicely under my Dellorto manifold, and wires directly to my MSD unit. I got mine off Ebay for about $100.00. Keep in mind there is no 'right' curve. At this point, none of our engines are stock, nor are they running the same blend of gasoline used in the 1970s. Literally ALL of the variables have changed which makes ALL the initial factory settings obsolete. |
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