Lucas distributor advance curves
Lucas distributor advance curves. Of these there are standard and sport versions - the advance curves differ. In the Lucas “Overseas Technical Correspondence Course” Section 3 “Coil Ignition” Part 2 the following is explained: Engine Curve: “ In building up the many different advance curves required by the engine manufacturers, we operate from a curve taken from the engine test which shows the degrees of advance required at different engine Nov 29, 2019 · The additional advance on the Ser II distributor at the lower rpm is not particularly significant IMO - in the upper rpm ranges it is. What is not covered. Please be aware that the marketplace is flooded with low grade reproduction copies of the original UK Lucas distributors which cost $7. The correct weights for the distributor are P/N 410033/S and spring set is 54411290. I have seen some discussions of advance curves in the past, but unfortunately the search function isn't working for me this morning. The CSI ignitions AH3000 MK III have improved curves for this six-cylinder engine. See more complete description below. I go over the basics of springs, both primary and secondary. Jan 22, 2009 · I'd be concerned about the advance curve in the 123 distributor. (each) Qty. £208. The 123/GB-6-R-V distributor replaces most 6 cylinder Lucas-distributors The unit offers 16 different advance-curves, which can be selected by means of a small switch. Alternatively if you have a distributor that already works, use the Lucas number off the body to match up. Now slowly and carefully advance the ignition timing by turning the dizzy clockwise whilst keeping your eyes or your assistant's glued to the tacho. Dec 23, 2014 · Here is the advance curves for most 998 and 1275 engines for comparision;-. our distributors have been created to run on modern fuel, with a modern advance curve giving them. One extensive list of Lucas distributor specifications has been removed from the internet and the page I have book marked is no longer there. 3 HC The result is a loss of performance and Drivability. As the dizzy is turned, the revs should start to rise. Most versions are available with an option of having a mechanical advance for engines using twin sidedraught Oct 22, 2004 · plotted to optimize this engine. The weights and the different types that are This 123 Ignition Distributor is specifically designed to replace Lucas distributors on classic Mini A-Plus engines (There is another distributor for pre-A-Plus engines, refer to 080. If you have an unknown or questionable distributor (or not) distributor that seems to need adjustments you can always use a vacuum gauge to set basic timing. Taking the unit apart revealed that someone had removed the pri Apr 16, 2017 · A simple way of looking at why advance curves are different is to consider why they are needed in the first place! Combustion of the fuel air mixture in the combustion chamber is not instantaneous, and the fire spreads (the flame front) from the tip of the spark plug across the combustion chamber. +++1 Rob Medynski at British Vacuum Unit is a genius and master distributor rebuilder and highly recommended. **What I'm stll looking for is the number of degrees centrifugal advance at specific sample revs for a TR5/6 so I can check the whole advance curve on the distributor. I was curious where you found info on the B variant of the 25D you have. PLEASE correct me if I am wrong. distributors that were used in 3,4 litre, 3,8 litre and 4,2 litre “XK”-engines. In the healey manual it states the advance is 35 deg. Problems come with wear in the advance mechanism, with the earlier type of Lucas distributor being far more susceptible. I like to aim at the notch on the flywheel. I'm planning to fit my TR6 PI with the 123 ignition distributor (number 8898 without vacuum port). Programming. That advance curve is: 4 deg at 600 rpm 19 deg at 2,300 to curve RPM 1 Advance1 ± 1° RPM 2 Advance2 ± 1° RPM 3 Advance3 ± 1° RPM4 Advance4 ± 1° no advance below vacuum code Connection years make models Comments 40116D/E DVZH6A CW 387 1500 15 470 7 300 3 100 superceeded by 40359 40116F/H DVZH6A CW 387 15 1948-52 Commer 1948 Commer 5 and 7 ton, 1950-52 5 and 7 ton Forward Control, 1949-50 6. In real life the Lucas test sheet may be the 7 hg can have a start test range of 6 to 8, full advance @ 14 hg may be 13 to 16 and the degrees may be 7 to 9. In the days of hand cranked engines, you retarded the ignition manually to ATDC for starting, or ran the risk of a broken wrist! Feb 1, 2024 · I discuss the basics of tuning Lucas distributors. Our competition Lucas distributors are rebuilt units with low advance curve suitable for modified cars, sold on exchange basis for your old unit. Use the table below to choose the appropriate curve for your mini. – Hook up a timing light, cap off the vac advance and rev the engine to 3K RPM. Dec 6, 2023 · At a recent tuning session, this distributor was determined to be giving bad ignition timing. Both units 54410415 and the later replacement 54412348 are the same code. The original look of the Lucas distributor. distributor # 40320 on the early 100s. (15 in total) Has anyone in the forum experience/knowledge A word about ignition advance curves. 80. Apr 11, 2012 · I'm rebuilding the Lotus 907 engine for my '77 S1 Esprit, have a very small collection of Lucas 25D distributors and would like build up one with appropriate centrifical and vacuum advance characteristics. In order to make it “difficult” for an amateur, there is a “Wood” of possible settings/advance curves given in a small pamflett which followed. The ECM curve is no. Even with the rather unusual H. You have to look at the Lucas part number to determine what the specifications were originally. Use as much initial advance as possible without encountering excessive starter load. Sep 7, 2013 · It looks to me as though the shop manual gives the advance data in terms of distributor rpm. LUCAS DISTRIBUTOR SPECIFICATIONS - IG-126. My apologies if this has been covered. Now for the cam and bob weights. Visit our "Lucas Distributors" page for distributor re-build information! The 123\JAG-6-R-V replaces most 6 cyl. Based on either the Lucas 25D style or the Lucas 45D style. Dec 28, 2017 · Modifying and altering distributor advance curves has become something of an increasing interest/obsession for me as my car (P5 coupe) is setup to run dual fuelLPG (primary) and Petrol (secondary backup fuel source. to the H. thanks, Fritz. All Lucas distributors will be set the original advance curve with the correct vacuum settings. Click for 20-page 159-KB pdf file. Unless this is an advance problem due to the lack of vacume advance, I want to send this distributor to a shop to get checked out. V12. - Rotation CW and CCW (autodetect) - For 6 Volt and/or 12 Volt cars (autodetect) - For positive and negative grounded cars. Uprated Distributor, Lucas (Exchange) Part Number: TT1271E Application: TR5-6 Tacho Drive. Andrew Edited 1 time(s). Our. Because the distributor is rotating anti-clockwise, moving the points plate clockwise causes the points cam follower to meet the lobe of the cam earlier to advance timing: The vacuum solenoid (arrowed) on Bill Etter's 76: And the microswitch (A) used briefly so OD still worked in 3rd and 4th whereas vacuum advance was only applied in 4th gear. C is John Saunders’ curve. g Dec 15, 2003 · Sent: Monday, December 15, 2003 2:16 PM. All. In the Lucas “Overseas Technical Correspondence Course” Section 3 “Coil Ignition” Part 2 the following is explained: Engine Curve: “ In building up the many different advance curves required by the engine manufacturers, we operate from a curve taken from the engine test which shows the degrees of advance required at different engine The Lucas Distributors 25D4 or the 45D4 were used and also with different advance curves. The CSI ignition for the MGC has 16 different improved curves for this six cylinder engine to select the best advance curve for Please be aware that the marketplace is flooded with low grade reproduction copies of the original UK Lucas distributors which cost $7. If there is a better advance curve than my old, stock Lucas that would run better with this engine I would like to send that curve to the shop. combustion chamber design, I think the total vacuum advance curve at low throttle is pretty similar to other Sep 3, 2013 · Lucas made a huge variety of distributors, with different advance curves, maximum advance, etc. This will bring me really close to John Twist numbers at low rpm, thus As you can imagine, there are thousands of different ignition advance curves, which makes sense considering there are hundreds of different engines each working under vastly different conditions. Oct 5, 2002 · Help identify distributor. The 25D is better made, although apparently it can suffer from points bounce more than the later one. The. If you take a 123/tune, you can set the advance and vacuum curves yourself, as well as a rev limiter, and store two sets of maps, which you can select via an external switch (ie, you can have a regular and a race map). In most cases, neither the advance curves nor vacuum characteristics bear any relevance to the vehicles they are claimed to be suitable for. As you can see at idle (900 rpm) 40897 dizzy grants 19 total degree advance (10 static + 9 centrifugal) while 30 deg max (10 static + 20 centrifugal) at 2. All of our Jaguar distributors have been created to run on modern fuel, with a modern. See graph on web site from Peter Baldwins rolling road. B is typical standard T type. What I looking for is an "advance curve" so that I can get the spec on the RPM and the related advance. The 21 degrees stamped on the cam, indicated the distributors static advance setting. 4 and 6 cylinder Lucas distributors. Lucas technical manuals go to some length to note that distributor rotational direction is Jun 18, 2015 · Thursday 18th June 2015. 8 model 61. Steel parts are re-plated. Re: Delco Remy D204 Advance Curve. British Vacuum Unit is not affiliated with ZF Friedrichshafen AG, the owner the US trademark for Lucas®. Distributor, Standard, new Part Number: RKC5044. Complete rebuild / restore 22D6 XKE 6 cylinder $199. 5 deg at 550 revs, 9 deg at 1100 revs and 12 deg at 2000 revs. What is covered:This document will look at tuning the advance curve of Lucas distributors, 23D/25D and43D/45D types in particular, but the principles and approaches used apply to anydistributor with mechanical advance. These two parts rotate against each other depending on the “advance” of the distributor relative to the engine RPM. . Manufacturers can never anticipate all conditions under which a vehicle will be operating, except in general terms and they most certainly could not anticipate that it The majority of ignition advance curves for BMC A series engines are contained within the The Ultimate ignition system for your MG-C. D My curve, ahead of the others to compensate for modern fuel in a low cr MPJG engine 6. Special advance curves for the MGB 1800 cc engine. DUI Street/Strip Distributors are available for these engines: • Small and big block Chevy • Chevy 348-409 V8 • Chevy 194-292 inline 6 British Vacuum Unit is the only manufacturer in the world to re-manufacture and furbish long detailed Original Lucas® Distributor, Vacuum Advance, Vacuum Retard and Duel Units. advance curve giving them a wide universal fitment. Subject: [E-Type] Series 1 Lucas distributor. They sell it as a general purpose distributor but most every engine out there has a different curve so how does that work? Most applications that run DCOEs and no vacuum advance have 10 to 15 degrees advance where most stock distributors are 18 to 26 degrees. For example the XK150S also uses a DMBZ6A unit but it is the. Hi, I have got hold of an Electronic distributor of the type 123, which I am about to install in my Jag Mk2 3. I simply disconnected the vacuum to the distributor and advanced the timing. May 17, 2016 · So, I tend to have a little less advance at the low rpm's and just enough at the high rpm's to prevent pinging/pinking. Feb 14, 2017 · Tr6PI. 5 & 7 Rylan shows you how to tune your distributor for maximum performance and power "the old fashioned way". For Lucas distributors only. 95. I’ve installed a few 123s, I particularly like the TUNE variant. research of the archives and the JCNA article in the Jag-Lovers site I. Shafts are plated and refit for proper cam spec. My car configuration is basically stock CP 150bhp, original Lucas injection, fitted with a sport exhaust. Hello, I have a table showing the different Lucas distributor part numbers applicable to Rover V8 variants, one of the columns has alphanumerics for the advance curve e. Jul 4, 2011 · The distributor that I have is a type 22D6, Lucas p/n 41558 which is not covered in any of my shop manuals. 8. Manufacturers can never anticipate all conditions under which a vehicle will be operating, except in general terms and they most certainly could not anticipate that it The majority of ignition advance curves for BMC A series engines are contained within the Mar 22, 2017 · The spec I have gives the following data: no advance upto 225 revs, 3. Mazzini wrote:I have 123 Ignition distributors running in a S3 with a Nick Stagg Q420 head and a free flow exhaust system, I also have a perfectly standard Sprint, both engines have 10 degrees at idle and are fully advanced at 3,000 at 30 degrees. However the listed vacuum advance for. As you can imagine, there are thousands of different ignition advance curves, which makes sense considering there are hundreds of different engines each working under vastly different conditions. In. It appears I do not have the original distributor in my 1964 3. The Lucas distributors 25D6 or the 23D6 were used. Vacuum advance units are defined by three statistics: 1. The Advance spring set is a set of 5 specially selected distributor advance springs will allow you to adjust your own unit to suit your engines requirements. A Compilation of Lucas and Delco Remy distributor specifications as used on the MG and Triumph automobiles, listing advance curves and vacuum curves where available. , at 4,800 rpm engine, you should see 32-36 degrees further advance beyond static timing. This replaced the. I think that there is a subtle improvement. Advance Distributor may well be in my future. However, studying advance curve data in the reference table reveals that all ignition advance curves have the same basic pattern, dictated by physics This distributor has more advance curve similar to the 41033 (Mk3 "S") which was better for acceleration and economy. This is a mechanical requirement of all internal combustion engines, but the time it takes an engine to develop that pressure is a function of engine design and operating conditions. We did a lot of dyno work on XK engines when I was racing. All parts are replaced as needed, bushings, bearings, springs, weights etc. Sent my original Lucas 22D - 41202B distributor to Rob for re-curving, he uprated my vacuum advance to an early 5 13 10 spec among other improvements. Minis with engine number 12A2BG01, 12A2BG03, 12A2BG05. For the replacement of most 4 cyl. Main features: rev counter, antitheft system with a PIN code, Bluetooth, Real time tuning, vacuum advance, boost retard, soft rev limiter and more. This is a great feature to easily fine-tune your engine! curve RPM 1 Advance1 ± 1° RPM 2 Advance2 ± 1° RPM 3 Advance3 ± 1° RPM4 Advance4 ± 1° no advance below vacuum code Connection years make models Comments 40116D/E DVZH6A CW 387 1500 15 470 7 300 3 100 superceeded by 40359 40116F/H DVZH6A CW 387 15 1948-52 Commer 1948 Commer 5 and 7 ton, 1950-52 5 and 7 ton Forward Control, 1949-50 6. The CSI ignition for the MGA/B has 16 different improved curves for all those four-cylinder engines types. I believe that I should be using a Lucas model 41605 or a 41623 but can not find any data for the advance springs and cam or the vacuum Dec 26, 2019 · Restart the engine. There is power to be made with ignition advance as the stock Jaguar curves are very timid. Jan 1, 2016 · A is a typical Metro A+ high compression 9/10cr curve. Nov 12, 2014 · That is correct, but DMBZ6A is just the Lucas model number. If you have an MGB or Midget, we have a Street/Strip distributor with an electronically-controlled advance. Lucas-distributors for engines in Great-British (hence 'GB') cars, where the distributor shaft is turning in a CCW direction. This distributor is designed for the later blocks with cotter bolt clamping (cotter means wedge or tapered, so not a split pin). By watching the original ignition curve of the lucas 22D According to my workshop manual the distributor for the TF stage 3 using the AEG122 cam is the Lucas D2A4/DA47/40441. The unit offers 16 different advance-curves, that can be selected via a little switch. The MGC with the 2600 cc six-cylinder engine, was made as a two-door sportscar and as a three-door MGC GT (1967-1969) During this years the Lucas Distributor 25D6 was used. Jun 25, 2016 · If you fit a 123 distributor you will have various advantages. The static timing can be done on TDC, by means of the built-in LED. The 41033 Cooper S mk3 distributor was replaced by Rover with a 45D type BAU1850 less a vac unit and lucas 41372 D4) which fitted Canadian 998cc minis and Marina 1. Features of the 123/TUNE-4-R-V-G. On a lark I installed the vacuum 'advance' unit. 700 if you can ever find a source of these curves - I never have. 8 cr. The purpose of the distributor timing is to Vacuum Unit, Screw Pin Type. The vacuum strength at which it starts to move the timing. To translate to engine rpm, multiply by two, e. 40617A. '66 OTS. Andrew I've added above the data for the curve 40897. In theory the centrifugal figures show only the additional advance at the given rpm, whereas the strobe figure is the sum of the static and the centrifugal advance at the given rpm, and this can be seen to be true with some distributors e. Description. There is a distributor cap for the 25D4 that enables you to use push-on leads (Intermotor 44140; the screw-in type: 44720). – fbing Our competition Lucas distributors are rebuilt units with low advance curve suitable for modified cars, sold on exchange basis for your old unit. Metro 998, Minis with engine number 99Hxx, 1988- onwards. a wide universal fitment. Reliable modern digital technology. all under the same model number. Mar 7, 2017 · 105 Posts. 121-3606a. and this gives specific information about specific timing etc. The starting point of the centrifugal advance curve is controlled by the installed length and tension of the spring. 50 in batches of 500. This document will look at tuning the advance curve of Lucas distributors, 23D/25D and 43D/45D types in particular, but the principles and approaches used apply to any distributor with mechanical advance. £47. However, studying advance curve data in the reference table reveals that all ignition advance curves have the same basic pattern, dictated by physics What is covered: This document will look at tuning the advance curve of Lucas distributors, 23D/25D and 43D/45D types in particular, but the principles and approaches used apply to any distributor with mechanical advance. special vacuum advance Nov 8, 2014 · Tuning the Lucas Distributor. How quickly the centrifugal advance (slope Advanced Distributors, LLC 17495 Marystown Road Shakopee, MN 55379 (612)-804-5543 Classic mini distributor guide. … and here it is, slotting back together. TIPS ON SELECTING AN ADVANCE CURVE. Jan 15, 2024 · Made in Holland (Netherlands), the CSI fully-electronic distributor is a wonderful piece of equipment. Disclaimer: The numbers and concepts explained in this Dec 5, 2021 · In Bob’s 123 curve, he has programmed 12 degrees of advance at 1000rpm, which from what we understand was about the rpm his engine was running when he set up the distributor position for 10 degrees advance using a timing light. the 40897 and 40916 for the 18G, GA, GB etc engines (4 degrees centrifugal @ 600 rpm plus 10 degrees Most DUI Street/Strip Distributors come with vacuum and mechanical advance. The design closely follows the look of original 25D4 Lucas distributors, and there are 16 easily-changed advance curves to get your ignition system's performance just the way you want it. at 6400rpm , as the red line is around the 5500rpm I am very reluctant to rev the engine to 6400 . Feb 7, 2011 · I am rebuilding an Excel 912 for my S1 Esprit, and the distributor that came with it is a Lucas 43DM4. Distributor # 40495A - 1956 Austin Healey 100. complete selection includes Lucas 45D, Lucas 25D, Lucas 59D and Lucas DK4A just to name a few. 2. As this distributor did not offer vacuum-advance, the manifold-pressure curve shows a straight line at zero degrees. Both engines, though different seem to work well with similar, if not identical, advance curves. Factory ignition curves are an approximation, at best, at the time of manufacture. He returned my dizzy into an absolute masterpiece, his craftsmanship is so Apr 10, 2005 · 3000 RPM etc) and the Lucas Injection Manual (Red book) gives the metering unit specs for Saloons and TR's (so fuel is covered). The app makes it possible to adjust the ignition curve and shows an electronic dashboard. classic car. 40616A and it has a different advance curve from the E type. Take that, Lucas. Load that curve into the 123 distributor. Aug 1, 2021 · The advance curves of the Lucas distributors are far from optimal - they just reflect what was possible at the time. come up with the following table of usage and mechanical advance curve. 803). Reference a Lucas 400 Series Master Catalog, 1945-1960. 6 cr. have. Afterward I realized that the 'retard' can was still functional. E. But you need to be really careful. The Ultimate ignition system for yourAUSTIN HEALEY 3000 MK III. The effect of changing spring rates and free lengths will be analyzed, design charts and examples will be presented. The graph and some spec information show the curve and some show the range. This is a great feature for easy fine-tuning your engine! A good book is “How to powertune Jaguar XK-3,4 3,8 & 4,2 litre engines Here at Powerspark Ignition, we have a huge collection of Jaguar and Daimler Distributors for your. For the advance curve there is a slight confusion. This was pretty typical, because they were providing the data for use on a distributor tester, not for use on the car. Distributor body’s are acid dipped and cleaned to OE finish. g. The vacuum strength at which maximum advance is achieved. 8 OTS. 1971-76 TR6 22D6 distributor. stamped number on the side of the unit is the Service number. We totally rebuild, re-curve and recondition the DVX, DK, D2A, DM6, DMBZ6, DM2P4, 22D and 25D. ) It also has a compression ratio of around 11:1 so the ignition timing can be critical. Can use vacuum gauge to also adjust mixture of carbs. 1. So, for example, if we put a 998 distributor in a 1275 engine, it would over advance and likely ruin the pistons (seen that more than once). Aldon performance distributors are based on new Lucas or Bosch units and have been dyno developed to provide the correct ignition advance curve to suit different states of engine tune. Manufacturers can never anticipate all conditions under which a vehicle will be operating, except in general terms and they most certainly could not anticipate that it The majority of ignition advance curves for BMC A series engines are contained within the As you can imagine, there are thousands of different ignition advance curves, which makes sense considering there are hundreds of different engines each working under vastly different conditions. To add complication, the vacuum advance unit was also designed for specific applications, so if you swap one from an unknown source, it may change the advance curve. land rover 110 Distributor lucas 35DM8 & 35DLM8 / LPG Afstellen op 8 graden voor bdp bij 750 rpm mat stroboscoop lamp. There are two Lucas distributors: 25D or 45D. Our full range includes Lucas 45D6 Cylinder and Lucas 25D6 Cylinder just to name a. CCW 'Lucas'-distributors The 123\GB-4-R-V replaces most 4 cyl. I was happy with performance. Here at Powerspark Ignition, we have a wide range of Lucas Distributors for your classic car. However, studying advance curve data in the reference table reveals that all ignition advance curves have the same basic pattern, dictated by physics Jun 24, 2019 · Saloons. (autodetect) - Coil current protection time-out after 1 second (autodetect) - Two centrifugal advance curves (500 to 8000 rpm) We set and test the advance curve of each distributor on a Sun distributor testing machine for optimal performance with vehicles using 4-cylinder, vacuum-advance, points-based Lucas 45D distributors. 5 & 7 Advance curve for 23D4 41189A distributor. As you know, it has 16 pre-memorized curves selectable by a rotary switch. Now, the ignition may have to be retarded a little to avoid knock or pinking but otherwise the standard mechanical advance curve should still be OK. This distributor requires an ignition module, Lucas AB14. There will be some confusion when refering to the direction of rotation of the distributor. For those interested my MGB is 9:1 compression, 060" overbore, mild road cam, twin HIF's and TT header and exhaust, Lucas 123 ignition curve #1. equipped with a 3000cc six-cylinder engine. The Austin Healey 3000 MK III is a two-seat roadster produced from 1964 to 1967 and. An ignition advance curve is designed to light a fuel-air charge and place the peak cylinder pressure at around 18Ú ATDC. This is the long list of all known original Lucas distributors (and specifications). 40. couple. The next most complete list, still in existence, does not show a 41270 specification, but does show a 41271 which is listed for the 71 Sprite. Price. After some further investigation I've found that the main chip inside this Lucas ignition module is a GM Delco part, easy for me to get as I am in California. You may have seen John’s article of modifying a type 25 distributor to fit an XPAG in the May Octagon Bulletin. Ready to install. An engine will be easier to start if the advance is zero, or even a little ATDC, at cranking speed. Jan 20, 2018 · I installed the advance on mine because I thought that the 'retard can" was ruptured. Feb 10, 2016 · Re: Using Lucas 40897 distributor curve on an 18V780 engine. Just as an example, compare the pre-H. Using the idle adjustment screw on the carb, increase the idle speed to near-enough 2,000rpm. Bob weights on the cam. May 11, 2018 · Breaker plate slots back together. Start the centrifugal advance just above the idle rpm. Oct 31, 2005 · centrifugal advance curve is depends on the engine design (mainly the compression ratio), which is why there are so many different ones out there. What is covered: This document will look at tuning the advance curve of Lucas distributors, 23D/25D and 43D/45D types in particular, but the principles and approaches used apply to any distributor with mechanical advance. ) Distributors and Distributor Parts. I've found someone who will morph my 40953 distributor into a 41189A (for a Weber Sprint conversion) as well as rebuild it. (The Lucas part number is a 5 digit number, usually with one letter after it, like 40698B. – Set a curve point for 8 degrees @ 1K RPM, a point for 27 degrees @ 3000 rpm and a point for 27 degrees at 5K. If you already have SU carburetors with ported vacuum simply have us re-built and re-curve your distributor to a early advance spec. I guess this may be in the TR5/6 workshop We also supply two alternative units with reduced curves to be used with either SU carburettors with vacuum advance, or side-draught Webers without vacuum advance. This read-only message was archived from a public mail list. ”. We supply a whole range of new, outright Lucas distributors, below is just a small selection. lucas distributor tuning Control your 123\Tune+ with your iOS or Android phone or tablet. If this is the case, his distributor is actually positioned with -2 degrees of “static” advance. The effect of changing spring rates and freelengths will be analyzed, design charts and examples We use the industry standard Sun 400, 404, 504, 680, and MDT distributor machines, and keep a Snap-On Distrib-U-Scope as a backup! Vacuum Advance Rebuilds!!! We can rebuild your Lucas vacuum advance to new specifications! Starting at just $30, we can install a new fuel resistant diaphragm to bring your advance mechanism back to life. 200. - Variable dwell constant current, fully autom. When an engine is modified, just as we do usually need to change our Carb Needle, we also usually need to change the Distributor Apr 27, 2016 · I have fitted an electronic distributor brand 123, with vacuum advance, I have tried to find the Lucas advance curve for the 25d6 original distributor with no luck so far. my. ho fj qm il hb gt sh mi tj gn