{"id":28836,"date":"2016-07-20T16:48:12","date_gmt":"2016-07-20T23:48:12","guid":{"rendered":"http:\/\/www.racingjunk.com\/news\/?p=28836"},"modified":"2016-11-30T11:45:25","modified_gmt":"2016-11-30T19:45:25","slug":"how-to-set-up-an-msd-distributor-part-i","status":"publish","type":"post","link":"https:\/\/www.racingjunk.com\/news\/how-to-set-up-an-msd-distributor-part-i\/","title":{"rendered":"How to Set Up an MSD Distributor Part I"},"content":{"rendered":"

\"MSD<\/h4>\n

Directing the Spark: MSD Distributors<\/strong><\/h4>\n

The coolest, most powerful, most feature laden ignition system in the world can\u2019t function alone.\u00a0 It needs to be triggered by a distributor (or crank trigger) of some sort.\u00a0 MSD Performance<\/a> tells us that many of the ignition boxes in their arsenal can be triggered by way of a set of points or any number of OEM (and select aftermarket) electronic ignition systems.\u00a0 Something like a GM HEI, a Pertronix Ignitor electronic, a Mallory 9000, a Hall effect distributor and many others can be used in conjunction with the 6AL-2.\u00a0 The best trigger setup is most likely a matching MSD magnetic pickup distributor of some sort. Or even better, a crank trigger system.<\/p>\n

Let\u2019s start at beginning and examine MSD\u2019s Pro Billet distributors.\u00a0 Each of them features a CNC machined billet aluminum housing along with a billet aluminum base.\u00a0 Models are available with and without vacuum advance.\u00a0 The Pro Billet distributor shown in the accompanying photos is designed for use with an MSD Ignition Control.\u00a0 It\u2019s configured as a mechanical advance only model (more on advance systems later).\u00a0 The shaft is a polished QPQ (liquid nitride) coated, large diameter (0.500-inch) steel assembly. \u00a0MSD incorporates a sealed ball bearing on the topside of the shaft that works along with an extra long sintered bearing on the bottom end (this provides increased shaft support). The mechanical advance weight pins are staked and TIG welded to the plate.\u00a0 MSD makes use of special nylon pads beneath the advance weights.\u00a0 The reason? They allow for smooth action as the weights advance.\u00a0 In addition, the advance system can be locked out if necessary.\u00a0 Internally, MSD has engineered the distributor with a special oil tract, which improves lubrication to both the distributor and the cam gear.\u00a0 In Chevy applications, the distributor is machined to accept o-ring seals. These seals can be used in modified blocks as a means to improve oil pressure control. The pickup used in the distributor is a maintenance-free magnetic model that works in conjunction with a precision reluctor wheel.\u00a0 The idea here is to provide stable timing throughout the RPM range.\u00a0 The distributor comes with a two-wire harness that plugs directly into most MSD ignition boxes.<\/p>\n

Something you\u2019ll really appreciate is the ease of setting the ignition advance curve.\u00a0 As most of you know, the curve is important because in the vast majority of situations, you\u2019ll need to bring in the spark before the piston reaches Top Dead Center. Doing this provides the spark with sufficient time to light the air-fuel mixture.\u00a0 As the RPM rises, the time required to bring in the advance increases.\u00a0 Having advanced timing tends to increase cylinder pressure, which in turn improves low RPM torque.\u00a0 You\u2019ll also gain throttle response, which is important down low.\u00a0 It\u2019s not all bliss however:\u00a0 In high gear there can be a loss of power (at higher engines speeds) if there is too much timing. That’s the reason why high gear spark retard systems have been used in many race applications.\u00a0 It\u2019s also possible to dial in too much advance into the ignition system.\u00a0 The end result is usually detonation.<\/p>\n

It’s no secret that initial advance is what is dialed into the engine before the centrifugal advance begins.\u00a0 That\u2019s easy enough to accomplish (by moving the distributor), but really, how much initial does your engine really require?\u00a0 It depends upon a wide range of circumstances. MSD\u2019s chart (below) lays out your timing options for a given factor:<\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
FACTOR<\/strong><\/td>\nADVANCE TIMING<\/strong><\/td>\nRETARD TIMING<\/strong><\/td>\n<\/tr>\n
Cylinder Pressure<\/td>\nLow<\/td>\nHigh<\/td>\n<\/tr>\n
RPM<\/td>\nHigh<\/td>\nLow<\/td>\n<\/tr>\n
Vacuum<\/td>\nHigh<\/td>\nLow<\/td>\n<\/tr>\n
Energy of Ignition<\/td>\nLow<\/td>\nHigh<\/td>\n<\/tr>\n
Fuel Octane<\/td>\nHigh<\/td>\nLow<\/td>\n<\/tr>\n
Air\/Fuel Mixture<\/td>\nRich<\/td>\nLean<\/td>\n<\/tr>\n
Temperature<\/td>\nCool<\/td>\nHot<\/td>\n<\/tr>\n
Combustion Chamber<\/td>\nOpen<\/td>\nCompact Shape<\/td>\n<\/tr>\n
Spark Plug Location<\/td>\nOffset<\/td>\nCenter<\/td>\n<\/tr>\n
Combustion Turbulence<\/td>\nLow<\/td>\nHigh<\/td>\n<\/tr>\n
Load<\/td>\nLight<\/td>\nHeavy<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Honestly, there is no one perfect curve for any engine.\u00a0 As a total package each racecar (or street-strip car) is different and because of this, each ignition curve will have to be different.\u00a0 That\u2019s why it is important to have a distributor that can be re-curved easily.<\/p>\n

Before we dig into setting up the curve, ponder this:\u00a0 In most production line distributors, there are two advance systems in use \u2013 Vacuum and Centrifugal, and almost all (vintage) production line cars incorporated both systems. These advance systems operate independently of each other.\u00a0 Centrifugal advance functions by way of a pair of governor weights and springs, that are controlled by engine RPM.\u00a0 Centrifugal force shifts the weights outward against the tension of the springs.\u00a0 This causes the distributor cam to move which advances the timing.<\/p>\n

The vacuum advance system includes a diaphragm that responds to the difference between atmospheric pressure and induction pressure.\u00a0 Pre-emission vacuum advance systems were hooked to a manifold vacuum source (usually located downstream of the carburetor throttle plates).\u00a0 At idle and during part throttle operation, manifold vacuum is high.\u00a0 This advances the ignition timing. If the engine is operated at wide-open throttle, manifold vacuum is low.\u00a0 As a result, the vacuum mechanism inside the distributor doesn\u2019t advance the timing.<\/p>\n

This all changed in the middle of the Sixties. The vacuum source was changed from the manifold to “spark ported vacuum”.\u00a0 With this setup, vacuum is lowest at idle and it increases as the throttle is opened (completely opposite to manifold vacuum).\u00a0 At idle, a spark ported vacuum system provides zero vacuum advance where the older manifold vacuum advance system might have provided as much as 10-12 degrees additional timing.<\/p>\n

Given the slew of variables most high performance (or race) distributors do not make use of vacuum advance (case-in-point is the MSD Pro Billet Distributor shown in the accompanying photos).\u00a0 A vacuum advance system can increase the total timing to 50 degrees or more.\u00a0 Obviously, there aren\u2019t too many high performance or race applications that can accept that much ignition advance. Vacuum advance was helpful in low compression applications, where it could improve fuel economy.<\/p>\n

Total ignition timing is the sum of initial timing and centrifugal advance.\u00a0 For example, if a car has 12 degrees of initial (which is set by \u201cdialing\u201d it into the distributor by way of the timing marks on the harmonic damper) and it has another 23 degrees of timing in the centrifugal advance mechanism, the total timing works out to 35 degrees.<\/p>\n

Bringing in the advance in late was pretty much standard issue on production cars.\u00a0 It would often take 4,000+ RPM to see all of the timing \u201cin\u201d.\u00a0\u00a0 If ignition timing (what we\u2019d refer to as \u201cthe curve\u201d) is brought in sooner, you\u2019ll often see much improved performance.\u00a0 MSD notes: “The function of the advance curve is to match the ignition timing to the burning rate of the fuel and the speed (RPM) of the engine.\u00a0 Any factor that changes the burning rate of the fuel or the engine speed can cause a need for an ignition timing change.”<\/p>\n

Here\u2019s a list of tips courtesy of MSD for setting up an advance curve in their Pro Billet Distributors:<\/p>\n

    \n
  • Use as much initial timing as possible without encountering excessive starter load or engine kickback.<\/li>\n<\/ul>\n
      \n
    • Start the centrifugal advance just above the idle RPM.<\/li>\n<\/ul>\n
        \n
      • The starting point of the centrifugal advance curve is controlled by the installed length and tension of the spring.<\/li>\n<\/ul>\n
          \n
        • How quickly the centrifugal advance (slope) comes in is controlled by the spring stiffness. The stiffer the spring, the slower the advance curve.<\/li>\n<\/ul>\n
            \n
          • The amount of advance is controlled by the advance bushing. The bigger the bushing, the smaller the amount of advance.\u00a0 Five extra advance stop bushings are supplied with the MSD distributor. The distributor comes with a Blue (21-degrees) bushing already installed. The bushing selection includes:\u00a0 Red-Smallest (28-degrees), followed by:\u00a0 Silver (25-degrees), Green (23-degrees), Blue (21-degrees), Purple (19-degrees) and Black, which is the largest (18 \u2013degrees)<\/li>\n<\/ul>\n

            MSD\u2019s Pro Billet distributor offers a huge range of adjustment when it comes to ignition curves.\u00a0 It allows you to dial in how quick the timing comes in, and it also allows you to limit the amount the timing can be advanced.\u00a0 The general idea is to bring the curve in as quickly as possible without the engine detonating.\u00a0 This means you should work with the springs supplied with the distributor to reach the ideal curve for your combination. Some applications might need one very light spring along with a heavy spring, while others might work best with a pair of light springs.\u00a0 Some might need a pair of medium strength springs and so on.<\/p>\n

            In the end, the Pro Billet line of distributors from MSD are jam-packed with tuning features.\u00a0 They\u2019re also easy to work with and equally important, they\u2019re plug and play with most MSD ignition boxes. \u00a0In Part II, we\u2019ll take a look at another option \u2013 crank triggered ignition.<\/p>\n

            \"MSD
            MSD\u2019s Pro Billet distributor includes CNC-machined 6061-T6 housing, along with a small diameter HEI style cap. The trigger wire harness plugs directly into most MSD ignition systems.<\/figcaption><\/figure>\n
            \"MSD
            Once removed, you’ll find a bushing. You can swap it for another bushing. The smallest bushing (red in color) allows for 28 crankshaft degrees of advance followed by: Silver (25-degrees), Green (23-degrees), Blue (21-degrees), Purple (19-degrees) and Black, which are the largest (18-degrees).<\/figcaption><\/figure>\n
            \"MSD
            An important factor when setting up the advance curve is to limit how much advance is added. It\u2019s not that easy on a factory distributor (we\u2019d usually weld up the advance plate). But it\u2019s easy with a MSD distributor. Beneath the advance assembly plate you\u2019ll find a locknut and washer (they’re fastened to a post on the bottom side of the distributor shaft).<\/figcaption><\/figure>\n
            \"MSD
            The lightest springs included in the package are silver — they provide the quickest rate of advance. They get progressively heavier.<\/figcaption><\/figure>\n
            \"MSD
            Curve changes in the distributor are made by way of springs. Weights are not changed (which was common in the old days with factory distributors). MSD includes a wide range of springs with their distributors.<\/figcaption><\/figure>\n
            \"MSD
            The ignition trigger is magnetic and it includes a precision reluctor wheel. This setup is designed for stable timing throughout the RPM range.<\/figcaption><\/figure>\n
            \"MSD
            The distributor is laid out much the same as a vintage Delco component. That means the mechanical advance system is located directly under the rotor.<\/figcaption><\/figure>\n
            \"MSD
            The rotor in the Pro Billet distributor is a race quality job molded from DuPont Ryanite. It\u2019s designed with a deep skirt and thick vanes in order to prevent ionization and reduce spark scatter.<\/figcaption><\/figure>\n

             <\/p>\n","protected":false},"excerpt":{"rendered":"

            Installing MSD’s Pro Billet distributor will give you access to a variety of tuning and timing features in your engine. Part I of this new series covers the basics.<\/p>\n<\/div>","protected":false},"author":20,"featured_media":28838,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[3448,5013,11,3698,9],"tags":[1389,961,281,629,557,4701,4764,461,2413,4702,321],"class_list":["post-28836","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-drag-race-101","category-electronics-wiring","category-how-tos","category-tech","category-tech-tips","tag-distributors","tag-drag-race-101","tag-how-to","tag-msd","tag-msd-performance","tag-msd-pro-billet-distributor","tag-tech","tag-tech-tips-2","tag-timing","tag-tuning-options","tag-wayne-scraba"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2016\/07\/MSD-Spark-2.jpg","jetpack_shortlink":"https:\/\/wp.me\/p42YSK-7v6","jetpack_sharing_enabled":true,"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts\/28836","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/users\/20"}],"replies":[{"embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/comments?post=28836"}],"version-history":[{"count":1,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts\/28836\/revisions"}],"predecessor-version":[{"id":28847,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts\/28836\/revisions\/28847"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/media\/28838"}],"wp:attachment":[{"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/media?parent=28836"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/categories?post=28836"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/tags?post=28836"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}