How to Set-up Your Classic Mini's Initial Ignition Timing
Any deviation away from the original standard engine specification, or where a dizzy from another source is used in the engine you have, the ignition timing will generally be different from that set by the manufacturer.
Distributor Timing Basics FirstDizzies that have had their advance curves altered to suit a particular specification by a specialist should come with an initial setting of some sort - either static or strobed. Even having a strobe figure stated has its pitfalls - least of all having no reliable or accurately set TDC mark/pointer on the crankshaft pulley!
To get the engine started for running in or to a rolling road for initial set-up or where no rolling road exists where no such information is given, it's essential to get the ignition timing in the right operating envelope to avoid damage caused by incorrect ignition timing. Results of which can be disastrous.Terminal even.
Rules To Follow ? Not Really.
There are no hard and fast rules or methods carved in stone with guarantees on how this should be done. But clearly a starting point is needed, so the following is the method I use where information is a little thin on the ground!There are two stages to this method.
- The first to get the engine started and warmed up- a static setting.
- The second to get the best from an unknown quantity without costly damage - a running setting.
Step One In Setting Up Your Distributor's Timing - Setting the Ignition
The first is very quick to sort out, as it is merely to ensure easy starting for warm-up. Whatever distributor you have, setting the ignition statically to have no more than 5 or 6 degrees advance (firing BTDC) is the way to go. You certainly don't want it set to fire ATDC - it causes all sorts of problems including exhaust pipes glowing red hot at idle! So just run through the standard method for setting ignition statically (see relevant separate article).
Step Two In Setting Up Your Distributor's Timing - Run The Engine
Once satisfied the static ignition is set, start the engine and run it until it reaches as close as you can get to normal running temperature or at least until the thermostat opens where one is fitted. Easily detected by the sudden increase in temperature of the top rad hose to the touch. Switch the ignition off,holding the throttle wide open to avoid any possibility of running on. Slacken the dizzy clamp bolt off slightly so the dizzy can be reasonably easily turned by hand. Connect a tacho up so it's easily read, or get an accomplice to advise you what the dash mounted one says. Also disconnect the vac pipe if applicable.
Restart the engine
Using the idle adjustment screw on the carb, increase the idle speed to near-enough 2,000rpm. 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.
As the dizzy is turned, the revs should start to rise. Keep advancing the ignition until the revs stop rising, then retard the ignition by turning the dizzy anti-clockwise until the revs drop by around 250rpm. If the revs don't rise, retard the ignition until you get a marked decrease in the rpm shown, then progress as previously outlined.
Once satisfied, turn the ignition off, and nip the dizzy clamp bolt up. Try to do this in a reasonably swift manner to prevent any possible over-heating. Let the engine cool for a while,then re-start and re-set the idle speed. Don't forget - for cams with very sporty profiles that cause rough idling - DO NOT set the idle speed as standard (750-800rpm). This will cause premature valve train damage, let alone cause a mechanical cacophony! An idle speed of 1,000 to 1,100rpm should be your goal.
Double Check For Detonation Problems
To double check you're not running into detonation problems, drive the car around using minimum loading (part throttle and use the gearbox) to get the engine up to running temperature. Then drive the car at about 25mph/40kph in third gear and slowly apply the handbrake to two-thirds operation, then accelerate swiftly(i.e. don't just floor it).
If any rattling/pinking (detonation) can be heard,back the ignition timing off by a very small amount statically and try again until detonation is eradicated. Alternatively, if no detonation occurs, you can advance the static ignition timing until detonation registers then back it off.The idea is to test the engine at it's most critical rpm range for detonation -around 2,500-3,500rpm (dependent on cam type).
If the engine just bogs down, try a slightly higher speed with the aforementioned rpm envelope in mind.
Your Your Strobe To Check Ignition Advance
Once happy you've achieved the required goals, check what ignition advance you have at 2,000rpm using a strobe, engine hot, vac-pipe disconnected, using the standard timing marks/pointers if there are any. If not - contrive a pointer that's easy to use. Doesn't have to be exactly at TDC, it's just a reference should you need to disturb any of the ignition components in the future for whatever reason. Make a note of the reading some place safe.
TDC- Top Dead Centre
BTDC- Before Top Dead Centre
ATDC- After Top Dead Centre
CR- Compression Ratio
Tacho- Tachometer, rev counter (not to be confused with Mexican food delicacy!)
Vac- vacuum (pipe, unit, etc.)
For Aldon distributors only, the manufacturer's recommendations are as follows:
|CAM SPEC.||9-1 CR||10-1 CR||11-1 CR||12-1+CR|
Fast road upto
|Rally/Race up to 643, 286, 285||
649,296, 300 and up
17-19deg @ 2,000rpm BTDC
'Y'- is Aldon 'Yellow' spec dizzy
'R'- is Aldon 'Red' spec dizzy (note - this dizzy is only suitable for race use).
Application Guide for Selecting The Correct Distributor For Your Classic Mini, Sprite, Midget or Morris Minor car
This table can be used as a guide to selecting the appropriate curve for your particular application. Select either the standard engine specification, or if you have a distributor with a curve that works well already, you can read the Lucas service number from the side of the distributor body to match.
|Service number||123/Mini curve||Application|
|40767||C||848 Mini UK Vehicles Regular Fuel|
|40774||3||997 Mini Cooper HC|
|40819||C||Mini Cooper S Mk III, 1275 cc|
|40873||F||997 Mini Cooper LC|
|40899||C||Minor, Van and Pickup, 1098 mini Low Compression|
|40931||4||Mini early including Wolseley Hornet and Riley Elf|
|40941||F||850 mini Late Model High Compression|
|40955||F*||998 Mini Cooper High Compression|
|40958||F*||998 Mini Cooper LC and special order for low grade fuel|
|40979||B||Works special for Rally Mini's|
|41007||C||848 Mini UK Vehicles Regular Fuel|
|41026||E||848 Mini UK Vehicles Premium Fuel|
|41030||0||Mini 1000 Saloon, clubman and Estate, 998 cc,|
|41031||F*||998 Mini Cooper LC|
|41032||F*||998 Mini Cooper HC, 1971-75 Morris Marina 1.8 TC|
|41033||E||Mini Cooper S Mk III, 1275 cc|
|41045||A||998 mini Early Model High Compression|
|41057||B||998 mini Late Model High Compression|
|41134||A||850 and 998 Mini Automatic including Riley Elf and Wolseley Hornet, 1100 automatic|
|41212||B||Mini 1000 and Mini Clubman, Saloon and variants, 998 cc,|
|41214||2||1275 non S Mini, Austin 1300 HC and automatic, Riley Kestrel 1000, Wolseley 1300 and Vanden Plas Princess 1300, MG 1300 Automatic|
|41242||A||850 and 998 Mini automatic, Vandel Plas Princess 1300 and Wolseley 1300 twin carb|
|41246||B||Mini 1000 and Mini Clubman, Saloon and variants, 998 cc, 1972-74: Mini Clubman 1100, 1098 cc, Allegro 1100|
|41249||F||Later Minis and Moke|
|41250||C||Mini Moke, van and pickup, later models|
|41251||A||850 and 998 Mini Automatic including Wolseley Hornet and Riley Elf|
|41254||5||998 Mini 72 to 74 including Wolseley Hornet and Riley Elf|
|41255||D||998 Mini Cooper, late|
|41257||2||1275 non S Mini, Austin 1300 HC and automatic late|
|41404||0||998 Mini ( Canada ) 1975-80, 1974 onward Leyland (SA) 1.3 van, 1974-77 Morris Marina 1.3, 1975-78 Morris 1.3 HC|
|41410||4||1970-73 Austin 850 LC, 998 Mini automatic, 850 van and pickup, 1976-78 Morris Marina 1.8 GT and HL|
|41411||B||Mini 850 Saloon and variants, 848 cc|
|41412||5||Austin 1000 Mini automatic and Clubman, 1975 Authi Mini 1000|
|41417||A||1969 Austin 850 Mini automatic, 1976-80 Austin 850 Mini, 1970-80 Austin 1000 Mini automatic, 1976-80 Austin 850 van and pickup, 1970-77 Austin 1100 Automatic,|
|41418||8||Mini 1000 and Mini Clubman, Saloon and variants, 998 cc, manual and auto, Allegro 1.1|
|41419||0||1970-80 1275 non S Mini, 1973-79 Austin Allegro 1300 HC,1969-74 Austin 1300 HC Automatic, 1970-74 Austin 1300 France, 1969-73 Austin 1300 Princess including automatic|
|41532||C||998 Mini ( Canada )|
|41569||F*||Mini 850 Saloon and variants, 848 cc|
|41570||5||850 Mini, van and pickup|
|41858||B||Minis with engine number 12HC18AA, 12HC19(AA), 12HD20(AA) 12HE41, 12HE42, 1984 onward Austin Metro 1.3 van, 1981 onward Morris 440, 575 Van and Pickup 1.3|
|41882||4||Metro 998, Minis with engine number 99Hxx, 1988- onwards.|
|41938||D||Minis with engine number 12HC09AA, 12HC10AA, 12HD14(AA) 12HD15(AA), 1983-84 Austin Metro 1.3 HLE|
|42535||2||Minis with engine number 12A2BG01, 12A2BG03, 12A2BG05.|
|42626||4||Minis with engine number 12HD09, 12HD10, 12HD11, 12HD12, 12HD13, 12HD21, 12HD22, 1984-86 Austin 1.3 L and HLE|
|42627||4||Minis with engine number 12HD17, 12HD24, 1986 onward 1.3 Vanden Plas, 1984 onward MG Metro|
|42628||7||Minis with engine number 12HD26(AA) 1984 onward MG Metro turbo|
|42630||A||Minis with engine number 12HC17AA, 12HD18|
|42635||4||Minis with engine number 12HD25|
|42681||6||Minis with engine number 12HE48, 12HE25|
* These engines require more maximum advance than the 123/Mini can provide, but curve F should allow the engine to operate well.
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