1. grumpyvette

    grumpyvette Administrator Staff Member

    IM only too aware that most guys have a timing light or at least know what they are used for and its just not that glamorous, but its a very necessary tool, and the first step in timing any engine will be a mandatory CHECK to insure the MARKS ON THE DAMPER INDICATE TRUE TDC, FIRST, to be sure that the TDC mark on the DAMPER lines up with the TDC mark on the timing tab/pointer... Often these two marks are MIS ALIGNED
    having a few basic meters,gauges etc. helps


    every mechanic needs an ANALOG multi meter for testing capacitors with a micro farad scale, AND a DIGITAL MULTI METER



    There's no question that timing lights are a rather basic tool,and are reasonably easy to use, but there's a great difference in accuracy between different models.
    the basic concept is deceptively simple, get the ignition to light off the compressed cylinder full of that fuel/air mix at the exactly correct instant that will produce the best torque and least wasted pressure working against the piston before it passed over TDC to drive the connecting rod down against the crank journal and spin the crank.
    naturally its nearly useless to try and time the ignition until you've carefully verified TDC marks on the damper are correct
    To do that you need to know the exact piston location in its repetitive 720 degree cycle. by watching the TDC indicator mark on the damper in relation to a timing tab on the timing chain cover.

    Get that ignition to fire a bit early and detonation can cause major problems, if its delayed in relation to the pistons location it will result in less effective pressure and a hotter exhaust header.

    http://www.dragracingonline.com/technic ... hts-1.html


    Many timing lights are less than consistent or accurate, nor can they give exactly consistent results at different rpm levels.
    MANY are cheaply constructed and not all that accurate. some won,t work well with solid core wire, some are heat sensitive. the type that allows you to set the timing advance or retard for the flashing strobe light,with a dial are usually not nearly as consistent, as many of the ones without that feature.
    IF you own a couple timing lights check them all at the same engine at at least 3000 rpm, and you'll commonly see variations in the results and THAT'S BAD, if its off a couple degrees at 3000rpm, at 6000-7000rpm it can and probably will cause problems, when your engine timing is not even close to what you expect it to be.
    The older model Sears Craftsman Timing Light (P/N A-2134) is usually consistent, MSD, makes their own, timing light (P/N 8990). that is also one of the better ones. When your using a timing light you'll need to verify the battery connections are correct as to polarity, and the wires cant contact moving components like fans, fan belts and pulleys, you'll need to verify that only the wire from the #1 cylinder contacts the timing lights inductor clip, and that NOTHING contacts the hot headers, and you should NEVER wear a TIE or LOOSE clothing around a running engine!
    read these links
    http://www.dragracingonline.com/technic ... hts-1.html
    http://www.corvette-restoration.com/res ... ing101.pdf
    watch video
    http://www.youtube.com/watch?v=UYGU7mTw ... r_embedded

    Obviously getting the ignition timing correct in relation to the compression stroke and piston location in the engine will result in far less chance of detonation and piston damage or loss of potential hp, and getting the ignition advance curve correct is also critical, IVE generally found havering full advance all in by about 2900-3100rpm is a good compromise and while the components used in the engine can change the results, full advance at about 36-38 degrees at 3100rpm is a good basic starting point.
    your total timing will be in the 32-40degree range, on a timing tape on the damper

    the use of timing tape on the damper is a huge help and yeah, the glue on the tape tends to get loose so use some contact cement sparingly, the contact cement works, but a simple spray coat of a clear lacquer spray paint sprayed over the tape and allowed to dry locks it on the damper fairly well also, or you can spend just a bit more, and buy a damper cover, and adjustable timing tab, just remember to verify TDC
    obviously you need to have a consistent base line advance curve to work with,
    on most Chevy v8 engines that run cams designed for street/strip use Ive generally found a advance that goes from about 8 degrees at idle speed (800-900rpm in most cases) and smoothly advances the ignition to about 36 degrees or about 28 degrees at about 3200rpm , is generally a good place to start, or about 82 degrees advance per hundred rpm, you can then play with the engine and determine what changes MIGHT be required.


    stock timing marks are very limited in the extent of timing changes that can be indicated

    you start by verifying TDC on the damper and timing tab reflects TRUE TDC




    http://www.dragracingonline.com/technic ... hts-1.html


    you then use a timing light and a tach to verify the ignition advance stops advancing with rpm increases at about 3000rpm-3200rpm

    vacuum drops as the throttle opens, and centrifugal force pulls the distributor weights outward against spring pressure as rpms increase





    links with info that's well worth reading thru

    finding TDC


    http://www.equus.com/product_info.php?p ... ry_id=1_20
    http://www.centuryperformance.com/ignit ... g-219.html



    remember you'll YOULL want to read the shop manual for instructions for specific. info that applies, to your car and year, like youll need to disconnect this connector before setting the timing on a tpi c-4 vette, or anything else that pertains to your specific cars engine
    http://www.digitalcorvettes.com/corvett ... /2/cat/652
    a spark checker can be useful
    Id also label BOTH ends of each ignition wire, any decent label maker can produce sticky number tags far cheaper that the kits but even the kits are cheap
    3M sells these really handy number tape tags


    http://www.clarcorpindustrialsales.com/ ... -p/wmd.htm
    at about $30- $45 for a fully loaded dispenser it seems expensive but its really a bargain

    KEEP IN MIND that theres TWO totally different damper and timing tab locations that are correct on the SBC engines and you must use matched components for almost all years the ting tabs and dampers show TDC to be at about 2 o,clock, but theres a few applications that used a 12 o,clock timing tab and damper combo and you can,t mix&match the two types


    be aware that some damper designs do tend to fail over time!

    so be sure to verify TDC on the damper and TRUE TDC match!
    beating a balancer onto a crank, pulling it with the wrong type of tool, or letting it get fuel or oil soaked can damage a damper, this can easily result in the outer damper ring with the TDC mark rotating to a random location
    if your front crank seal leaks, over time it can dissolve the elastic, between the inner and outer damper hub weight, beating on a damper tends to hurt the flex ring seal alsos

    in many or most cases engine dieseling after the ignition is turned of is caused by a combination of a bit too rich of a fuel/air mix being drawn in and a bit too much heat in the combustion chambers this is common when a holley carbs transfer slot is badly adjusted to expose too much slot at idle

    Last edited by a moderator: Aug 18, 2017
  2. grumpyvette

    grumpyvette Administrator Staff Member




    SBC cylinder numbering;

    Last edited by a moderator: Aug 24, 2017
  3. grumpyvette

    grumpyvette Administrator Staff Member


    http://www.tooltopia.com/electronic-spe ... =nextag_r1

    having a built in tachs nice



    http://www.rodandcustommagazine.com/tec ... index.html

    http://www.hotrod.com/techarticles/sett ... index.html





    How to Use a Timing Light

    Make sure the auto engine is off and the key is removed from the ignition.

    For the next steps, make sure the battery terminals are clean enough to allow for a good connection. If not, then clean as required being cautious not to allow any contact on your skin because this is battery acid. If it does come in contact, then just wash with soap and water.
    Step 2

    Clamp the red clip to the positive terminal of your car battery.
    Step 3

    Clamp the black clip to the negative terminal of your car battery.
    Step 4

    The largest clip (the one with the thickest insulation) goes on your #1 spark plug wire by attaching the clip around the wire that leads to your #1 spark plug.
    Step 5

    Next, you will want to rotate the lower crankshaft pulley so that it has the timing marks called out on the crankshaft pulley. Be aware that on some cars the timing marks are located somewhere else and you should consult either your owner’s manual (another instruction manual), or automobile dealer. You may also see a pointer on the engine block that will point to these marks as well.
    Step 6

    Your auto’s spec sheet should tell you what your timing degree should be. For example, a 1969 Ford 429, 6 Degrees BTDC @ 550 rpm in drive gear - with automatic trans, with a firing order of 1-5-4-2-6-3-7-8. All this means is that you want to line up the pointer on the timing light with the 6° timing mark when the engine is idling in gear at 550 rpm. As you can see, it also says something about "BTDC" for this Ford. There is also an "ATDC." “Before Top Dead Center” and “After Top Dead Center” – top dead center is the point where the piston reaches the highest point in the cylinder and that is when the compression is the greatest. Now, your timing marks with have a line labeled “0” with marks above and below it, and depending on which way the wheel rotates, you will see the lines before the “0” (BTDC), or after the “0” (ATDC).
    Step 7

    If you want, you can use some chalk to mark the timing marks to make them more visible. Then, on the side of the distributor, disconnect the rubber hose from the vacuum advance and put a piece of duct tape on the end of the hose to seal it off.
    Step 8

    Okay, now start up your engine, letting it warm up. We will assume that your auto is properly idling, otherwise, if the idle is off, and your mechanical advance may influence your timing adjustment.
    Step 9

    Take your timing light and aim it at the timing marks, pressing the button on the light. Because you have the light hooked up to your spark plug means that it has current passing through it every time your spark plug fires, making the light go off and on, creating the strobe effect. Because of this, the timing marks should appear to be standing still. Now, is that pointer (earlier described) pointing at the correct mark? If yes, you are all set, you do not need to adjust your timing. You are good to go! If it is not, you should adjust your timing. See the next steps to adjust the timing.
    Step 10

    Adjusting the Timing

    Below the distributor, at the base of your distributor shaft, is a fastener called the distributor hold-down clamp. We want to loosen this fastener so the distributor can turn on the shaft. Grasp the vacuum advance and move it back and forth.
    Step 11

    Rotate the distributor slightly, then aim your timing light back at the timing marks again. How does it look? If it is farther away from the marks, then move the distributor in the opposite direction. Then, check again with your timing light. Continue doing this until the pointer is pointing at the correct degree point as required.
    Step 12

    Once the timing is good, re-tighten the fastener for the distributor hold-down clamp, making sure you do not move the distributor!! After re-tightening this fastener, just double check your timing again to make sure -- tightening the distributor may change your timing.
    Step 13

    Turn off your engine, remove the key from the ignition, and disconnect the timing light.

    http://www.sears.com/craftsman-professi ... 914066000P

    http://www.sears.com/shc/s/p_10153_1260 ... 0000100600

    http://www.sears.com/craftsman-professi ... 914066000P

    the sears timing light with built in tach has been working well for over two years now
    this picture shows almost exactly where the timing mark should be when the timing light flashes at idle

    Here's a guide for V8 domestic engines that might make the next "late-night" tune-up a little easier:

    * AMC (most V8 engines): Clockwise 1-8-4-3-6-5-7-2
    * Buick (most V8 except HEI): Clockwise 1-8-4-3-6-5-7-2
    * Chevrolet: Clockwise 1-8-4-3-6-5-7-2
    * Small Chrysler: Clockwise 1-8-4-3-6-5-7-2
    * Big Chrysler and Hemi: Counter-clockwise 1-8-4-3-6-5-7-2
    * Ford (5.0L HO, 351W, 351M, 351C, 400): Counter-clockwise 1-3-7-2-6-5-4-8
    * Ford: Counter-clockwise 1-5-4-2-6-3-7-8
    * Oldsmobile (1967 and up): Counter-clockwise 1-8-4-3-6-5-7-2
    * Pontiac (most 1955-81 V8 engines): Counter-clockwise 1-8-4-3-6-5-7-2


    chevy sb

    chevy BB


    383-440 mopar

    318-340-360 mopar

    ford 429-460

    302-351 windsor ford

    351 cleveland ford

    352-428 ford
    Last edited by a moderator: Oct 6, 2015
  4. grumpyvette

    grumpyvette Administrator Staff Member


    ITS not complicated, pull the #1 plug and put you thumb over the hole tightly, turn the engine in the normal direction of rotation, with a breaker bar and socket until you get compression in the #1 cylinder, as the damper TDC line approaches the TDC timing tab, drop the distributor in with the rotor facing the #1 cylinder,compensate for the way the distributor gear causes the rotor to rotate as in seats,so its seated pointing where you intended, if it won,t fully seat turn the oil pump drive with a very large flat blade screw driver until it will,with the distributor removed and try again, once it seats,facing the correct direction, install and tighten the distributor clamp so its difficult to spin the distributor easily by hand but still possible to spin the distributor by hand, re-install the #1 plug and wire, install the cap and all ignition related wires, use your timing light and set the ignition timing,per the shop manuals instructions, tighten the distributor hold clamp so it can,t move, IF it takes more than 10 minutes your in need of more practice or nearly hopeless as a mechanic.
    Make sure TDC on the damper is marked with white paint or chalk.
    Crank the engine over with a breaker bar on the crank/damper bolt until you begin to come up on compression in number 1 cylinder. (A compression gauge will help if you are not sure how to do this.) As the compression rises up on the gauge, TDC will come around and will land under the pointer. ( I set mine up at 8 to 12 degrees BTC). This is the number 1 firing position.use a timing light and the timing tab to locate the timing on the dampers timing tape after you get it close to correct,with a new cam install you don,t want to run at low rpms, so time the engines ignition advance curve on the car at 3000rpm to show 34 degrees total advance on the timing tape and let the at idle timing fall where ever it lands as a starting point while your breaking in a new combo, you can make adjustments later but this will get you very close to correct without running the engine at low rpms while the cams lapping in.


    how come its 180 degs out of phase?
    I get this question all the time, well here’s something I see lots of guys don’t understand, ONCE YOU'VE INSTALLED A CAM WITH THE TIMING MARKS YOU MUST ROTATE THE CRANK 360 DEGREES BEFORE DROPPING IN THE DISTRIBUTOR, while its true that if the, timing marks are positioned so the crank is at 12 o,clock and the cam gear is at 6 o,clock that the cam lobes will be in the position that fires #6 cylinder that HAS NO EFFECT AT ALL (on finding TDC,) for aligning the degree wheel with TDC,or THE timing tab pointer, for degreeing in the cam, the piston passes thru TDC TWICE in every firing cycle once on the firing/power stroke and once on the exhaust stroke, the cam rotates at exactly 1/2 the speed of the crank so to make it easy to line up the marks they install it with the marks at the closest point 6/12 for easy indexing, rotate the engine 360 degrees to the #1 TDC power stroke and the crank gear will still be at 12 o'clock 12/12 but the cam will be at 12 o,clock also, rotate another 360 degrees and your back where you started. its simply easier to index the cam at the point where the index marks align closely. look at how the cam lobes themselves open the valves when the cam is just installed the #1 cylinder valves are slightly open and the #6 are closed per "Lunati" ‘’YES YOU ARE RIGHT - WHEN CRANK IS AT TWELVE AND CAM IS AT SIX THEN #6 CYL IS FIRING AFTER YOU LINE UP YOUR MARKS AND INSTALL GEAR THEN ROTATE YOUR CRANK ONE REVOLUTION AND THEN DROP THE DIST. IN - AT THAT POINT


  5. bob

    bob Guest

    I have a Model #161213400 Craftsman Inductive Timing Light which I've had since the 1980's. It's worked flawlessly until yesterday. I checked on Sears.com, and only the flash tube (and the decal) is available. Does anyone know how would I check to see if the flash tube is bad, or if the problem is elsewhere?
    I opened the metal (not plastic) case on it, and didn't see anything amiss. I'll add that the quality of construction was impressive; inside were the handwritten initials (written in English) of the person who assembled it. Love to fix it if I can.

    Thank you


    this is one area where an old analog multi meter makes it easier to diagnose a problem, an ANALOG multi meter, with a swinging needle voltage indicator on a dial,like this one usually costs well under $30 and its a valuable tool for any mechanic.

    connected to both electric leads to the bulb while you try to use the the timing light should indicate by the needle movement on the dial bouncing that theres voltage reaching the bulb, if the bulb won,t flash its the bulb, if theres zero voltage indicated start back tracking until you find a fuse or break in the connections
  6. grumpyvette

    grumpyvette Administrator Staff Member

  7. DorianL

    DorianL solid fixture here in the forum Staff Member

    A buddy of mine had some odd readings with his light last week. Suggested that he use mine... problem solved.

    These things can be off - especially the dial-backs
  8. Indycars

    Indycars Administrator Staff Member

    This question has been bouncing around inside my head for quite a while now, but
    since I'm getting kinda close to starting my new engine, I wanted to clarify something
    about the adjustable advance in a timing light.

    If the adjustable advance is set to ZERO, then can it be considered to be as accurate
    as a timing light without the adjustable timing ???

    This is the timing light I referring to:

    http://www.amazon.com/INNOVA-3568-Digit ... B000EVYGV4


    Attached Files:

  9. mathd

    mathd solid fixture here in the forum

    Well, i did test 3 model of timing lamp on my car. and i can say all 3 give the exact same result, no one flickering or bouncing around(working with msd ignition).
    I did not test the "advance" function on the summit one.(i did for the innova 3568 and it was accurate) innova 3551 is plain jane ( no advance function)
    the innova 3551 has weak light(hard to see reading on damper)
    i did try the summit model SUM-G1059 (this is the one am using)

    INNOVA® Digital Timing LightPart #3568 $100-$140
    INNOVA® Digital Timing Light

    Top-of-the line timing light for the selective do-it-yourselfer
    Split-screen digital LCD readout displays Tachometer and Advance functions simultaneously
    Digital Tach: 249 to 9,990 RPM
    Digital Advance: 0° to 90°
    Slim, rotating barrel for better aim at timing mark
    Detachable leads, metal inductive pickup
    Protective Hand Guard
    Patented Skip Circuitry Test up to 9,990 RPM
    One-hand Operation

    the innova 3568 (i dont remember if there was 4 or 5 button and that alligator clip on the picture Rick posted vs this one)
    and innova 3551 (plain jane)
  10. Indycars

    Indycars Administrator Staff Member

    Cool, thanks Mathieu !
  11. 87vette81big

    87vette81big Guest

    If you have a Vintage Sun distibutor machine like I have you can check your timing light if choice against that for a highly calibrated standard.
    Aim timing light against the degreed outer ring.
    Spin from 50 RPM To 6-7K.
    Compare every 50 to 100 RPM increase.
    Snap On #2261 digital advance timing light is what I use on my own.
    Accurate since I bought it new in 1990.

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