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Thread: 100-4 Timing Pointer

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    100-4 Timing Pointer

    Anybody tell me where to look for the timer pointer on a 100-4?
    Trying to get a 54 year old dormant engine to fire...it has spark...but I am not sure I have the plug wires correct. Determining TDC would be a great help.
    Michael Bowie
    1954 100-4
    Boerne, Tx

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    Senior Member Dougal's Avatar
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    Re: 100-4 Timing Pointer

    Well I have just been through this exercise myself and fired my 54 up after 7 years and an engine rebuild just this weekend. The timing marks on the 100 are not extensive. There is a small hole drilled on the crankshaft pulley to indicate TDC and some timing chain covers have an arrow stamped on them. I am lucky my cover had a small tab welded on with a couple of marks. If you don't have a pin/tab/mark/arrow on your cover you can still get to the right place by first finding TDC.

    I put some masking tape on a screwdriver put it carefully into No1 cylinder plug hole (the one nearest to the radiator) . By marking the depth of the screwdriver on the tape, removing it and rocking the car forward in gear and repeating, I was able to find the point where the piston was at its highest. Just be careful not to scratch your bores or piston. Once at TDC you can mark the timing chain cover at a point where it corresponds with the hole in the pulley. If you peer down from the front of the engine looking at the hole in the pulley and bring your line of sight to the left edge of the water pump body you can repeat the procedure and look at the same mark.

    Your actual timing mark should be 6 to 10 degrees before this. As the pulley goes clockwise a second mark to the left of the first TDC mark (looking from the front of the car) should be approximately in the correct spot.

    To get your distributor in about the correct spot you need TDC again but making sure you are on the compression stroke i.e piston up and valves closed. I simply did the screwdriver thing but with the rocker cover off checked that both the rockers on valves 1 and 2 rocked.

    You can google the approximate orientation of the distributor to allow you to get the advance copper tube connected and not interfere with the coil. If you insert it so that the rotor arm when the distributor is fully engaged is pointing approximately at the number 1 cylinder contact on the cap (if your looking straight down at the distributor cap its about the 2 O'clock position) you will be close.

    Firing order on the cap is 1,3,4,2 remembering rotor arm rotates anticlockwise.

    Good luck hope the above ramble makes sense, I am sure the good and clever people on this forum will be able to simplify what you need to do and point out any mistakes in my explanation.

    While i have run my engine, i have the carbs back in bits as I found it was running incredibly rich. I mean petrol puddle on the floor under the manifold drains rich. I bought new needles but never checked them and have now found I have BN7 needles in my H6's. I can tell you they are not a great match .

    Dougal
    Currently Hangs out under a 54 Healey BN1
    Old Flames 1960 MGA 1600MK1, 1960 MF(Fergy)35, 55 Healey BN1

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    Re: 100-4 Timing Pointer

    Thanks for the reply...the counter-wise rotation of the rotor now makes total sense...I was arranging my plug wires based on a clockwise rotation. Hopefully I will get a little life tomorrow...will use some starting fluid. I do not seem to be getting oil pressure...I think I need to loosen the filter housing and fill it with oil. Anybody know a modern part number for the original canister filter? I saw a post some time ago about how to prime the oil pump...but cannot seem to find it now. Other posts say it is not necessary.
    Enjoying bringing this back from the dead.
    Michael Bowie

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    Senior Member Dougal's Avatar
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    Re: 100-4 Timing Pointer

    Hi Michael, For oil pressure i removed plugs and turned the engine over for 5- 10 seconds with a good rest gap in between. After a few attempts pressure started to build up. I did not prime or fill the canister but let the pump do its thing with the plugs out. I would not attempt to start without knowing you have some oil pressure. The counter clockwise rotation of the rotor arm got me initially as well.
    Good luck, fingers crossed.
    Currently Hangs out under a 54 Healey BN1
    Old Flames 1960 MGA 1600MK1, 1960 MF(Fergy)35, 55 Healey BN1

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    Re: 100-4 Timing Pointer

    I did as suggested...loosened the oil feed banjo fitting to the tappets and soon got a slow flow of oil. I sprayed some starting fluid in the spark plug hole, screwed in the plugs, gave the carbs a blast and tried to start it....nothing.
    I have spark, but it seems weak...buy a cheap generic coil for testing? All 4 plugs get a spark...but very weak.

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    Re: 100-4 Timing Pointer

    http://herald-tips-tricks.wikidot.co...agnosis-manual the Lucas fault manual linked from this page gives a very good step by step to figure out ignition problems.

    Quick and simple approach, I have started, and helped others start a few cars after rebuild by rotating the distributor with clamp a little loose while someone cranks the motor.

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