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  1. #1
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    Default carby tuning and ignition timing

    I have a red 202 which I will be installing a cheap DSM distributor with a viper high energy coil and some eagle 9mm leads, doing that I would need to time it, once I find tdc(which I will just do it with a screwdriver on compression stroke) what advance/retard should a stock red 202 have?

    As for the carby, after I time everything I was thinking of tuning the stock carby myself with a boost/vacuum gauge, getting the highest amount of vacuum I can, is this a good way of tuning the carby?

    I'm only 17 so I only have money left from my other HQ I sold, and this is only my second HQ, the other I tuned it with a vacuum gauge but just enough for the guy to drive home with it, it wasn't a clean burning tune.

  2. #2
    Sure why not? 76lxhatch's Avatar
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    All this assumes a standard HQ 202, other models may vary in specs but the general idea is the same. First check the points are in good condition and set the dwell. Preferably use a dwell meter to get 30-35 degrees, failing that set the points gap to 0.019-0.025". Then set the initial timing to 4-6 degrees advance (I'd go 6 if your fuel is good), then move on to tuning the carb.

    Carb specs:
    * Float level should be 5/8" to 11/16" below the top surface of the float chamber, with the air horn (top section of carb) removed. The bowl must be full/needle seated - the manual says to check with engine running but as long as the needle is seated it will be accurate enough.
    * Set the idle speed to 480-520rpm at full operating temp with choke off, do this before anything below.
    * Yes use a vacuum gauge at idle and adjust the idle mixture screw to get maximum (steady) reading, it should achieve 18-22in.Hg (last one I did was bang on 22). Re-adjust idle speed if necessary.
    * The accelerator pump piston should move 7/32" to 9/32" between closed and fully open throttle - measure the distance from the carb body with the air horn removed.
    * The vent valve should be open with a 0.050" to 0.060" gap at normal hot idle with throttle closed.

    Beyond that you would need to start reading plugs or get a wideband oxygen sensor to determine the results and make minor trims to the float level and possibly the idle mixture.

    Once the carb is tuned if you need to revisit the timing (e.g. if its pinging and needs less, or you think you can add a couple more degrees without pinging) do that, then check the affected carb tune items again. Repeat as necessary. Hopefully your new distributor has an advance curve suitable for the engine.

  3. #3
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    In installing a DSM distributor which is electric ignition, there is no points, do electric distributors have dwell angles? I would be using 98 as much as I can, but reading all this it seems more complicated then I thought, I will just get someone to do it, hopefully it won't cost much, I'm guessing the carby tuning should be around $90-100 bucks but no idea what ignition timing will cost.

  4. #4
    Do you ever leave? paulzig's Avatar
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    Quote Originally Posted by ETUQHNEDLOH2791 View Post
    In installing a DSM distributor which is electric ignition, there is no points, do electric distributors have dwell angles? I would be using 98 as much as I can, but reading all this it seems more complicated then I thought, I will just get someone to do it, hopefully it won't cost much, I'm guessing the carby tuning should be around $90-100 bucks but no idea what ignition timing will cost.
    Do you have a timing light?

    Whats the DSM distributor? A magnetic pickup style?

    You'll need an ignition module to work with it too...

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    Do you ever leave? paulzig's Avatar
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    Looked up DSM, looks like they have the ignition module with it ...

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    No, but can buy one for $35 on eBay

    Its a clone of the Bosch dizzys found on blue 3.3 engines

    Seller says all I need is a low resistance coil, the DSM distributor and that's all. Once installing the distributor into the engine I then need to connect the Wire's from the distributor to the coil, this still uses the gears within the engine.

    I was going to do the timing like this,

    1. Take out the points distributor, and install the DSM one, making sure the rotor and frame are in the same spot as the previous distributor, its not timed right currently so I'm thinking I don't need to find tdc first.

    2. Find tdc on compression stroke, then mark the balancer

    3. After finding tdc, I connect the ignition leads to the cap making sure the rotor is at number 1 piston while at 0 degrees

    4. Advance timing a few degrees to get it running, once running use a timing light to set it at correct timing.

    Haha i dont know if that is at all correct, but i would love to learn how to do it at 17yo instead of 60. One question is does the engine have a 0 point with the advance and retard positions, i m guessing the harmonic balancer won't but the block?

  7. #7
    Do you ever leave? paulzig's Avatar
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    It will have a mark on the balancer already, and a timing marker on the cover...

    All you need to do is make sure you are on compression stroke on no.1 cylinder then set the mark to the pointer on the cover. You can even set the pointer to mark at 10 Before Top Dead and then install and line up the rotor in the distributor exactly to number one plug on the cap and you have a better starting point. Then set with the light.

    Easy...

  8. #8
    Do you ever leave? paulzig's Avatar
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    You know around $400-500 will get you a VN 5.0 304 Efi engine on gumtree. People want more for older 308s for some reason.

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    Okay, anyway if anything goes horribly wrong you would hear it in the news haha, but after the timing is done, I can tune the carby with just a vacuum gauge, I'm not gonna check all the extra float level etc etc, just vacuum gauge, and then check timing again correct?

    And you say to time it at 10 advance


    They want more maybe because you don't need any engineering done, its just a drop in engine, but the 304s although they are still the same engine as a 308 it was not a factory option so I might need to do some extra work, or maybe not idk, can you convert the 304s to carby, as I would much rather have a carburettor then efi.

  10. #10
    casual poster TonnerGuy's Avatar
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    Quote Originally Posted by paulzig View Post
    You know around $400-500 will get you a VN 5.0 304 Efi engine on gumtree. People want more for older 308s for some reason.
    Ha ha yes have noticed that, makes the EFI 304 a cheap horsepower upgrade, saw one a while back complete with 4 speed auto (TH700 ?) all looms ECU ect for $800 bargain ready to go package for a early Holden on Bumtree.

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    Do you ever leave? paulzig's Avatar
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    Quote Originally Posted by TonnerGuy View Post
    Ha ha yes have noticed that, makes the EFI 304 a cheap horsepower upgrade, saw one a while back complete with 4 speed auto (TH700 ?) all looms ECU ect for $800 bargain ready to go package for a early Holden on Bumtree.
    Only thing that kills you is converting to carburetor the quality manifolds are expensive... Some states might frown upon putting a carb on a factory EFi engine. Might as well keep the fuel injection.

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    Do you ever leave? paulzig's Avatar
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    Quote Originally Posted by ETUQHNEDLOH2791 View Post
    Okay, anyway if anything goes horribly wrong you would hear it in the news haha, but after the timing is done, I can tune the carby with just a vacuum gauge, I'm not gonna check all the extra float level etc etc, just vacuum gauge, and then check timing again correct?

    And you say to time it at 10 advance


    They want more maybe because you don't need any engineering done, its just a drop in engine, but the 304s although they are still the same engine as a 308 it was not a factory option so I might need to do some extra work, or maybe not idk, can you convert the 304s to carby, as I would much rather have a carburettor then efi.
    Young man gets penis stuck in Holden news at 6 'Says he was tuning car'...

    But, yeah for a stock engine around 10 to start with. Remember what you give it in initial will add to the total timing. On a chinese distributor this could end up high because who knows how they are setup. To check total rev the engine up until the mark stops moving and see what the timing is there to do that you need a fully degreed balancer or a dial back timing light.

    Engineering my arse, you need a HQ style sump and engine mounts and it drops straight in.

  13. #13
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    Quote Originally Posted by paulzig View Post
    Only thing that kills you is converting to carburetor the quality manifolds are expensive... Some states might frown upon putting a carb on a factory EFi engine. Might as well keep the fuel injection.
    Agree on that point yes is a bit of stuffing around wiring wise, but keeping it EFi is really the better option in the long run.

  14. #14
    casual poster TonnerGuy's Avatar
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    But on second thoughts would probably go carby on a early girl with a 304, cause probably could not be stuffed with doing all the mucking around with speedos and other gauges, cats in the exhaust and all the other sensors involved. (Yes getting Lazy in my old age will take the easy route if possible LOL)

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    Best bet with HQ to make it totally legit is put all the EFI engine top end and cam into a red 308 with good compression, then there is no cats, no Engineering etc. Of course you’d buy a new cam. We did this with my mate’s tonner, good red short motor, new cam and lifters and bolted the EFI’s top end on. Went like the clappers too, partially due to the better cam but also as it was a 9.7:1 HJ bottom end so had more compression than the original 5L engine, plus we used a 180kW HSV memcal.

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