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  1. #76
    been here .......too long Smitty2's Avatar
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    Quote Originally Posted by kavesh View Post

    Please advise how you would go about testing the ignition system, I have the large HEI dizzy with built in coil in the cap.

    Thanks in advance
    Are you SURE that HEI ignition is getting 12V ALL the time??

    Did you originally have points ignition and changed to HEI?
    and
    did you rewire the ignition circuit when you did that???
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  2. #77
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    Quote Originally Posted by Smitty2 View Post
    Are you SURE that HEI ignition is getting 12V ALL the time??

    Did you originally have points ignition and changed to HEI?
    and
    did you rewire the ignition circuit when you did that???
    Originally had points dizzy, when I changed over to HEI i rewired to ensure 12v to HEI. Just for information, the HEI was installed about 5 years ago. Even though the motor smoked alot she ran fine with no miss or erratic idle, with the QJ. Was only rebuilt late last year.

  3. #78
    Not the Kingswood! hq308's Avatar
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    Even though you went through the electrics a few years ago you've had the engine out at least twice and there is the potential for something to go amiss during engine removal. The other more likely issue is the switches and at least some of the wiring is over 50 years old which means several potential sources for a voltage drop. My personal preference for converting old Holdens from points to HEI is to wire a relay into the ignition circuit. This ensures you get 12v and allows the original wiring/switches to only need to handle the small amount of current required to activate the relay. I had this very issue with the starter circuit in my HQ and used a relay to correct that.

  4. #79
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    Start with fuel. If the old girl has sat for any time without use then there will more than likely be a layer of jelly-like crud in the tank that gets stirred up every time you add more fuel.

    I’d take out the tank and get it to a fuel tank cleaner who will charge mere peanuts to reline it and give it a coat of paint. After that it’s good for 20 plus years.

    At the same time check that all the lines. I had an erratic power drop problem in one car and it turned out to be that a mud wasp had made a nest in the fuel breather. All the rubber hoses are old and were never designed to last this long, most will be perished and even those looking good on the outside are likely to be deteriorated internally. I’d get new hoses and put them in. It’s cheap and then you know you’re starting from a sound base.

    Check over your sender/feed unit in the tank. There’s a mesh filter over the inlet, replace this and clean it all or (again) replace it because they’re cheap. Similarly with the fuel pump, these are old and although very durable wear out.

    After that go over every breather pipe and hose on the engine.

    Electrics after fuel. After all, you had good running for a bit with a carb swap so it’s likely it’s something “upstream” of the carb.

  5. #80
    Senior Member BasicQ's Avatar
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    Quote Originally Posted by hq308 View Post
    Even though you went through the electrics a few years ago you've had the engine out at least twice and there is the potential for something to go amiss during engine removal. The other more likely issue is the switches and at least some of the wiring is over 50 years old which means several potential sources for a voltage drop. My personal preference for converting old Holdens from points to HEI is to wire a relay into the ignition circuit. This ensures you get 12v and allows the original wiring/switches to only need to handle the small amount of current required to activate the relay. I had this very issue with the starter circuit in my HQ and used a relay to correct that.
    Ive done the Same. Use relay for switching full 12v power to HEI. Inline ballast resistor wont be part of the supply equation to dizzy.

  6. #81
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    He says he has the 12v relay, post 77.

    It is probably time to look at ign. Process of elimination. Run a jumper from the 'Bat' terminal of the HEI to the bat [+] terminal to eliminate wiring as the culprit. Disconnect the tach lead if connected, in case it is causing the problem. New plugs? New leads? If you have the old points dist, re-fit it. If not, probably easier/quicker to just buy a new HEI, $80 from Road Star in Sydney.

  7. #82
    Senior Member BasicQ's Avatar
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    Quote Originally Posted by GtoGeoff View Post
    He says he has the 12v relay, post 77.

    It is probably time to look at ign. Process of elimination. Run a jumper from the 'Bat' terminal of the HEI to the bat [+] terminal to eliminate wiring as the culprit. Disconnect the tach lead if connected, in case it is causing the problem. New plugs? New leads? If you have the old points dist, re-fit it. If not, probably easier/quicker to just buy a new HEI, $80 from Road Star in Sydney.
    Canít say I seen Kavesh reply in post #77 had the word relay, but he will confirm.

    You know electronicals better than me Geoff, but wouldnít he measure BATT+ at the dizzy for 12v while the engine is running? No 12+ volts at dizzy start looking for why.

    If the carb is swapped out and runs good then turns to crud with the same symptoms as previous carb then fuel issue would be the focus, although I can see the logic in checking for a sound ignition.

    What would happen if the first carb was put back on? Run well and go south again like second carb or not right straight up? The fuel pump has been mentioned hasnít it?


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  8. #83
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    Dunno if it's been mentioned but poor fuel would do it, slightest bit of moisture is all it would take. You would get away with it on EFI but carb is a different story with the idle circuits.
    Some Metho would sort that out.
    If fuel has been covered, carry on.

  9. #84
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    Kavesh, cleaning your tank some time back will not mean it is clean now.

    Reading back it seems the car sat for some time while things were repaired. This will be likely to have had some consequences.

    Petrol isn’t a stable fuel, there is reasonably complex chemistry involved in its production and refinement and it deteriorates with exposure to the atmosphere. In warmer climates the more volatile components evaporate off and the day/night heating and cooling cycles facilitate polymerisation. The same heating and cooling puts atmospheric water into the tank which is drawn in via air through the breather. This water gets incorporated into the polymer, further accelerating break down of the fuel. No ordinary fuel filter can solve these problems because it won’t be particulate matter (I.e. solids). The contaminating materials are instead dissolved or suspended in the fuel.

    There’s specific formulations for fuel used by petroleum engineers for different climates, seasons and regions. Some areas have specific stabilisers added to their fuel because the climate rapidly accelerates fuel breakdown.

    I’m not saying you are guaranteed to have a fuel contamination issue. However, you said the engine ran fine initially when the carb was swapped in but the car has now reverted to the same symptoms of poor running. Provided you didn’t make any other changes that tells me that the problem is most likely something “upstream” of the carb.

    With these types of issues it’s necessary to systematically eliminate each possibility. This usually involves tediously, one by one, ensuring each of the car’s systems is working as intended.

  10. #85
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    Quote Originally Posted by hq308 View Post
    Even though you went through the electrics a few years ago you've had the engine out at least twice and there is the potential for something to go amiss during engine removal. The other more likely issue is the switches and at least some of the wiring is over 50 years old which means several potential sources for a voltage drop. My personal preference for converting old Holdens from points to HEI is to wire a relay into the ignition circuit. This ensures you get 12v and allows the original wiring/switches to only need to handle the small amount of current required to activate the relay. I had this very issue with the starter circuit in my HQ and used a relay to correct that.
    I will look into installing a rely into the ignition system. (I will have to think and research hard on this as I am no sparky). I did however, install a relay to the starter when I swapped in the 308 from the chevy 6 motor.

  11. #86
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    Quote Originally Posted by Horaldic View Post
    Start with fuel. If the old girl has sat for any time without use then there will more than likely be a layer of jelly-like crud in the tank that gets stirred up every time you add more fuel.

    I’d take out the tank and get it to a fuel tank cleaner who will charge mere peanuts to reline it and give it a coat of paint. After that it’s good for 20 plus years.

    At the same time check that all the lines. I had an erratic power drop problem in one car and it turned out to be that a mud wasp had made a nest in the fuel breather. All the rubber hoses are old and were never designed to last this long, most will be perished and even those looking good on the outside are likely to be deteriorated internally. I’d get new hoses and put them in. It’s cheap and then you know you’re starting from a sound base.

    Check over your sender/feed unit in the tank. There’s a mesh filter over the inlet, replace this and clean it all or (again) replace it because they’re cheap. Similarly with the fuel pump, these are old and although very durable wear out.

    After that go over every breather pipe and hose on the engine.

    Electrics after fuel. After all, you had good running for a bit with a carb swap so it’s likely it’s something “upstream” of the carb.
    Noted, thanks. My fuel lines are mostly metal lines and the longest rubber line is about half a meter from pump to carb. Yes there are a couple of small rubber pieces at the sender. These were all changed but will be going over them again.

    I will explore all options before dropping the tank. I have a full tank of fuel.

  12. #87
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    Quote Originally Posted by GtoGeoff View Post
    He says he has the 12v relay, post 77.

    It is probably time to look at ign. Process of elimination. Run a jumper from the 'Bat' terminal of the HEI to the bat [+] terminal to eliminate wiring as the culprit. Disconnect the tach lead if connected, in case it is causing the problem. New plugs? New leads? If you have the old points dist, re-fit it. If not, probably easier/quicker to just buy a new HEI, $80 from Road Star in Sydney.
    Thanks for that tip, I will run the jumper wire from HEI to battery.
    Remember I am in South Africa and not easy to just buy another dizzy. We pay so much more here for everything. My points dizzy was junk therefore I changed to HEI.
    I will admit that the plugs are not new, however, they have less than 3000km on them. I did test all plugs with a multimeter and they are confirmed good.
    Last edited by kavesh; 25-03-2021 at 05:40 AM.

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    Quote Originally Posted by BasicQ View Post
    Can’t say I seen Kavesh reply in post #77 had the word relay, but he will confirm.

    You know electronicals better than me Geoff, but wouldn’t he measure BATT+ at the dizzy for 12v while the engine is running? No 12+ volts at dizzy start looking for why.

    If the carb is swapped out and runs good then turns to crud with the same symptoms as previous carb then fuel issue would be the focus, although I can see the logic in checking for a sound ignition.

    What would happen if the first carb was put back on? Run well and go south again like second carb or not right straight up? The fuel pump has been mentioned hasn’t it?


    Sent from my iPad using Tapatalk
    Yes no relay, just wired up for 12 volts to dizzy when HEI was installed.

    My original carb is on its way back to me so very curious to see whether it runs any better than the borrowed carb that is on at the moment.

    Btw, I have opened up the carb that is currently on the motor to inspect for dirt and I must say that the carb is very clean. There is no traces of dirt in the float bowl, so I am suggesting its not dirt maybe.

  14. #89
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    Quote Originally Posted by Horaldic View Post
    Kavesh, cleaning your tank some time back will not mean it is clean now.

    Reading back it seems the car sat for some time while things were repaired. This will be likely to have had some consequences.

    Petrol isn’t a stable fuel, there is reasonably complex chemistry involved in its production and refinement and it deteriorates with exposure to the atmosphere. In warmer climates the more volatile components evaporate off and the day/night heating and cooling cycles facilitate polymerisation. The same heating and cooling puts atmospheric water into the tank which is drawn in via air through the breather. This water gets incorporated into the polymer, further accelerating break down of the fuel. No ordinary fuel filter can solve these problems because it won’t be particulate matter (I.e. solids). The contaminating materials are instead dissolved or suspended in the fuel.

    There’s specific formulations for fuel used by petroleum engineers for different climates, seasons and regions. Some areas have specific stabilisers added to their fuel because the climate rapidly accelerates fuel breakdown.

    I’m not saying you are guaranteed to have a fuel contamination issue. However, you said the engine ran fine initially when the carb was swapped in but the car has now reverted to the same symptoms of poor running. Provided you didn’t make any other changes that tells me that the problem is most likely something “upstream” of the carb.

    With these types of issues it’s necessary to systematically eliminate each possibility. This usually involves tediously, one by one, ensuring each of the car’s systems is working as intended.
    Yes I hear you and damn your theory on fuel contamination makes me want to swear. I may be looking at fuel that appears to be clean but in reality it may be contaminated...
    Since I got the motor running I have run the tank to about a quarter and them filled up, ran to half tank and filled up again.
    I have been running unleaded fuel and used a fuel additive to protect my valves. I was told by a mate that rather not use the additive as my motor will not be doing very high RPM, nor will it be doing huge mileage. I am not sure whether this would mean that its safe not use the additive. I have also heard talk of a litre of diesel to a tank of petrol to protect valves. Would you agree with any of these?

  15. #90
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    Quote Originally Posted by HQ 368 View Post
    Dunno if it's been mentioned but poor fuel would do it, slightest bit of moisture is all it would take. You would get away with it on EFI but carb is a different story with the idle circuits.
    Some Metho would sort that out.
    If fuel has been covered, carry on.
    There is a lot of talk about fuel contamination. Is there a simple enough way to test the fuel?

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