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    Default Dwell vs Gap

    Just wondering what the best method for setting points is. I thought I would adjust mine as the dwell angle was a bit on the low side. Reset the gap to 0.0016" as the manual says, only to find that the dwell angle was now arounde the 44 degree mark. So I used a bit of trial and error and made small adjustments to the gap until I got a angle of 57 degrees - as it should be. I cannot see how there can be so much difference, but the gap is now definately smaller than the specs.

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    After I set the points I had to retime the car as it had retarded a bit as a result of the change. I set the timing at around 7 degrees BTDC - 8 is the spec.

    Now I have found that the car is lacking a bit on what it was before. It is harder to start, even warm, and seems low on power and runs a bit rough at times. Would I be better off in just setting the point gap as set out, or am I correct in working form the dwell angle as that is what determines the length of your spark - which is the important thing. It's just strange that there is such a descrepancy between the two.

    I'm confident that advancing the timing was the correct thing to do as it was pinging before and now, although I've advanced the timing further, there isn't a ping in sight.

    Any thoughts that could be offered would be a great help.

    Thanks

    Matt
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    Wow, this is a blast from the past! I bet most people on this forum couldn't answer it - only those with grey hair! The dwell and the gap are related. The bigger the gap, the smaller the dwell, as you've discovered. The dwell in normally more accurate, particularly with 2nd hand points. However, if it feels better at your measured 0.016", go with that, and set the advance to suit.
    Last edited by PeterT; 19th May 2005 at 10:54 PM.

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    Matt, advancing the timing should make it ping MORE, not less. This fits in with 7 degrees BTDC being actually less advanced than 8 degrees. That is, more advanced means that the spark occurs earlier - the more degrees BTDC the earlier the points open.

    Stuey


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    Quote Originally Posted by Stuey
    Matt, advancing the timing should make it ping MORE, not less. This fits in with 7 degrees BTDC being actually less advanced than 8 degrees. That is, more advanced means that the spark occurs earlier - the more degrees BTDC the earlier the points open.

    Stuey
    Yeah, I know that. What I probably should have said is when I adjusted the points, I had to retime it as it had become retarded. I turned the distributor in the direction which advances the timing to bring it back to 7 degrees. The car did ping before, although it doesn't now that I retimed it, so what I am saying is the car is better from a timing point of view, so I'm laying the blame on the points.

    To make things clearer.
    Before - Car pining
    Adjust points (close)- timing retards as a consequence
    Timing needs to be advanced again to 7 degrees BTDC
    No more pinging

    In effect I did not change the timing over what it was before, although the position of my distributor has changed.

    Makes sense? I hope so, because I'm confused

    Matt
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    ah but you have redex'd the car as well so that will help in the pinging stakes

    i'd go with a good gap and run it from there

    aren't you lucky you only have one set of points to worry about
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    Quote Originally Posted by pugrambo
    ah but you have redex'd the car as well so that will help in the pinging stakes

    i'd go with a good gap and run it from there

    aren't you lucky you only have one set of points to worry about
    I've been thinking also that I may have erred a bit too much on the side of caution with my timing. Whereas before it was set at 8 degrees or a bit extra, I set it this time at 7ish just to avoid pinging. Now what if the pinging was due to carbon build up, not timing - it did seem to come from nowhere and maybe even get worse (I just put it down to poorer grade fuel). So by backing the timing off, my car is now firing too late (retarded) and this is causing the poor starting and running. The points themselves may be set ok.

    Does this make sense?

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    Budding Architect ???? pugrambo's Avatar
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    retarded timing should make the car easier to start

    is the timing plate correct on the timing cover ?
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    Quote Originally Posted by PeterT
    Wow, this is a blast from the past! I bet most people on this forum couldn't answer it - only those with grey hair! The dwell and the gap are related. The bigger the gap, the smaller the dwell, as you've discovered. The dwell in normally more accurate, particularly with 2nd hand points. However, if it feels better at your measured 0.016", go with that, and set the advance to suit.
    Sure is Peter, I used to memorize the statement "bigger the gap, smaller the dwell" when I used to set points on my Cortina and Charger back in the good ole days when electronic ignition was but a wishful fantasy LOL
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    Grey Haired(beard) points setter to the rescue.

    Set the gap as per the specs, (they will wear in, (close)).
    Now set the timing using the static method, (no light required).
    Set mark to the rqd advance and now turn the dizzy until the gap starts to open on No 1.
    Reassemble the dizzy and go for a run.
    If it "pings" retard a spot.
    If it seems a little dull advance a bit.
    Use a fave bit of road where a little acceleration is possible and a cruise section.
    A K or so is enough.
    A light can be used to check the setting once found so as to speed the next installation of points.
    Best to get the dizzy cam replaced with one less worn or you may be able to get a re-grind.
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    Quote Originally Posted by Gamma
    Grey Haired(beard) points setter to the rescue.

    Set the gap as per the specs, (they will wear in, (close)).
    Now set the timing using the static method, (no light required).
    Set mark to the rqd advance and now turn the dizzy until the gap starts to open on No 1.
    Reassemble the dizzy and go for a run.
    If it "pings" retard a spot.
    If it seems a little dull advance a bit.
    Use a fave bit of road where a little acceleration is possible and a cruise section.
    A K or so is enough.
    A light can be used to check the setting once found so as to speed the next installation of points.
    Best to get the dizzy cam replaced with one less worn or you may be able to get a re-grind.
    Grey-haired back-up Tuner reporting for duty.
    Agree with Gamma. I used to time my R17 that way until I could a fford a timing light. (they were dear when I was an apprentice)
    You may find that you go out on the road 4 or 5 times till you are happy.
    Once you are happy, just go find a hill and get to it in top(not overdrive 5th) and accelerate up it, to see how long it takes to ping.

    Have you got access to a dwell meter, and what sort of Dizzy is it? Does it have external points adjustment?? If it does, set the points at the recommended initial setting, warm the engine, attach d/meter and adjust the dwell if necessary. (you should have a dwell setting in the manual you'd obviously have being a good frogger )
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    Quote Originally Posted by pugrambo
    is the timing plate correct on the timing cover ?
    With the way this car is I wouldn't be surprised if it had been moved. Any real way of checking besides taking the head off and putting a dial gauge on the piston?
    Quote Originally Posted by Gamma
    Set the gap as per the specs, (they will wear in, (close)).
    Now set the timing using the static method, (no light required).
    Set mark to the rqd advance and now turn the dizzy until the gap starts to open on No 1.
    Reassemble the dizzy and go for a run.
    If it "pings" retard a spot.
    If it seems a little dull advance a bit.
    Use a fave bit of road where a little acceleration is possible and a cruise section.
    A K or so is enough.
    A light can be used to check the setting once found so as to speed the next installation of points.
    I'll have a recheck of the angle and see what the gap is. The points aren't new, they were just cleaned and readjusted. The timing at the moment is ballpark so there's no need to set it statically, so what I'll do is advance it a bit, go for a run and keep advancing until it pings then back off. I'll put a white mark on the timing plate for future reference, just in case the plate isn't where it should be.
    Quote Originally Posted by Gamma
    Best to get the dizzy cam replaced with one less worn or you may be able to get a re-grind.
    There's no concern about the dizzy cam. It's come from a good source who gave it a going over before we fitted it. The dwell angle remains constant when the engine is running so I'm confident the shaft and cam is all straight and true.

    Thanks

    Matt
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    Quote Originally Posted by HONG KONG PUGGY
    Grey-haired back-up Tuner reporting for duty.
    Agree with Gamma. I used to time my R17 that way until I could a fford a timing light. (they were dear when I was an apprentice)
    You may find that you go out on the road 4 or 5 times till you are happy.
    Once you are happy, just go find a hill and get to it in top(not overdrive 5th) and accelerate up it, to see how long it takes to ping.
    That's the plan. A bit of trial and error never hurt anyone
    Quote Originally Posted by HONG KONG PUGGY
    Have you got access to a dwell meter, and what sort of Dizzy is it? Does it have external points adjustment?? If it does, set the points at the recommended initial setting, warm the engine, attach d/meter and adjust the dwell if necessary. (you should have a dwell setting in the manual you'd obviously have being a good frogger )
    Chris
    Yes I have a dwell meter. As mentioned above, what I did was set the gap as per the manual, then checked the angle - 44 degrees, should be 57. Then it became a case of trial and error as I kep closing them a touch until I got the correct angle. Unfortunately I haven't got externally adjustable points so I hade to take the cap off each time - the distributor's a Ducillier M48. This is the cause for my confusion, what is more important in setting your points, gap or dwell angle, because they do not seem to match in this case? My thoughts say angle, although I've been wrong before - I once thought I'd made a mistake, but I hadn't .

    Matt
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    Quote Originally Posted by mlb
    the distributor's a Ducillier M48. -
    Matt
    What engine is the dizzy on?
    I had an R18 with externally adjustable points, and I have seen one suitable for an R12 that had it too. Would be fairly easy to adapt a non adjustable one though.
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    Quote Originally Posted by HONG KONG PUGGY
    What engine is the dizzy on?
    I had an R18 with externally adjustable points, and I have seen one suitable for an R12 that had it too. Would be fairly easy to adapt a non adjustable one though.
    It's on a Pug XN1. I not sure if it's going to be worth the effort of adapting the dissy as hopfully it won't be too long and I get around to building the high energy ignition kit and it will all be academic, especially after I squeeze in a Halls effect sensor to replace the points
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    I never even looked to see that you had a 505GR mentioned in the sig.
    No adapting is a long road, but wouldn't be too hard. As far as I can tell, most of the Ducilliers used by Ren/Pug are very similar.
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    I agree with the grey haired brigade (you will have another member before long, and i am only 22).

    I don't have a timing plate so the timing light is just a nice looking flashy thing. I advance and retard until i have decent acceleration and cruise without any pinging under load eg accelerating at 70 in 4th.

    mlb, do you use premium unleaded in the xn1? I use ultimate and i have advanced the timing to good effect with it, whilst using flash lube.

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    Quote Originally Posted by HONG KONG PUGGY

    I never even looked to see that you had a 505GR mentioned in the sig.
    No adapting is a long road, but wouldn't be too hard. As far as I can tell, most of the Ducilliers used by Ren/Pug are very similar.
    Might have a closer look at it and see what's possible.

    As for not reading my sig, don't be . You can't be sure just what has been done to some cars. I may have put a 350 Chev in it. Oooh there's an idea
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    Quote Originally Posted by mlb
    There's no concern about the dizzy cam. It's come from a good source who gave it a going over before we fitted it. The dwell angle remains constant when the engine is running so I'm confident the shaft and cam is all straight and true.
    The shaft can be true and each lobe the same.
    With wear the lobes are lower in profile and therefore when you set the dwell the gap is way out, (common Holden problem).
    Have you checked the lobe profile?

    HKP.-by the time I could afford a good timing light/dwell meter, I did not need it to set the points, (bought it any way). I then promptly got a car with electronic ignition and havenít taken it out of the box since.

    A fresh set of points and a condenser would not go astray. If you are feeling flush, go the rotor button, cap, leads, plugs option while you are at it, the car will love you for it.
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    Quote Originally Posted by Shobbz
    mlb, do you use premium unleaded in the xn1? I use ultimate and i have advanced the timing to good effect with it, whilst using flash lube.
    Yep, running PULP with flashlube. So to my way of thinking that allows me to set the ignition as per original specs.
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    Quote Originally Posted by Shobbz
    I agree with the grey haired brigade.
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    Quote Originally Posted by Gamma
    The shaft can be true and each lobe the same.
    With wear the lobes are lower in profile and therefore when you set the dwell the gap is way out, (common Holden problem).
    Have you checked the lobe profile?
    So this could explain the gap/angle descrepancy then wouldn't it?
    Quote Originally Posted by Gamma
    HKP.-by the time I could afford a good timing light/dwell meter, I did not need it to set the points, (bought it any way). I then promptly got a car with electronic ignition and havenít taken it out of the box since.
    I'm currently operating with a $20 timing light from SuperCheap and an engine tuner (tacho/dwell) that my old man was using on his performance car 30 years ago.
    Quote Originally Posted by Gamma
    A fresh set of points and a condenser would not go astray. If you are feeling flush, go the rotor button, cap, leads, plugs option while you are at it, the car will love you for it.
    Part way there. Distributor had new points 20,000kms ago. Along with a new rotor, cap, and plugs. The only things left to replace are leads, condensor, and coil. The leads will probably be next. I'm sick of getting zapped when I play with them when the car's running
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    Quote Originally Posted by mlb
    I'm currently operating with a $20 timing light from SuperCheap and an engine tuner (tacho/dwell) that my old man was using on his performance car 30 years ago.

    :
    Long live the old tach/dwell meter. I have one that I got for my 21st(I am approaching 40 so that's a fair old meter now), and I dropped the timing light and broke it, and I am on my second one since. They just don't make them like they used to. (bit like old grey-haired/balding tuners)
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    Matt,

    I fitted an electronic ignition setup to my 505GR that I got from a 505SR and haven't had a problem since. It used to run rough and misfire. I'd replaced the coil, leads, points, cap, plugs and exrensions, and I even rebuilt the carby which didn't fix it. With the electronic kit it runs like a new car. It still occasionally plays up so I think there might be a problem with the head. I've set the tappets but still can't get rid of the tappety noise.

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    Quote Originally Posted by Ralph
    I've set the tappets but still can't get rid of the tappety noise.

    Matt.
    Exhaust leak? As I've just found out, run a good deal of Redex through the engine and all exhaust leaks will be revealed .

    Just make sure you're friendly with your neighbours. Because you may not be by the end of it

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    Quote Originally Posted by mlb
    So this could explain the gap/angle discrepancy then wouldn't it?
    Yes

    Quote Originally Posted by mlb
    I'm currently operating with a $20 timing light from SuperCheap and an engine tuner (tacho/dwell) that my old man was using on his performance car 30 years ago.
    Got the good one and it was $400 DIGI TAC all the bells and

    Quote Originally Posted by mlb
    Part way there. Distributor had new points 20,000kms ago. Along with a new rotor, cap, and plugs. The only things left to replace are leads, condenser, and coil. The leads will probably be next. I'm sick of getting zapped when I play with them when the car's running
    Due for another set of points- every second or third service and checked for gap 100 miles after installation and then every 2000 miles. Plugs every second oil change.

    You should not get enough voltage leakage to get zapped off the leads????
    This may indicate cracked insulation and partial shorting. This can be a cause for rough running as it can result in poor or intermittent spark. Lets go back to solid core leads, who needs suppression any way, (how many greys out there remember the interference on the Telly from the neighbours old Viva when he arrived back from the pub at all hours).
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