Date: Sat, 15 Feb 2003 09:03:58 -0700
Reply-To: Ben McCafferty <ben@VOLKSCAFE.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Ben McCafferty <ben@VOLKSCAFE.COM>
Subject: Re: Gap of Sparks
In-Reply-To: <BA739EEF.2810%mwmiller@cwnet.com>
Content-type: text/plain; charset="US-ASCII"
Well, yes and no. Points have a dwell angle, which is the amount of time
(in degrees) they are close enough together to arc and send spark out the
rotor and dist. cap to the plug. But if you consider that once set, dwell
is a constant, then changing gap will in fact affect timing. I'm basing
this on experience only, so like you say, maybe an EE can jump in and help
out. Further, since you set timing based on plug #1 only, having different
gaps in each cylinder can also cause problems.
tx,
bmc :)
Ben McCafferty
ben@volkscafe.com
Volks Cafe
1823 Soquel Avenue
Santa Cruz, CA 95062
831-426-1244
http://volkscafe.com
> From: Mike Miller <mwmiller@cwnet.com>
> Date: Sat, 15 Feb 2003 07:38:23 -0800
> To: Ben McCafferty <ben@volkscafe.com>, <vanagon@gerry.vanagon.com>
> Subject: Re: Gap of Sparks
>
> Ben,
>
> You're probably right but doesn't when the points close [either directly or
> as a sensor] determine when the plug fires, not the distance across the gap?
>
> Somebody on this list has got to know how this works really. Given the
> state of my knowledge practically anybody will do.
>
> Where's David B when we need him?
>
> Sylvan! Wake the old bear up.
>
>
>
> Mike
>
>
> On 2/14/03 11:20 PM, "Ben McCafferty" <ben@VOLKSCAFE.COM> wrote:
>
>> No, I think you're right and we're saying the same thing. Now I'm really
>> reaching here back to high school physics, but if I recall correctly, it
>> takes about 20,000 volts to jump 1 centimeter. Can someone confirm or
>> refute that? In any case, if it takes more volts to jump a longer distance,
>> a larger gap would mean higher voltage before the spark would get across,
>> and a smaller gap would mean lower voltage to get across. I think that
>> means smaller gap=quicker spark=lower voltage=cooler fire and larger
>> gap=slower spark=higher voltage=hotter fire.
>>
>> Am I missing something here?
>> tx,
>> bmc :)
>> Ben McCafferty
>> ben@volkscafe.com
>>
>> Volks Cafe
>> 1823 Soquel Avenue
>> Santa Cruz, CA 95062
>> 831-426-1244
>> http://volkscafe.com
>>
>>
>>> From: Mike Miller <mwmiller@CWNET.COM>
>>> Reply-To: Mike Miller <mwmiller@CWNET.COM>
>>> Date: Fri, 14 Feb 2003 23:07:21 -0800
>>> To: vanagon@GERRY.VANAGON.COM
>>> Subject: Re: Gap of Sparks
>>>
>>> Really?
>>>
>>> Darn I misunderstood gap and timing then. I thought too wide a gap and it
>>> was hard for the plug to fire and too narrow and the spark wasn't big enough
>>> to light the fire efficiently.
>>>
>>> Mike
>>>
>>> On 2/14/03 5:37 PM, "Ben McCafferty" <ben@VOLKSCAFE.COM> wrote:
>>>
>>>> If gap is too short, spark happens early; if too long, spark happens late.
>>>> In either case it will affect timing and combustion. I believe it will
>>>> also
>>>> tend to shorten the life of the electrode on the plug, but I'll let the EEs
>>>> chime in on that.
>>>> tx,
>>>> bmc :)
>>>> Ben McCafferty
>>>> ben@volkscafe.com
>>>>
>>>> Volks Cafe
>>>> 1823 Soquel Avenue
>>>> Santa Cruz, CA 95062
>>>> 831-426-1244
>>>> http://volkscafe.com
>>>>
>>>>
>>>>> From: Mark Dorm <mark_hb@HOTMAIL.COM>
>>>>> Reply-To: Mark Dorm <mark_hb@HOTMAIL.COM>
>>>>> Date: Fri, 14 Feb 2003 12:16:49 -0800
>>>>> To: vanagon@GERRY.VANAGON.COM
>>>>> Subject: Re: Gap of Sparks
>>>>>
>>>>> So what happens when the sparks you've got installed are not of the
>>>>> correct
>>>>> gap? I use only W7CCO by Bosch
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>> From: Mike Miller <mwmiller@cwnet.com>
>>>>>
>>>>>>
>>>>>> I only use Bosch and they're rarely the correct gap right out of the box.
>>>>>>
>>>>>> Mike
>>>>>>
>>>>>> On 2/14/03 9:24 AM, "Mark Dorm" <mark_hb@HOTMAIL.COM> wrote:
>>>>>>
>>>>>>> I thought Bosch plugs were preset to gap no problem...
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>>
>>>>>>>> As to the slow starting, there's lots of things, but have you checked
>>>>>> your
>>>>>>>> timing? Also, with your new plugs, did you check the gap? Lots of
>>>>>> times
>>>>>>>> people think they come preset to the correct gap, and they usually
>>>>>> don't.
>>>>>>>>
>>>>>>>> tx,
>>>>>>>> bmc :)
>>>>>>>> Ben McCafferty
>>>>>>>> ben@volkscafe.com
>>>>>>>>
>>>>>>>
>>>>>>>
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>>
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