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mailman Samba Member
Joined: March 24, 2005 Posts: 1663
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Posted: Mon Jul 31, 2006 6:51 pm Post subject: Point gap? or Dwell angle? |
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Which spec is more important? Proper point gap, or proper dwell angle?
My tune-up specs (1200 40HP) call for .016" point gap. If I do that, the dwell angle is much too large.....about 58 or 59*. The dwell spec calls for 50* plus or minus 2*. If I set it at 50*, I have a point gap of about .020".
It seems to run very well at the 50* setting, so that's where I've left it.
Any thoughts? _________________ '64 Bahama Blue Beetle / steel sunroof
'64 Bahama Blue Beetle Sedan (future ragtop) |
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Dazed42 Samba Member
Joined: May 01, 2004 Posts: 1148 Location: Copperas Cove, Tx
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Posted: Mon Jul 31, 2006 6:53 pm Post subject: |
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I set mine with the tach dwell since the dwell is what matters. _________________ Proud owner of a super fatty.
Do you love the KAC?
www.dallasaircoolers.com |
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nsracing Samba Member
Joined: November 16, 2003 Posts: 9481 Location: NOVA
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Posted: Mon Jul 31, 2006 8:34 pm Post subject: Re: Point gap? or Dwell angle? |
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mailman wrote: |
Which spec is more important? Proper point gap, or proper dwell angle?
My tune-up specs (1200 40HP) call for .016" point gap. If I do that, the dwell angle is much too large.....about 58 or 59*. The dwell spec calls for 50* plus or minus 2*. If I set it at 50*, I have a point gap of about .020".
It seems to run very well at the 50* setting, so that's where I've left it.
Any thoughts? |
What is this, trick question?
They are one and the same. The point gap will exert how long or how many degrees the points will stay on contact with each other. This is the dwell.
The dwell reading, in degrees, is the really fancy way to know your actual "gap". The larger the gap...the smaller the dwell.
This degree figure will give the longest wear on the peg and points.
Last edited by nsracing on Tue Aug 01, 2006 10:07 am; edited 1 time in total |
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Bruce Samba Member
Joined: May 16, 2003 Posts: 17290 Location: Left coast, Canada
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Posted: Mon Jul 31, 2006 8:35 pm Post subject: |
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Hands down, the Dwell is much more important.
The spec is 47º +-3º.
Then you have to set your timing after you alter your dwell. Later, when you replace the points in the future, set them to 47º, and your timing won't have changed. |
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krusher Samba Member
Joined: September 24, 2002 Posts: 7652 Location: europe
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Posted: Tue Aug 01, 2006 12:04 am Post subject: |
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Have any of you used a timing light with dwell that can be used to set up a 6volt car?
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mailman Samba Member
Joined: March 24, 2005 Posts: 1663
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Posted: Tue Aug 01, 2006 3:50 am Post subject: |
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nsracing...
Not a trick question.... My point is, you can't have it both ways. Altering one alters the other. I can't acheive both specs at the same time, so which should take precedence?
My thought is dwell. Apparently others agree.
I thought the spec was 50* plus or minus 2*...... If indeed the spec is 47*, I'll have to open the point gap even farther! _________________ '64 Bahama Blue Beetle / steel sunroof
'64 Bahama Blue Beetle Sedan (future ragtop) |
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Glenn Mr. 010
Joined: December 25, 2001 Posts: 76940 Location: Sneaking up behind you
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Posted: Tue Aug 01, 2006 4:07 am Post subject: |
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Dwell angle is not "as" critical as it is on a 8 cylinder engine since 4 cylinder engine have more time to charge the coil.
Dwell IS the spec, not point gap. The point gap is just a starting point for setting the dwell.
Do what I do and install a CDI box. with an electronic system dwell angle is not as important since the system will charge the coil faster so you can run a much smaller gap. I runs .010" with my system. _________________ Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
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nsracing Samba Member
Joined: November 16, 2003 Posts: 9481 Location: NOVA
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Posted: Tue Aug 01, 2006 6:51 am Post subject: |
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mailman wrote: |
nsracing...
Not a trick question.... My point is, you can't have it both ways. Altering one alters the other. I can't acheive both specs at the same time, so which should take precedence?
My thought is dwell. Apparently others agree.
I thought the spec was 50* plus or minus 2*...... If indeed the spec is 47*, I'll have to open the point gap even farther! |
This is like tweaking an idle screw...then you read the RPM figure on the timing light or a meter. The final result is the "dwell".
You adjust the points by hand...just as you adjust idle screw..by hand.
The feeler guage sets the width of the gap. This will vary because the "drag" is by feel. Just because you stuck a 0.016" feeler there does NOT mean it is. That is why the dwell varies.
It is a little tricky tightening the screw, isn't it? Too much and you move the points even when the feeler is in.
Try this trick: If the dwell is too big (meaning points is too tight) ....add 0.001 - 0.002 (to the feeler 0.016") to compensate. Yes...2 feelers ( you do the math...whatever will give you the gross figure.)
Stick the 2 feelers in there, and don't hold it when you tighten the screw.
Hope this helps. |
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KTPhil Samba Member
Joined: April 06, 2006 Posts: 34021 Location: Conejo Valley, CA
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Posted: Tue Aug 01, 2006 8:58 am Post subject: |
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The dwell is the relevant measure, since that is what electrically affects ignition characteristics. Correct point gap will give you correct dwell ONLY if the points are new, flat, and parallel. With worn, rounded, pitted or titted, or misaligned points, the gap as measured with a feeler gauge will induce too large a dwell angle. Use a dwell meter if you have it; if you don't, make a pully mark as shown at the end of this description, and set it with a simple test lamp:
http://www.desperado.scvnet.com/~philh/images/dwell.pdf
Last edited by KTPhil on Tue Aug 01, 2006 2:03 pm; edited 1 time in total |
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67Beetle2017 Samba Member
Joined: August 01, 2006 Posts: 399 Location: Pasadena CA
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Posted: Tue Aug 01, 2006 1:55 pm Post subject: |
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mailman wrote: |
nsracing...
Not a trick question.... My point is, you can't have it both ways. Altering one alters the other. I can't acheive both specs at the same time, so which should take precedence?
My thought is dwell. Apparently others agree.
I thought the spec was 50* plus or minus 2*...... If indeed the spec is 47*, I'll have to open the point gap even farther! |
You are correct in having to open the point a little further.
Just a thought. Points must meet squarely inorder to last the longest. Make sure the points are perpendicular to each other (both stationary and movable arm). Only tweak the stationary arm to square the point contact patch. Make sure to use Bosch point lube on the rubbing block also. The points will not close up so fast if you use the rubbing block lube. |
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sharkskinman Lateral Lunatic
Joined: April 26, 2006 Posts: 4030 Location: Deep In My Own Psyche
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Posted: Sat Jul 07, 2007 3:33 pm Post subject: |
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went back and messed with the dwell on mine
67 type 3 1641 stock
i have my gap set at .010 nad im hitting 46 about
i replaced them but didnt know (at the time)
you should put a condenser in as well
well
i got a condenser and its a bolt on one not a push in a bottom hole one
what does the condenser do exactly
and i know it "condenses"
but why
and what will a new points and an old condenser do exactly
will replace both soon prob but am not yet completely comfortable to take out the dist
is it slot (rite on or 180 off)
or is it a gear or what
but doesnt it seem strange that i have to have .010 with a stock engine??? _________________ 74 Mexi Swamp Thing. 70 square volksrod (Swamp Rat)..65 C10
Me of Course wrote: |
Extremity is relative to how far your willing to jump |
Ward Cleaver wrote: |
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VW Vet Samba Member
Joined: July 31, 2006 Posts: 218 Location: Maine
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Posted: Sat Jul 07, 2007 6:13 pm Post subject: |
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The condenser reduces arcing at the points when they open. It gives the electricity somewhere else to go without going to ground. |
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fubab Samba Member
Joined: April 17, 2004 Posts: 143
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Posted: Sun Jul 08, 2007 12:36 pm Post subject: |
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One thing to be aware of . . . some meters measure dwell in "degrees," some measure in "percent." For 4 cyl engines, 50 degrees equate to 56 percent. So if your meter measures in percent (pretty common), you're shooting for 56 percent. _________________ It glared at him from his own soul, and dogged him all his days. He knew only too well the human propensity to displace the real with the illusory, which is not restricted to the individual. It operates in human systems . . . |
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Bruce Samba Member
Joined: May 16, 2003 Posts: 17290 Location: Left coast, Canada
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Posted: Sun Jul 08, 2007 11:55 pm Post subject: |
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The spec is 47º, not 50º. _________________
overheard at the portland Swap Meet... wrote: |
..... a steering wheel made from a mastadon tusk..... |
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