[T3] Ignition on with points closed.

[Keith Park]

Well, that gets me wondering, because ive NEVER seen a tit on any of the 
lubripoints ive used, they are all ventilated.  Hmmm, guess Ill have to 
bring an old set of points from my pre-mark10 days to the invasion with a
monicle and we can come up with theories!

Keith


Topnotch Restorations
topnotch at nycap.rr.com
http://www.a383ina68.addr.com/radiorest/main.htm
71 Squareback  "Hothe"
65 Notchback  "El Baja Rojo"
93 RX7  "Redstur"
87 Golf  "Winterat"
 

-----Original Message-----
From: type3-vwtype3.org [mailto:type3-vwtype3.org-bounces at lists.vwtype3.org]
On Behalf Of Jim Adney
Sent: Wednesday, March 30, 2016 4:28 PM
To: type3 at vwtype3.org
Subject: Re: [T3] Ignition on with points closed.

On 30 Mar 2016 at 15:53, Keith Park wrote:

> ;-)
> Ventilated points dont get the "tit" on them,

Why? If they don't, it can't have anything to do with having that 
hole in the middle. They don't get hot, and if they did, the solid 
form would dissipate heat better than the annulus.

Think of it this way: Nothing's perfect, so either shape will have 
some single point of contact. Any heat that's generated will have to 
be dissipated from that point. On solid points, that point is 
surrounded 360 deg by more solid material, a great heat sink. On 
annular points about half of that heat sink path has been removed. 
The thermal conduction to air can't be more than a few % of the 
conduction to metal.  

Perhaps the vented points you use have some special metallurgy that 
makes them better, but I can't see any reason why the shape would 
have any effect other than a down side.

-- 
*******************************
Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
*******************************

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