I just had my distributor apart (66 B, 25D) and it had 2 different size
springs precisely as described. I also discovered a few anomalies which
required attention: the breaker plate was frozen and resisted all
attempts to rotate (cured by disassembly and lubrication); and the spring
link from the advance diaphragm was snapped off (hmm, could this be
related?). This required a new advance mechanism. But the mechanical
advance seemed to be working fine...
Paul Hunt had this to say:
>Four different distributors I have for 4 cyl and V8 B's all have one thin
>and one thick spring, the thin spring is under tension on its pegs whereas
>the thick spring has some play - i.e. the weights will have to move out a
>little before it takes effect.
>
>One of the dizzies I have has a very much lighter spring than the other. I
>dynamically adjust the timing to 8 degrees BTDC then checked the static
>timing and found it was about 2 degrees *A*TDC. This does seem to confirm
>to me that the light spring controls advance at low rpm and the heavy spring
>controls advance at higher rpm, and gives relatively retarded timing for
>starting as opposed to running.
>
>PaulH.
>http://freespace.virgin.net/paul.hunt1/
>
>-----Original Message-----
>From: Bill Eastman <william.eastman@medtronic.com>
>To: mgs@autox.team.net <mgs@autox.team.net>
>Date: 08 July 1999 15:56
>Subject: Dizzy springs, MG sightings
>
>
>>Well, I have seen one brave fellow who offered up an opinion on why
>>distributors have two sizes of springs. His was the explanation that I
>>have heard many times before- that the light spring controls the advance
>>at low rpm while the heavy spring kicks in at high rpm. Until a few
>>days ago, I too subscribed to this belief...
>
>
--
Max Heim
'66 MGB GHN3L76149
Runs great,
looks particularly bad since some SUV clown backed into it.
If you're near Mountain View, CA,
it's the red one with the silver bootlid.
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