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Discussion Starter · #1 ·
What is the normal range of timing degree jump(advance) when the vacumb is connected to the distributor? That is, compared to vacumb disconnected.
Thankx
 

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Discussion Starter · #2 ·
> What is the normal range of timing degree
> jump(advance) when the vacumb is connected
> to the distributor? That is, compared to
> vacumb disconnected.
> Thankx
You do not state what year car or whether single point, dual point or electronic dist.

The 70-71 have ~8-10 degrees of vacuum advance.

72 manual trans (single point) have ~5-7 degrees of vacuum advance.

72 auto trans (screwy dual point - one set phase retarded 7*) have ~8-10 degrees of vacuum advance.

All three of these start vacuum around 12-13 inHg and it's full in by 18-20 inHg.

I don't know about any others....hope this helps.

tomh
 

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Discussion Starter · #3 ·
> You do not state what year car or whether
> single point, dual point or electronic dist.

> The 70-71 have ~8-10 degrees of vacuum
> advance.

> 72 manual trans (single point) have ~5-7
> degrees of vacuum advance.

> 72 auto trans (screwy dual point - one set
> phase retarded 7*) have ~8-10 degrees of
> vacuum advance.

> All three of these start vacuum around 12-13
> inHg and it's full in by 18-20 inHg.

> I don't know about any others....hope this
> helps.

> tomh

Actually, it's a 1975 280z, electronic ignition.
I'm getting about 5 degree vacuum advance once the car runs for minute or two. When I first start it, it's at +13 degree advance. Any idea
why it changes like that?
Thanks
Tom
 

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thats in the normal range. 4 - 5 degrees +
sounds like you have dual pickups in the distributor.
The advance is first controlled by a temp sensor in the thermo housing
that causes the car to run on the advance pickup when cold.
As the engine warms it will switch over to the retarded side.
This is all done for emission purposes.
 
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