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Dizzy full advance lock...need help


Guest jeff1216

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Guest jeff1216

1978 280z

 

Head is back from the machine shop ( e88 head all new 280 valves and springs, hot cam)

Arizona intake with a holley 390.

MS square port header

 

 

I am going to be putting it all back together this weekend.

 

I am interested pinning the dizzy at full advance......How do I do this?

I can see how to pin the vacuum advance with a small machine screw but doesnt this car also have a mechanical advance?

If so how do I pin it?

 

Do I need to remove the entire dist. to do this?

 

How many degrees of advance do I need to set it at while at 3k rpm?

 

What type of performance gains can you get by doing this?

 

 

Thanx in Advance

 

Jeff

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I had to do this when I installed my Haltech FI system...

 

I basically took the entire dizzy apart and epoxied the cams, springs and weights on the mechanical advance... Then I removed the vacuum advance mechanism and shaved off that part of the distributor...

 

If I'm not mistaken you don't want to do this on a street car.... it will make it difficult to drive normal.

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I had to do this before I had the SDS. I removed the wieghts and wired the tabs the weights were on. I had my total between 20-25*. Being that you are N/A I would assume you'll be around 35*, too much and you'll get a light rattle even at cruise. Don't know if emissions is required for you but it will be hard to pass with the timing so high at idle. You can adjust your timing so you total timing is were you want it. just keep the revs above 3500 so all the mechanical is in and then set it. Anytime I adjust timing I always go for total and not idle. Except when going throught emissions. You'll need a timing light with a dial on it.

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If you're looking for performance, you don't want full advance all the time. Leave the mechanical and bolt/JB weld/braze the vacuum advance to the breaker plate. Then do as suggested above and set timing to ~35 total. You can also adjust the mechanical by lengthening or shortening the slots in that advance mechanism to give you more or less mech advance. If it idles at 15 or more and totals at 35 or so than you should be doing pretty well. You can change the springs on the mech advance, you want it all in by about 2500 rpm.

 

Here's a webpage showing the tear down and reassembly steps for a ZX distributor, I'm sure it's pretty close to what you have.

 

http://www.jrdemers.com/280ZX/distributor/distributor.html

 

HTH,

 

Jon

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