Simon Perks

Active Member

• Feb 15, 2018

• #1

Greetings from the Alps,
So I have the following 'lectronic dizzy on my SIII, I am unable to actually work out which curve i need for the engine (5MB) and was wondering if anyone else has such a piece of kit fitted or can decipher which curve setting i should use, at the moment it's on E.

Ticks over fine but it flats out real early ..

http://www.123ignition.nl/product.phtml?id=271

thanks for any advice.

Simon

 

cornish rattler

Well-Known Member

• Feb 15, 2018

• #2

Do it by ear advance or retard it with the engine running, drive it and re-adjust again if need be

 

Simon Perks

Active Member

• Feb 15, 2018

• #3

cornish rattler said:

Do it by ear advance or retard it with the engine running, drive it and re-adjust again if need be

Click to expand...

The timing point is bang on, as i have a new timing chain fitted it really is as close as it can be but this is not the problem.
The problem is that as the dizzy has no real advance retard vacuum tube so this is a setting based on the table in the link.

I cant find any info in the haynes or online to give this ... this is what im looking for ..
so the maximum number of advance degrees at 4500rpm, 2000 & 3000 ( at the moment its at 26 & 12 )

 

T

Tall Ratbag

Active Member

• Feb 15, 2018

• #4

The green book gives 40 degrees of advance at the crank at 4500 rpm

 

Simon Perks

Active Member

• Feb 16, 2018

• #5

Tall Ratbag said:

The green book gives 40 degrees of advance at the crank at 4500 rpm

Click to expand...

Ok so that tells me that with an advance at the crank of 26deg plus 14at the vacuum I have the 40, what does the green book say at 2000?
the options are:
7.5
10
12
14

Simon

 

T

Tall Ratbag

Active Member

• Feb 16, 2018

• #6

No, the 40 degrees is not including the vacuum advance.

 

Simon Perks

Active Member

• Feb 16, 2018

• #7

Tall Ratbag said:

No, the 40 degrees is not including the vacuum advance.

Click to expand...

max curve is 26@4500 Mmmmm
anyhow what does it give for 2000?

simon

 

C

Citizen Kane

Well-Known Member

• Feb 16, 2018

• #8

I think its up to you to decide which curve best suits your engine. It might not even be one of the curves that gives you the full 26deg advance. The original advance curve would probably have a +/- tolerance at 2000 rpm as large as the variation in the choices you have available in the C to F range, after all it was only a simple pair of bob weights and springs.