[Tigers] Timing

[Tom Witt]

A rambling mind:
I find it interesting that most performance articles refer to the “all in” timing in the 2,500-3,000 RPM range.  And when you consider most performance driving (racing for instance )one rarely would be under that limit, it makes a timing curve a somewhat mote point. It seems about the only advantage is getting the car started.

In the daily driving realm it does have its application. Unfortunately yesterday’s combustion chambers and today’s gasoline seem to be fighting one another. A knock sensor based timing curve does make sense.  >From what I can see modern cars have a conservative timing curve and I’d think that is to protect the manufacture.  I use to have an Audi 5000 Turbo and for a mere $800 you could send the ECU off to be “re-programmed.”  My understanding was the  jump from 190HP to 240HP was primarily in the timing changes (premium fuel required). The fuel and boost changes were minor.  I saw a significant “snappiness” in my daily driver Mazda Protégé when I slotted the crank triggered reluctor wheel and snuck in an extra 4 degrees (still no pinging on regular gas). 

So, timing can sure make power. The question is does the available gas, combustion chamber shape, quench, flame path etc. allow for that on the SBF head design(s)???

As Ron stated timing is an art form..., - that can be aided when computer generated “drawing” is involved. A mechanical advance system like the stock Tiger would seem to fall into “cave drawing” art.

From: Ron Fraser via Tigers 
Sent: Monday, October 30, 2017 4:45 PM
To: tigers at Autox.Team.Net 
Subject: [Tigers] Timing

Here is a picture of the stock Ford primary distributor spring, on the left and secondary distributor spring on the right.

 

The primary spring should always have tension so the timing can always returns to its zero mechanical advance position.

 

The secondary spring has longer loops so it will not be part of the advance curve until higher rpms – the dog leg of the curve.   You can change the position the dog leg of the advance curve starts some by moving the spring’s tang position but changing springs maybe easier.

 

Timing requirements are different for every different engine configuration and operating condition.

Timing is kind of an art form and most of us are just rookies in this field, with some insights, just wanting our engines to run well.

 

Ron Fraser


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