Static Timing Question

[ken180]

Hi All,

I have a Static/Dynamic Timing Question

I obtained a motor with the following specs:

Solex cams
B & S = 92mm x 66mm = 2632cc
40IDA Carbs
Ported "S" heads

What are the factors that determine where to set the timing??

With the above specs what would be a "good" static/dynamic timing setting??

Thanks,

Ken

[Henry Schmidt]

Compression ratio ________
RPM @ max torque ________
Fuel octane _________
Intake temperature __________
Fuel mixture __________
Twin or single plug __________
Piston dome configuration ________
Combustion chamber shape ________
These are all factors that determine timing settings.

With Solex cams and Weber carbs we know 2 things.
Max torque 4600 RPM or so.
Webers run rich.
Now you fill in the rest of the blanks and we'll try to answer your questions.

[ken180]

Not sure I have all the answers you need.

Compression ratio ________ 9.5:1
RPM @ max torque ________ 4700
Fuel octane _________ 91
Intake temperature __________ 25c
Fuel mixture __________ 12.5:1
Twin or single plug __________ Single
Piston dome configuration ________ ?? not sure what you need - it has a "high dome"
Combustion chamber shape ________ not sure what you need - it is an "S" head

Ken

[Henry Schmidt]

Originally Posted by ken180

Not sure I have all the answers you need.

Compression ratio ________ 9.5:1
RPM @ max torque ________ 4700
Fuel octane _________ 91
Intake temperature __________ 25c
Fuel mixture __________ 12.5:1
Twin or single plug __________ Single
Piston dome configuration ________ ?? not sure what you need - it has a "high dome"
Combustion chamber shape ________ not sure what you need - it is an "S" head

Ken

Hi dome is what I was looking for. This type of dome will split the chamber offering challenges to smooth combustion.
Chamber shape in 911 Porsches is a hemi so detonation is built in. ( hemis tend to detonate if under varying conditions .)

The specs below are intended to be a starting point not definitive conclusion.

static timing 4-6
quick advance to 18-20
24-26 @ 4500 or so
32 @ 6000

Good luck

[ken180]

Thanks,

Ken