California 200 Timing

[bobtheclassic]

First of all I want to thank everyone on the forums. I've been restoring my 66 Mustang for over 5 years now and been using this site for a couple years as I've worked on the motor.

My 200 is the Cali version. As far as I can see the only difference is in the head. It has air injection ports on the exhaust ports, but that is the only thing I can see.

I have a 1968 MOTOR'S brand shop manual and it tells me that the initial timing should be set at 6* on standard 200 and 0* if it has the Thermactor Emissions. I removed all of the smog equip and plugged the holes in the exhaust ports.

Now for my question. When I set the timing an additional 5* should I set it to approx 11*, or should I add it to the 0* and set it at 5*?


To give you all an idea of how the engine is set up. I have a rebuilt bottom end with stock head, Dual-out Clifford headers, Pertronix II, T-5 tranny conversion, and an Autolite 2100 (1.21) on adapter.

Thank you for any help

 

[Mercury Mike]

Start at 12*, drive it, and adjust from there.

 

[bobtheclassic]

Start at 12*, drive it, and adjust from there.

It runs pretty decent at the 10 to 12 range, but the idle is way too high. This is when the choke has already shut off and the warm idle on the carb is adjusted all the way out until the screw isn't even touching. It idles around 1100, the only way I can get it to the sub-1000 range is to drop the timing down to about 6*. Do you think this is because of the old Cali emissions stuff, or is something to do with the carb maybe?

 

[addo]

Almost certainly a carb issue. Your investment in maximum timing with these motors (to the point of just 2° before pinging) is to optimise the potential of an older combustion chamber design and poor gas flow.

Backing timing off, really just gets less mileage. I'd suggest looking for a small vacuum leak, or an imperfect idle position on the throttle blade.

 

[Mercury Mike]

I'm with Addo. =)

 

[CobraSix]

Me too, check your carb.

I personally run 10* and love it. Good power, good mileage.

Slade

 

[bobtheclassic]

That's what I was hoping. Thanks all for the help. I just bought the rebuilt carb for about $100 about a month ago. It comes with a 3 month warranty so I'll look it over and if I can't see anything, I'll just trade it out for another. I'll let you all know what happens. Thanks again.

A question though...Is the only reason to set California Spec cars timing to 0* for the emissions? Does it improve emissions by retarding the timing just a bit? Not that I'd do it, just curious.

 

[JackFish]

It was about that time that they all became victims of emissions era vacuum controls, and sensors, computer chips, etc. to control advance.
At least that's my theory.

 

[CobraSix]

Yes, it is an old trick to improve emissions on old car, to retard the timing to crazy levels. I had a neighbor who had an old, mid 70's Chevy Silverado (the old 2 door, Bronco II styled) truck with a 350 in it. All sorts of performance mods, but couldn't pass emissions in Mexico and this was Southern Cal. He would drive it to the emissions place, pop the hood, retard the timing and it would pass.

Slade