Engine TDC timing ?

[My 69 Mach 1]

I have the pertronix ignition in my car , the engine spec for the 351 is 6 degrees TDC . But I have been told I should or can advance the timing to as much as 15 degrees TDC .  Who has info on this ?

 

[danno 128]

I have mine set at about 20.  I understand you can advance it until is starts pinging, then back if off a few.  Do a search on timing advance, there has been a lot written in this forum about it.

[Midlife 814]

Ford spec'ed the timing for the widest range of operating conditions, with the hardest to comply was high elevations (e.g. 8000 feet).  The goal was a quiet, smooth idle that would work just about anywhere, anytime that reduced vibration, harshness, and noise.  In fact, one typically gets better fuel mileage (efficiency) with a bit more advance and simultaneously a cooler running engine.  However, those settings won't work in a wide range of environmental conditions, which is why us old geezers recommend tuning and setting timing for YOUR engine and YOUR environment.

As they say, Your Mileage May Vary.

[rutkak 0]

All things being considered on a 351W (I have two of them)...You probably can't go wrong with 12 degrees.  You also want to clean your spark plugs and run the car about 100-200 miles then check again.  Goggle reading spark plugs for an understanding of how to read them.  Based on the ground strap you should adjust your timing.  Rinse, wash, repeat.  I've tuned my 69 Torino about perfect with an a/f gauge and reading plugs on an Edelbrock carb.  She's a consistent 14.1-14.5 AF ratio at all times. 

[danno 128]

remind me of what an AF gauge  and AF ratio is?  Anti Foul? Anti Fungus?  Anterior Federation?

[fvike 173]

Air/Fuel

[rutkak 0]

Yep, air / fuel ratio. 

[danno 128]

How to you measure the air to fuel ratio?  how does this gauge work?  Do you stick it in a spark plug hole?

[Rsanter 152]

Whatnthe correct timing is, is based on the specs of the engine. If you have a different cam, heads, headers, intake....etc then the timing spec will change.

so how do you know what the initial and total timing should be?

well ideally you will run as much as gives peak performance without pinging/preignition.

so how do you figure that out?

you find an upoccupied section of road and you do time trials from 0-60.

what gives you the quickest time is where you should be setting things up

 

typically ford specified 6 degrees. In general you can bump that to 8 or so degrees. If you have a different cam, intake...etc then you can give a little more.

 

then it also depends on the engine. The 351c likes advance timing. If you have a 4V and a big cam, it will demand lots of timing. My neighbor has a built up 351c closed chamber 4V and I have his initial timing set at 15 degrees

 

bob

[Rsanter 152]

3 hours ago, danno said:

How to you measure the air to fuel ratio?  how does this gauge work?  Do you stick it in a spark plug hole?

There is a guage you buy and you install a sensor in the exhaust. If you have headers it should be in or right behind the collector.

when I have set these up I install one guage and two sensors. One in each pipe. Then I use a double throw switch so you can flip back and forth to check both sides

 

bob

[Mach1 Driver 560]

On 4/27/2017 at 5:42 PM, Rsanter said:

If you have headers it should be in or right behind the collector.

bob

That makes sense, that's the same place to put the O2 sensor hole if you add EFI, which is how it measures the A/F ratio.

[rutkak 0]

Right, same location.  I have an air / fuel gauge with O2 sensor on my 69 Torino that tells me how rich or lean the car is running.  I watched it at idle, moderate cruise and WOT.  I've tuned her a good bit based on the read outs.  My 70 Mach 1 needs it for the Edelbrock EStreet2 EFI but my Torino is carbed (Edelbrock 600 cfm).  You have to have an exhaust bung drilled (or torched) and installed which costs about $50 and the gauges cost about $200 or so.  Sounds steep for some but I swear by it.  I love my Torino's A/F gauge, it really helped me tune the hell out of it so I'm not smelling rich or lean exhaust.  I'm confident you'll end up with a good burn on your spark plugs but I also swear by reading the spark plugs for timing...it's all about the ground strap. 

  Most say you only need only side of the manifolds or headers but both is good also.  I'm running only one and she works well for me.  It's better than taking it to a shop to get it dyno tuned. 

  To be honest, my carbed 69 Torino probably runs better (at least until engine operating temp) than my 70 Mach 1 with Edelbrock EFI.  It's all about tuning these old girls, especially when you have aftermarket carbs and intakes in them. 

Ken