Question about timing

Actually, the 6 degrees BTDC does not apply to your specific mustang, it applies to the THOUSANDS (if not millions) of 351C engines (of the era your 351C was built )that are out there and is just a setting that safely applies to all of them. If you can set your timing for more horsepower without detonation, pre-ignition, or bucking when you are starting the car, so be it. I would also imagine that your MSD ignition has a different timing advance than the original ignition anyway.

Not sure how many 351C 4V's they made. 92% of the 351C's were 2V's. Of the remaining 8% 4V's, there were four variations and only made in

1970,71. Guess if the engine runs "smoothly" without ping etc. timing is subjective. Was going to dyno the car but read somewhere you can't measure real time under your feet street performance on a dyno. BTW the car is very fast :)

mike

"goodnigh" wrote in news:6WBTg.1121$Lv3.776 @newsread1.news.pas.earthlink.net:

Loosen the dizzy, attach a choke cable to it that you can control from the cockpit. Find the best timimg, stop the car, and lock the dizzy bolt down. Don't forget that altitude, load, and temp can play a role in timing.

So may I surmise the recommended setting of 6 BTDC means nothing. Or at least it means Ford knows the car will operate at that setting. Thanks for your insight.

Q-code 4v 351's were available through 1973 models.

Rob

That would be the CJ. My M-code was only made for two years.

mike

I have a 72 Mach 1 with the HO ( 72 BOSS ) 351 C. The way I timed it was to advance the timing until it would just start to ping under full a throttle heavy load, back it off a bit and tighten down the bolt. Test, no ping, great!

Your best bet is to have the distributor recurved.... you'll be looking for base timing (vacuum disconnected) around 10ish degrees... a bit more might not hurt but advancing ignition timing is a bit like walking along a cliff.... too close to the edge and...........

You'll want total timing all in around 2700 rpm - if you haven't gotten fancy with the compression ratio, look for 38 ~ 40 total advance... this is probably a good compromise between power and "safe".

"goodnigh" wrote in news:y9OTg.1366$Lv3.858 @newsread1.news.pas.earthlink.net:

As I said, many things affect your best timing setting - fuel, altitude, mods that have been made to the engne, etc. Power timing is always the best way to go. 6 degrees was merely a manufacturer's recommendation - a fit all solution, if you will.

The car did perform differently while visiting Yosemite earlier this year. Altitude was 7200 feet. Normal altitude for this car is 100 feet. Rhetorical question; would you delay or advance the timing for altitude. Also, would you adjust the fuel/air mix more rich or lean. These cars don't have computer chips, just a few screws. I love it! The car did not perform poorly at altitude, just a bit less spunky.

less air, less fuel

"goodnigh" wrote in news:UwYTg.5558$o71.353 @newsread3.news.pas.earthlink.net:

The only way to adjust the fuel/air mix is by changing jets. The screws are only for the idle mix. Just for the record, you would want it more lean as altitude increases, since there is less air density.

I can tell you by experience that the higher the altitude, the more advance you can run. I live at 3,500 feet, but my car will ping horribly if I drive it down to Redding (500 feet.) There is a lot to be said for computers and automatic timing adjustment.

Proper timing depends on a lot of facters. Getting it just right takes a little time, but it's generally worth it.

Rememeber that timing is broken up in to three parts: initial (or base), mechanical advance, and vacume advance.

In your stock distributer, mechanical and vacuum are not easily adjustable, so we'll skip over them.

Base timing can be moved around a bit to make your engine work best in your conditions. 6* is a good starting point. Get the engine warmed up. Get a drinking glass, and fill it about half way with water. Set the glass on the fender. With the engine running, advance the timing until the water is the smoothest. That will also be the point where your vacuum is highest. Adjust the idle again, and then the timing. You'll have to go back and forth until you get them both exactly where you want them.

Shut off the engine, and restart it. If it starts easily right away, your base timing is perfect. If it hesitates, seems to have a hard time starting, back off the timing about 2* and try again.

Once it starts easily and the idle is smooth, leave it alone. There's no more power to be found there.

----- .boB Arrived: 2006 FXDI, Red.

1997 HD FXDWG - Turbocharged Stolen 11/26/05 in Denver 1HD1GEL10VY3200010 CO License J5822Z 2001 Dodge Dakota QC 5.9/4x4/3.92 1966 Mustang Coupe - Daily Driver 1965 FFR Cobra - 427W EFI, Damn Fast.

When checked with a timing light, the car runs poorly at 6-8*. This makes no sense as it seems to run best at around 12-14*. Unless I am missing something, I have never heard it ping. Unless I am doing something wrong or the light is bad those are the readings I am getting. The car has a dual diaphragm distributor and I plug both lines. 700 RPM on hand held tach. The car always starts instantly. It also has an after market high torque starter but don't know what brand. I think it has a cam because it idles roughly. At 3000 RPM it sounds fast and it is! This engine has been B*B'd so I don't know what they did to it. I would ask the mechanic I bought it from but he is still suffering from separation anxiety.

mike

If it doesn't ping, starts easily, and idles smoothly, it's perfect. You might take a close look at the damper. SOmetimes the stock damper will wear out, and the outer ring will slip a little. If that's the case, you'll need to replace it.

It appears the customary tuning implements are useless on these cars. You tune the car by sight, sound and feel. A flathead screwdriver and box wrench. Need to find a mechanic that moonlights as a piano tuner.