10° vs 14° Timing

[Xkuzme1]

Wholly smoke fellas. Still working out a few bugs with settings on my car.
It’s a fairly new rebuild from a 93 FB, with lots of upgrades in an AC Cobra body. I have it running really good. Have worked through MAF, plug wires, base idle resets, IAC, bad grounds, ignition problems... a few other misc items.

So today I was doing one final idle reset after all the other things are all playing nice and most settings are good. I timed it to 10° BTDC. Took the car out on a drive. Wow. It was smooth steady power but it was missing some cheese for sure.

I went back home and waited for the car to cool off a bit, then set the timing back to 14 degrees. What a difference it makes. It’s like the difference of riding a 4 stroke motorcycle me vs a 2 stroke motorcycle. Seriously, at 14° I feel like the car has a powerband.

My 0-60 time prior to getting all my settings ironed out timing tweaked was 4.5 seconds. Once all my settings were fine tuned and the timing was put back to 14°, I’ll bet i just dropped .75 seconds off that time. Maybe .5 but i wouldn’t be shocked if it was more.

Can’t wait to drive it tomorrow and get a 0-60 time. Hopefully it is warm enough for the tires to get some traction.

Cheers,

X

 

[Potomus Pete]

WTF I guess I need a timing light . It can really matter that much ???

 

[Xkuzme1]

As they say in the commercials, “you’re results may vary”. But for me... damn.

I wouldn’t advance the timing unless you run premium.

cheers.

 

[General karthief]

You can't set your timing without the light.
every mechanic is born with one.
side note: I do not have one but I never said I was a real mechanic
I do play one here on stangnet.

 

[FastDriver]

You'll pick up some power for sure, but it's not going to make a 3/4 second difference to 60. You'll pick up a tenth or two in the 1/4 on a stock engine.

As an example, in Richard Holdener's 5.0L Ford Dyno Tests, going from 10* base to 15* brought peak power from 197 to 203 rwhp. The timing advance at low RPM can certainly make it a lot snappier off idle and seemingly make a bigger difference than it actually does. I do it because it's my hobby, but as a practical every day matter, most people would probably be better off using 87 octane and saving a couple hundred a year or more on cheaper gas if they daily drive.

 

[junkyardwarrior]

Factory timing is ~26 degrees total depending on the EEC used. They run better with 32 to 40 depending on the engine combination (iron heads like it on the higher side). That is figured with a 10 deg base (which is included in the ~26 deg total timing). So if you advance the base to 14, you now have 28-30 degrees total, yes it outta pick up some power. BUT....what happens at part throttle where it can be up around 43 degrees (10° base)? At 14 base, you now have potentially 47 degrees, again depending on the EEC used, and that doesn't account for the ACT, IAT timing addition/subtractions. At 47, it may run a little rougher, potentially detonate, etc.

If you really sit down & halfway learn the factory Ford EEC fuel and timing, you'll realize that it's a trainwreck from a performance standpoint, but it runs smooth and meets emissions (for 1993 standards).

Should one install a quarterhorse /tunerpro RT and then load in a more performance-oriented tune it'll pick up quite a bit of power, torque, potentially get better MPG and runs just fine.

 

[a91what]

WOT timing in the MAF ECU is not 26 in the a9l (most common) it is closer to 29*.

An iron head does not want more timing, an aluminum head does. Heat is being removed from the chamber quickly by an aluminum head this reduces power, most engine builders will say an aluminum head is the equivalent of dropping one point of compression in a performance environment.

Www.veryuseful.com has all the stock a9l curves available to view. The base timing curve and the open loop WOT curve are not the same.

 

[FastDriver]

If these are to be believed, then it actually goes to 30* at WOT with stock timing:

In general:
- inefficient combustion chamber wants more timing
- Aluminum wants more timing
- increased compression wants less timing
- more boost wants less timing
- lower loads want more timing

In this case, we are not dealing with an unknown. Iron stock heads want ~14* on 93 octane. That means they like 34* total at WOT, and are detonation limited. They'd probably like even more on a race fuel or E85.

 

[Potomus Pete]

As a stupid question for someone who is going to Harbor Freight to buy a timing light . We are talking about before the zero , or passenger side is where we want the 12 or 14 marked . Probably marked with two different colors . Thanks for the clarification . My car is good but I feel something may be a little off . Stock heads with big air in , BBk shorties out.

 

[HotFox]

Had a similar experience with a Ford F150 with 302 that I went through this on completely stock except K&N, NGK plugs, 351 radiator and Ford performance wires. I check timing with spout removed it had like 9 went to 15 or 16 it ran so much better but had spark knock. Settled on 13. It ran so much better mid range. Maybe it only made 3hp up top, I bet it picked up 10 ft lbs in the mid range it sure felt like it. It was a auto and off idle in lock up it really felt a whole lot stronger. This was 87 octane.

 

[FastDriver]

As a stupid question for someone who is going to Harbor Freight to buy a timing light . We are talking about before the zero , or passenger side is where we want the 12 or 14 marked . Probably marked with two different colors . Thanks for the clarification . My car is good but I feel something may be a little off . Stock heads with big air in , BBk shorties out.

I'd suggest getting an adjustable timing light and marking the 0. Then you will be free to adjust as you see fit.

 

[JD1964]

The timing at 14 will give some extra noticeable torquey throttle response down lower on the rpm band for sure. But, if you like to zing it up to 6k rpm for that good top end (considering your setup supports that rpm), you might sacrifice a few hp up there. When my car was NA, I found 12 degrees to be the sweet spot.

These 5.0's are not necessarily TQ monsters in the low and mid range. They shine better up top at the higher rpms. I think anything that hampers top end production on these small blocks is a questionable move.

 

[Xkuzme1]

It was a big enough difference that just stepping on the throttle in second gear broke the wheels lose. At 10° there was a loss of grip, but not like this.

Edelbrock Victor Jr aluminum heads.

I did notice that when I set it to 15-16ish it seemed to run a little choppy. A little detonation.

 

[Habu135]

Great discussion.

 

[Wayne Waldrep]

As a stupid question for someone who is going to Harbor Freight to buy a timing light . We are talking about before the zero , or passenger side is where we want the 12 or 14 marked . Probably marked with two different colors . Thanks for the clarification . My car is good but I feel something may be a little off . Stock heads with big air in , BBk shorties out.

There ya go Pete.

 

[junkyardwarrior]

If these are to be believed, then it actually goes to 30* at WOT with stock timing:

In general:
- inefficient combustion chamber wants more timing
- Aluminum wants more timing
- increased compression wants less timing
- more boost wants less timing
- lower loads want more timing

In this case, we are not dealing with an unknown. Iron stock heads want ~14* on 93 octane. That means they like 34* total at WOT, and are detonation limited. They'd probably like even more on a race fuel or E85.

Some of that information is only partially correct.

 

[a91what]

So please post correct information, I believe those tables were lifted directly out of an a9l.
Provide ecu number and vehicle used to lift the eec tables.

 

[FastDriver]

Some of that information is only partially correct.

You're missing a few sentences, there... If you're going to dispute fairly well established information, you need to go a little further than just casting doubt. What part? How is it partially incorrect? What is your source? If I'm not mistaken, Tom Moss is the source of this data, and so far as I know it has not been disputed.

@Decipha is an EEC IV guru. Perhaps he can weigh in.

 

[Potomus Pete]

Got my new timing light $23 adjustable light from Harbor Freight with a 20 off coupon .. Did it according to Stagnet directions. Was set at 5 degrees . Moved it to 12 and all is well. Better thru the throttle all the way up. Glad I did it now I know for the future

 

[jrichker]

As a stupid question for someone who is going to Harbor Freight to buy a timing light . We are talking about before the zero , or passenger side is where we want the 12 or 14 marked . Probably marked with two different colors . Thanks for the clarification . My car is good but I feel something may be a little off . Stock heads with big air in , BBk shorties out.

Setting the timing:
Paint the mark on the harmonic balancer with paint -choose 10 degrees BTC or 14 degrees BTC or something else if you have NO2 or other power adder. I try to paint TDC red, 10 degrees BTC white and 14 degrees BTC blue.

10 degrees BTC is towards the drivers side marks.

Note: setting the timing beyond the 10 degree mark will give you a little more low speed acceleration. BUT you will need to run 93 octane to avoid pinging and engine damage. Pinging is very hard to hear at full throttle, so it could be present and you would not hear it.

Simplified diagram of what it looks like. Not all the marks are shown for ease of viewing.

ATC ' ' ' ' ' ' ' ' ' '!' ' ' ' ' ' ' ' ' ' BTC
---------------- > Direction of Rotation as viewed standing in front of the engine.

The ' is 2 degrees.
The ! is TDC
The ' is 10 degrees BTC
Set the timing 5 marks BTC. Or if you prefer, 5 marks towards the driver's side to get 10 degrees.

To get 14 degrees, set it 7 marks BTC. Or if you prefer, 7 marks towards the driver's side to get 14 degrees.

The paint marks you make are your friends if you do it correctly. They are much easier to see than the marks machined into the harmonic balancer hub.

At this point hook up all the wires, get out the timing light. Connect timing light up to battery & #1 spark plug. Then start the engine.

Remove the SPOUT jumper

It is the 2 pin rectangular plug on the distributor wiring harness. Only the EFI Mustang engines have a SPOUT. If yours is not EFI, check for a SPOUT: if you don’t find one, skip any instructions regarding the SPOUT. The SPOUT (Spark Out) enables the computer to control the spark advance. When the SPOUT is removed, the ignition timing reverts to the base ignition timing set by either the spark rod inside the distributor or the physical position of the distributor.

Warning: there are only two places the SPOUT should be when you time the engine. The first place is in your pocket while you are setting the timing and the second is back in the harness when you finish. The little bugger is too easy to lose and too hard to find a replacement.
Start engine, loosen distributor hold down with a 1/2" universal socket. Shine the timing light on the marks and turn the distributor until the mark lines up with the edge of the timing pointer. Tighten down the distributor hold down bolt, Replace the SPOUT connector and you are done.

The HO firing order is 1-3-7-2-6-5-4-8.
Non HO firing order is 1-5-4-2-6-3-7-8