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KwiknFast

KwiknFast

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The only decent explanation of swirl I've found, here as applied to SBF heads.

 
Those E7TE heads that commonly show up in Youtube videos I think are junk. They have the smallest intake port volume of any small block Ford head and the chamber as you can see in this video are compromised. People spend a bunch of time trying to port them, but would be better off to switch to a GT40, GT40P, or aftermarket head. Maybe Ford engineers believed the small port was good for low end torque, and with the high swirl chamber might have been good for low end power and fuel economy. However real life usage has shown that engines with those heads in trucks ping under even slight loads and fuel economy and power is mediocre.
 
KwiknFast said:
Those E7TE heads that commonly show up in Youtube videos I think are junk. They have the smallest intake port volume of any small block Ford head and the chamber as you can see in this video are compromised. People spend a bunch of time trying to port them, but would be better off to switch to a GT40, GT40P, or aftermarket head. Maybe Ford engineers believed the small port was good for low end torque, and with the high swirl chamber might have been good for low end power and fuel economy. However real life usage has shown that engines with those heads in trucks ping under even slight loads and fuel economy and power is mediocre.
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Because the Chevy corkscrew port head will not tolerate more than 25 degrees total (even with the highest octane fuel available)* you hear people say the same about it, but the reality is people are so ignorant they won't simply retard the timing and set the timing by ear to best power. The Chevy head, and all the heads pictured in the video above, require much less total timing than ignorant old school habits which cause loons to try to use 36 degrees on every engine.

In the mid-80's when that head was the only available for the 90 deg. V6 GM had a section in the "Chevrolet Power Manual" about this engine and in the part about preparing the heads used bold type to say "25 degrees maximum spark advance". A fool I knew at the local oval track burned up several using 36 bitching "this race fuel is junk" and when I showed him the GM book insisted GM was stupid to say 25. I found the Ford head in the video is good with 26 total.

* Even with high octane fuel that will not knock, fast burn heads like these are very sensitive to the advance required for best power and the power drops dramatically with only one or two degrees too much advance.

The problem people have is with a sporty cam the engines still need near 18 degrees initial to idle OK and have acceptable performance at low RPM, and nearly all distributors have advance mechanism with more than 7 crank degrees, so some distributor machine blacksmith time is necessary because if the timing is set to 25~26 total the engine won't idle and runs hot because the timing is retarded at low RPM.

To sum, the urban lore that the high swirl heads are junk is because people won't make the effort to find the ideal spark advance for best power.
 
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Most people are using the E7TE heads on trucks. The Fox body Mustangs came with them, but by now most of them have aftermarket heads installed. But Ford made millions of F-Series trucks with these heads, and being fuel injected the only tuning that's easy is the initial timing. The trucks start and run and do around town easy driving fine with the stock timing, but going up hills, towing, highway driving there's a lot of pinging unless mid-grade fuel is used. This is a well known characteristic of these heads.
 
An older Youtube Ford head comparison. Most of this video series appeared in magazines.



 
In all that video time did the guy even one time mention different ignition timing requirement between any of the heads, or mention ignition timing at all?
 
I think he fixed the timing across each test series using the E7TE heads as the baseline timing setting.
 
Some years ago, several people told me they put AFR 165 heads on their trucks, and not only did power improve, but fuel mileage went up 1 or 2 mpg.
 
KwiknFast said:
Those E7TE heads that commonly show up in Youtube videos I think are junk. They have the smallest intake port volume of any small block Ford head and the chamber as you can see in this video are compromised. People spend a bunch of time trying to port them, but would be better off to switch to a GT40, GT40P, or aftermarket head. Maybe Ford engineers believed the small port was good for low end torque, and with the high swirl chamber might have been good for low end power and fuel economy. However real life usage has shown that engines with those heads in trucks ping under even slight loads and fuel economy and power is mediocre.
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The E6's on 86's were supposed to be a high swirl head and totally sucked balls.
 
The E5AE head on the 85 5.0L were like E7TE heads, but lower compression.

And the intake manifold used on the 83 thru 85 Mustang GT was aluminum but had ridiculously small ports. Ford never put a good carbureted intake on any SBF from the factory.
 
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Another Mummert video.

The 64 to 67 heads were the best. Back in the day the drag racers liked the C6AE heads. They were running them up to 10,000 rpm.

 
Lead-Farmer said:
The E6's on 86's were supposed to be a high swirl head and totally sucked balls.
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Same urban lore about the Chevy swirl port TBI head because people are too stupid to believe GM instructions to use 24 degrees total, and if you play on a dyno you will find they like 20 at 2000 and a degree per 1000 above that up to 5000 and power drops like a rock above 25 degrees. The swirl port head is very little different with any cam timing and any fuel, except radical cams need 18 degrees initial and mild "torque" and gas mileage cams might be best with 5 or 10 degrees initial for smoothest idle.

It would raise sea level a foot when all the bench racers in all the world pissed themselves at once if they all realized at the same moment the amount of power they are leaving unrealized by not determining the ideal advance curve for their engines from idle up to valve float. What ever advance makes peak power in 99.44% of engines is always more than is best at the torque peak, sometimes a lot, several degrees, you probably wouldn't believe it unless you saw it yourself, and even then ?? I have seen an idiot go with a locked distributor because that dyno pull was 3 HP better than the distributor with a curve with less advance at the torque peak RPM and made 40 ft.lbs. more torque. ..no kidding.. Some peoples kids, you can lead them to power but they won't drink unless it's beer.
 
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itey said:
Same urban lore about the Chevy swirl port TBI head because people are too stupid to believe GM instructions to use 24 degrees total, and if you play on a dyno you will find they like 20 at 2000 and a degree per 1000 above that up to 5000 and power drops like a rock above 25 degrees. The swirl port head very little different with any cam timing and any fuel. Radical cams need 18 degrees initial and mild "torque" and gas mileage cams might be best with 5 or 10 degrees initial for smoothest idle.

It would raise sea level a foot when all the bench racers in all the world pissed themselves at once if they all realized at the same moment the amount of power they are leaving unrealized by not determining the ideal advance curve for their engines from idle up to valve float. What ever advance makes peak power in 99.44% of engines is always more than is best at the torque peak, sometimes a lot, several degrees, you probably wouldn't believe it unless you saw it yourself, and even then ?? I have seen an idiot go with a locked distributor because that dyno pull was 3 HP better than the distributor with a curve with less advance at the torque peak RPM and made 40 ft.lbs. more torque. ..no kidding.. Some peoples kids, you can lead them to power but they won't drink unless it's beer.
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Many guys with 86 Mustangs learned very quickly if you wanted it to run like the 87 to 93 Mustangs you could just put e7s on it. E6's were done around 4k rpm.
 
This is like preaching to a pack of luddites living in mud huts. Until you know, you don't know. I started understanding how important advance curves are in the late '60s, mostly by screwing up properly set up factory distributors by putting soft, "all-in at 2500" springs in them and noticing the mid-range torque disappeared but high RPM power was OK.

What almost nobody understands is because of emissions the OE combustion chambers were modified to reduce or eliminate squish area and this resulted in engines being hungry for more spark advance because the chamber was less efficient. The combustion chamber shapes evolved into "open chamber" and moar and moar spark advance, so people forgot or most younger people never knew how sensitive a good engine is to ignition timing.

Follow urban lore about the swirl port Chevy head and you will see the biggest complaint is "the ports are so small they don't breathe above 4000 RPM" when what is actually happening is retards are not retarding, they are using the traditional 36 degrees and that much advance with the fast burn peaks cylinder pressure before TDC, so it feels like a huge load the engine can't pull because it is.

I learned in the late '60s the small block Ford, '65 and '66 289 closed chamber head is best with 26 at 3000 slope to 30 at 6000, coincidentally that is the advice in Ford racing literature. Some of the better heads available nowadays want less than that.
 
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itey said:
This is like preaching to a pack of luddites living in mud huts. Until you know, you don't know. I started understanding how important advance curves are in the late '60s, mostly by screwing up properly set up factory distributors by putting soft, "all-in at 2500" springs in them and noticing the mid-range torque disappeared but high RPM power was OK.

What almost nobody understands is because of emissions the OE combustion chambers were modified to reduce or eliminate squish area and this resulted in engines being hungry for more spark advance because the chamber was less efficient. The combustion chamber shapes evolved into "open chamber" and moar and moar spark advance, so people forgot or most younger people never new how sensitive a good engine is to ignition timing.

Follow urban lore about the swirl port Chevy head and you will see the biggest complaint is "the ports are so small they don't breathe above 4000 RPM" when what is actually happening is retards are not retarding, they are using the traditional 36 degrees and that much advance with the fast burn peaks cylinder pressure before TDC, so it feels like a huge load the engine can't pull because it is.

I learned in the late '60s the small block Ford, '65 and '66 289 closed chamber head is best with 26 at 3000 slope to 30 at 6000, coincidentally that is the advice in Ford racing literature. Some of the better heads available nowadays want less than that.
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Of course new heads want less timing they have had 60 years of technology to create more efficient designs. Neither you nor anyone else is going to take a E6 head and change the timing curve and make it out perform a E7 head it's not going to happen, it wouldn't happen with a cam change or compression bump either it was an experiment that simply didn't work. There's been plenty of engine builders and engineers since the late 80s working on heads for SBF's and none of them has used those heads as a basis for anything except for what not to do. There's a reason Ford made them for one year they knew the messed up and that was that.
 
I still don't quite understand how to find the best timing at a specific rpm. I'm assuming it's not linear even though the springs weights act that way.

I have a digital 6al2 and I can program it to adjust timing based on vacuum and rpm, but ultimately end up just following a generic linear curve
 
Lead-Farmer said:
Of course new heads want less timing they have had 60 years of technology to create more efficient designs. Neither you nor anyone else is going to take a E6 head and change the timing curve and make it out perform a E7 head it's not going to happen, it wouldn't happen with a cam change or compression bump either it was an experiment that simply didn't work. There's been plenty of engine builders and engineers since the late 80s working on heads for SBF's and none of them has used those heads as a basis for anything except for what not to do. There's a reason Ford made them for one year they knew the messed up and that was that.
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The last "60 years of technology" agreed, but the 60 years before that are when the "fast burn" technology was developed. The recent 40 years has improved air flow significantly and air flow is the reason power has improved so much.

I have repeated this several times but it doesn't seem to be easy to understand for the younger guys. The "Fast Burn Combustion Chamber" concept to reduce ignition advance requirement began before 1919 when Sir Harry Ricardo's patented his "Ricardo Combustion Chamber" and the concept of combustion chamber squish and turbulence was actively used in nearly every engine until the late '60s when Lyndon Johnson's blue wave liberal takeover of the US Congress gave misguided libtard bureaucrats the power to control engineers and emissions became more important than thermodynamic efficiency.

The late '60s is when engines began to require more advance because combustion chambers were made less efficient and that is when the baby boomers bloomed into hot rod cars, so most everybody's experience formed the urban lore and moar is bettah.

I don't know E6 or E7 from squat, but I do know that nearly every hot rod mustang, camaro or whatever I have tuned for whoever comes along, the owner has too much advance because that makes his engine feel 'snappy' when blipping the throttle. I don't understand why people will mindphuk a carburetor to death and never try to find the best spark advance.

One more time, '65~'66 289 closed chamber head, 26 at 3000, slope to 30 at 6000, and any quicker than that kills the low and mid range torque and more total kills the top end. Then people say, "the ports are too small" or with the Boss 302 "the ports are too big" always somebody else's fault when too much advance is the problem.
 
itey said:
The last "60 years of technology" agreed, but the 60 years before that are when the "fast burn" technology was developed. The recent 40 years has improved air flow significantly and air flow is the reason power has improved so much.

I have repeated this several times but it doesn't seem to be easy to understand for the younger guys. The "Fast Burn Combustion Chamber" concept to reduce ignition advance requirement began before 1919 when Sir Harry Ricardo's patented his "Ricardo Combustion Chamber" and the concept of combustion chamber squish and turbulence was actively used in nearly every engine until the late '60s when Lyndon Johnson's blue wave liberal takeover of the US Congress gave misguided libtard bureaucrats the power to control engineers and emissions became more important than thermodynamic efficiency.

The late '60s is when engines began to require more advance because combustion chambers were made less efficient and that is when the baby boomers bloomed into hot rod cars, so most everybody's experience formed the urban lore and moar is bettah.

I don't know E6 or E7 from squat, but I do know that nearly every hot rod mustang, camaro or whatever I have tuned for whoever comes along, the owner has too much advance because that makes his engine feel 'snappy' when blipping the throttle. I don't understand why people will mindphuk a carburetor to death and never try to find the best spark advance.

One more time, '65~'66 289 closed chamber head, 26 at 3000, slope to 30 at 6000, and any quicker than that kills the low and mid range torque and more total kills the top end. Then people say, "the ports are too small" or with the Boss 302 "the ports are too big" always somebody else's fault when too much advance is the problem.
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I think a lot of people don't fully understand ignition timing even people who have been in the racing industry give conflicting information mostly from something they heard or were told and not from first hand experience and what works on a street driven car isn't best for racing and vice versa and less people every day understand how a carburetor works.
 
89 Fox 427 said:
I still don't quite understand how to find the best timing at a specific rpm. I'm assuming it's not linear even though the springs weights act that way.

I have a digital 6al2 and I can program it to adjust timing based on vacuum and rpm, but ultimately end up just following a generic linear curve
Click to expand...
Dyno or drag strip but I don't fully believe there is a magic number since weather, altitude, fuel type all play a role in it.
 
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