Anyone run a Lion Head

[McMimmcs]

No I have not tried the Buttermore "crowfoot" 7:1 yet.....may I ask what is so controversial about the Lion Head?

Read the attached thread and find out !

 

[Jack Shaft]

Brierley's stepped combustion chamber is superior to Winfield designs..turbulence is key..but hey,Charley's heads look really busy don't they.Fact is Briggs and Stratton (yeah the lawnmower guys) refined flat head chamber design over the decades..with the Silberstein stepped chamber...but hey,it's your money..

 

[Jack Shaft]

Btw,the crowsfoot was Ed Winfield's design,Todd is casting and marketing it..

 

[Dave in MN]

I am running a Lion Speed Head lll on a B engine. I machined the head .074" to increase the compression and increased the clearance around the intake valves. I also rounded the sharp edges in the combustion chamber to eliminate any hot spots. The engine produced about 85 HP at 2700 rpm on the dyno. In a car, the engine and head combo pulls real well between 1900 and 2500 rpm.

Note; I have tight clearances between the piston and head after removing the flycut. My pistons rise .024" above the surface of the block. I am using a "Best' composite head gasket. I assume this may be helping with the timing advance issues (pinging) I noted before increasing the compression ratio. I also opened up the clearance between the intake valve and the combustion chamber wall. These changes "tamed the Lion". I have no problem with "pinging".
Good Day!

 

[nkaminar]

So, if you graft a lion's head on to a turtle, will you get a cheetah? Seems you also need a larger wind pipe.

 

[alexiskai]

Btw,the crowsfoot was Ed Winfield's design,Todd is casting and marketing it..

Good clarification – I phrased it that way because, when Tod's design was launched, there was some grumbling on the HAMB that he had modified the "true" Winfield crowfoot chamber.

One thing I think is really important to note here is how quickly even a HC engine starts to starve for air. So look at these two dynos:
HC head, no other changes
HC head and dual carbs

You can see that by 1700 RPM, that's 40 mph, the torque curve on the engine with the stock carb is already starting to drop, and by 2000 rpm it's down significantly. This manifests as a slowing acceleration as you climb from 40 to 50 mph. Whereas the engine with modified carbs stays in the power band right through 2000 rpm.

If you're taking rides in modified cars, and you're impressed by their performance above 40 mph, that's the carb/manifold talking, in my opinion.

 

[Tim Ayers]

Good clarification – I phrased it that way because, when Tod's design was launched, there was some grumbling on the HAMB that he had modified the "true" Winfield crowfoot chamber.

One thing I think is really important to note here is how quickly even a HC engine starts to starve for air. So look at these two dynos:
HC head, no other changes
HC head and dual carbs

You can see that by 1700 RPM, that's 40 mph, the torque curve on the engine with the stock carb is already starting to drop, and by 2000 rpm it's down significantly. This manifests as a slowing acceleration as you climb from 40 to 50 mph. Whereas the engine with modified carbs stays in the power band right through 2000 rpm.

If you're taking rides in modified cars, and you're impressed by their performance above 40 mph, that's the carb/manifold talking, in my opinion.

Makes sense to me. If you think about the carb cfm vs. the CI of the motor, it's certainly seems like it's under carbureted. I'd like to see some dyno charts of the following:

1) Head only with original updraft
2) Head with dual Model B (or better than stock) updrafts
3) Head with single downdraft like a Stromberg 97
4) Head with dual downdrafts like Stromberg 81's
5) Head with triple downdrafts like Stromberg 81's
6) All of the above with a hotter cam added to the mix

 

[BRENT in 10-uh-C]

Brierley's stepped combustion chamber is superior to Winfield designs..turbulence is key..but hey,Charley's heads look really busy don't they. Fact is Briggs and Stratton (yeah the lawnmower guys) refined flat head chamber design over the decades..with the Silberstein stepped chamber...but hey,it's your money..

Yeah John, some truth in that. Actually, more specifically it was the engine builders for the jr. drag racers and lawn tractor pulling guys that pioneered and redesigned the 5hp Briggs flathead chamber for Briggs. The engine on my son's 5hp kart dynoed over double the stock hp with a different cam and head mods, ...and as I recall, the jr dragster engine made nearly 30hp on methanol. All started their origins as a stock 5 hp Briggs engine.


,
.

 

[Tim Ayers]

Interesting. Is there a reason why the refined B&S head/chamber design can't be replicated for a Model A head?

 

[Jerry in Shasta]

I have a LSH I It pings/detonates at 10 degrees advance light acceleration on 103 octane fuel.



I have soften all the share machining corners an smoothed out the chambers, still pings badly to the point that it is unusable.


It was given to me by a very knowledgeable Model A guy that could make it work either



Any ideas?? Sorry I don't own a boat.
JB

 

[alexiskai]

Another way to think about HC head performance at high RPM is that, when you say a given head provides 6:1 compression, you're assuming that the intake stroke is filling the cylinder with a fuel/air mixture at atmospheric pressure. But as the RPM increases, the time available to fill that cylinder decreases. 2000 rpm means the crankshaft turns once each 0.03 seconds, and an intake stroke is half a revolution, so the carb needs to fill that cylinder in about 15 milliseconds.

The stock carb flows about 63 cubic feet per minute at 2000 RPM, which means that in 15 milliseconds it should flow 0.01575 cf, or 27.2 cubic inches. A stock cylinder bore is about 50 cubic inches. So at 2000 rpm, the stock carb is only able to flow enough air to fill each cylinder about half full. Which means the compression is also halved. So at 2000 rpm, your 6:1 head is only compressing to 3 times atmospheric pressure. It's like the carb is swapping in weaker and weaker heads as you keep the throttle open.

 

[Tim Ayers]

Another way to think about HC head performance at high RPM is that, when you say a given head provides 6:1 compression, you're assuming that the intake stroke is filling the cylinder with a fuel/air mixture at atmospheric pressure. But as the RPM increases, the time available to fill that cylinder decreases. 2000 rpm means the crankshaft turns once each 0.03 seconds, and an intake stroke is half a revolution, so the carb needs to fill that cylinder in about 15 milliseconds.

The stock carb flows about 63 cubic feet per minute at 2000 RPM, which means that in 15 milliseconds it should flow 0.01575 cf, or 27.2 cubic inches. A stock cylinder bore is about 50 cubic inches. So at 2000 rpm, the stock carb is only able to flow enough air to fill each cylinder about half full. Which means the compression is also halved. So at 2000 rpm, your 6:1 head is only compressing to 3 times atmospheric pressure. It's like the carb is swapping in weaker and weaker heads as you keep the throttle open.

Makes sense and supports my thoughts on a stock Model A engine is under carbed.

 

[johnneilson]

Interesting. Is there a reason why the refined B&S head/chamber design can't be replicated for a Model A head?

It has, in a few different heads.

What you need to keep in mind is that the Model "A" engine is different.
B/S ratio, cam timing, ignition etc.
There is no free lunch when you start making these changes.

You also have to realize that when the Model "A" motor was designed, the theory of internal combustion was not well understood. The motor is a compromise of details that would run under many different conditions.

John

 

[Tim Ayers]

It has, in a few different heads.

What you need to keep in mind is that the Model "A" engine is different.
B/S ratio, cam timing, ignition etc.
There is no free lunch when you start making these changes.

You also have to realize that when the Model "A" motor was designed, the theory of internal combustion was not well understood. The motor is a compromise of details that would run under many different conditions.

John

Thanks, John. Totally get it and understand the gas of the day was also very poor as well.

I'm always interested in how to take advantage of modern advances to maximize performance in vintage engines.

 

[BRENT in 10-uh-C]

Makes sense and supports my thoughts on a stock Model A engine is under carbed.

You are correct in that a Model-A engine is under carbureted however many other carbureted engines are/were under-carbureted too, so that is not a big deal.

Colin's info above is kinda misleading IMHO though. To begin with, yes dyno testing has shown that at a steady 2000 rpm, the carburetor is drawing a little over 60 cfm, ...HOWEVER nothing in his comment mentions where the stock Zenith can flow more (-as in over 20 cfm more). The throttle blade that is partially closed is what is limiting the airflow and setting the engine's rpm level. If the engine needs more power, the driver presses on the pedal which opens the throttle blade and more air/fuel is added to each cylinder. It is worth noting that even though a stock Model-A engine makes 40 horsepower, it may only use 40%-50% of the available horsepower when driving 45 mph.

As mentioned above, the stock Zenith is capable of flowing in the low 80s cfm at higher rpms whereas the 32/26 Weber two-barrel carb and/or the Model-B Zenith are only capable in the higher 80s cfm at those same rpms.

There are two major limiting factors that enter in on this entire airflow scenario which IMO does not put the blame solely on the carburetor. First is the intake valve and bowl area are too small and they impede airflow. Second (-and equally important) is the exhaust manifold is too restrictive. Because of this, not all the spent gasses at higher speeds are evacuated from the cylinders. If we need to add a third reason, it would be the camshaft lift & duration are under spec-ed. Therefore just because we add a higher compression head does not mean our performance increase will be the same as someone elses. I can likely put a 5.5 CR Snyder head on an engine where I have enlarged the bowls, installed 1.750 intake valves, and an IB330 camshaft and outrun his present engine with a 7:1 Lion head added.

 

[Tim Ayers]

Brent:

I was assuming and should have stated that headers, valve port and larger valves would be part of the equation. That was my error in making those assumptions.

 

[Benson]

I have a LSH I It pings/detonates at 10 degrees advance light acceleration on 103 octane fuel.



I have soften all the share machining corners an smoothed out the chambers, still pings badly to the point that it is unusable.


It was given to me by a very knowledgeable Model A guy that could make it work either



Any ideas?? Sorry I don't own a boat.
JB

I see that you have a LSH I.

1. I had a BRAND NEW early LSH III that did same thing.

If I pushed it under load for a short time after the pinging started, there was a big bang and engine would die until I let up on the gas.

I removed it SHORTLY AFTER I installed it.
Then a guy offered me $145 more than paid for it 3 months earlier.

At the time I did not know about the sharp edges in chambers.

2. One other place for sharp edges is the spark plug threads if plug reach is too long and the threads extend into combustion chamber they will glow and detonate.

Gaskets with sharp edges also which extend into combustion chambers.

Like if the bore is 0.100 and the wrong gasket is used.

Some early GASKET versions are for standard to .060 and if installed on a 0.100 engine the gasket will extend into chamber.

My friend had a LSH III, with Weber 2 barrel, recently (last 6 to 12 months) which had no problems. Not sure what was done to it make it work before he bought the car.

 

[alexiskai]

You are correct in that a Model-A engine is under carbureted however many other carbureted engines are/were under-carbureted too, so that is not a big deal.

Colin's info above is kinda misleading IMHO though.

Thanks for the details, my math was definitely just off-the-cuff. To tie it back to the original post, what I was trying to do is show how you have to be careful attributing "impressive" performance to the head once you cross the threshold where a stock engine would begin to encounter obstructed airflow (of any origin) – and that threshold happens pretty early.

 

[Model A Ron]

Brent
I am just trying to understand and learn so from the below statement you are saying you can get more out of a 5.5 head than a Lion Head? Have you experimented with the Lion Head? I have limited knowledge at this time but the car I drove with the Lion Head was much faster than a car with a 6.1 Head. To be fair I do not know what additional mods the owners made.

Thanks
Ron

I can likely put a 5.5 CR Snyder head on an engine where I have enlarged the bowls, installed 1.750 intake valves, and an IB330 camshaft and outrun his present engine with a 7:1 Lion head added.

 

[alexiskai]

He's saying an engine modified for increased compression, airflow, and valve timing can have more power than an engine that's modified for high compression but otherwise stock.