Porting a Lister cylinder head and intake

[listard-jp2]

I just have to laugh at any suggestion that there are specific features in this intake port which are designed to do any specific thing. That lip is there on the port not because the Lister engineers or the Listeroid manufacturers are rocket scientists who put it there for a specific reason, but because the Indians' casting technology is stuck back in the stone age and that's just how it ended up.

Not so!

You will not see that lip on a geniume Lister CS engine, the pictures shown in this thread was of a direct injection Listeriod head.

The ledge you refer is there for a reason (to promote turbulance to the incoming airstream on direct injection engines). The Indians have copied this feature straight from Petter engines such as the AV and PH range.

Prior to the advent of computer modeling of port design to impart turbulance to the incoming airstream, the options were limited to placing what appears to be casting obstructions in the inlet port, or having shrouded inlet valves. Petter used both features in there engines (PAZ1, BA, and PJ engines used shrouded inlet valves).

[selmawp]

Hi Quinnf, would like to point out that the engine we are running is a 10/1.

[buickanddeere]

If the ported vs factory cast port comparison is made with engines producing 90-100% power than yes the ported engine has lower pumping losses and higher peak torque and HP due to being able to burn extra fuel with the extra air.
    Part load efficiency on a diesel , gas turbine , boiler or stove is another issue.
    Any extra airflow beyond what is required to burn the fuel reduces overall thermal efficiency. Drawing unused air through the combustion chamber just drags heat out the stack.
    Some diesels, some gas turbines and certainly boilers have the intake air throttled when operating at part load.
     It's a point sorry missed by diesel truck fans who think a 345 HP engine running at 45HP to roll the vehicle down the highway is " more efficient".  Diesel does win out over carbureted gassers and to a degree port injected gassers if continuously making 200+HP pulling a high drag trailer at 70MPH.
    The new DI gassers with their high EMP are every bit as efficient or more than the diesels per btu of fuel in. Diesel will win out in comparisons per gallon in some instances due to more btu per gallon.
  Water injection will improve efficiency in a 11:1 compression carbureted or port injected gasser running 87 octane gasoline. Timing and mixture can be returned to approx the settings used with 94 octane fuel. Not easy to calibrate and uses a lot of water. Mineral build up is a problem unless demin water is used. Makes the process cost prohibitive.

[Quinnf]

Hi Quinnf, would like to point out that the engine we are running is a 10/1.

OK, but you said you were running that engine at 770 rpm.  So that's in the neighborhood of the number I calculated (for the sake of simplicity) for the 6/1.  Your cfm will be 770/650 * 16.4 cfm, or 19.4 cfm.  Still far less airflow than the flow you'd measure passing into one cylinder of a V-8 at 5000 rpm (2500 breaths/minute).  And that speed difference is very important.  The effects aren't linear.  As flow increases, the pressure drop within the intake increases as nearly the square of the flow.  So double the flow, and the pressure drop increases almost 4 times.  That is why such attention is focused on porting and polishing race engines, but you never hear of that being done on slow speed stationary diesel engines.  Well, until now, I'll grant.  

But my point, which Shiftless seemed to either miss or ignore, was that, in a throttled engine with a constant fuel/air ratio, more air means more fuel which means more power.  In a diesel engine, which, except at full load, always has excess oxygen remaining in the cylinder after combustion, more fuel means more power.  So at conditions of partial load at constant RPM in a diesel engine, such as running a generator at 2 kw load, increasing airflow won't buy you very much.  

In regard to pumping losses, in a diesel engine, pumping losses are a function of engine speed, while in a gas engine, pumping losses are a function of engine speed and throttle position.  In order to maintain constant fuel/air ratio the gas engine restricts the airflow through the intake by means of a throttle valve, increasing pumping loss, while in a diesel the intake is always wide open to the atmosphere.  For that reason, and because of the slower airflow in the diesel example I cited, I don't see much benefit in treating the diesel engine as if it were a gas race engine. 


Quinn

[Tom]

Great point on the heat loss to higher air flow than needed B&D. It will be interesting to see the numbers Shiftless comes up with.

[mobile_bob]

another thing to consider is this "what are the big boys doing"?

most of the big boys have reduced the port dimensions and manifolds to increase velocity

take a look at cummins with their pulse manifold technology they started in with some 30 years ago.

compare the powerstroke 7.3 with the newer 6.0 exhaust systems

as stated by Q, the flow rates are not linear with engine speed, a bigger port while in theory might flow more air, the reality is for all the reasons mentioned by others, the added air will not result in added hp or increased efficiency... at least not in amounts that are going to be outside the margins of error in testing.

measure you valve lift, then do the math to calculate the actual opening to the cylinder in sq/inches... i think you will find the ports are larger than this opening, so increasing port dimensions are not going to increase airflow at all.

the only way you are going to increase flow with larger ported out ports, is with more lift and/or duration on the cam... and to what end?  again you will see almost no gains from all the effort, at least not measurable gains.

whatever gain there is to make, will come from simply port matching to the manifolds and a basic cleanup of the port by removing flashing and smooth it up a bit... this has been the truth since the first die grinder was used to port a 265 chevy in '55 and is still the truth today.

again far more heads are messed up by porting than are improved, that being for gas engine's. and likely this will hold true for diesel heads as well.

when the engine rpm is this low you just don't have the inertia needed to get any real benefit.

don't believe me, check out the engineering text!  its all there in graphic detail, there is a reason the graphs don't start plotting until something on the order of 1200rpm.  this of course for engine's of the bore/stroke class we are talking about here... of course engines with 30inch bores and 6 ft strokes are going to have much different dynamics down to very low rpms (~120rpm),

its you engine, its you time, you mind is made up, so go forth and prove the world wrong!

just don't come back whining if you grind through a thin spot in the casting, or into a bolt/stud boss and have a head that won't hold water, or if you end up with an engine that makes more smoke than it used to.

fwiw... don't forget the carbon fiber pushrods!

bob g

[shiftless]

measure you valve lift, then do the math to calculate the actual opening to the cylinder in sq/inches... i think you will find the ports are larger than this opening, so increasing port dimensions are not going to increase airflow at all.

lol.

Bob I know it may not be apparent to you since you are currently posting in an echo chamber, but you continue to demonstrate your profound ignorance of airflow through this pointless and absurd line of argumentation which you seem determined to doggedly pursue. In fact it's quite comical to observe since a lot of the same arguments errors I see you and others making here are the same urban myths I've seen repeated time after time on the gasoline engine forums............10 years ago.

There are so many eggheads in this world who think they can boil down a port's flow characteristics (or any number of other complex phenomena) to a simple math equation, but such is not the case, and never will be. The size of the valve, the dimensions of the port, are nothing more than numbers, a couple variables in a sea of a thousand variables that effect how the port flows.

the only way you are going to increase flow with larger ported out ports, is with more lift and/or duration on the cam... and to what end?  again you will see almost no gains from all the effort, at least not measurable gains.

That's your assertion anyhow, which you continue to repeat over and over despite having no evidence or personal experience to substantiate it.

whatever gain there is to make, will come from simply port matching to the manifolds and a basic cleanup of the port by removing flashing and smooth it up a bit...

Also known as "completely useless noob porting" or just plain "a waste of time", which was, again, once quite common on the various hot rod forums 10 years ago.

its you engine, its you time, you mind is made up, so go forth and prove the world wrong!

It's not "the world" arguing against me...it's just you and a few other ignorant souls. Every other diesel engine forum on the planet agrees with my analysis. Go on the Dodge Diesel forums and tell them port work is useless and won't even make a 1-2% difference....they will laugh you out of the room.

My mind is made up just as well as yours is. Except my thoughts are based on concrete knowledge, while yours are based on conjecture and superstition.

just don't come back whining if you grind through a thin spot in the casting, or into a bolt/stud boss and have a head that won't hold water, or if you end up with an engine that makes more smoke than it used to.

None of which are even the slightest bit likely to occur.....which you would know, if you knew anything.

If I seem insulting maybe it's because it's tiring to be called dumb by the ignorant.

[shiftless]

If the ported vs factory cast port comparison is made with engines producing 90-100% power than yes the ported engine has lower pumping losses and higher peak torque and HP due to being able to burn extra fuel with the extra air.

Correct.
    

Part load efficiency on a diesel , gas turbine , boiler or stove is another issue. Any extra airflow beyond what is required to burn the fuel reduces overall thermal efficiency. Drawing unused air through the combustion chamber just drags heat out the stack.

Incorrect. Port work decreases the amount of fuel necessary to burn to sustain a certain RPM, due to reduced pumping losses. But for a minute let's assume the fuel burned is the same.

There is a certain fixed amount of heat contained in each volume of fuel. If a greater volume of air is pumped through, with the same or lesser quantity of fuel burned....the total heat loss is the same, and the difference is lower EGTs.

[buickanddeere]

If the ported vs factory cast port comparison is made with engines producing 90-100% power than yes the ported engine has lower pumping losses and higher peak torque and HP due to being able to burn extra fuel with the extra air.

Correct.
    

Part load efficiency on a diesel , gas turbine , boiler or stove is another issue. Any extra airflow beyond what is required to burn the fuel reduces overall thermal efficiency. Drawing unused air through the combustion chamber just drags heat out the stack.

Incorrect. Port work decreases the amount of fuel necessary to burn to sustain a certain RPM, due to reduced pumping losses. But for a minute let's assume the fuel burned is the same.

There is a certain fixed amount of heat contained in each volume of fuel. If a greater volume of air is pumped through, with the same or lesser quantity of fuel burned....the total heat loss is the same, and the difference is lower EGTs.

Why do we throttle back the airflow to the boiler fireboxes when we are at reduced power and injecting less coal powder?

Why do we have throttle blades on the Utilitie's  Natural gas combustion turbine inlet. These throttle blades appear very similar to a stationary stator blade stage. They turn to either feather and allow full airflow or turn and throttle airflow at reduced power levels. 

Why do the new VM DOHC diesels in the Chev Cruz adjust intake cam timing at reduced power cruise to limit airflow into the combustion chambers?

[shiftless]

OK, but you said you were running that engine at 770 rpm.  So that's in the neighborhood of the number I calculated (for the sake of simplicity) for the 6/1.  Your cfm will be 770/650 * 16.4 cfm, or 19.4 cfm.  Still far less airflow than the flow you'd measure passing into one cylinder of a V-8 at 5000 rpm (2500 breaths/minute).  And that speed difference is very important.  The effects aren't linear.  As flow increases, the pressure drop within the intake increases as nearly the square of the flow.  So double the flow, and the pressure drop increases almost 4 times.  

Yeah, and that's all well and good if you just like quoting stuff out of an engineering textbook. But there is a long way between an engineering textbook and the real world.

Why are you still talking about a V8 at 5000 RPM? Go back to 2000 RPMs and try again. What part of "port work increases efficiency/power at all RPMs" did you miss from my last explanation?

But my point, which Shiftless seemed to either miss or ignore, was that, in a throttled engine with a constant fuel/air ratio, more air means more fuel which means more power.

In a gasoline engine at steady cruising RPMs, a better flowing port means less throttle opening required to make the same speed and power. Not more fuel...less fuel being burned.

You do understand that all else being equal, a gasoline engine typically will get better MPG with port work? How would that be possible, if MORE fuel were being burned per cycle?

[shiftless]

Why do we throttle back the airflow to the boiler fireboxes when we are at reduced power and injecting less coal powder?

Seems to me you would throttle back airflow to your firebox so that you can maintain high temperatures inside the boiler. Which is nothing like a reciprocating engine, because in your firebox you don't have a piston being forced downward by the expansion of hot gases.......... before the exhaust valve opens to release the remainder of unused heat out of the cylinder.

Why do we have throttle blades on the Utilitie's  Natural gas combustion turbine inlet. These throttle blades appear very similar to a stationary stator blade stage. They turn to either feather and allow full airflow or turn and throttle airflow at reduced power levels.  

From http://en.wikipedia.org/wiki/Torque_converter :

"A design feature once found in some General Motors automatic transmissions was the variable-pitch stator, in which the blades' angle of attack could be varied in response to changes in engine speed and load. The effect of this was to vary the amount of torque multiplication produced by the converter. At the normal angle of attack, the stator caused the converter to produce a moderate amount of multiplication but with a higher level of efficiency. If the driver abruptly opened the throttle, a valve would switch the stator pitch to a different angle of attack, increasing torque multiplication at the expense of efficiency."

Same principle. It has nothing to do with "throttling", and everything to do with ensuring optimum exhaust gas entry angle/velocity into the turbine, which will vary depending on turbine RPM/load.

Why do the new VM DOHC diesels in the Chev Cruz adjust intake cam timing at reduced power cruise to limit airflow into the combustion chambers?

One word: Emissions. Specifically, reduction of NOx (nitrides of oxygen.)

Edit: Just Googled it, and sure enough...

http://www.designnews.com/document.asp?doc_id=266687

"General Motors is bringing diesel technology back to an American-made compact car by using an air intake technique called “variable swirl.”

The technique enables the company’s new 2.0-liter diesel engine to generate more power with less fuel, while minimizing nitrogen oxide (NOx) and soot levels. As a result, the Chevy Cruze Diesel's new engine is said to be the cleanest ever produced by GM. It’s also the first diesel to be offered in a GM compact car since the 1986 Chevette.

”The Cruze diesel engine, by virtue of its smaller bore configuration, is more in need of a way to make sure the fuel and air mix properly,” Mike Siegrist, GM’s 2.0-liter turbo diesel assistant chief engineer, told Design News. “That’s what the variable swirl does. It mixes the air and fuel more effectively, so optimum combustion occurs.”

Variable swirl accomplishes that by employing a throttle valve in the cylinder’s air intake port. Under high speeds and high engine loads, the throttle valve is wide open, allowing air to flow freely into the cylinder. But at low speeds and low loads, the valve is partially closed, creating an air velocity differential between the opposing sides of the cylinder. That differential causes a “mixture motion,” or swirl, which burns the fuel in a compression-ignited engine more thoroughly."

[broncodriver99]

One word: Emissions. Specifically, reduction of NOx (nitrides of oxygen.)

Edit: Just Googled it, and sure enough...

http://www.designnews.com/document.asp?doc_id=266687

"General Motors is bringing diesel technology back to an American-made compact car by using an air intake technique called “variable swirl.”

The technique enables the company’s new 2.0-liter diesel engine to generate more power with less fuel, while minimizing nitrogen oxide (NOx) and soot levels. As a result, the Chevy Cruze Diesel's new engine is said to be the cleanest ever produced by GM. It’s also the first diesel to be offered in a GM compact car since the 1986 Chevette.

”The Cruze diesel engine, by virtue of its smaller bore configuration, is more in need of a way to make sure the fuel and air mix properly,” Mike Siegrist, GM’s 2.0-liter turbo diesel assistant chief engineer, told Design News. “That’s what the variable swirl does. It mixes the air and fuel more effectively, so optimum combustion occurs.”

Variable swirl accomplishes that by employing a throttle valve in the cylinder’s air intake port. Under high speeds and high engine loads, the throttle valve is wide open, allowing air to flow freely into the cylinder. But at low speeds and low loads, the valve is partially closed, creating an air velocity differential between the opposing sides of the cylinder. That differential causes a “mixture motion,” or swirl, which burns the fuel in a compression-ignited engine more thoroughly."

The purpose is not just emissions but also increased fuel efficiency. So from your linked article there is benefit in a restriction as well. Hmm. In fact the last paragraph sums up exactly what everyone else has been saying. The only time there is a need for increased airflow is at high speeds and high loads. Neither of which is a slow speed CS variant.

In fact porting can be detrimental to performance in many circumstances. Sure if you want to show higher horsepower numbers at RPM's above 2500 then porting is worthwhile, but at lower rpm's where torque is the ultimate goal it is often detrimental.

[millman56]

Well Quinn, I was hoping for the patent for a diesel assisted CS compressed air motor developing 50 HP   !!   Back to the drawing board .

Mark.

[buickanddeere]

Why do we throttle back the airflow to the boiler fireboxes when we are at reduced power and injecting less coal powder?

Seems to me you would throttle back airflow to your firebox so that you can maintain high temperatures inside the boiler. Which is nothing like a reciprocating engine, because in your firebox you don't have a piston being forced downward by the expansion of hot gases.......... before the exhaust valve opens to release the remainder of unused heat out of the cylinder.

Air flow is limited at low power as the higher combustion chamber temp maintains a higher combustion chamber pressure than allowing extra unused airflow.

Why do we have throttle blades on the Utilitie's  Natural gas combustion turbine inlet. These throttle blades appear very similar to a stationary stator blade stage. They turn to either feather and allow full airflow or turn and throttle airflow at reduced power levels.  

From http://en.wikipedia.org/wiki/Torque_converter :

"A design feature once found in some General Motors automatic transmissions was the variable-pitch stator, in which the blades' angle of attack could be varied in response to changes in engine speed and load. The effect of this was to vary the amount of torque multiplication produced by the converter. At the normal angle of attack, the stator caused the converter to produce a moderate amount of multiplication but with a higher level of efficiency. If the driver abruptly opened the throttle, a valve would switch the stator pitch to a different angle of attack, increasing torque multiplication at the expense of efficiency."

Same principle. It has nothing to do with "throttling", and everything to do with ensuring optimum exhaust gas entry angle/velocity into the turbine, which will vary depending on turbine RPM/load.

I have no idea where you made the connection between variable angle stator vanes in an transmission's torque converter. And the air control vanes located just upstream of the turbines 1ft stage of stationary stator blades.

Why do the new VM DOHC diesels in the Chev Cruz adjust intake cam timing at reduced power cruise to limit airflow into the combustion chambers?

One word: Emissions. Specifically, reduction of NOx (nitrides of oxygen.)

Edit: Just Googled it, and sure enough...

http://www.designnews.com/document.asp?doc_id=266687

"General Motors is bringing diesel technology back to an American-made compact car by using an air intake technique called “variable swirl.”

The technique enables the company’s new 2.0-liter diesel engine to generate more power with less fuel, while minimizing nitrogen oxide (NOx) and soot levels. As a result, the Chevy Cruze Diesel's new engine is said to be the cleanest ever produced by GM. It’s also the first diesel to be offered in a GM compact car since the 1986 Chevette.

”The Cruze diesel engine, by virtue of its smaller bore configuration, is more in need of a way to make sure the fuel and air mix properly,” Mike Siegrist, GM’s 2.0-liter turbo diesel assistant chief engineer, told Design News. “That’s what the variable swirl does. It mixes the air and fuel more effectively, so optimum combustion occurs.”

Variable swirl accomplishes that by employing a throttle valve in the cylinder’s air intake port. Under high speeds and high engine loads, the throttle valve is wide open, allowing air to flow freely into the cylinder. But at low speeds and low loads, the valve is partially closed, creating an air velocity differential between the opposing sides of the cylinder. That differential causes a “mixture motion,” or swirl, which burns the fuel in a compression-ignited engine more thoroughly."

The NOX is controlled by varying the exhaust cam advance/retard, not the intake cam. Late cam closing allows exhaust gasses to flow back into the combustion chamber which provides EGR function.
The intake cam advance /retard is used to limit combustion chamber filling by closing late and letting some air be pushed back out of the combustion chambers on the start of the compression stroke. 
   Swirl is important in carburetored and port injected engines to keep the fuel mist in suspension until it flashes to vapour. Combustion chamber swirl in a gasoline DI engine or a diesel form an intake valve is of minimal importance as fuel is not even in the combustion chamber until combustion starts. Intake valve swirl in minimal  compared to the swirl induced by the quench area have less than 25 thou hot clearance. Forcing the gasses as a "jet" into the remaining open area of the combustion chamber. 

[Quinnf]

Mark,

Don't feel bad.  There's nothing wrong with thinking about ways to improve efficiency.  I’ll admit to the whole internet, what my wife and whatever governmental organization is sifting through these words knows all too well: 

These engines are just bigger, heavier versions of the Mammod steam engine we may have had as a child.  Or the Cox .049 screaming at 18,000 rpm and dripping castor oil all over the carpet on a rainy Saturday afternoon, or the Honda 90/350/550 we had later, or the Kawasaki that we had even later that scared some sense into us when we realized we had a wife and kids and bills to pay and what if . . . .

Just keep in mind that this mistress isn’t exactly a virgin.  She’s been around the block and she’s older than she looks, and you and I aren’t the only ones to have laid eyes on her.  The technology has been around for a long time.  Several generations have wondered at the marvel of turning fuel into work.  It may be new to you or to me, but the reciprocating engine isn't new.  Keep an open mind and don't be disappointed (or surprised) if it turns out your idea doesn't produce the results you hoped it would.   

People forget that reciprocating internal combustion engines were based on the theoretical work of Nicolas Carnot way back in 1823.  For over 150 years, the reciprocating engine, whether fueled by gunpowder, steam, liquid or gaseous petroleum fuels, has been on the cutting edge of technology.  So it's a mature technology, perhaps even a senescent one, because new people come along and "discover" what their grandfathers knew before them.  The Lister 5/1 and later the 6/1 first appeared in 1930.  At the time, they were not cutting edge.  They were simply an improvement over what was then available, based on, to no small measure, the introduction of the Cold Start valve, which accorded Freeman-Sanders a patent and marketing protection. 

Rudolf Diesel's first patent was published in 1892.  He filed another important patent in 1898, and a few later ones that were bitterly contested.  At that time he was already besieged by competitors vying for investment capital needed to build the next generation of compression ignition engine.  His 1892 patent claimed extraordinarily high fuel efficiency by means of extraordinarily high compression, which got him a LOT of attention.  He had ample investors who were willing to finance his experiments, he marketed himself widely as the Wunderkind of the new technology, and he lived and spent money like a rock star.  But by 1900 there were several examples of compresion ignition engines in industrial operation.  And by 1920 all engines looked pretty much the same and everyone had switched from air blast induction to high pressure fuel injection.  From then on it was simply a matter of tweaking. 

1892 to 1930 was only 38 years.  From concept to mass market.  The fact that a Lister 6/1 made in 1930 wrings about as much work out of a liter of fuel as does a Kubota diesel indicates that the technology, as far as naturally aspirated standard (non-electronically controlled) diesels go, is mature.  There's really nowhere to go to get better efficiency without redesigning the engine. 

But for you and me, although Solomon lamented that there's nothing new under the sun, that shouldn't stop us from playing around with propane or natural gas induction, or even hydrogen if you have the nerve (I don't).  So what if that which you "discover" was common knowledge long ago?  The process of learning and discovery is its own reward.  And I can think of no engine better suited to that pursuit of answering the question "What if” than the 6/1 and its variants.

Quinn