Author Topic: Listeroid intake porting  (Read 1609 times)

38ac

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Re: Listeroid intake porting
« Reply #30 on: January 03, 2021, 01:48:42 AM »
Shrouding may not be the technically correct term but the 45 seat angle starts at the deck and continues down past the full face of the valve and below it. The head of the valve recessed at .100 below the deck. Certainly not conducive to good flow past the valve,, or great seating either.
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gadget

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Re: Listeroid intake porting
« Reply #31 on: January 03, 2021, 04:08:44 AM »
Shrouding may not be the technically correct term but the 45 seat angle starts at the deck and continues down past the full face of the valve and below it. The head of the valve recessed at .100 below the deck. Certainly not conducive to good flow past the valve,, or great seating either.

Ah yes, I see what you mean. Just curious, what kind of life are you seeing out of the factory seats? Are they prone to sinking?

cujet

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Re: Listeroid intake porting
« Reply #32 on: January 22, 2021, 09:57:39 PM »
In theory at a .9 volumetric efficiency, the 6/1 could produce 9 HP at 650 RPMs. Will never get that high with this type of head though. 

I don't believe that is correct. Can you show the math involved?

The Listeroid lends itself amazingly well to a direct measurement of volumetric efficiency. Simply take a known quantity of air and run the engine. Quick calculations with time it takes to consume the air and RPM will give a reasonably accurate answer.

My guess is that VE is pretty good, and that there is little to be gained with intake airflow management.

Combustion efficiency may be a factor in the smoke limit, and internal (and maybe external flywheel aerodynamic) frictional losses on a Listeroid do reduce output somewhat.
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dkmc

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Re: Listeroid intake porting
« Reply #33 on: January 22, 2021, 10:23:29 PM »

I think valve timing and lift is worth the investment of time to research. Even if that means correcting back to Lister specifications as has been discussed before. But beyond stock specs, maybe there's a 1/4 horse or 2 to be had.

Hugh Conway

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Re: Listeroid intake porting
« Reply #34 on: January 22, 2021, 11:47:37 PM »
@Gadget
"It would be really interesting to see how much better an original Lister runs vs a clone. I can't imagine the port quality of an original cast head is as bad as these clones."

You got my curiosity up......I looked into the intake ports of my Dursley 6/1 and my JKSON 6/1 to compare. Opposite of what I thought, the JKSON has a smoother port. They are both somewhat rough, but the Lister is definitely the more rough of the two. Of course, this is just a comparison of 2 engines, we may see something different with a more broad range of comparisons.
Cheers
Hugh
JKson 6/1  (Utterpower PMG ) Off-grid
Lister 6/1 Start-O-Matic engine......running with PMG
1978 Royal Enfield (glutton for punishment by Indian iron)
1963 BMW R-27 project

38ac

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Re: Listeroid intake porting
« Reply #35 on: January 23, 2021, 12:40:35 PM »
I still think ya'll is barking up the wrong tree screwing around with the ports in the OEM head. Those tiny valves would be the first thing to go in the trash of I was so inclined to mess with one. India has a nice part in stock for you. Its the direct injection head that is used on some of the large displacement engines. The valves and porting under them is much larger. When I have time I will take some side by side pics.
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38ac

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Re: Listeroid intake porting
« Reply #36 on: January 23, 2021, 02:33:46 PM »
Direct injection 18/1 head and valves compared to 6)1 valves.
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38ac

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Re: Listeroid intake porting
« Reply #37 on: January 23, 2021, 02:42:20 PM »
Bottom of DI 18/1 head and DI piston. This setup is available for 114MM bores, my very first Listeroid was a DI 6)1 Metro. You need head, piston, injector and fuel line. You can also upsize your fuel pump element to 8MM to take advantage of any increase in air flow you might get.

All this would be an interesting project for someone who wishes to spend the time to properly test and document the results. I don't have suchcuriosity. When I needed more power than my 6/1 I bought a twin 😊

Sorry for the lousy picture quality. Dropped my phone and cracked the camera lenses.
« Last Edit: January 23, 2021, 02:44:11 PM by 38ac »
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gadget

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Re: Listeroid intake porting
« Reply #38 on: January 23, 2021, 06:52:23 PM »
WOW 38ac, thats a pretty big difference is size. I'm starting to wonder if the original lister team was focusing on some modified atkinson cycle type gains with this motor. Less compression ratio(low intake volume) vs expansion ratio. Thats one thing I love about the motor is the RPM / HP vs Displacement. Leaves lots of time to absorb the energy and keeps the numbers high for such an old design.

You are right though, best way to get more power is to go with a twin. I'm picking up an 16/2 as soon as the budget allows for my gen head. Then I can use my 8/1 for my low RPM always on axial flux CHP. Who says you only need one motor? I missed that rule. I'll just tell the wife the other motor was getting lonely....
« Last Edit: January 23, 2021, 08:44:17 PM by gadget »

gadget

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Re: Listeroid intake porting
« Reply #39 on: January 23, 2021, 08:40:25 PM »

Atkinson cycle if anyones curious;
https://www.youtube.com/watch?v=z45fM2N-4C4
« Last Edit: January 23, 2021, 08:49:20 PM by gadget »

dkmc

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Re: Listeroid intake porting
« Reply #40 on: January 23, 2021, 11:22:13 PM »
Who says you only need one motor? I missed that rule. I'll just tell the wife the other motor was getting lonely....

Agree completely. I'm up to 3 at this point. And my GF even went on the trips to get them, and helped with loading.

38ac, The picture of the piston reminded me of the story of the old clock repairman. Customer brings in their non-working coo coo clock. The old feller takes the back off and shakes out a dead fly....He says "There's yer problem, the Operator's dead".

Hugh Conway

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Re: Listeroid intake porting
« Reply #41 on: January 24, 2021, 07:11:04 PM »
I ran across this on a vintage BMW forum. Relates to carburettor/intake manifold interface and roughness in the intake porting. Of course it is for a carburetted engine with a throttle body , not a diesel, so may not apply at all. Interesting never the less.
Snowing heavily here this morning, so I'm wasting time poking around the internet.
Cheers
Hugh

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Mismatched bores are actually a good thing and we use them on our race car engines that have carburettors all the time. The physics is as follows:

1) Picture the column of air that is travelling down the carb throat when the intake valve opens, it is moving at quite a fast rate and is laden with fuel.

2) When the intake valve closes the column of air slams into the closed valve. "An object in motion tends to stay in motion"

3) The air now wants to "revert" back up the intake track. This is what is commonly called "reversion".

4) The amount of reversion, time, length, etc is quite dynamic and changes with throttle position, RPM, barometric pressure, etc etc.

We have found after years of working on racing engines that we can put this to work for us! A step in the intake manifold works in two ways:

1) A smaller manifold creates a lower pressure area under the step (in the intake tract) and the lower pressure resists going "back up" into the higher pressure area. We have also found that a larger manifold created positive turbulence and has the same type of anti-reversion benefit, but not as much.

2) It creates turbulence in the incoming charge and this is REALLY good. Yes, I said turbulence IS GOOD for intake tracts!

Years ago many engine builders were flowing their heads with complicated flow benches and new ways to make intake tracts as smooth as possible in order to (so they thought) get a better flow rate. We have one in the back of the shop collecting dust right now! This thinking is wrong. A bit of roughness on the walls of the intake tract breaks the boundary layer of the air. I.e. If you look at any aerodynamics book worth its salt you will see that when a flow is right->left (for explanation purposes) there is a VERY THIN boundary layer actually going the OTHER way (left->right in this case) on the surface of the object (in this case our intake tract). This reverse boundary layer is actually what creates disruptive turbulence and having a non-smooth surface helps break the boundary layer and increases flow rate.

I will not go further into the physics behind it and the "amount of roughness", and the "amount of turbulence", because it depends on a myriad of factors.

In other words, if you have a step where the manifold is SMALLER than the intake tract that is the best scenario. We have also seen that using a manifold that is larger than the intake holds benefits but not as much as the smaller one.

In other words, don't worry about it! :-)







JKson 6/1  (Utterpower PMG ) Off-grid
Lister 6/1 Start-O-Matic engine......running with PMG
1978 Royal Enfield (glutton for punishment by Indian iron)
1963 BMW R-27 project

gadget

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Re: Listeroid intake porting
« Reply #42 on: January 25, 2021, 08:06:42 AM »
I was taught crossing the boundary layer was a no no and one must keep the flow laminar. Now your telling me turbulence is ok at the boundary layer. I feel like I may have missed out by avoiding the port altogether..Oh well I'm married now and don't have to worry about getting turbulent in the port.
« Last Edit: January 25, 2021, 03:04:00 PM by gadget »