Article for you torque monster stroker dreamers

commando1 said:
Q: How much power can you make with a BB?
A: How much money you got.
You dump 10 grand into an engine and a doctor with a checkbook pulls up with a Hellcat Crate Engine in his Cuda.

It never ends...

Regardless, nothing like building your own. Thanks for the tip on the article. I'll go down to BookSmith and read it there.
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Miss your optimism, Stan. I’ll have to check in here more often for my daily affirmation.
 
commando1 said:
Q: How much power can you make with a BB?
A: How much money you got.
You dump 10 grand into an engine and a doctor with a checkbook pulls up with a Hellcat Crate Engine in his Cuda.

It never ends...
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These Tesla kids are just getting started. Yeah they run out of steam on the top end as the Hellcats have less steam than the Teslas on the low end. But the electric motors are running a one speed transmission. They are out of their torque band at high speeds. Even with these early electric motors with one speed trans they are hauling over 4500 pounds.
I anticipate a 2 speed or cvt ,,battery advancements ,motor advancements. These things require no experience except the tree. Point and shoot, no water box to heat the hides. Hell a base model Tesla model 3 with the + package is 3.2 to 60 and over 300 miles of range.. Lotta Geeks gonna wanna beat the old guard.
It's just a matter of time. Doesn't matter to me. I want a stroker. My daughter wants me to buy a Tesla.....


 
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Model 3 | Tesla 0 to 60 3.2 seconds. top speed 160 mph. This is their most affordable car.

I still would want a stroker before this...
 
PontiacJim said:
twostick - "The material that the roller cam distributor gear is made from doesn't play nice with the iron gear on the distributor so you have to use a bronze distributor gear which wears out quickly.

Listen to this video on YouTube. Composite is what you want. Other factors will cause a gear to wear out quickly, not just because it is bronze. Higher oil pump pressures and that good 'ole 20w-50 weight racing oil used for street engines are contributors.

bajajoakin - "Regarding torque, the long stroke doesn’t give you more torque directly. There’s a longer lever, sure. But torque is a function of the lever length, cylinder pressure and area of the piston for the pressure to push on. For a given displacement, cylinder area will go down as lever arm goes up. It’s a wash."

WHAT???? LOL

bajajoakin - "As does the fact that a long stroke motor can’t spin that fast so they had better be torquey because they sure couldn’t be revvers!"

Huh? You must be talking about a factory cast iron engine.

MEV - "I personally feel a roller cam is a valid and necessary expense. I have seen too many flat tappet lifters fail. Usually they fail on startup, even with zinc additive, and breakin-oil."

OK, photo of the lifter shows a result, but what was the cause? People are all to quick to fault the lifter when in fact it was something else. Then they blame the oil. "While having an adequate level of ZDDP content in the oil is important, examination of those engines with camshaft and lifter failures finds that those failures are more often the result of other issues not related to the Zinc/Phosphate levels in the oil. Current available oils if properly selected based on the information in the API bulletin do still have adequate amounts of Zinc/Phosphate for the older flat tappet camshafts. The key here is to know which oils have had the Zinc/Phosphate amounts reduced and which have not. This essentially means reading beyond the first paragraph of the API bulletin to get that information."

READ this long list of some causes that can damage a lifter & cam- Camshaft and Lifter Failure Causes | Eaton Balancing
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Do the math. What is torque? It’s a twisting force acting on an object. How does it act on an object? By applying a force through a surface to a lever.

In a car, that force is measured in PSI. “Per square inch.” There is an area component. Reduce the area of the surface that is receiving the force and you reduce the force that is applied. If you achieve this by having a longer stroke then yiu have gotten a longer lever which balances it.

Note I assumed the displacement being equal.

The longer stroke does not in and of itself make the engine torquier. The materials don’t matter.

Now, of course nothing exists in a vacuum. That’s what I was saying that there are secondary effects. Cast parts can’t rev as high, and are even more compromised as the piston speeds get higher. But that’s an engineering issue, not a physics issue.

For a given displacement, a longer stroke will have a smaller bore. Your valves will have to be smaller and or have flow shrouded by cylinder walls. That will restrict the engine’s ability to breathe at high rpm. But the length of the lever on the crank is not the same thing.

Bore and stroke will also affect the shape of the combustion chamber. This will have an effect on how the engine performs at various rpm. But that is not the same as the longer lever providing more torque.

Long stroke engines tend to make more torque at a lower rpm. But that’s because the other design characteristics affect it, not because the lever is longer.

In other words, they have to produce more torque, because they can’t rev to compensate.

What I’m getting at isn’t that strokers aren’t torque motors (generally). It’s that if you focus on the lever, you’re missing the important characteristics that do matter.
 
bajajoaquin said:
more torque, because they can’t rev to compensate
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This is only true if you restrict the heads. Sticking with what is available in BBM a Predator or 572-1 on a 505 would allow 8-9000 rpm pretty easy.
Prostock engines are NHRA limited to 500" and they spin well over 10,000 rpm. The no prep/ grudge match cars around now (the big Nitrous engines) are anywhere from 600 to a rumoured 900+ inch Pat Musi engines running around and I would make bank on the fact they are not redlining at 6000 rpm. So no a offset ground stock 440 cast crank is not going to last at 6500 rpm but to say a long arm engine can't rev is not true. More accurate is they can't rev with stock BBM heads.
 
70bigblockdodge said:
This is only true if you restrict the heads. Sticking with what is available in BBM a Predator or 572-1 on a 505 would allow 8-9000 rpm pretty easy.
Prostock engines are NHRA limited to 500" and they spin well over 10,000 rpm. The no prep/ grudge match cars around now (the big Nitrous engines) are anywhere from 600 to a rumoured 900+ inch Pat Musi engines running around and I would make bank on the fact they are not redlining at 6000 rpm. So no a offset ground stock 440 cast crank is not going to last at 6500 rpm but to say a long arm engine can't rev is not true. More accurate is they can't rev with stock BBM heads.
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My friend's ProMod is a Pat Musi 959 cu in with 5 stages of nitrous. He shifts at 9200 rpms at ends up in 5.70's @ 253 mph.

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Turboomni said:
Thanks for that PontiacJim. Now the gear wear and it's causes makes sense along with the video. Thick oil and high psi and high rpms + the video of application of different type gears to the cam material all contribute big time. Seems by the video and the possible problems this applies to both roller and flat tappet designs. I could easily see that a high volume/psi oil pump with thick oil and high rpms could make that little gear very unhappy.
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If you care to learn a little more, check out this website. I have several of their video's and they are well done, informative, and use visual aids in explaining exactly what they are trying to get across to the veiwer. They also have a great tech Q&A section you can read through. Are high volume oil pumps OK to run on the street?
 
bajajoaquin said:
Do the math. What is torque? It’s a twisting force acting on an object. How does it act on an object? By applying a force through a surface to a lever.

In a car, that force is measured in PSI. “Per square inch.” There is an area component. Reduce the area of the surface that is receiving the force and you reduce the force that is applied. If you achieve this by having a longer stroke then yiu have gotten a longer lever which balances it.

Note I assumed the displacement being equal.

The longer stroke does not in and of itself make the engine torquier. The materials don’t matter.

Now, of course nothing exists in a vacuum. That’s what I was saying that there are secondary effects. Cast parts can’t rev as high, and are even more compromised as the piston speeds get higher. But that’s an engineering issue, not a physics issue.

For a given displacement, a longer stroke will have a smaller bore. Your valves will have to be smaller and or have flow shrouded by cylinder walls. That will restrict the engine’s ability to breathe at high rpm. But the length of the lever on the crank is not the same thing.

Bore and stroke will also affect the shape of the combustion chamber. This will have an effect on how the engine performs at various rpm. But that is not the same as the longer lever providing more torque.

Long stroke engines tend to make more torque at a lower rpm. But that’s because the other design characteristics affect it, not because the lever is longer.

In other words, they have to produce more torque, because they can’t rev to compensate.

What I’m getting at isn’t that strokers aren’t torque motors (generally). It’s that if you focus on the lever, you’re missing the important characteristics that do matter.
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No offense, but I think you are reading the wrong source materials. First read this and note Paragraph 6, "Torque is like using....." What is the difference between horsepower and torque?

And you might want to read this as well - Is it better to de-stroke or increase stroke on an engine for more power?

Care to educate yourself further on stroker engines, this is a great video, and I do have it. Performance Engines & Strokers
 
Edited to remove mocking and rudeness. My apologies.

Updated:

I totally overstated things in my summary comment that they can’t rev. I was thinking of the extreme examples of early automotive and aircraft engines that were very long stroke and less sophisticated materials. I didn’t share that and it really didn’t make sense.

If you look at the core of my comments: it’s not about the length of the lever and focusing on that you miss the things that are important, I think the pro stock example is a good one. By focusing on the engineering challenges of flow and materials, you can overcome the limitations of high piston speed. Nobody refers to those engines as torque monsters just because they have a long stroke.

Again, im not saying strokers don’t make more torque than stock stroke engines. I’m saying it’s not because of the longer lever if he crank.
 
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Well to change the subject a little bit but stay on the stroker theme ,as I said before I am considering a roller cam. In studying them a bit it is my understanding that yes they do have less friction but the more important thing is they can have more radical ramps to open the valve much quicker than a tappet cam. Many including me thought they were mostly for high rpm engines. But reading further the advantage is they can fully open a valve much quicker, stay wide open longer and close quickly for the same duration as a flat tappet cam. Please correct me if I am wrong on any of this. This got me thinking as I want to use HP manifolds with dual exhausts. Since the HP's don't flow like headers wouldn't a roller cam's ability to open the valve wide open sooner and stay wide open longer help the breathing through the HP manifolds because there is more time with a fully open valve? A flat tappet opens slower and peaks quickly I see so as soon as it is wide open it starts to close unlike a roller. My thinking is simply the valve is wide open for a longer time to get the flow out the HP manifolds. Redline for me will I guess be around 5000 rpms or so. Just seeing what you guys thought about this and if it makes any sense.
 
Turboomni said:
they can fully open a valve much quicker, stay wide open longer and close quickly for the same duration as a flat tappet cam
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At full lift longer because of ramp speeds, stay open longer is longer duration no matter the cam style.
Turboomni said:
wouldn't a roller cam's ability to open the valve wide open sooner and stay wide open longer help the breathing through the HP manifolds because there is more time with a fully open valve
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Just more duratuon to allow time for exhaust to flow out. Roller cams work, but the expense can be a negative.
 
70bigblockdodge said:
At full lift longer because of ramp speeds, stay open longer is longer duration no matter the cam style.
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I guess what I meant was the valve can open quicker than a FT, stay wide open for a longer span before returning to the closed position where as a flat tappet will peak and start returning sooner even though the time span or duration is the same with opening/closing of both cams.

70bigblockdodge said:
Just more duratuon to allow time for exhaust to flow out. Roller cams work, but the expense can be a negative.
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Thanks for confirming that as that is what I was thinking. Yes the roller setups are pricey and is why I ask about them.
 
Duration is the time the valve is open, measured in degrees of rotation. If a cam is open for 230 degrees of rotation it has the same duration as any other cam of 230 degrees, regardless of lifter type.

One of the things affecting flow is just how far open the valve is. It flows more at .500” lift than it does at .250” lift. The faster you can get to .500”, the more it will flow.

One of the things limiting how fast you can open the valves is the physical limitation of the interaction between lifter and cam lobe. At some point, a flat tappet lifter will dig into the edge of the cam face if you try to make the lift profile too steep. A roller lifter doesn’t have this limitation and can open much faster. The valve spends more time more open and flows more.

It’s not the same as adding more duration.

Life is a series of compromises. A roller cam can do things that a flat tappet can’t. But it is more expensive, retrofit lifters are heavier (particularly in hydraulic versions) and may be less reliable.

I’m also considering one, but don’t know if the marginal $1000 is worth it. I think the same money would be better spent on more cubes through a stroker crank. If you could afford both, I think you’d have a freaking unbelievable engine.
 
This discussion shows one of the problems with the performance industry from the perspective of a C-body. All the testing and data is really focused on making power with more revs and moving lighter cars. We are left arguing among ourselves about how parts designed for 3000-6000 rpm will work when used at 2000-5000.
 
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