"High RPM is for high power".

Knitting was your thing, right?

Once you have a good oil film, metal to metal contact and wear almost stops on any engine (largely independent of RPM). And a higher RPM engine could have a slower piston speed than a Lister. And for the same engine design and output, as RPM goes up, load goes down (load also effects wear and it's not linear).

FWIW, people have reported 6000 hours and still going on well maintained little Honda inverter generators. Perhaps more hours than you will ever need for backup.

Well done jonr. How refreshing.

Posted By sailawayrb on 22 Jan 2015 10:30 PM
Planned obsolescence is by engineering design. However, engine wear is proportional to the square of the engine RPM. Just ask any mechanical engineer who specialized in machine design (like my husband) or consult Joseph Shigley, Mechanical Engineering Design sometime.

Lister engines were designed to run at low RPM expressly for the purpose of increased longevity…like decades of continuous 24/7 operation. This is only a 6 HP engine that weighs about 700 lbs! It all comes down to the purpose of the design and accepting the tradeoffs. High RPM is for high power…and that doesn’t make high RPM bad...but the tradeoff is significantly increased wear and reduced longevity.

I cracks me up that you can never admit when you are wrong, but love pointing out when everyone else is wrong. We are not perfect people and make mistakes, but to learn from mistakes you have to acknowledge them.

I can pick apart almost ever sentence you write.

The most obvious one is "High RPM is for High Power" - That is wrong, engines will produce their most power at a certain RPM but that does not have to be at their highest RPM.

An engine can last longer at a higher RPM if the lower RPM creates a resonance that will destroy it quickly...

A 700 lb engine that is only 6 hp sounds like a waste of material and horribly designed machine.

You are a smart person but need to acknowledge that you are not the smartest person....even though you think you are.

This is a forum to share knowledge and learn from the shared the knowledge. So if you post ignorance on this forum, you should expect to get called out on it. I am not wrong, you are just obviously ignorant about engine design. 6000 hours on a high speed Honda engine is nothing. We have 41,200 hours on our Lister engine. People have reported over 250,000 hours on these engines. No, the problem here that some folks post their ignorance and they don’t like getting called out on their ignorance. So get over it…or don’t do it!

HP = Torque (ft-lbs) x RPM / 5252

True, maximum torque doesn’t occur at maximum RPM. Wrong, higher RPM generates higher HP. Higher torque also generates higher HP.

Are we changing the subject from RPM to vibration and resonance? If so, this is why the 6 HP Lister engine weighs 700 lbs. Perhaps you have heard of stress and strain and know how to calculate. As I said, planned obsolescence is by engineering design. However, engine wear is proportional to the square of the engine RPM.

..................

Thus sailawayrb.....you are, as you state "ignorant" and it is incredible the disrespect you show people....it is a wonder anyone purchases stuff from you.

Posted By sailawayrb "Wrong, higher RPM generates higher HP."

Higher RPM does not generate higher HP....all engines have a HP peak, and once you are over the HP peak it produces less and less HP.

Some engines have high rpm peak HP and some engines like Diesels have lower RPM peak horse power.

Picture a engine unloaded at full throttle, it wont go any faster, thus it is not producing any HP because the torque in your equation goes to zero.

Respect is something that is earned. What you wrote makes zero sense. If you are going to refute as simple and fundamental an equation as the HP equation, I am clearly not going to convince you of anything and I am certainly not going to respect your knowledge of engines either.

Posted By sailawayrb on 23 Jan 2015 08:09 PM
Respect is something that is earned. What you wrote makes zero sense. If you are going to refute as simple and fundamental an equation as the HP equation, I am clearly not going to convince you of anything and I am certainly not going to respect your knowledge of engines either.

What I said makes no sense to you because you don't completely understand the equation you pulled off the internet. You talk in circles trying to make yourself look like you know what you are talking about because you are not a big enough person to admit when you are wrong or don't know something. I have extensive knowledge of engines because that is what I do for a living. You constantly try to belittle many of the people on this forum trying to make yourself look better and this is just another case. I'm an engineer that designs and test engines for living. I have tested over 7.3 million engines over the last 25 years. I am also a master mechanic and licensed builder. Home building is not my strongest point but engines is. I question your background?

I'm guessing she stayed in a Holiday Inn Express...

Newbostonconst, your statement makes no sense because the equation clearly shows that lower RPM or lower torque results in lower HP. If you look at the actual performance curve for any engine you see the exact same thing because the equation is always valid. Sure, peak HP occurs at a certain RPM and then the HP decreases with increased RPM. However, no one I know operates an engine on the backside of the power curve where you have to increase the RPM further to obtain less HP. Is this where you operate your engines? And what exactly is your point anyhow given your vast engine knowledge and experience? Do you have a 3600 RPM engine that has accumulated more hours than our 600 RPM Lister engine which has 41,200 hours? Are you aware of a 3600 RPM engine that has accumulated more hours than the 250,000 hours reported by Lister engine owners?

I simply provide information and facts. True, that can make some people look ignorant and feel belittled…and there are also people who are truly ignorant and post their ignorance too. However, that’s the nature of a forum because the goal is truthful information and fact sharing over BS marketing. Each post stands on its own merit. I am not trying to win a good old boy popularity contest. So when you made the statement “someone is pulling numbers out their arse…”, you implied that you disagreed with the information I provided. You still have not convinced me.

I have extensive knowledge of engines because that is what I do for a living

In which case I'm a bit surprised you're not familiar with the Lister diesels.