Another Rant/pet peeve!!! Small motor ratings

I hate how that lawsuit made the small gas engine manufacturers quit putting horse power rating on any new motors. No consumer got anything out of it but a few lawyers got more money.

How do you know what a 270 cc motor horse power out put is???? Or even more useless is torque rating.

So if I want a 5 hp motor what do I need to buy?????

It is sounding better each day to just shot all of the lawyers, judges, and politicians. None of them are worth the problems they cause the rest of us.

I don't know if this will help you in your case but if they do give torque at a specific rpm, multiply that torque rating x the rpm, and then divide by 5252 to get the horse power. If no rpm is given with the torque, most small gas engines are run at 3600 rpm no load so that would get you close.

Easiest way to tell is just go by engine size. The rest can be very misleading. The only thing that's changed is that an overhead-valve version of an engine can make a bit more power for it's size as compared to a flat-head. A 10 horse flat head often gained 1.5 to 2 horse when switched to overhead valves. Note also that diesel engines always have less power then gas engine if aspirated the same and with same bore and stroke. That is why tractors sold at a certain power level will have bigger diesels to make up for the loss.

20-30 years ago -

A 3 horse engine was 7 3/4 cubic inches or 127 ccs.

A 4 horse was 10.5 c.i. or 172 ccs.
A 5 horse was 12 c.i. or 197 ccs.
A 10 horse was 24 c.i. or 393 ccs.
A 16 horse was 32.4 or 531 ccs.

Besides all that, direct-drive push mowers often post specs at RPMs that engine are not legally permitted to run due to blade-tip-speed regs.

Easiest way to tell is just go by engine size. The rest can be very misleading. The only thing that's changed is that an overhead-valve version of an engine can make a bit more power for it's size as compared to a flat-head. A 10 horse flat head often gained 1.5 to 2 horse when switched to overhead valves. Note also that diesel engines always have less power then gas engine if aspirated the same and with same bore and stroke. That is why tractors sold at a certain power level will have bigger diesels to make up for the loss.

20-30 years ago -

A 3 horse engine was 7 3/4 cubic inches or 127 ccs.

A 4 horse was 10.5 c.i. or 172 ccs.
A 5 horse was 12 c.i. or 197 ccs.
A 10 horse was 24 c.i. or 393 ccs.
A 16 horse was 32.4 or 531 ccs.

Besides all that, direct-drive push mowers often post specs at RPMs that engine are not legally permitted to run due to blade-tip-speed regs.

Hello Jdseller,
Like pete 23 said you multiply the torque by the R.P.M.'s and divide by 5252 to get the H.P.
Becouse of the lower R.P.M.'s the engines are running today, your H.P. will be a bit lower.
Since the law suit for H.P. most engine will have a torque rating instead.
Againg torque times R.P.M.'s devided by 5252 equal H.P.
Guido.

It's not like they were telling the truth, anyway. Rating are constantly manipulated to give the manufacturer a better number. After awhile, you look at an engine and say to yourself that it is to small, while your wife say's, "It has a billion horsepower! That engine will easily hsndle what you want!" To which you will reply, "There is not an engine on the market that will fit into that shoebox and still provide enough power for a Bulldozer.". All engine makers did was add the power required to run the engine, sprinkle with fantacy pixie dust, multiply by the square root of X and tell us whatever they want, anyway. If you look at the engine and think about it a moment, you're best guess is more reliable than what engine manufacuterers ever tell us.

My thought is if in doubt "go big-ger". If you work an engine full bore it won't last as long as one that has life easier.

270CC is about 16 CID. If the engine is a modern OHV model it will produce around 7 to 8 HP. I am like you I HATE the new rating system. I always look a the engine displacement in Cubic inches and divide by two for HP.

Kent

Amen to that!

Did not realize they changed the ratings till I got looking for a replacement 8HP engine for my log splitter.

You know they could have done like Wisconsin used to do and gave the engine HP at the different RPM levels instead of using one specific HP number.

I've got a VE4 Wisconsin torn down right now. It's a 3" bore, a 3 1/4" stroke which makes it having 91.9 cu inches. If you look at the chart in the manual it's rated anywhere from 13HP @ 1400 RPM to 21.5 HP @ 2400 RPM. Hey that's an 8.5 HP difference they "admit" to so it looks to me like there's nothing underhanded and hidden about those ratings is there? I guess the problem is that this engine was built in the 50's and some people/companies tended to use a bit of common sense back then.

If MFGS/s nowdays would simply give their engines honest ratings like this then we'd all be better off than we are with the cubic inch BS our illustrious government is cramming down our throats now. If the 'we know better than you crowd" in DC wanted to do something RIGHT for a change all they had to do was require a rating like Wisconsin used and then there would be no confusion...

Wait a minute, that wouldn't work either because that 13 HP - 21.5 HP might only be at .99999inches above sea level, and at exactly 70.999999999999 degrees. Problem is though is any any of those parameters are changed the slightest bit and a customer lost .0000001 HP then some lawyer would happily sue claiming they misrepresented their product.vinstead they just tell us a displacement and let us make a guestimation as to the HP we MIGHT get out of the engine. By doing this we are more likely to buy a larger engine than we need, spending more money as a result, along with creating more polution from the larger engine.................

OH well, I guess it's about time to for all of us to go to Washington and practice our "3 S'es" .....LOL .

The problem isn't the new system. The new system is the solution. The problem is that manufacturers were testing their engines in abnormal situations and using that horsepower rating. Ideally an engine's horsepower number would come from the power output of the engine at normal operating speed. In most cases this is 3600 rpm. What manufacturers had been doing is to test the engine at very increased rpms, in some cases nearly twice that. Whatever horsepower the engine was able to create slightly before it blew itself up was the "peak horsepower" and therefore legal to claim because the engine was capable of creating that horsepower.

Case in point. Briggs and Stratton introduced there horizontally opposed vertical shaft engine in the early 80's as a 12hp engine. The exact same engine; no crank changes, no displacement changes was rated at 20.5 hp when they discontinued that engine style in the early 2000's. Absolutely nothing changed internally. Briggs new that people wanted bigger engines because we all think that bigger is better. People were much more likely to purchase the engine if it was in a tractor that said 16hp instead of one that said 12hp.

By changing to displacement the manufacturers are unable to skew the numbers to increase sales. We just all need to get used to it. Just because something is different doesn't mean it is stupid.

Yes, it is still stupid because now all they are doing is giving a displacement and expecting the customer to make a mostly uneducated guess as to what HP to expect from a given displacement. Heck, look at the replies over the last year or so in regard to all the different ways just the guys on here use to get close to a HP rating. On the other hand the OEM should be expected to test their engines under real world conditions and post the ratings accordingly. Like I said before, if they all did like Wisconsin origionally did they would have a chart giving the expected HP at a specific RPM, under specific conditions.

Heck, Wisconsin went so far as to give the conditions their engines were tested under and go on to tell you that for every 1" lower barametric reading to deduct 3.5 percent, for every 10 degree rise in temp to deduct 1 percent, for every 1000 feet altitude rise to deduct 3.5 percent. Not to mention that they also told the consumer that the engine left the factory only capable of 85 percent of the rated HP due to friction losses but to expect the HP to increase as the parts ran in.

Like I said THERE IS A WAY for the MFGS to give an accurate HP rating on their own engines, under a specific set of operating conditions. If they were able to do it with the technology available nearly 60 years ago then they can dang sure do it nowdays. Problem is they chose to ignore good business practice and basically lie to everyone and expect them to be smart enough (or not) to know the lie and make their decisions based on their knowledge or lack thereof. Now, instead, they simply rely on the consumer to do it all themselves, only now with even less info readily available then before.

I mean seriously, the displacement of an engine means nothing. Different brands can run different lifts and durations on the cam, different sized valves, longer or shorter stroke and larger or smaller bores but each having the same displacements, etc, etc, etc. Basically there are way too many variables that are going to affect the HP and torque of an engine that go way beyond aything the dsplacement can even begin to tell you to make even the mention of the displacement in regard to rating an engine laughable to say the least. But that's what they are doing now.

Again, to me, that is about as stupid as it gets.............The fact that our government not only is allowing it, but actually pushed it into existance in the name of 'consumer protection' is even more stupid........ But that's just my .02

The new system was put in place because the manufactures keep cooking the books. Briggs 10HP wasn't what Kohler's 10HP was. It seems to me it would have been simpler to just have a third party do all the HP testing, more like the auto industry.

I look at the big 16HP engine that was in my Cub Cadet 169, that thing had some really decent power. Then I look at the new 23HP engine that's in my uncles new JD lawn tractor and it's power is just so so. Things have changed...

K

A friend, whose brother worked for "Briggs" said
that they fed pure oxygen into the intakes when
testing for horsepower!

You were buying engines based on a meaningless rating for all those years, and you didn't know it. What's the difference now, other than you have to change to a different rating?

I think the problem was they were using the same engines for so many applications.since hp is directly rated to rpms the hp ratings were all over the place.if they would list a engines hp at such and such a rpm like the car companies do it would be fine. but they would take the same emgine run it at 3600 rpms ,and of course it would be say a 12 hp,run it at 1800 rpms and it may only be a six hp.hp goes up as rpm increases,torque gets to a certain point and then falls off as rpm increases.so depending on what amount of torque ,or hp needed they could adapt a single engine to many uses.however the american public has a fetish for hp so they listed the max hp you could get out of an engine,instead of the hp at whatever govered speed you were running at the time at the true applications speed.they werent particularly lying,because you could theoretically get that much hp on test bed,but they were using the numbers as a marketing ploy.