Torque Disparity Kohler vs. Briggs

[stumper63]

I am going to re-power my 03 252 and wanted to upgrade the hp at the same time. I was looking at the specs for the Kohler Command Pro 36hp vs. the Briggs Vanguard 35hp. The torque for the Vanguard is 53 ft. lbs., while the torque for the Kohler is 63 ft. lbs. Nearly same rpm for max torque values. Does anyone know how Kohler can get 10 more ft. lbs of torque at virtually the same horsepower?
Also, does anyone have experience with either of these size hp engines as far as reliability/issues? I'm totally happy with the 25hp Kohler, no problems in 2800 hours, but I don't think Kohler has had these larger v-twins but for a couple years or so. Any reports on the 35hp Vanguard's? Seems Vermeer, Bandit, Carlton, Rayco, all use them on their machines. Does that say anything about the Kohler?
More torque is good, but don't want to have reliability issues. Anythings is an upgrade from the 39 ft. lbs. of the 25hp.

Thanks,
Stumper63

 

[TreeBot]

I just put the 35hp Vanguard on my chipper, I have heard very good things as far as reliability, we will see. I looked at the Kohler too but it was a more than $500 upgrade.

I would love to put a 35hp on my 252, I just wonder if the machine can handle it. I don't know how many more stumps my original motor has, and the price for a replacement 25hp Kohler was about $1800! The Vanguard I got new complete for $2k.

 

[gink595]

My experience with Kohlers has been good, but they are expensive to repair. I'm not familiar with the new lineups you are talking about, what are the bore and strokes of these motors? That will come to play with the different torque rating @ RPM, as well as cam profiles and ignition timing.

 

[stumper63]

Treebot,

Plyscamp has a 35hp Vanguard on his 252, says it handles it just fine. I think he increased the jackshaft to 1.5", to match the cutter wheel shaft, but not sure. He also has a 252 with a diesel, but had to make more mods to handle the torque.
Stumper63

 

[stumper63]

Gink,

Kohler Bore is 90mm x stroke of 78.5. Briggs bore is 85.5 x stroke of 86.5.
So does larger bore and shorter stroke result in more torque?

Thanks,
Stumper63

 

[441_Stihl]

yes

 

[Jonsered2095]

I am going to re-power my 03 252 and wanted to upgrade the hp at the same time. I was looking at the specs for the Kohler Command Pro 36hp vs. the Briggs Vanguard 35hp. The torque for the Vanguard is 53 ft. lbs., while the torque for the Kohler is 63 ft. lbs. Nearly same rpm for max torque values. Does anyone know how Kohler can get 10 more ft. lbs of torque at virtually the same horsepower?
Also, does anyone have experience with either of these size hp engines as far as reliability/issues? I'm totally happy with the 25hp Kohler, no problems in 2800 hours, but I don't think Kohler has had these larger v-twins but for a couple years or so. Any reports on the 35hp Vanguard's? Seems Vermeer, Bandit, Carlton, Rayco, all use them on their machines. Does that say anything about the Kohler?
More torque is good, but don't want to have reliability issues. Anythings is an upgrade from the 39 ft. lbs. of the 25hp.

Thanks,
Stumper63

Spec.s I read were:

Kohler 60 lb-ft @ 2400 RPM [oversquare]
B&S 52.2 lb-ft @ 2200 RPM [square]

200 RPM difference. Is the Kohler a peaky engine? It may stumble more...

Gink,

Kohler Bore is 90mm x stroke of 78.5. Briggs bore is 85.5 x stroke of 86.5.
So does larger bore and shorter stroke result in more torque?

Thanks,
Stumper63

Where?

Knowing its max. Torque alone is irrelevant - you want to know the relationship between Torque & Power ie. where Torque lays in relation to Power @ X[&Y] RPM.

http://en.wikipedia.org/wiki/Stroke_ratio

 

[joecool85]

Gink,

Kohler Bore is 90mm x stroke of 78.5. Briggs bore is 85.5 x stroke of 86.5.
So does larger bore and shorter stroke result in more torque?

Thanks,
Stumper63

Typically a longer stroke with small bore gives more torque at lower rpms, larger bore with short stroke gives more hp at higher rpms. It could be the cam has a different grind making it have high peak torque, but not necessarily good low end torque which is good if the engine starts to bog down ever.

I'd go with the Briggs personally.

 

[stumper63]

Note Jonsered's torque specs in an earlier post. Close to same torque peak, 2200 vs. 2400 rpm for the Kohler. Is 200 rpm difference in torque peak a big deal in this size engine?
It just seems that a 17 percent increase in torque from the Kohler over the Vanguard would be worth a few hundred bucks, as long as reliability isn't an issue. If I can go from 39 to 52 ft. lbs that's good, but why not go up to 60-62 (depends on which site you look at) for close to same money?


Like I said, my Kohler experience has been trouble-free with the 03 252 25 hp engine. That said, the larger v-twins are newer for Kohler, but would think they know how to build engines by now, but.......

Any other experiences with this size or similar Kohler engines?

Thanks for the comments,

Stumper63

 

[gink595]

I would say that a motor with a longer stroke than bore would give more torque when needed, The kohlers over square motor would make me think that it is developing it's torque at a higher RPM, if they are the same displacement.

 

[gink595]

Spec.s I read were:

Kohler 60 lb-ft @ 2400 RPM [oversquare]
B&S 52.2 lb-ft @ 2200 RPM [square]

200 RPM difference. Is the Kohler a peaky engine? It may stumble more...




Where?

Knowing its max. Torque alone is irrelevant - you want to know the relationship between Torque & Power ie. where Torque lays in relation to Power @ X[&Y] RPM.
http://en.wikipedia.org/wiki/Stroke_ratio

I agree, I see this HP rating stuff in motorcycles and it is highly misleading. Peak power ratings has very little to do with real world performance. Knowing where the working range power is most important rather than peak power outputs.

 

[pdqdl]

I have been mad at Kohler ever since they made the Command engines and I had one on a mower. It kept developing oil leaks under the flywheel !

It seems that this 25hp twin has NO bearing on the flywheel side of the engine. Both the vertical thrust and side-thrust forces on the crankshaft are handled by a special machined surface on the aluminum block. It is NON-REPAIRABLE !! If the machine you have the engine mounted on ends up applying more side force to the crankshaft than it likes, excessive wear occurs (just a couple of hours is enough) and the engine blows oil out from under the flywheel. The output shaft is supported by a roller bearing and seal, but the flywheel side of the crankshaft is built cheap and unrepairable.

When you attempt to get a warranty claim honored by Kohler, you will be told that there is no warranty repair due because the belt on the engine was "too tight: operator induced failure". [After the first engine failure, we made SURE that the belt was not too tight.]

I'll never buy another one if I can help it, and I check ALL engines I buy now to see if they have repairable bearings on the flywheel side of the engine. This cost me many thousands of dollars, several short block & engine replacements, countless hours of downtime, and ended up causing the death of the mower that was designed around that engine.

Conversely, I do have a couple of Kohlers that have done OK for me; I'll just never buy any more unless I have to.

 

[stumper63]

Hey Gink,

I'm not talking about peak horsepower ratings, I'm asking about the peak torque ratings. I'm aware that torque is more desirable than hp in a stump grinder application. That's why my original question about the higher torque in a similar sized and rated engine. I appreciate now the reason is the bore and stroke differences.

As noted earlier the Kohler 36hp (999 cc displacment) reaches its maximum torque at 2400 rpm, the Briggs 35hp (993 cc displacement) at 2200 rpm. The max rpm on both of these engines is about 3600 rpm and that's where the max horsepower is developed, so the max torque is being reached at about 2/3 max rpm for each of them. So is that enough information to know where the "torque lays in relation to power"? Let us know.

I sympathize with pdqdl about his Kohler 25 problems. Like I said, my experience with my 25hp Kohler has been trouble-free for 2800 hours. So the engine's reliability may have everything to do with its application. So on my Vermeer 252 I guess the application works fine.

It is interesting to find out about the crank only having a bearing on the output shaft side. I'll see what I can find out about these larger Briggs and Kohler engines. It seems like a bearing on each side is a no-brainer, but I'm no engine desinger, just a user.

Thanks for the help.
Stumper63

 

[gink595]

As noted earlier the Kohler 36hp (999 cc displacment) reaches its maximum torque at 2400 rpm, the Briggs 35hp (993 cc displacement) at 2200 rpm. The max rpm on both of these engines is about 3600 rpm and that's where the max horsepower is developed, so the max torque is being reached at about 2/3 max rpm for each of them. So is that enough information to know where the "torque lays in relation to power"? Let us know.

Thanks for the help.
Stumper63

What RPM are you going to run this motor at? That would be the question you need to know, what is the torque rating at your operating RPM? Say if your running this motor at 3400 RPM's and the torque curve falls 20ft. lbs. compared to where the 2400 peak is, I'd try and compare and see what the torque rating is at say 3600, because if it falls flat on it's face at your machines required operating speed it would be a bummer!!! Maybe call the manufacturer and see if you can get access to the dyno charts and compare where the power is, thats what I was trying to get at with the peak HP ratings they are kinda misleading.

 

[stumper63]

Gink,

Stump grinders are run at full throttle. They slow up during the actual sweep through the stump, probably to about 2400 rpm, I've no tach tho to confirm. The torque curve is similar on each of these, you can check online if you want. You get the feel for where the machine's effective work rpm is after awhile, it's way below full throttle.
So in comparing these two engines it seems they are on a basically level playing field, except the Kohler should do a better job with more torque available due to engine design.

Thanks for the info.
Stumper63

 

[gink595]

Gink,

Stump grinders are run at full throttle. They slow up during the actual sweep through the stump, probably to about 2400 rpm, I've no tach tho to confirm. The torque curve is similar on each of these, you can check online if you want. You get the feel for where the machine's effective work rpm is after awhile, it's way below full throttle.
So in comparing these two engines it seems they are on a basically level playing field, except the Kohler should do a better job with more torque available due to engine design.

Thanks for the info.
Stumper63

Yeah, I agree. Those small motors are designed to run at full throttle. So which one are you thinking about going with?

 

[stumper63]

Leaning towards the Kohler, but will wait a little to hear more about reliability and try to find out about the bearing thing. The little 25hp is still going strong and it's my busy time, so may wait a bit for that too. But I do look forward to having a bit more grunt and speeding up things a bit. But if hshe blows up I'll be doint something quicker.
Thanks

 

[redprospector]

Going from a 25 hp to a 35 or 36 hp motor is going to be such a jump in power that I doubt that the torque question will even be in the equasion.
If you can beef the machine up enough to handle it, you'll be smiling with either enging.
As far as reliability, I can't say on the Kohler. I put a 35 horse Brigg's on my chomper firewood processor last winter. It's got a little over 200 hours on it right now with absolutely no problems. It replaced an 18 horse Honda, and I love it. That motor never even grunts.
I got mine from Small Engine Warehouse for just under $1800.00 delivered. You might want to check them out, a couple hundred buck's might help you decide.

Andy

 

[cuttinscott]

Go with the Briggs Big Block, Daihatsu (toyota) actually builds it for Briggs, It is far superior to anything out of the kohler camp. We have sold alot of these and they ear kohlers for lunch. Not to mention durability the friggin kohlers are a electrical nightmare with their magnets falling out of their flywheels and taking out stators, Their head gasket issues, etc. etc. I love going to kohler update schools and learning how they bandaided all the issues of the prior year every year lol. Hell the 25 hp command was junk when it came out and still is today.


Just my .02


Scott

 

[stumper63]

Thanks redprospector.

Cuttinscott,

Thanks for the input. In what way do they "eat Kohler's for lunch"? Is that in terms of reliability or performance? The torque difference (17% more on the Kohler) isn't noticeable to a user? What is the "Kohler school" saying about their larger v-twins like the 36hp? Are they having specific problems?

I guess I don't understand why you say the Command 25hp engines are junk. I've got 2800 hours on my 2003 without any problems, just changed plugs and filters, that's it. Still doesn't smoke or use oil. Heck, when I upgrade I'm hoping to get a few bucks for it. Some kid would probably love to have it on his go-kart. Would you say mine is an anomaly? Seems pretty reliable to me, or are the Vanguards getting alot more hours than that as a rule?

Thanks for the comments, all helpful in the decision-making process.

Stumper63