K161 vs K181 Reliability?

[Crmaverick 91]

Im curious if theres any opinion out there on if the K181 sacrificed some reliability with that extra 1/4” of stroke more than the k161 has?
Any other noticeable differences? 

Does anyone own both and notice any difference? 

[Stepney 2,354]

Both are just about bombproof honestly. The 161 is just a little smoother running I find, otherwise nothing to note. About the only failure I've ever seen on small kohler engines is the tab for the governor.. more commonly on the small ones too. Strange. 

[WHNJ701 4,165]

Both are great, the k181 in my 854 had a stuck exhaust valve when I got it, some pb and freed up, been purring like a cat ever since, the k161s I have are pull starts which start with barely a tug.

I am working on a k160 now let's hope it behaves, it has the scary bendix coil set up.

I have a bunch of k90/91s some have gov issues but I think in the past they were ran hard by who ever had them

[adsm08 3,237]

The K181 likes to have oil. This seems to be important.

 

I have no experience with the 161, but I assume it would be the same.

[Crmaverick 91]

3 hours ago, Stepney said:

Both are just about bombproof honestly. The 161 is just a little smoother running I find, otherwise nothing to note. About the only failure I've ever seen on small kohler engines is the tab for the governor.. more commonly on the small ones too. Strange. 

That’s interesting, must be from the shorter stroke 

[adsm08 3,237]

7 hours ago, Crmaverick said:

That’s interesting, must be from the shorter stroke 

 

Possibly.

 

Larger displacement engines with low cylinder counts and no opposing cylinders (so single cylinder or In-lines) often have poor NVH qualities. That's one of the things that led to the demise of the I-6 and I-8 engines.

 

The 2.5L I-4 in the 2wd Ford Escapes had an engine vibration damper that was huge and I still had a lot of people come in complaining that it was a rough engine, especially at idle. They were just kind of buzzy.

 

Engines with opposing cylinders, so V configured, or Boxer engines, balance better because there are pulses coming at the crank from opposing angles.

[Pullstart 66,712]

I don’t know as if anyone could really feel a butt dyno difference between the two, overall.  

[oilwell1415 563]

On 12/19/2020 at 5:19 AM, adsm08 said:

Larger displacement engines with low cylinder counts and no opposing cylinders (so single cylinder or In-lines) often have poor NVH qualities. That's one of the things that led to the demise of the I-6 and I-8 engines.

Actually, those two types of engine are naturally balanced and are about as smooth as you can make an engine.  They went away because they were difficult to package.

[adsm08 3,237]

1 hour ago, oilwell1415 said:

Actually, those two types of engine are naturally balanced and are about as smooth as you can make an engine.  They went away because they were difficult to package.

 

Naturally balanced and poor NVH are not mutually exclusive concepts.

 

The issue is that in larger displacement engines like Ford's 300-6, or the 307-8 Chrysler had the crank was long enough to flex under normal running, which would introduce a harshness to the system that isn't present in a V or H engine. Ford's 6.8L V-10 suffered from the same issue. I-4s do not suffer the same issues because the crank is much shorter.

 

If you really want to go down the rabbit hole look up Ford's T-drive system. It would have been a completely modular power train based off in-line engines. It was abandoned largely over expense as it would have meant major re-engineering for almost every platform they had at the time.