Which Engine to rebuild?
 

I have a 1000 and a 1650. The 1000 recently broke a rod (previous owner ran it w/o oil) and the 1650 smokes really bad (looks like rings)
Anyway this got me thinking... which is the best "quietline" engine in everyone's opinion? I know the 1650 vibrated like an SOB... the 1000 I've had were smoother. So where do these engines go from smooth to rough? What is the sweet spot?

I'm only going to rebuild (or replace) one of them and I'm open to any of the engines.

Thanks

The 1650 gets smoother @ wide open throttle.
It vibrates because it is a big single.
If you want a smooth engine at any rpm, get an opposed twin. :beerchug:

LOL well that wont fit easily in my Cubs.

My 1650 was never smooth. Even at WOT. I've read this is a common problem with them. Myth? Truth?

1650 has a bore size of an early small block chevy.
It vibrates like a rigid frame Harley.
Going to a spread frame 82 series opposed twin, compares to a gold wing.
No big bore single is going to be without serious vibrations.
I have one, it vibrates, that is why I keep it only as a back up mower or loaner.
The 782 with power steering does mowing chores,--- about 100 hrs a year:beerchug:

OK so where is the sweet spot? If the 1000 is (relatively) smooth and the 1650 is a thumper... do I stick with the 1000 or can I go to a 1200 and be happy?

What I'm getting at is that I have the option of putting any engine in the tractor I keep. I want more power if I can get it without massive vibrations.

it depends on what your power requirements are, seriously.:bigthink:
throwing snow you want mucho power.
A 50" deck can use the bigger engine but a 12 hp is absolute minimum.
But there are fellows that go slower or mow often, or have a smaller deck.
sort of common sense here.
Some fellows don't have a problem with shake rattle & roll.
some rigid mount them and swear they are better, others, no way and rubber mount them.
I have my 1650 on rubber mounts and it is manageable but to say it is even remotely smooth is just not true.
The best system of mounting the big kohler singles is what Deere does.
They set it on rubber mounts @ the crankshaft center line and set it with the crankshaft left/right not front/back like cub.
they still vibrate, but more like a small bore engine.

I've noticed from my work on these tractors, that a lot of vibration perceived as coming from the engine. It can be calmed down A LOT by going thru chassis and getting rid of all of the "slop" in linkages and such, like mounts, flex disc joints, clutch linkage, etc. Add the Cradle modification while you're in there.

I have been thru 2, 1200 in recent years. I tried solid mounts in 1st one, and it about rattled my teeth out. I had done the clutch with a new driveshaft and solid mounts. Those solid mounts stayed in the machine about 10 minutes. I put sway bar link bushings in it from a car for mounts and it was much better but not completely so. That made it "tolerable", didn't know about Cradle mod then.

On the 2nd 1200, which got a complete engine overhaul besides the clutch job, also got those solid mounts that were "too much" for the 1st 1200, put into it. . A lot better almost from the get go, but not totally smooth. Tractor owner (same guy owns both, and no/ its not me) was not very nice to this one when he got it back. I went thru the clutch in short order (he likes to run 3rd gear in shin-high grass) and more blade drive belts than he should have eaten up in that amount of time, as well went with HD "pulling" pressure plates and driver, right off the bat. and the cradle mod.

When I went thru the clutch the 2nd time, I replaced the pressure spring with a "blue" one, replaced everything in the driveline between the 2 clutch jobs but the drive shaft itself, it was still fine. (surprisingly didn't show any wear where it goes into hub on flywheel, which was where the wear was on the 1st tractor)

I reused the "pulling" pressure plates and driver that I put in on the initial clutch job. I remember having to replace the driveshaft in the 1st 1200, when I had done that one a few years prior.

I found slop in frame on 1200 #2 where clutch arm shaft goes thru there, clutch fork needed some re-welding and re-drilling plus added some stiffening. I welded some steel bushings to clutch hanger and clutch fork at the pivot, and a few other spots I never really thought to look. The clutch fork pivot shaft was wallowed and worn down too. I tightened up all of the worn areas, reassembled with those same solid mounts that he wasn't happy with on the 1st tractor, changed out the engine oil pan to cast iron, and WOW I was amazed, what a difference between the 1st time thru the clutch, and the 2nd time thru it all. The difference between the 2 1200s is huge. A lot less vibration in the most recent clutch job on the 2d 1200. I didn't even think to check that stuff out, when I did the repairs on the 1st 1200, back then.

Remember the 1x8s and 1x9s have the engine solidly mounted from the get go, and don't generally shake so much. So there is more to vibration reduction than just the engine itself.

I have a 12hp version, a 14hp version, and a 16hp version, in a competing brand of tractor, that is likewise shaft driven/ all Kohler K series engine powered like these Cubs. All engines solidly mounted (Ariens) and none of them vibrate like that 1st 1200 did, when I tried mounting that engine solid. Yet the 2nd 1200 never was as bad when mounted solid, with either iteration of the clutch job. Same tractors, same model engine same everything.

Figure out your hp needs. I love hp but those 16hp singles really love their fuel. Almost as much as mag 18. Mike:biggrin2: PS i'd still rebuild any 16 also.

Actually,
I did a unscientific comparison of both my lawnmowers.
The 1650 Vs the 782 mag 18 while mowing the feedlot of old.
The grass there is heavy, so both were exercising the governor.
Power ways the big single seemed to keep the exhaust note the same,
as it encountered heavier grass.
The Magnum noticed the change with a different note, more of authority than anything else.
As far as fuel consumption, the 1650 seemed thirstier but given it has a tank of approx 1/2 the capacity of the 782, @ the end of the day, I honestly could not tell any difference.
What I do notice is, just putting along @ part throttle, like picking up sticks or visiting the neighbor, is seems to use more fuel and is not as pleasurable to drive due to vibration.
I have equipped both with power steering so there is no difference in effort to maneuver,
and both have the super-steer front axle, so steering radius is reduced equally.
To sum it up, I prefer both my 782 opposed twins, to the 1650 due to the fact they feel gentler/quieter/more user friendly.
( and they are red) :biggrin2:
Just opinion, your mileage will vary, no animals were maimed or used for
experiments and no little children were scared of otherwise harmed.:beerchug:

My 1650 runs as smooth as my 1450. One of my 1200's shakes more than his big brothers.