Archive through May 20, 2013

[lbuttke]

I will be working this holiday weekend,
however it will be at the Veterans home at Chippewa Falls Wi.
I am reminded every day what happens to our elder veterans, 4 of them have made the finial voyage since I started work back in March of this year.

 

[bbranstetter]

Here's a picture of the motor going back in before she broke the rod. Sure looked good after that seal job and oil filter upgrade. Took the filter assembly out of a Mag 15, just had to knock out a new hole location for one of the oil lines. Turned out good.

Had my Dad pull the shroud off of the other side of the motor to inspect the block. He said there was no damage, or at least external. I looked at one side but forgot about the opposing side. I'm praying for just rods needing to be replaced.

 

[kide]

Brian:
I don't have any experience with the Mag series, but your comment about the oil line makes me wonder if you were sure of full oil flow through that remote oil filter. Snapping a rod is consistent with oil starvation on the rod journal. Just a thought......

 

[sblunier]

Brian,

4 bolts take that fuel tank off.......worth it to avoid the BS of uncoupling the engine in a space the size of a Dixie cup........

 

[bbranstetter]

Yup. She had oil, cracked open the return line to check and the filter was full. Would getting the lines full be too much for it to handle? I cranked the motor with out starting it to purge the lines as much as possible, maybe that was too much for it.

Steve-

LOL. Its not too bad, only took me a few minutes to get it apart.

 

[sblunier]

Coincidence.......rebuild and run........

...I take that back....it's possible that you lost enough oil out of the failed rear main seal to starve the rod before you made the repair, and it just failed shortly thereafter.

Any way you look at it, you will need to tear it all down and will have a chance to inspect ALL of it, including the oil pump, governor, etc.

Small syringe, used for kids medicine, makes a great tool for applying the silicone to the halves of the crank case upon reasssembly....

 

[mgerecke]

Has anyone ever looked into a rod that uses bearings like a car for these Cub engines? Seems like it would be a good idea. I have noticed on more than one Cub of mine that they seem to have the Kohler knock at slow speed. I had my 1250 motor bored and the crank turned and it still does it!

 

[jchamberlin]

Mark: I think it has been discussed before on the Forum, perhaps in the "Pulling & Hot Rodding" section or in the "Cool IH Cub Cadets Not OEM but better'n' new ! ! !" section. Maybe Nic Bextermueller will drop by and educate us all on the topic.

Under Edit: The issue with rods is that their failure is not simply due to a lack oil (although that will certainly do it too), but the fact that the metal in the rod can only convert the vertical force at the piston to the rotational force at the crank so many times before the metal fatigues (at least as I understand it). The forces active in a reciprocating engine are fascinating: it takes some pretty sophisticated calculus (as well as algebra, geometry, physics and metallurgy) in order to take them all into consideration.

Also under Edit: I'm taking Brian's story as a cautionary tale regarding my own struggle to get an M18 going in my 782. I was considering "getting by" without going the "the whole 9 yards," but I think I had better try to find a couple of rods if I want the engine to last any time.

 

[bbranstetter]

Steve-

Good advice on the syringe. Thanks.

It does seem to be a coincidence and I have wondered about how much impact that seal might have played in the whole mess. Being that the engine was hot maybe it dropped pressure long enough to stress the rods out and caused the failure.

The service manual states that the KT17 rods are cast as opposed to forged. I'm guessing that they are talking about aluminum?

 

[sblunier]

Mark,

That could be the cam end play adjustment causing the knock (common and often overlooked), piston skirt slap,....or the PTO clutch.

Brian,

Yes, they are made from AL.

Jeremiah,

Yes, they have a finite life, and yes they will eventually break...BUT, additional stress caused by lack of lubrication at the rod journal would certainly be an "accelerated wear" factor on a used rod....if it's tight on the journal it wants to bend not pivot.....lots of extra stress.....

Can't say that the seal was the cause, could be pure coincidence....BUT, it likely didn't help any either

 

[kide]

Pullers do use rods with inserts (see Brian Miller's website, but I don't see an advantage in stock applications. They are using them in high load, high RPM, high horsepower situations. Face it, literally billions of hours have been put on small engines, used within the intended design parameters (and abused in a lot of cases) and typically they wear out and get thrown away without the rods letting loose, all on non-insert rods. Brian, you probably touched on another point that could have been the issue - these ARE cast rods and along with the "finite" life of any aluminum rod, a non-forged, cast only rod can have casting defects (stress risers, etc) that weaken the rod and could cause it to break. One of the reasons Hot Rodders polish even forged rods is to get rid of scratches that can initiate stress risers. I agree with Steve - s%$t happens, sometimes for no discernible reason - rebuild it and get to mowin' ..

 

[mmasheris]

I have had the machine shop put inserts in some of my single cyl Kohlers due to the fact I had the crank .020 ground and only .010 rods .I have had them run many hours with no knock.

 

[bdmiller]

Hey guys, anyone ever used the water and dawn dish soap trick to weight tires? Everything I've read says the soap prohibits rust and keeps the water from freezing. I need some weight in my tires on the 122 and would like to get any opinions from fellow cub nuts before I actually do it. Thanks

 

[bbranstetter]

I really think Steve is correct in the thinking that it was just its time to break. But it still leads me to wonder if the replacement rod(s)are going to be finite in there life? Would an after market part be a better option? I've always used genuine Kohler parts as much as possible but maybe there is some thing better in this case.

 

[rbeem]

Brandon,

Just use RV antifreeze (in an inner tube) and be safe. It is cheap enuff and safe.

 

[sblunier]

You'll wear out the bores/rings/pistons in a Mag 18 before you break the 2nd set of rods.......

 

[bbranstetter]

I wish I had the Mag 18.

This is the KT Series II but there pretty close to the same other than there ignition systems, right?

 

[bjamison]

The 126's engine now turns over when I hit the key. Heart/engine transplant may be starting to work - YIPPIE!!!!!

The problem was not the ground. Turns out the battery was weak. It had enough power to click the solenoid, but not crank the engine. This battery came with one of the tractors I picked-up and when I looked at it, it is a 195 CCA battery. I had put a charge on it prior to using, but maybe the charge wasn't so good. Last night I put a 2 amp charger on it and left it overnight. This morning, it cranked over pretty strong. Tonight I might try to get some gas in the tank and see what I've got.

 

[dtanner]

Bill Jamison

Most of my Cubs have the 340 cc batteries in them. the less amp ones are not worth buying I have found.

 

[nbextermueller]

Mark and Jeremiah,

On the topic of rob bearings, yes we do use them in pulling applications. But not 100% because of the wear properties. We use them because most pullers use a custom forged or billet aluminum rod that can cost a couple hundred dollars. If we have a problem in the rotating assy, it's alot cheaper to replace an $8 bearing than a $200 rod because it got scored. Think of it as insurance.

Although they would be nice, bearings aren't necessary in stock engines. As stated below, working inside the intended work limits, the stock rods can last decades.

Secondly,the know bearing only fits the 12-16 singles, and finding a machine shop with a small enough tooling kit to bore the rod is hard. I have a bearing in my stock 128. And the aforementioned Brian Miller did it for me. Let's just say it was "less than perfect" and I had to adjust things to get the clearances right. I won't go that route again.