K241 winter project.

[slim67 2,735]

I picked up a C-101 last summer with a broken connecting rod for a little less than scrap in otherwise decent shape and complete. I had a little time today to pull the head and see what happened. I put compressed air into the oil fill hole to pop the piston out. I fished all the broken pieces out and felt the cylinder skirt which was intact. Now time to pull engine and disassemble. Hoping to be able to get it back into shape. Fortunately the crank journal looked good to boot.

[Snoopy11 5,714]

 

@Snoopy11 is in. Looking forward to this, @slim67

 

I'll be around, and am a pretty friggin' good engine builder, so if you have any questions/things you need, you lemme' know! 

 

Don

[Snoopy11 5,714]

It'd be a good idea to soak that crankshaft in muriatic acid if you don't have other plans with it...?

 

Don

[sparkie333 265]

11 minutes ago, Snoopy11 said:

y friggin' good engine builde

 

so can I jump in and ask a question engine related but no on topic----I need to find a muffler like this one for a 16hp WH do you know where I can pick one up?

[slim67 2,735]

15 minutes ago, Snoopy11 said:

It'd be a good idea to soak that crankshaft in muriatic acid if you don't have other plans with it...?

 

Don

Thanks don, yes muriatic acid is on the list. I got to get it apart first but I have a good feeling based on what I’ve seen so far. I’m like you, I like messing with engines too. 

[Gregor 4,846]

That's the brokenest broken rod I have ever seen. Looks like the rod cap bolt on the left is broke. Where's the rest of it?

[ebinmaine 67,593]

36 minutes ago, sparkie333 said:

 

so can I jump in and ask a question engine related but no on topic----I need to find a muffler like this one for a 16hp WH do you know where I can pick one up?

That for a C165 black hood?

I've got one I'd sell for cheap like. 

 

[ebinmaine 67,593]

30 minutes ago, Gregor said:

That's the brokenest broken rod I have ever seen. 

That's about what I was thinking too.  

 

 

[slim67 2,735]

33 minutes ago, Gregor said:

That's the brokenest broken rod I have ever seen. Looks like the rod cap bolt on the left is broke. Where's the rest of it?

I think that’s all of it but I’ll know better when I open it up. Hopefully this week.

[sparkie333 265]

3 minutes ago, ebinmaine said:

ve got one I'd sell for cheap like. 

 

 

Yep it looks like it would fit my C160 -----what u think I need to get one

[Gregor 4,846]

6 hours ago, sparkie333 said:

 

----I need to find a muffler like this one for a 16hp WH

Which 16 HP do you have?

 

C-160

 

C-165

 

WH 16 may have yet another part number.

Should have read closer. I see now you have a C-160

Edited November 29, 2021 by Gregor

[ebinmaine 67,593]

8 hours ago, sparkie333 said:

 

Yep it looks like it would fit my C160 -----what u think I need to get one

 

I'll send a PM so as not to interrupt this thread. 

 

[squonk 41,150]

10 hours ago, Gregor said:

That's the brokenest broken rod I have ever seen. Looks like the rod cap bolt on the left is broke. Where's the rest of it?

Honorable Mention!

 

 

[Gregor 4,846]

5 minutes ago, squonk said:

Honorable Mention!

My broken rods have always been in 2 or 3 pieces. Maybe they aren't rally THAT broke. Maybe I could JB Weld them back together.

[Maxwell-8 4,277]

On my self of shame: 

The middle section of the rod flew out the block to be never seen again. 

The oil dipper disintegrated 

 

[ri702bill 8,328]

Goes without saying, but - take a good look at the block and the camshaft - cam is cast iron and does not tolerate impact - any evidence of it being struck by the rod fiddeleybits as they whipped around and I would not trust it.

Bill

[ri702bill 8,328]

@squonk

I look at that oil pan and it looks more and more like an open casket holding the remains of the recently departed ...... I've seen a similar view on a C81 K181 I got as a package deal a few years back.

Bill

[slim67 2,735]

11 minutes ago, ri702bill said:

Goes without saying, but - take a good look at the block and the camshaft - cam is cast iron and does not tolerate impact - any evidence of it being struck by the rod fiddeleybits as they whipped around and I would not trust it.

Bill

I certainly will. I looked down and inspected the crankshaft cam drive gear and cam gear which were also intact. But again until it’s apart and all cleaned up in the parts washer, who really knows?

[squonk 41,150]

27 minutes ago, ri702bill said:

Goes without saying, but - take a good look at the block and the camshaft - cam is cast iron and does not tolerate impact - any evidence of it being struck by the rod fiddeleybits as they whipped around and I would not trust it.

Bill

Yes! Keep an eye out for stuff like this! 

 

 

[ri702bill 8,328]

@squonk Doesn't that just burn your biscuits when that happens to a virgin stock bore block??? The C81 block I mentioned was just that - except it had a hole thru it the size of my fist where most of the rod went out.

Bill

[slim67 2,735]

2 hours ago, squonk said:

Yes! Keep an eye out for stuff like this! 

 

 

The skirt looked and felt good thank God.

[Snoopy11 5,714]

16 hours ago, Gregor said:

That's the brokenest broken rod I have ever seen. Looks like the rod cap bolt on the left is broke. Where's the rest of it?

 

15 hours ago, ebinmaine said:

That's about what I was thinking too.  

 

 

 

5 hours ago, Gregor said:

My broken rods have always been in 2 or 3 pieces. Maybe they aren't rally THAT broke. Maybe I could JB Weld them back together.

 

5 hours ago, Gregor said:

My broken rods have always been in 2 or 3 pieces.

 

5 hours ago, Maxwell-8 said:

On my self of shame: 

The middle section of the rod flew out the block to be never seen again. 

The oil dipper disintegrated

Guys, ain't no rods get broke worse than those in racing engines. This is a little hard to see, I know, but the bottom of the rod is laying under and to the right of the crank.

 

Zee rod against the cylinder wall...

 

 

 

Pretty bad, eh...? 

 

That engine was completely rebuilt, ARC rod installed, crankshaft journal cleaned. PURRED like a kitten.

 

I sold that engine, GOD it was awesome once it was fixed.

 

Don

 

 

 

 

 

[Snoopy11 5,714]

17 hours ago, slim67 said:

By the way, Slim, that is exactly how my Techy 6 hp engine's rod looked. Kinda like deja vu... 

 

Don

 

[Gregor 4,846]

So what do you all think is the main cause of broken rods ? Engine revving too high?  Metal fatigue? Bolt failure? Under designed? Weakest link in the motor?

[Snoopy11 5,714]

3 minutes ago, Gregor said:

So what do you all think is the main cause of broken rods ? Engine revving too high?  Metal fatigue? Bolt failure? Under designed? Weakest link in the motor?

Lack of oil clearance. 

 

I have screamed it on the rooftops for as long as I can remember... quality oil. These little engines are dependent on oil for survival. If, at any time, that crank journal is not lubricated properly, it is game over. It isn't really the fact that cast rods can't handle rpms, it is the fact that the design of the rods are limited, On vehicles, we see babbitt bearing inserts, and this is also the case in performance small engine builds. However, without proper oiling, even the babbitt bearing inserts are useless. 

 

These engines will sit and run at 3,600 rpm from now until doomsday. However, you start adding strain, torque, lugging, etc... to the mix, this is when rods get stressed. The more you stress the engine, the harder that rod at the crank journal is literally forcing itself against the crank. If your clearances are not correct, for whatever reason... that engine is a ticking time-bomb. 

 

Due to the normal wear of the rod at the crank journal, the rod opens a gap in the rod journal, causing the rod to slap the crank journal, rather than smoothly pushing it. Cast rods will not survive this.

 

Then, when they break in one spot, as the engine continues to revolve, while it is dying, the rod gets hit again by the crank, causing it to break in multiple places. 

 

So, in other words, wear over the years is what causes rod breakage in older engines. Incorrect oil clearances due to wear (such as aluminum on the crank journal) can cause excess heat at the crank journal, which these cast rods cannot abide. I think, what happens is... due to lack of oil at the crank journal, the aluminum rod bearing contacts the crank journal directly, causing the rod to heat and wear (basically grinding the aluminum off the rod), causing an opening gap of the rod at the crank journal. This causes the crank "slapping" I mentioned above... which is detrimental to the rod. 

 

Don