Animal Thrown Rod, is the rest okay?

[IanCaz]

Hey all, I'm hoping you can provide me some advice. I threw a rod in my kart the other day, getting ready to parade. Was at max throttle & then nothing. Got home, tore it apart, and found that I'd broken my connecting rod. I pulled everything out & there is some scoring on the crankshaft & piston. I was wondering if this looks okay to you guys, or do I need a new crankshaft and piston as well as a new connecting rod?

 

[landuse]

Dang!! That doesn't look good. If it were me I would probably replace all the internals

 

[Kartorbust]

I'd buy all new internals. Can you get us a good picture or several of the cylinder bore?

 

[IanCaz]

I'll snag one of the cylinder bore tonight. Looking in, I didn't see anything. Of course, that being said, I thought the piston & crank were still okay to use, so I'm not the best judge of these things!

Thanks!

 

[karl]

The arc rod uses steel babbit bearings , so the cranks probally damaged , so needs turned down or replaced

By the looks of the piston , the cylinder will need bored over.

So your rebuying the entire rotating assembly and machine work, I would look into a new shortblock, especially if your new to this stuff.

 

[Budget GoKart]

What happened did you even have oil in it? Dang thats some misfortune if ive ever saw it. That really sucks i hope you can contact briggs and stratton or whoever you purchased it from ( if you got it new) and get a replacement or parts

 

[JTSpeedDemon]

Jeepers.
Animals are $700 brand new!
Hope you can get it runnin' again!

 

[IanCaz]

What happened did you even have oil in it? Dang thats some misfortune if ive ever saw it. That really sucks i hope you can contact briggs and stratton or whoever you purchased it from ( if you got it new) and get a replacement or parts

I actually got it used from a friend of a friend, so no warranty. I installed it 2 weeks ago, drained & filled the oil just after I put it on my cart. When it blew it was the 2nd time I had run it with the "new" motor.

 

[Kartorbust]

He must've really beat the crap out of it, if the piston and and crank were that badly scored. Long as the block can be salvaged, you can rebuild it to be better.

 

[Budget GoKart]

Aw dude that really sucks

 

[itsid]

that sucks indeed (we call that naturally aspirated )

Anywhoo.. piston and crank need to be replaced
(well crank might be serviceable but tbh it's just as expensive as buying a new I'd say)

By the look of that piston, chances are your cylinder wall needs more than a quick hone to be useable again I'm afraid;
I too think the next oversize bore is likely due

Unfortunately there is no way to tell if you caused that or the PO...
if it ran fine on day one.. chances are it's been you..
Although that crank looks like it ran w/o oil for a few hours to me... but maybe the scars match the now broken conrod... can't tell

Sorry, but if you do not have the tools and experience you might want to start over instead
but first get a quote from a machinist, maybe you're lucky enough *shrugs*

'sid

 

[IanCaz]

That's the worst part, not knowing if it was me or not. Like I said, I drained & filled it with oil right after installing it, so it wasn't running dry. I think I had maybe 2hrs runtime on it total.

Ah well, it's a learning experience, right? Either don't buy used engines, or if you do, pop it open, look at it, and make sure everything is up to snuff!

I forgot to post the cylinder pics last night. No good news here it seems. It may be time to try out a predator until I get the funds together for a new Animal.

 

[karl]

https://www.ebay.com/i/283553619030

https://cometkartsales.com/555715-Briggs-LO206-Sealed-Short-Block.html

https://www.dynocams.com/item/555715/

 

[IanCaz]

https://www.ebay.com/i/283553619030

https://cometkartsales.com/555715-Briggs-LO206-Sealed-Short-Block.html

https://www.dynocams.com/item/555715/

Wow, I didn't realize that was a thing! And the Lo206 & Animal lowers are the same? I'm obviously a noob & appreciate the info.

So, all I'd have to do is:

• Buy this
• Move all my other parts over
• fill it with oil

Then I'm good to go?

---------- Post added at 02:06 PM ---------- Previous post was at 02:02 PM ----------

Sorry, but if you do not have the tools and experience you might want to start over instead
but first get a quote from a machinist, maybe you're lucky enough

You don't get experience without trying things right? But I definitely don't have the tools to hone the cylinder and fix the cam. So it would either be replacing parts, or buying new & starting over.

After seeing karl's post, I'm curious about replacing the bottom half entirely. Then I've just got to worry about the valves.

 

[JTSpeedDemon]

Yep, your 3 steps should result in a healthy ANIMAL!

 

[karl]

Im no expert, but this is what I read on Aussiespeed's site

The Briggs & Stratton Local 206 Racing engine uses the same cylinder head, valve train and camshaft and short block as the other models in the Animal family. The LO 206 or Local Option engine is a 12 cubic inch 206cc engine with a forged steel 3/4 crankshaft PTO, squeeze cast conrod and performance camshaft. Its different features to other members of the Animal family is it is designed for class racing. The PVL ignition coil limits the Local 206 engine to 6100 RPM. The Briggs & Stratton Local Option 206 engine block is fitted with two Anti tamper engine side cover seals to prevent modifications & is supplied with an engine build specification sheet to keep the rule set for class racing and competitors on an even level. The Briggs & Stratton Local 206 racing engine can be used on both dirt & bitumen tracks & has standard features included with every engine. Below are just a few of the components used in the Briggs & Stratton Local 206 race engine.

High RPM rated flywheel, fixed rpm limited PVL ignition coil, heavy duty blower housing, forged steel crankshaft, camshaft compression release for easy starting, Anti tamper engine block seal, Factory engine specification build sheet.

 

[Hellion]

Is the cylinder bore actually scored or is it just "smudged" by the aluminum piston?

Furthermore, it's a steel/iron cylinder liner, is it not? Steel being harder than aluminum, it might be fine after some honing, as long as it didn't suffer ring damage.

Typically when the rod goes, it's a result of oil starvation and the resulting high heat/friction bonds the rod material to the crank journal; melts it and it eventually seizes and stops suddenly, usually with a bang.

 

[itsid]

You don't get experience without trying things right? But I definitely don't have the tools to hone the cylinder ...

VERY GOOD POINT!
A three stone honing head is not too expensive...

might be worth to give it the cylinder a good clean (brake cleaner) and then a gentle lick with the stones to try..

That way you at least got a new tool, and maybe learned a few things in the process..
maybe watch a video or two about how to hone a cylinder the proper way
and if you're lucky the cylinder wall will reward you with NOT being all chewed up..
and that's all you need already
It might not be perfect in the end, but if it's good enough to be useable,
maybe that's all you need for now
crankshaft is a whole different game I'm afraid...
you need a really good lathe to do it correctly (that's still really straight and true running), and that alone is no tool that comes cheap or should be handled without proper training (and experience)
A Lathe can kill you rather efficiently if it gets the chance

Also: the other side of your cylinder wall looks very nice, with all the crosshatching still visible and such.
Sooo I'm afraid that leads me to conclude it wasn't POs fault.
Or say.. I doubt the previous owner knew that this is going to happen soon.

If it ran w/o oil (as the crankshaft suggested) the crosshatching would've been gone as well IMHO..
So more likely it's been 'just' the failing con rod.
And while that could've been the fault of whoever installed it.
It might not have been foreseeable at all

'sid