Yet another balancer gear failure M16

[AlexR 2,949]

A friend gave me this engine that I assume the balancer gears let loose first and broke the rod.

What's interesting is I am finding no damage on the camshaft

 

Or anywhere on the block other then maybe a few scuffs. The bottom apron of the cylinder walls are all good no cracks or broken pieces and the oil pan is good as well. 

 

The crank shaft is very galled up with aluminum from the rod, hoping that cleans up good.

 

I was half thinking I could convert the block back to a K series but there is one thing preventing that and that is there is no hole (not even plugged) for the points plunger and no threaded holes for the points or cover either. And I am about 95% sure that the camshaft has a lobe for the point, I can feel a machined surface behind the gear. 

But honestly the magnums ignition system are way better anyway the only thing is I would like the K series tins better, might be able to work a tin to fit. 

 

One other thing I thought I read that the Magnums had 3 balance gears this one had 2, with no place for a 3rd one to even go. 

Edited 18 hours ago by AlexR

[WHX?? 56,624]

11 minutes ago, AlexR said:

no damage on the camshaft

Some one got lucky then. that coulda easily went the other way.

Crank will buff out. 

13 minutes ago, AlexR said:

had 3 balance gears

I thought they only had two. 

[AlexR 2,949]

8 minutes ago, WHX?? said:

I thought they only had two. 

Found where I saw it on garden tractor pulling tips

I missed the part where it says certain magnum engines had the 3 balance gears not all of them.

[WHX?? 56,624]

 learn something new every day. 

[AlexR 2,949]

7 minutes ago, WHX?? said:

 learn something new every day. 

Sure do! Key is to stay humble enough to know you will never know everything, and someone will always know more then you. 

[ineedanother 2,409]

I've never done a bunch of forensics on failures but it looks like the rod was destined to fail regardless of what might have been going on with the balance gears. I'm wondering if the oil had ever been changed or occasionally checked.

[WHX?? 56,624]

1 minute ago, ineedanother said:

oil had ever been changed or occasionally checked.

Good point Ineed 

Edited 17 hours ago by WHX??

[AlexR 2,949]

I was kind of wondering if possibly the rod went first, due to the amount of galling. But that's crazy that it would take out both balance gears and nothing else.

I don't know on the oil part the small amount of oil left in the pan was obviously dirty and full of metal but that doesn't really mean anything in this case. 

[WHX?? 56,624]

2 minutes ago, AlexR said:

that's crazy that it would take out both balance gears and

Luck of the draw when a rod goes it generally takes out the cam or goes the other way and hole the block. Balance gears might have saved the block so they are good for something.

Kinda like when lightning strikes ... all bets are off on what's gonna happen. 

[JoeM 9,973]

5 hours ago, AlexR said:

I was kind of wondering if possibly the rod went first, due to the amount of galling.

Great point! 

There is no way the crank got like that because the gears broke. They used the wrong brand of oil, "lack of" 

[ebinmaine 78,973]

@Bill D and I were talking about the Magnum balance gears. 

He and I have both read that they can't be run without them.  Perhaps this two vs three gears is the difference.  

[ri702bill 12,167]

I too agree that looking at the crank journal, the rod siezed up first, broke, & took out the grenade gears - in that order.

Plan on rebuilding it?? I am skeptical that there is no damage to the cam - wash it down with BrakeKleen until it is shiny, let it dry & look closely at it with good illumination to check again. Rotate it & check again...

Looks like there are 2 ways to go - The "Low Budget, no Budget" slap it back together & pray method, or a total dis-assembly & inspection prior to measurements and addressing all the issues. Your choice. I suspect the ball bearings may be nicked & due to be replaced anyway.

 

[AlexR 2,949]

50 minutes ago, ebinmaine said:

@Bill D and I were talking about the Magnum balance gears. 

He and I have both read that they can't be run without them.  Perhaps this two vs three gears is the difference.  

I'm thinking the same thing, that a 3 balance gears can't be run without them without balancing the crank itself. But ones with 2 balance gears can be ran without the gears. 

[AlexR 2,949]

6 minutes ago, ri702bill said:

I too agree that looking at the crank journal, the rod siezed up first, broke, & took out the grenade gears - in that order.

Plan on rebuilding it?? I am skeptical that there is no damage to the cam - wash it down with BrakeKleen until it is shiny, let it dry & look closely at it with good illumination to check again. Rotate it & check again...

Looks like there are 2 ways to go - The "Low Budget, no Budget" slap it back together & pray method, or a total dis-assembly & inspection prior to measurements and addressing all the issues. Your choice. I suspect the ball bearings may be nicked & due to be replaced anyway.

Once I get the crank cleaned up and get measurements on that and the bore I will go from there. 

I did rotate the cam to check all the sides but yes if I use the engine I will check closer, the cam needs to come out to replace that crank bearing anyway.

 

It's probably unlikely but if the crank is still within spec I may just use the crank on a K321 block I have. 

I have a feeling the bore in this M16 is out of round to much to just throw back together.

[ebinmaine 78,973]

3 minutes ago, AlexR said:

bore in this M16

Do you have usable machine shops nearby?

[AlexR 2,949]

33 minutes ago, ebinmaine said:

Do you have usable machine shops nearby?

Not really, closest one that I know of is about a hour away. 

[ebinmaine 78,973]

21 minutes ago, AlexR said:

Not really, closest one that I know of is about a hour away. 

 

 

 

That's not a big deal. In fact it's an old joke up here in Maine. "Everything's an hour."

Obviously not true anymore but...

I drive 33 miles one way to get to work so I understand the logic better than most.

[Wild Bill 633 935]

9 hours ago, WHX?? said:

Crank will buff out.

Use muriatic acid to remove the aluminum from the crank.

[AlexR 2,949]

37 minutes ago, Wild Bill 633 said:

Use muriatic acid to remove the aluminum from the crank.

I think I will try the lye method, would rather not mess with muriatic acid if I don't need to. 

[953 nut 66,249]

Sodium Hydroxide eats aluminum and is not harmful to steel. Years back I had a large heated tank filled with 10% Sodium Hydroxide for rust removal on automotive body parts. Unbeknownst to me one pair of front fenders I put in the tank had aluminum headlight buckets, when I pulled them out there was nothing there.   

[ri702bill 12,167]

Sodium Hydroxide - aka Oven Cleaner??

[AlexR 2,949]

1 hour ago, ri702bill said:

Sodium Hydroxide - aka Oven Cleaner??

Yes or drain cleaner. 

[Goldnboy 1,117]

Is it possible the oil sensor broke and the plastic jamed the balance gears?

 

I just recently rebuilt a K321 that had green plastic all over inside in a previous post.

[8ntruck 8,903]

I'd use dye check on the cam shaft to look for cracks.  Another possibility would be to take the camshaft, and maybe the block to a shop that has a magnaflux system to have them checked for cracks.

 

I think the rod went first.  The fracture surface on the balance gear looks like a brittle fracture - looks like it broke all at once.

Edited 1 hour ago by 8ntruck