Balancer pin shearing caught on time.

[Delta.Speed]

So I'm in the process of piecing my engine back together and I was getting ready to set the valve clearances when I ran into this.

I found that the balancer had about 1/2 - 1° of rotarional play on the crankshaft pin. I took the balancer back off and saw whats in the picture. The pin has notches on both sides where the balancer has started to shave the tip off of it. I'm pretty sure that if left uncorrected this would've eventually led to the balancer stripping the pin completely and spinning on the crank. So no way in hell I'm leaving that as is.

So a couple of questions I want to ask on this:

1) Can anyone verify this part number for me? GM 94048159. I think thats the OEM pin.

2) Anyone know how to get that pin outta there? I've read that when its already broken you can punch it in and then retrieve through the bolt hole, but does that work if the pin is not completely broken yet? Will it fit in the bolt hole if it's full sized? I've also read that you can drill it, but if at all possible I would prefer to remove it by punching and not risk damaging the crank.

I know that there are crankshaft pin kits that address this issue, but again I don't like the idea of drilling the crank, so I'm gonna take the expensive route and buy a SoCal balancer that presses on instead of being slip on, but since I've just thrown over $11k at this truck that'll have to wait a bit, which is why I want to replace the pin with the OEM GM part.

Let me know y'alls thoughts on this.

 

[08lmm72mm]

That is the correct part number and you should be able to get it out with a pick or the end of a sharp knife. They aren't too bad to get out. Also, the Socal dampner won't save you for when the oil pump drive gear pin shears. Only way to fix the issue is to have it keyd.

 

[N2BRK]

Or a fixture to add an addition pin. I have the old Empire kit and last I knew XDP was now selling it as theirs.

 

[Delta.Speed]

That is the correct part number and you should be able to get it out with a pick or the end of a sharp knife. They aren't too bad to get out. Also, the Socal dampner won't save you for when the oil pump drive gear pin shears. Only way to fix the issue is to have it keyd.

Can you elaborate on that oil pump pin? I was not aware of any other pin that had issues. Since I'm here I'll probably want to check that one out too. Where is that other pin located?

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[2004LB7]

isn't the oil pump drive gear just behind the balancer? along with the reluctor wheel? and this is pinned too with the same weakness.

 

[Delta.Speed]

isn't the oil pump drive gear just behind the balancer? along with the reluctor wheel? and this is pinned too with the same weakness.

This is the oil pump on my truck. Not sure about other gens as this is my first Dmax truck. I do not see a key for that gear, and upon doing some research I dont think they are keyed. DHD sells this pump upgrade:

DHD 98091552-K High Pressure Duramax Pinned Oil Pump Asm. 2001-2010 LB7 LLY LBZ LMM

Add piece of mind to your Duramax engine build by replacing your stock oil pump with this high pressure keyed oil pump from DHD.

dirtyhookerdiesel.com

On the third photo you can see that the stock gear doesnt have a key on it. May be the reason for the failures. Definitely not wanting to lose an oil pump and/or gears after so much work and money spent, so I will probably order that or something like it once I've gotten some feedback on it from the dudes on here that know their stuff. An additional 15-30% more oil pressure sounds awesome too.

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[Delta.Speed]

Oil pump picture didnt post for some reason....

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[Delta.Speed]

Best damn feeling in the world.... not sure if its supposed to be that way or not but for me that sucker was ON THERE....

Tried the pick, tried the sharp knife and no go. Moved to needlenose, then to square nose pliers and no go. Tried square and needle nose pressure pliers, and still nothing...

Had to drill it out. I used Milwaukee Cobalt drill bits. Started by pinching a hole with a 1/16, then worked my way up the drill bits until it finally spun in place with a 1/8 drill bit. Kept spinning it clockwise as I pulled out and voila....

Side note, I saw a post somewhere that claimed that you can tap them and they come out from the thread side, insinuating that the hole is all the way through.....

The hole is NOT all the way through. It is just deep enough for the key, so you'll be tapping for all eternity and it wont come out the other side.

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[juddski88]

Best damn feeling in the world.... not sure if its supposed to be that way or not but for me that sucker was ON THERE....

Tried the pick, tried the sharp knife and no go. Moved to needlenose, then to square nose pliers and no go. Tried square and needle nose pressure pliers, and still nothing...

Had to drill it out. I used Milwaukee Cobalt drill bits. Started by pinching a hole with a 1/16, then worked my way up the drill bits until it finally spun in place with a 1/8 drill bit. Kept spinning it clockwise as I pulled out and voila....

Side note, I saw a post somewhere that claimed that you can tap them and they come out from the thread side, insinuating that the hole is all the way through.....

The hole is NOT all the way through. It is just deep enough for the key, so you'll be tapping for all eternity and it wont come out the other side.

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You can buy 5mm pins from McMaster for cheap that are harder than the factory pins (or go elsewhere for some even more hardened); also, I know you are leary of drilling the crank/balancer, but the xdp pin kit is your best option to never having to do it again. Even though the ATI balancers are press fit, it isn't nearly as secure as using the pin kit. I tore down my first built motor with an ATI balancer and noticed wear on the key. Not a lot, but it was there.
I have had several LMMs in the last couple years with excess play in the oil pump drive gear keyway/pin. There are a few options to correct it without drilling the crankshaft for a pin.

 

[08lmm72mm]

Can you elaborate on that oil pump pin? I was not aware of any other pin that had issues. Since I'm here I'll probably want to check that one out too. Where is that other pin located?

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It's under the timing cover there is 2 more pins behind the cover. When we found my balancer pin almost sheared we pulled the timing cover and found the one right behind it was almooooost sheared, it's under the gear on the crank

 

[Nate’s Dmax]

Ive got a handful of those OEM crank pins in my shop if you need any. I would advise doing the pin deal like was said. https://www.xtremediesel.com/xdp-duramax-crankshaft-pin-kit-xd331

 

[N2BRK]

If you’re local to NJ, you can swing by and use mine. Same offer for anyone else here.