LBZ: LBZ Cracked Block

[coker6365]

As promised. These things do not get spoken of very much so here is one of those unfortunate events...

This is the stock LBZ block with 234k miles. It's been overheated many times along with lots of abuse. First overheating incident was at Ennis, literally boiled coolant out all over the windsheld after 1/8 mile from a split waterpump impeller, found the failure later. Was overheated several times following with 3 total waterpump failures.

Symptoms of pressurized coolant system began after the first overheating incident with minimal change until recently. Engine oil analysis tested positive for coolant after DPC. Made 2 sled pulls to test some changes and symptoms became more severe. Finally began seeing moisture out of the crankcase breather and pushing coolant heavily. Last startup had a slight hesitation on cold start with a very short misfire and white smoke. Never saw and signs of engine oil contamination other than the analysis. After pulling glow plug delets and spinning the engine over, cylinder 6 was puking coolant severely.

No complaints on our end, we knew the risk keeping the LBZ block and not going to an LML or half fill. This thing has absolutely surpassed all expectations and performed phenomenally well in Denver. It's all part of pushing things to the limits.

Block/Rotating Assy Specs
.020 Mahle Forged (Roughly 15:1)
SoCal 14mm Head Studs
SoCal Billet Narrow Rod Crank
SoCal Girdle & Billet Mains
Carillo Rods
9100AF Cam
SoCal Valvetrain
SoCal Balancer & Flexplate
SoCal Stage 1 Heads

Air/Fuel
472/87/1.0 & 491/100/1.45
F1 250%
Dual 10mm Pumps

If your still reading, send this cracked cylinder pic to your wife and remind her that even a few inches can be painful.

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[Ne-max]

Does this mean you're buying my engine?

 

[coker6365]

I already told you. Send it to me, I will ship the pieces back after Denver.

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[Ne-max]

Send me that cash bub. Proven set up.

 

[coker6365]

Jackstand racing is not proven!

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[Don@F1]

Maybe sleeve that block and keep going?
Cummin guys use Darton, Powerbore and a few other companies for a supplier.
I cant imagine a high powered cummins that would not be sleeved in todays world and live too long.

 

[coker6365]

We will have to do some digging on the sleeves. Not sure I have seen anything on it for the duramax blocks. An LML block would certainly be an upgrade from what we have though.

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[Don@F1]

LA Sleeves makes a Duramax part.
Stay away from Melling though if you go with sleeves

On the deckplate stuff you always sleeve em, but that requires longer head bolts and pushrods, so a little more expense. Im not sure how that would effect the intake and other bolt ons either.

 

[JoshH]

I remember seeing fleece had played with sleeves a few years ago, but I never really heard much about their big bored and stroked engines after the initial announcement.

 

[Chevy1925]

Sleeving will work for sure but the block will need to be bored to .040 possibly. The moment you press the old sleeve out and a new one in, it distorts the cylinders next to it a couple thou. Unless you can get away with more piston to wall clearance as it sits

 

[Don@F1]

One caveat; dont use repair sleeves. Use the good stuff made for performance. LA Sleeve, Powerbore, Darton. Those can take a lot more cylinder pressure.

 

[duramaxzak]

I had a sleeve in my old built motor in my pull truck, never had a issue with it. Not sure on brand of sleeve it was.

 

[Tothemax]

think putting 8 sleeves in would bring you to the same cost as a new lml block but if the sleeves can handle more guess it would be worth it.

 

[Chevy1925]

think putting 8 sleeves in would bring you to the same cost as a new lml block but if the sleeves can handle more guess it would be worth it.

i dont believe anyone is recommending that. Fairly certain Richard is just talking about the single sleeve and Don is just cautioning him to put good quality performance sleeve in the cracked sleeve's place.

 

[coker6365]

If sleeves increase the resistance to cracking without any issues related, we be happy to do all 8. Already in the mindset of doing an LML block and possibly half filling. My curiosity on the sleeves is if it prevents one issue yet causes another from material being removed.

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[Leadfoot]

No experience with a DMAX, but I've seen 8 sleeves used in a BIG bore BBC pulling truck where the first sleeve per side was installed and then slightly cut into when installing the next (interlocking) due to the bore size.

It was done because when trying to run that bore on a stock block, the cylinders would distort over the course of a season (maybe 20 runs).


After 3 seasons with the sleeves it tossed a couple of rods and windowed the block, but the bores were still in tolerance. A quality sleeve should be better than the stock cylinder wall.

I don't remember the brand of sleeves used but I know they weren't the economy ones. The big thing is using quality sleeves and proper machining and tolerances. The block was heated and the sleeves were chilled prior to each cylinder install. Because of the size bore and interlocking sleeves, there was a ton of time involved as it had to be fixtured and removed multiple times, but standard sleeves should be able to be machined in one session.

I've seen other blocks with just one or two sleeves beat on during truck pulling and the sleeves were never an issue.

If sleeves increase the resistance to cracking without any issues related, we be happy to do all 8. Already in the mindset of doing an LML block and possibly half filling. My curiosity on the sleeves is if it prevents one issue yet causes another from material being removed.

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[Don@F1]

Throw everything at it. LML block and sleeve all 8 with ductile dry sleeves. That will take your cylinders from roughly 30k psi strength to over 80k psi and add ductility. :thumb: Its also very affordable.

Dry liners still use the parent block material for support Not enough meat is removed to weaken it. The best ones will have a flange at the top. This is because the cylinder pressure is highest up near the top of the bore.

 

[coker6365]

Make it happen Don. Lol. We just need to be able to pour the coals to this thing. I mean, a windowed block is a lot more exciting that just a measly little crack.

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[Chevy1925]

The way I see it, throwing those sleeves in are not addressing the weak block. Even being an lml block. Filling them helps but doesn’t stop how much they move. Putting sleeves in and out of it just stresses the block more. May never have a cylinder issue again but cracks may start in the block once you start abusing it. I’m looking at this from more of a longevity side though so if your planning on this thing getting a regular tear down and inspection, send it!

Man up and buy a billet block Richard!

 

[TheBac]

Sleeve it and dont look back, Richard.



(BTW, sorry about calling you Russ earlier...I get you two confuzzled.)