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Cracked Engine Block Repair

Is your local machinist your BFF? If he saves your cracked block, he better be on your Christmas card list.

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Is Your Local Machinist Your BFF? If he has cracked engine block repair skills, He Better Be On Your Christmas Card List!

Engines endure much abuse. Sometimes this torture results in damage to either the block or the heads--or both. The block can be very rare, such as a matching-number block for an LS6 Chevelle or the original casting for a Z/28 or an unusual 409 engine. In our case, the block is not necessarily rare, but it certainly is valuable and worth pursuing cracked engine block repair. While assembling a brand-new Dart Little M block, the unexpected happened, and assembly oil found its way into the bottom of one of the blind cylinder-head boltholes. Production small-block Chevy head boltholes are open at the bottom of the water jacket, which often allows coolant to seep up the threads unless thread sealant is used. The Dart team that designed the Little M block eliminated this hassle by ensuring these head boltholes were sealed. This requires the engine assembler to be careful not to allow any liquid to find its way into the holes. If that happens, the liquid in the bolthole can create a hydraulic-lock situation when the assembler torques the head bolts, which is what occurred during this engine's final assembly. Accidents happen, but this one was catastrophic. One of the cylinder head bolts hydraulic-locked, cracking the deck surface. But its close proximity to the two center cylinders allowed the crack to migrate in both directions into the cylinder walls. As you can imagine, this created quite a problem. Not only did the one head bolthole require cracked engine block repair, but now two cylinder sleeves were also needed.

We called our friend Don Barrington at Barrington Engines in Van Nuys, California, a cracked engine block repair expert, to get an idea of what would be required to put our block back into service. Barrington said the block could be repaired, and we thought it would be a good idea to chronicle the process so you can see how a qualified machinist resurrects a major fissure. Here are the major steps involved with sleeving a pair of cracked cylinders.

The Cost Of Repair
DESCRIPTIONPRICE
New sleeves$300.00
Cut sleeves to length 40.00
Install sleeves (2) 360.00
Deck block 190.00
Torque-plate-hone 190.00
Install cam bearings 60.00
Total$1,140.00

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