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6G72 Engine Rebuild Program

We are pleased to announce that we are offering our engine rebuild program to customers outside of our shop. Our engine rebuild program has only been offered to in house customers in the past, but we have streamlined the process to offer this service to our other customers.

Short Blocks: Our current offering for rebuilt 6G72 short blocks starts off with a thorough cleaning of the block to assess what needs to be done. The standard rebuild will consist of boring the block to the next acceptable size. New OEM style pistons are pressed onto the original connecting rods after the rods have been reconditioned. Reconditioning of the connecting rods ensures us that the big end of the rod is perfectly round and the small end will accept the piston wrist pin properly. The engine block machining process is done using an RMC CnC block center. The RMC block center probes the engine block’s cylinders and cylinder head mating surface to determine where to machine. This allows for perfectly straight cylinder walls every time. Here is a video demonstrating the process.

After the cylinders are bored to size, the RMC block center then resurfaces the cylinder head mating surface of the block to ensure a good seal for MLS head gaskets. This is essential, especially for early model cars that came with composite gaskets.

From there, the engine block moves over to the Sunnen SV10 to have the finish honing done to the cylinders. This machine creates the correct cross hatching, surface, and final sizing of the cylinders.

After the block is honed, it goes back into the jet wash machine for a final cleaning. All of the cylinders are measured again to make sure they are in spec. The main bearings are then installed into the block and we begin to measure the tolerances for the bearing to crankshaft clearances. This is very important. It allows us to choose the correct bearings to get the clearances within spec. The specifications for this varies depending on application. These clearances are important to know, as they will help you choose the correct engine oil to run in your completed engine assembly. We provide this information to you, so you can be well informed.

Once the crankshaft is properly fitted into the block, we test for thrust clearances. If the clearances are not ok, then there is either something wrong with the block or crankshaft. This is not something that can easily be remedied, so there are only a few options to choose from depending on which part has an issue.

If the thrust clearances check out ok, we move on to file fitting the piston rings. Just like bearing clearances, this specification will vary depending on application. When the rings are all fitted properly, we mount rod bearings into the connecting rods and measure both the connecting rod and crankshaft to calculate bearing clearances. This allows us to choose the correct bearing combination before installing the piston into the cylinder.

Finally, the piston and rod is assembled into the block and we rotate the assembly and check for any scoring of the cylinders (which would indicate an improper install of an oil retention ring).

Cylinder Heads: Our cylinder head rebuild starts off much like our engine block rebuild. They first get a trip through the jet wash machine. From there, they get fully disassembled and head over to the blasting cabinet to get looking brand new again. Another trip to the jet wash machine to clear out any remaining glass bead media. Then, they get resurfaced to ensure a proper seal with the head gasket. Finally, they go to the Serdi machine to have the valve seats cut and the valve guides checked. New guides are installed on any guide not meeting spec. New valves and valve stem seals are installed, along with the original valve springs. New valve springs can/will be used if the original valve springs do not meet the OEM specifications.

And these components can be offered in a pre-assembled long block assembly. This would include new MLS head gaskets and new cylinder head bolts and washers. We can also offer these long block assemblies loaded with cams, lifters, water pump, oil pump, and timing components. Even valve covers, oil pan, and turbos/manifolds if you wish.

All of these options are available on a core exchange basis. Check out our shop for pricing.