Another full engine rebuild on the go in the workshop, this time a Duramax 6.6L diesel, and the valve covers have just come out of the vapour blasting cabinet. Here’s the before and after.
Before
After
Why bother cleaning valve covers?
Fair question. They’re going to be bolted back onto an engine and covered by the intake and a loom. The answer is that on a Duramax the valve covers aren’t just lids. They carry the injector harness, seal against the heads and, on the earlier engines, sit over the injectors themselves. If there’s twenty years of baked-on oil and grime in every recess, you can’t inspect the sealing faces properly, you can’t see cracks or damaged threads, and any muck you leave behind ends up back in a freshly built engine.
When we do a full rebuild, every component that goes back on the engine is cleaned, inspected and known to be good. Not most of them. All of them.
The process
Our cleaning runs in three stages, and the valve covers went through all three:
- Hot wash to shift the loose oil and road grime
- Ultrasonic clean to pull the baked-on deposits out of the pockets and passages the brush can’t reach
- Vapour blast to bring the alloy back to a clean, satin finish without cutting into the casting
The covers are then flushed, dried and inspected before they go back on with new gaskets and seals. The finish you see in the after photo is bare alloy, not paint, so it won’t flake, and the slightly peened surface tends to stay cleaner than the original casting did.
Duramax rebuilds and vapour blasting in Perth
We rebuild Chevrolet and GMC Duramax diesels in-house at Welshpool, from cylinder head overhauls through to complete engines. The vapour blasting and ultrasonic cleaning is also available on its own if you’ve got parts from your own project that need bringing back to life.
Call (08) 9258 6409 or visit Unit 5/51 Division Street, Welshpool. Based in Welshpool – servicing Perth.
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We’re not your average mechanic. Our team has extensive experience working with American-made vehicles – from RAM 1500s and Ford F-Series to Chevrolet Silverados and GMC Sierras. Whether factory-delivered or privately imported, we understand the unique requirements of these utes and trucks and have the tooling, knowledge, and parts network to service them properly.
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