This is probably one of the most asked questions that we get. Why do I need to do this? Can't you just unbolt the baffle and clean it yourself? Well, the baffle is riveted to the valve cover from the factory, so... No. Powder coaters all over the world have never gone to these lengths, so does it really need to be done? Well, let us show you some of our findings and you can answer this question for yourself.Â
When prepping a valve cover for powder coating, there are various methods used to clean the old finish from the valve cover. Methods such as blasting with a wide array of medias, to chemical stripping in acid baths. Any and all forms used to strip the old finish will leave some sort of residue, dirt, and debris behind the baffle. But wait, you taped up the baffle and stuffed whatever crevices you could with foil right? You threw the cover into the parts washer three times and spent 15 minutes blowing out the baffle as best you could with compressed air. Cleaning chemicals? Ultrasonic cleaners? It has to be clean, right? Well, based on what we found, you'd be surprised.Â
Not every coater will go to these lengths to clean the covers, but the good ones will. Hell, we even did this ourselves before we decided to set a new standard. As a coater you've been paid to coat the cover, not worry about the engine. It's up to the end user to ensure it's safe for their engine after all, right? RIGHT!? (Sigh...) Here at Doryoku, we aren't just powder coaters. We're builders, racers, fabricators, engineers, and innovators. So we understand the importance of a clean valve cover and that's why we sought out a solution that's never been done at this scale. Before we get into it, let's take a look at a few examples of covers fresh from the powder coater.Â
Example 1:
This B-series VTEC valve cover came in for a baffle service from a customer that had the cover coated somewhere else. Although we didn't coat the cover, we're more than happy to still provide the baffling service! The more people we can help out the better. When we removed the baffle, this is what we found. Yikes...
Example 2:
This is an S2K/F-series cover that came in for a baffle service. Once again, this is a cover that was coated by another shop. Although not as extreme as the first example, this still isn't great. You can ignore the shiny bits of shavings as they're a product of the CNC process, but what's important to note is the dirt and debris that's still present.Â
Example 3:
This is another S2K/F-series cover that actually came in as a core. This cover had been previously coated and was used for some time. As we've mentioned before, 99% of the time you probably won't have any issues, but a level of unknown still exists. An owner of a newly rebuilt engine likely won't take that chance. We want to know with 100% certainty that the valve cover is clean and clear of debris. Take a look at what we found behind the baffle once it was removed.Â
The Process
By now you should have a good understanding of why we do what we do. Let's take a look at how this process is achieved through Doryoku. Enthusiasts and DIYers alike have addressed this problem in the past with a more "at-home", but practical approach. While it isn't wrong, this approach lacks precision. We get that your average enthusiast doesn't have access to a CNC machine and that's exactly where we come in.Â
Where the average enthusiast would use a hand drill to remove the rivets, we've developed the appropriate tooling and fixtures to achieve this process with a CNC machine. The rivet heads are precision cut then the rest of it is drilled out to a specific depth. Following the drilling procedure, the bores are then tapped by the CNC machine. Precision machining ensures consistency accross all threaded bores whereas this level of accuracy would be very difficult to achieve with a hand drill. We've even seen some instances where people intentionally drill straight through the cover! Bruhhh, for real!? (See below)
The CNC process allows us to achieve a class 3 thread tolerance in the cover which leaves zero tolerance in the threads. Since we intend to use stainless steel hardware in a cast aluminum cover, we offset the hardware thread class to a 2, which loosens the tolerance just enough to prevent any galling. The first video below shows the thread engagement on a cover that was modified by another shop. The second video shows the thread engagement on a Doryoku modified cover. See the difference for yourself!
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The baffle is then removed and the cleaning begins. The old gasket material is cleaned off the baffle, media blasted, then sent out for zinc coating. While that's happening, the areas behind the baffle are degreased, media blasted, and thoroughly washed to ensure 100% cleanliness. For most covers, this service leaves the baffle uninstalled so that the end user can see the cleanliness behind the baffle. This let's the customer work through the process of installing the baffle themselves with the supplied stainless steel hardware. The lock washers also help to keep the fasteners in place with the help of a little thread locker.Â
We've put a lot of thought into this process to ensure absolute precision and we truly believe we provide the best baffle mod service out there. A lot of companies will perform this service by hand, which isn't the worst thing. It still works, but it's just not as precise.
