Trickflow really let me down
The valves are different lengths brand new. The difference is made up in the valve job machining depth, which sets the depth of the valve in the head and ensures both proper rocker geometry, as well as good valve job blend into the bowl and chamber. These heads did not require lash caps.
There still seems to be confusion about the seat wear, and whether there were seat issues when these heads left our factory. Our conclusion was that there was not an issue with our manufacturing process or valve seat issues when these left our factory.
When we install seats, the heads are heated and seats are cooled with liquid nitrogen before being pressed in. This is necessary due to the significant interference fit. They are 100% gauged to verify the seats are full seated immediately after installation. They are 100% inspected again later prior to the valve job to ensure the seats are fully seated.
If there was evidence of a valve job concentricity problem, or the seat had moved in the head (either lifted, or dropped into the head after valve jobbing because it wasn’t fully seated when installed), we would have absolutely warrantied the heads without question. But that’s not the failure mode we observed here. The seats didn’t sink into the head. Instead, the exhaust valves sunk into the seats, and the seats mushroomed out and around the valve heads.
Our seats are heat treated – meaning, they are hardened, which ensures good wear properties and durability. If there were issues with other customer's heads, we would likely quickly conclude we have could have a heat treatment process issue on an entire batch of seats from our supplier, however that is also not the case.
The accelerated wear and deformation of the exhaust seats shows that the seats have been overheated to 1600-1700° F for several hours, which annealed the seats. This means they have lost their heat treatment and they are no longer hardened, instead they are very soft, malleable, and easily deformed. In this material state, the seats will no longer have good wear resistance, instead they will wear and deform very easily.
To illustrate what we mean, take a hammer and a file to a hardened steel drill bit (careful, it will be so hard that it is brittle and can shatter), and again to a regular nail. The hardness of the drill bit is what makes it both resistant to wear, and also resistant to deformation. But the nail will dent, bend, and file easily in comparison because it's not heat treated, it's soft. That’s what’s happened to your exhaust seats. Once they were annealed and lost their heat treatment, the valve closing against the seat hammered the seat and valve sunk into the head gradually as the seat deformed a little with every valve closing event.
This also means that the exhaust seats cannot be re-valve jobbed. The heads need to have new exhaust seats installed.
Again, elevated exhaust temps high enough to anneal and soften the exhaust seats is an indication of a significant cam timing or tuning issue. With thousands of heads and exhaust seats sold per year, we have only seen this level of seat deformation a few times over many years. It is more common on a boosted application, but it is possible on an NA build. It’s an indication of a cam timing, fueling, or ignition problem and never considered normal.
Our dyno technician is out of the office for the holidays, but we will review your logs with engineering once everyone is back in the office.
The bent valves, worn guides, and softened/hammered seats were all reasons we concluded there were significant problems outside of our control, and also why it was a little pricy to repair the heads. They needed new seats, guides, and valves.
It is also clear that we could have communicated our inspection results to you more clearly, perhaps with an inspection report with our measurements, observations, and a detailed estimate rather than just the verbal over the phone. We are always working to improve our processes and want to provide the best customer service we can, even when things don't go as planned for our customers.
Last edited by Lxjoshxl; Dec 30, 2024 at 02:59 PM.
Last edited by Lxjoshxl; Dec 30, 2024 at 03:14 PM.
Trickflow came to their conclusions because the whole seat was mushroomed, because it was annealed from the high exhaust gas temperature.
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Trickflow came to their conclusions because the whole seat was mushroomed, because it was annealed from the high exhaust gas temperature.










