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View Full Version : At what point is an upgraded TCT needed?



b16killer
03-19-2012, 10:12 PM
Hi. I am currently running I/RH/E and skunk2 stage1 cams (stock valvetrain) on my K20A3. I'm planning on raising rev limit to 7300rpm and was just wondering if an upgraded TCT (e.g. skunk2, hybrid, etc.) is needed in support of this mod. Looking forward to hearing from the experts.

Thanks!

Euro-Yellow-Ep3
03-31-2012, 07:11 AM
the stock tct is made for normal driving, but it my case not for my driving.

Here is a excerpt from Skunks2 website


Timing chain tensioners are simple but important. Take Honda’s K-series, for example. The crankshaft keeps the intake side of the chain tight but it’s the tensioner’s job to do so for the exhaust side. Without it, the cams would start spinning but ultimately just sit there doing nothing. Honda’s design incorporates both spring pressure and engine oil pressure. At low engine speeds, when oil pressure is low, the tensioner’s internal spring moves its piston toward the timing chain guide, reducing chain slack. As engine speed and oil pressure rise, the spring relaxes and oil pressure pushes against the piston. But Honda’s spring doesn’t always work as you’d expect, and excess tensioner piston travel and timing chain slack when oil pressure is low is common—especially during start-up when the spring is left to control the exhaust cam slamming shut all by itself. All of this can lead to engine damage, even on unmodified engines. Worst of all, you’ll never know any of this is happening until it’s too late.

The problem is intensified once camshafts with aggressive closing ramps and/or stiffer valve springs are added. When the exhaust valves close while idling or during start-up, the tensioner’s piston slams back toward its housing, which causes its teeth to bash against its ratcheting mechanism. This isn’t a good thing since the ratchet and piston teeth are the only things that prevent the piston from being pushed in too far, which would otherwise lead to a dangerously loose timing chain that can potentially jump teeth, so keeping it intact becomes even more important. Once the piston’s teeth wear down, the safety mechanism’s gone. Meanwhile, as the tensioner’s spring struggles to resist the exhaust camshaft’s closing motion, the timing chain continues to slack, which is obvious by its kinking in the upper region near the camshaft gears. All of this is caused by a spring that’s too weak to counteract the exhaust valves slamming shut and weak, undersized piston teeth that wear from repeated bashing against their ratcheting mechanism. Until now, the solution was to “add a click” to the OEM tensioner, which reduces tensioner piston travel but doesn’t solve the overall problem. Stiffer springs have also been experimented with, but neither solution addresses the bashing effect and potential for worn piston teeth.