garrett_garageJun 26, 04:46 PM

Valvetrain Harmonics: Valve float at 8500 RPM on built K24 head. Springs or retainers?

Building a high-revving Honda K24. Using Drag Cartel 3.2 cams. On the dyno, we saw power fall off a cliff after 8100 RPM, accompanied by minor ignition scatter. My tuner suspects valve float. I'm currently running dual valve springs rated at 95 lbs seat pressure. Do I need higher seat pressure (115 lbs), or are titanium retainers mandatory to drop moving mass?

Discussion

5 comments

detroit_iron_68Jun 27, 09:22 PM

What valves are you running? If you have heavy aftermarket flat-face valves, that extra mass requires even more seat pressure to control.

chicago_boostedJun 28, 06:09 AM

Drag Cartel 3.2 cams have a very aggressive ramp rate. 95 lbs seat pressure is not enough to keep da valves on the seat at 8500 RPM with that lift. Upgrade to Supertech 115 lbs springs.

boosted_austinJun 28, 03:14 PM

Valve float will destroy your valve guides and eventually lead to valve-to-piston contact. Do not spin it past 8000 RPM until you upgrade the springs.

chase_trackdaysJun 29, 07:49 PM

Titanium retainers help reduce weight, but they are a wear item. They will mushroom over time on a street car. Better to use tool steel retainers and just run a stiffer dual spring

brody.dieselJun 30, 09:53 PM

Check your installed spring height. If they were set up wrong, u might be close to coil bind, which creates crazy harmonics and mimics valve float on the graph.