Apologies, to Mr. Oak's resident AI, but valve float is not when: RPMs are high enough so both intake and exhaust valves are open at the same time...
Both the exhaust and intake valves are open at the same time every set of cycles. It was one of the things the early engineers learned - because of the inertia of all the items involved, an engine won't have the theoretical ideal of 180 degree cam timing but significantly more.
The stock 3.0 cam specs:
Valve Lift (Intake / Exhaust) .416" / .416"
(Intake/Exhaust) 282* / 288*
0.050" Duration (Intake / Exhaust) 198* / 198* (0.050" is used as a common reference in the industry as some cams have really long durations to get to the 0.050" valve; truly meaningful air flow doesn't start until valve is off the seat a reasonable amount, the industry settled on 0.050" as that value)
Lobe Separation Angle 110 / 118 (the lobe separation valve allows us to determine how much before/after BDC/TDC the valves are open) <sort of like offset vs backspacing on rims.>
We know from TDC to BDC or vice versus is 180 degrees. If Lobe Separation Angle was 90 degrees, we would know valves started and completed lifting equally before and after TDC () = 180/2. But for our Ranger's 3.0, the Lobe Separation Angle is 110 degrees. Letting Excel calculate the appropriate formulas comes up with:
Intake valve
start to open: 31* BTDC (before top dead center)
is open .050": 11* ATDC (after top dead center)
closes to .050": 29* ABDC (after bottom dead center)
finishes closing: 71* ABDC (after bottom dead center)
Exhaust valve
start to open: 26* BBDC (before bottom dead center)
is open .050": 19* ABDC (after bottom dead center)
closes to .050": 37* ATDC (after top dead center)
finishes closing: 82* ATDC (before bottom dead center)
So, both valves are open on a 3.0 for 113* (Intake 31* BTDC + Exhaust 82* ATDC) and 26* at meaning full 0.050" lift (Exhaust 37* ATDC - Intake 11* ATDC)
Valve float occurs when the springs aren't strong enough to pull the valve closed on the valve seat in the time allowed, so instead of the fresh charge staying in the cylinder it goes out the exhaust/back into intake depending on which valve is floating.
Usually the intake floats 1st as the valve is larger = heavier = harder to get closed in time
Floating the exhaust is bad as it allows unburned fuel over the valve head/seat - which being every hot ignites it - effectively torch them i.e. burnt valve/valve seat.
So, engineers tend to design engine to allow intakes to float 1st.
So when
@Lefty (OP) is considering changing his TB, he needs to consider what is happening with the airflow in the intake. Messing with the inertia of the airflow mass can have opposite effect to intended.