Variable Cam Timing

[SmokeOps]

Hi, I was just wondering how does this work on a SOHC engine because I know that it changes due to oil pressure but on more VCT engines they are DOHC and the can have 3 lobs per 2 valves so I get how it actually changes the lift but I don't get how a single cam can change the lift and it doesn't have any extra lobs for the valves to get more lift.

 

[SmokeOps]

And one other thing, are Ford Performance Hot Rod Camshafts compatible with the VCT?

 

[Dino Dino Bambino]

Hi, I was just wondering how does this work on a SOHC engine because I know that it changes due to oil pressure but on more VCT engines they are DOHC and the can have 3 lobs per 2 valves so I get how it actually changes the lift but I don't get how a single cam can change the lift and it doesn't have any extra lobs for the valves to get more lift.

Since the 4.6 3V engine has two intake valves and one exhaust valve for each cylinder, the single overhead cam (SOHC) on each cylinder bank has three lobes per cylinder to actuate them. Therefore each cam has 12 cam lobes (8 intake, 4 exhaust) with one lobe per valve. Valve opening duration, valve lift, and the lobe separation angle are fixed. The only variable parameters are the intake and exhaust centerline angles due to the cam timing either being advanced or retarded. The VCT system on this engine is simple but effective.
The 5.0 Coyote engine differs in that it's double overhead cam (DOHC) with an intake and exhaust cam on each cylinder bank. Each cam has 8 lobes and since there are four cams and the engine has 32 valves, that's one lobe per valve. The twin independent variable cam timing (TiVCT) system on this engine is more complex since it has four cam phasers, with secondary as well as primary timing chains. Valve opening duration and valve lift remain fixed but since each cam only actuates either intake or exhaust valves and not both, the lobe separation angle as well as the intake and exhaust centerline angles is variable, thus allowing the 5.0 Coyote to produce abundant torque over a wider rpm range than the 4.6 3V.

And one other thing, are Ford Performance Hot Rod Camshafts compatible with the VCT?

Yes, and this is a popular cam swap on the 4.6 3V. Since this is classified as an NSR (no springs required) cam, the stock valve springs (rated to 6800rpm) can be retained and since there's no need to install phaser limiters or lockouts, full VCT system functionality is retained.

 

[SmokeOps]

Thank you appreciate the answer I understand it now and am happy that the hot rod cams wont need anything else to install

 

[Dino Dino Bambino]

Thank you appreciate the answer I understand it now and am happy that the hot rod cams wont need anything else to install

Except a new tune, and the go to guy is Lito (real name Manuel Pazo). Shoot an email to [email protected]
The Hot Rod cams need to be tuned properly, otherwise the engine will run poorly.

https://performanceparts.ford.com/download/instructionsheets/FORDINSTSHTM-6550-3V.PDF

 

[07 Boss]

If you have an automatic you might want to think about a higher stall convertor or lower rear end gears. This will help the cams wake your car up a bit.

 

[Dino Dino Bambino]

A 3500rpm stall converter plus 4.10 axle gears would completely transform the driving experience in an automatic GT with HR cams!

 

[JC SSP]

4:10 wakes up any small block!