L&M Newsletter

Trick Flow Cylinder Head & Camshaft Issues

Do you have a set of Trick Flow’s 2V cylinder heads installed on your two valve Modular V8? Having issues with properly tuning your setup? Not seeing the power numbers you were expecting? If so, you are most likely experiencing a valve train geometry issue as a result of a peculiar engineering decision made during the creation of the TFS 2V cylinder heads.

 

Trick Flow's Design Change to Ford's PI Cylinder Heads

Trick Flow TFS-FMOD-1 Cylinder Head Issues

Ford PI cylinder heads (Left) vs Trick Flow TFS-FMOD-1 cylinder heads (Right). Trick Flow relocated the intake valves in order to allow for higher lift camshafts and air flow rates.

The original Ford PI cylinder head design essentially cannot be modified satisfactorily in order to increase performance due to the port alignment to valve. Any significant modifications would require re-engineering the Ford PI head from scratch. In order to allow for more airflow, Trick Flow switched the angle on the intake valves and placed them in line with the intake port. The intended result was higher flow numbers and more horsepower over the stock Ford PI heads, but the unattended result was a slight change in the geometry for the valve train.

Trick Flow TFS-FMOD-1 Cylinder Head Issues

Pivot locations on the Trick Flow 2v TFS-FMOD-1 cylinder head. Note the pivots for the exhaust and intake are no longer on the same side.

Designing a camshaft requires certain cylinder head design aspects to be taken into consideration. Valve train geometry i.e., follower radius, 2 different rocker lengths, cam center to pivot center, cam center to follower/roller center are required to calculate and design a correct camshaft lobe to obtain correct valve action. Rocker arm pivot location, right or left of cam center must be known in order to design the camshaft. Pivot location has a major influence in cam lobe design.. When Trick Flow designed the TFS heads they did not take into consideration what the change of pivot location and geometry of the intake valves would have on overall camshaft/valve timing.

Trick Flow TFS-FMOD-1 Cylinder Head Issues

Pivot differences between the stock Ford PI cylinder head and the aftermarket Trick Flow TFS-FMOD-1 cylinder head.

In the figure above you can see the pivot differences between the Stock Ford PI cylinder head and the aftermarket Trick Flow 2 valve cylinder head. Exhaust timing remains unchanged between the two sets of cylinder heads while the intake timing is skewed due to its pivot and valve position being modified to accommodate Trick Flow’s design requirements.

 

Performance Issues from Bad Design

The intake pivot switch effectively modifies the intake timing and duration of the intake lobe profile on the camshaft. Take note, since the stock exhaust pivots remain the timing is unaffected on the exhaust side.

The first issue is the design of the Trick Flow TFS cylinder head and the location of the intake rocker arm pivots. By switching the side of the pivot and not compensating for the change in the camshaft intake lobe profile design, duration at 0.050 is out of phase of where it should be on a stock Ford PI head; this also offsets the lobe separation angle by a few degrees. What does this mean? Any stock ford PI camshaft in a Trick Flow TFS cylinder head will be out of specification and suffer from asymmetrical valve train action.

The second issue is manufacturing based. When a camshaft design is sent to a CNC grinder, the operator will need to specify the required LSA in order for the intake and exhaust lobes to be properly in phase to one another. A Ford PI camshaft for a Ford PI cylinder head may have a LSA of 114 degrees while a camshaft for a Trick Flow TFS cylinder head requires a LSA of retarded on one side and advanced on the other side to get 114 degrees at the valve. This means a camshaft for a PI head and a Trick Flow 2 valve head are two separate entities of LSA and camshaft lobe grinds all together.

  • A camshaft made for a Ford PI cylinder head will not work properly in a Trick Flow 2 valve cylinder head
  • A camshaft made for Trick Flow 2 valve cylinder head will not work properly in a stock Ford PI cylinder head
  • The camshafts are not interchangeable between the two cylinder head designs. A new camshaft needs to be designed and manufactured specifically for the Trick Flow TFS 2V cylinder head

 

Data Comparison of a Camshaft Designed for a PI Head Installed in PI & TFS Heads

Below is the analysis of a set of camshafts designed for a stock Ford PI head installed in both a Ford PI cylinder head and an aftermarket Trick Flow TFS cylinder head. The first set of tables describes the overall event characteristics of the camshafts as installed in both types of heads.

Left Side Head
60055LC PI Head 60055LC TFS Head
OVERALL EVENT OVERALL EVENT
202.25° @ 0.200 202.25° @ 0.200
217.11° @ 0.150 217.11° @ 0.150
233.16° @ 0.100 233.16° @ 0.100
252.66° @ 0.050 252.66° @ 0.050
270.16° @ 0.020 270.15° @ 0.020
286.98° @ 0.006 286.98° @ 0.006
292.39° @ 0.004 292.40° @ 0.004
114° Centerline with a LSA of 114°
Right Side Head
60055RC PI Head 60055RC TFS Head
OVERALL EVENT OVERALL EVENT
205.51° @ 0.200 205.51° @ 0.200
220.49° @ 0.150 220.49° @ 0.150
236.63° @ 0.100 236.63° @ 0.100
256.19° @ 0.050 256.19° @ 0.050
273.74° @ 0.020 273.74° @ 0.020
290.68° @ 0.006 290.68° @ 0.006
296.15° @ 0.004 296.16° @ 0.004
114° Centerline with a LSA of 114°

The next table is the left head’s lift and duration as a function of crankshaft rotation. Both data ranges from the Ford PI and TFS cylinder heads are included.

Left Side Head
60055LC PI Head 60055LC TFS Head
Cam Degrees Cam Degrees
OUTPUT OPENING SIDE OUTPUT CLOSING SIDE OUTPUT OPENING SIDE OUTPUT CLOSING SIDE
50.17° @ 0.2000 50.96° @ 0.2000 46.42° @ 0.2000 54.71° @ 0.2000
53.88° @ 0.1500 54.67° @ 0.1500 49.82° @ 0.1500 58.74° @ 0.1500
57.91° @ 0.1000 58.67° @ 0.1000 53.57° @ 0.1000 63.01° @ 0.1000
62.82° @ 0.0500 63.51° @ 0.0500 58.26° @ 0.0500 68.07° @ 0.0500
67.23° @ 0.0200 67.85° @ 0.0200 62.55° @ 0.0200 72.52° @ 0.0200
71.38° @ 0.0060 72.11° @ 0.0060 66.66° @ 0.0060 76.84° @ 0.0060
72.61° @ 0.0040 73.59° @ 0.0040 67.88° @ 0.0040 78.32° @ 0.0040
Event = 85° Event = 90° Event = 80° Event = 94°

Lift and duration data from the right set of heads included below.

Right Side Head
60055RC PI Head 60055RC TFS Head
Cam Degrees Cam Degrees
OUTPUT OPENING SIDE OUTPUT CLOSING SIDE OUTPUT OPENING SIDE OUTPUT CLOSING SIDE
51.49° @ 0.2000 51.26° @ 0.2000 55.25° @ 0.2000 47.51° @ 0.2000
55.22° @ 0.1500 55.03° @ 0.1500 59.29° @ 0.1500 50.96° @ 0.1500
59.22° @ 0.1000 59.09° @ 0.1000 63.57° @ 0.1000 54.75° @ 0.1000
64.05° @ 0.0500 64.05° @ 0.0500 68.62° @ 0.0500 59.48° @ 0.0500
68.33° @ 0.0200 68.54° @ 0.0200 73.02° @ 0.0200 63.85° @ 0.0200
72.35° @ 0.0060 72.99° @ 0.0060 77.08° @ 0.0060 68.26° @ 0.0060
73.54° @ 0.0040 74.54° @ 0.0040 78.28° @ 0.0040 69.80° @ 0.0040
Event = 85° Event = 91° Event = 90° Event = 86°

Proper center-line for a camshaft designed for a PI head installed into a PI head. This data is for the right side cylinder head.

Right Side Head
60055RC PI Head
Crankshaft Degrees
OUTPUT OPENING SIDE OUTPUT CLOSING SIDE ACTUAL CENTERLINE
102.98° @ 0.200 102.52° @ 0.200 113.77
110.44° @ 0.150 110.06° @ 0.150 113.81
118.44° @ 0.100 118.18° @ 0.100 113.87
128.10° @ 0.050 128.10° @ 0.050 114.00
136.66° @ 0.020 137.08° @ 0.020 114.21
144.70° @ 0.006 145.98° @ 0.006 114.64
147.08° @ 0.004 149.08° @ 0.004 115.00

Data from a camshaft designed for Ford PI cylinder head as installed in a TFS aftermarket cylinder head. There is a 10 degree difference in center-line from the proper configuration. This data is for the right side cylinder head.

Right Side Head
60055RC TFS Head
Crankshaft Degrees
OUTPUT OPENING SIDE OUTPUT CLOSING SIDE INSTALLED CENTERLINE
110.50° @ 0.200 95.02° @ 0.200 103.26
118.58° @ 0.150 101.92° @ 0.150 102.67
127.14° @ 0.100 109.50° @ 0.100 102.18
137.24° @ 0.050 118.96° @ 0.050 101.86
146.04° @ 0.020 127.70° @ 0.020 101.83
154.16° @ 0.006 136.52° @ 0.006 102.18
156.56° @ 0.004 139.60° @ 0.004 102.52

Proper center-line configuration for a stock set of PI cylinder heads and camshaft. Repeated for the left cylinder heads.

Left Side Head
60055LC PI Head
Crankshaft Degrees
OUTPUT OPENING SIDE OUTPUT CLOSING SIDE ACTUAL CENTERLINE
100.34° @ 0.200 101.92° @ 0.200 114.79
107.76° @ 0.150 109.34° @ 0.150 114.79
115.82° @ 0.100 117.34° @ 0.100 114.76
125.64° @ 0.050 127.02° @ 0.050 114.69
134.46° @ 0.020 135.70° @ 0.020 114.62
142.76° @ 0.006 144.22° @ 0.006 114.73
145.22° @ 0.004 147.18° @ 0.004 114.98

Again a 10 degree difference in center line position. Repeated for the left cylinder head.

Left Side Head
60055LC TFS Head
Crankshaft Degrees
OUTPUT OPENING SIDE OUTPUT CLOSING SIDE INSTALLED CENTERLINE
92.84° @ 0.200 109.42° @ 0.200 125.29
99.64° @ 0.150 117.48° @ 0.150 125.92
107.14° @ 0.100 126.02° @ 0.100 126.44
116.52° @ 0.050 136.14° @ 0.050 126.81
125.10° @ 0.020 145.04° @ 0.020 126.97
133.32° @ 0.006 153.68° @ 0.006 127.18
135.76° @ 0.004 156.64° @ 0.004 127.44

 

Our Solution

If you have a set of Trick Flow 2 valves heads with improper camshafts, you will need a new set of camshafts that match the head setup manufactured. We have extensive experience with this issue and have camshaft lobe profiles on file that work perfectly with the Trick Flow TFS cylinder heads. We have modified the Ford PI camshaft design to allow for the relocated pivots while providing additional lift. We were the first to identify the issue and first to implement a correct solution. Call or email us today to get your lost performance out of the Trick Flow heads.