Engine Roller rocker question

My92cashtrap said:

Pretty simple question. I have what appear to be generic Crane roller rockers in my TF heads on my 347. I can't find any branding on them, except for the 1.6 ratio.

What's the advantage of going to a more expensive rr? I've read that TW heads need a select rocker arm because of the valves geometry. Is that the only reason to upgrade?

TIA

Click to expand...

Hi,
You certainly want a good, solid yet lightweight rocker from a reputable MFG., especially with higher spring tensions
(I’m guessing you’re running Hydraulic roller, not solid roller-correct?)).
WhichTF head’s are you running, 170’s, 11R 190’s, 205’s?
If the Rockers you have are indeed Crane’s Gold series, it’s a great selection for a stout hot street level build. Crane is usually a fairly avid one regarding product ID.. even if a stamped ID atop the Rocker.
A few less than resilient brands have anodized in their color, can you post a pic?
TF Head differences..
TW’s specific centralized valve in chamber locations necessitate a lateral swing from front to back in the Rockers for proper valve stem to pushrod alignment (studs are offset from the valve stems slightly).
TW Valves are also slightly Canted (Tilted), where the stud is not, so the Rocker tip doesn’t strike the Stems dead square, a little more load they have to bear vs. a typical application.
Few pic’s...in order.
Cranes Gold series, Harland Sharp, Comp’s pro Gold, all very good Rockers. There’s better, of course- but do you need 600$ Rockers on a H.R. Street motor? No.
-Best!
John

Hi,
Very Sorry for the delay.
What Cam are you running, and are you running it’s Springs? Spring loads around 125-130lbs (Valves on seats (closed), 310-330lb Valve open, or at full valve lift)(?).
I’m not able to see the distance between the Spring retainers and the Rockers are when valves are closed (valve(s) sitting on their Seat(s)).. Distance appears close, can you please take a pic showing that distance (Simply a pic taken from the front of the head showing the first Rocker from a side profile?). Any interference between the Rocker and the spring Retainers you’ve noted?
Are the pins that retain the roller tip to the Rocker body hollow, or solid? May just be my interpretation of the image.
They appear to be Comp’s 1.6 steel rockers with full roller Trunnions & roller tips. We’re these previously used?
Did you set your pushrod length, or was this part of a TrickFlow top end kit?
You want your roller sweep to be </= 0.080 across the valve stems, as centralized as possible.
A dry erase marker is perfect for this, temporarily using a solid roller lifter in both the intake and exhaust sides. You can also pump up the hydraulics by cycling the pump long enough to achieve this.
Another tip is to have the Stud swing equally within the Rockers slot, from Cam base circle (heel) to full lobe lift is desired, along with a good sweep pattern across your stem(s).. If you’re still in need of an answer, I’m happy to help!
If adequate clearance between Rocker underside to Retainer top exists, you’re running a hydraulic roller (or flat) Cam, your Geometry is the essential factor.
I’ll hold off until I see your Data, we’ll go from there-k?..
Best!
-John