Roller Rocker for a "Mild" Street Stroked 427?

[blykins]

Google my name.  Then Google yours. 

Have a nice day. 

[jayb]

That's enough please, gentlemen... 

[My427stang]

Jay - understand if you lock this one, but I dove into the catalog, both on the net and the PDF download version and may have found some things that could be confusing the discussion

I am trying hard to understand the 1.60/1.65 issue, and so far, the only thing I see on T&D's web page is rocker length listed at 1.60 for the FE and 1.65 for the 385s, not ratio.  It even lists some as 3.00 for the Boss 9, because they surely don't have a 3.00 ratio rocker. and Boss 9's use a short and long rocker, which supports the length versus ratio

Now, digging deeper, if you go to the tab that discusses that rocker length, it shows two dimensions for length.  "Fulcrum length" (then they show all the available ratios) and "Dimension A" (which honestly I am not sure why anyone would care enough about that dimension to post it)  Dimension A is the fulcrum length plus 1/2 the shaft diameter

As far as fulcrum length, it does affect spring choice.  Not in open/close pressure but in choosing a spring diameter.  In fact, they even note it in the footnotes under Note 109: Will clear most common spring diameters.  I haven't had to fight it on FEs, but I sure have had to either choose a smaller diameter spring or different style rocker on other engines that had interference issues with aluminum rockers in particular.  It certainly needs to be watched.

The catalog does not advertise what the common FE T&D rocker ratio is, which surprises me (and I have never bought a set, so I can't say I ever measured a set or checked for clearance with a T&D rocker) but it does show that the 1600 series rocker (1.6 fulcrum) can be had in 1.50-2.00 ratio in .05 increments. The way T&D has to do it if they keep fulcrum length the same on the valve side is to move the cam side.  Honestly that seems like a logical way to do it because they just drill the adjuster hole 1.0667 - .8000 from the fulcrum to change ratio and they don't have to mess with coming off the center of the valve by moving the valve side, or valve and spring diameter issues by moving the the pivot bore. 

To the guys that use them, do the T&Ds work out to be 1.75:1 not 1.76?

I still agree with the statement that you have to check spring/retainer clearance to rocker body, especially with a big bodied alum rocker and especially with an FE which could have as much as 1.55 diameter valve spring. 

Two more comments.

1 - I agree with the way Howie checked for lift using a dial indicator on the valve, it's the best you can do to see what the ratio ends up to be in final use at max lift or anywhere on the curve, as it accounts for all the mechanical loss (at least at zero RPM) and lash. In fact, I would even say that you could have some mechanical GAINS at some points on the curve where the ratio is above 1.76, especially if you have some push rod angularity, but it depends on setup

2 - I also agree with Brent that measuring rocker ratio using the fulcrum method to make sure you have what you think you have, especially with custom rockers.  In fact, in the catalog on page 5 T&Ds show exactly that

In the end, if there is more to this argument, then I am missing it, but I think everyone is making valid points...except for the T&D catalog... which seems to focus on everything OTHER than ratio 

[XR7]

I've installed 4 sets of T&D race rockers. 3 sets have been 1.75 ratio (this is stamped right into the rocker, so hard to miss!), the fourth set had 1.8 ratio on the intake side. Ross is correct that the RATIOS are available in .05 increments from 1.50 to 2.0 RATIO... LOL. I'm not yelling but this whole ratio deal is crazy. It is not that hard to understand. The numbers that are in the T&D catalog list the fulcrum length or "pivot" length as Jesel calls it. That remains the same on all (the FE) rockers. It is basically the geometry of the stand and the cylinder head that determine this.

Also the T&D race rockers are available on center, .080 left and right offsets, as well as .170 and .250 offsets available. I have one set here that are on a set of Kuntz Pro ports that have a .500 offset on the intakes (ports moved over and custom one off sheetmetal intake, .937 double offset lifters etc.) so lots of options as they are basically all made to order and can be customized as long as the Engineers say it is possible and draw it out in CAD, then they can machine anything.

As far as spring clearance, I have used up to 1.650 diameter springs with these T&D rockers, some guys use 1.750 springs or have in the past on high RPM engines.. but maybe not on FE's, they just list it as that is designed into it, and will be a different dimension with different pivot lengths. The newer "high tech" springs being used now are better material and going back to 1.500 (ish) diameter dual springs, so bigger isn't always better.

I don't see what all the fuss is about, but maybe there is more too it between Howie and Brent. None of my business...

[bn69stang]

Im pretty sure the  T @ D s ok for street use , they would nt have street versions , race versions if they were nt . AND Barry , Brent , Blair would nt use them in a build , sell them in a build if there was issues with them. My car is not a daily driver , but i drive it and im not worried bout going in a long trip anywhere with them . Insurance for our classic or collector cars is what defines daily driver or not to me . My Grundy insurance allows 4000 miles a year average for my coverage . When i put this motor together , i never put a mile figure on it , more of an idea that at 3000-5000 miles a year i would build a stroker or something else before i ever wore this one out ..Bud

[Drew Pojedinec]

Google my name.  Then Google yours. 

Have a nice day.

So I did as you said Brent....
this is Brent Lykins from Ohio:

[blykins]

ROFL...

That cat has a little more hair than me.  Nice 'fro....

[e philpott]

yep !! .. that's him ... lol

[bn69stang]

NICE MUG SHOT BRENT ......

[My427stang]

[cjshaker]

Brent you have it all wrong.
I'm telling you to pound sand.
You don't even talk a good game on the spiderweb let alone run something you own.
You could not cut 0.015" off the bottom of anything.
You don't have the gear.
Put that in your pipe and smoke it.
 

Now as for my picture.
The dial is on the spring and measuring the actual push on the valve. So There.

I build cars laddie.
You're going to have step up your game to get there.

Edit:  The question. "That dimension helps determine what kind of spring you can put underneath it. "  Brent is referring to the 1.60 and 1.65
that I had shown. Please explain to all of those potential customers how you use that number to select the spring they need.

Hurling insults at somebody who is trying to help? Nice, Howie. Shows a real lack of character.
Look at your pushrod angle compared to the rocker. Notice how it effectively puts the "push" point lower and nearer the shaft. The angle also changes the amount of lift that the rocker sees, or the effective lift of the cam lobe. Look at how far down or up your adjusters are. You know that this also changes the effective ratio. And if it's not clear how fulcrum length decreases or increases the length of the rocker, thereby changing the available space for a spring to fit, then maybe you should stick to building cars.