Subject: Re: [Fot] Rollers

From: "Steve Yott" <[email-masked]>
Date: Thu, 17 Oct 2013 16:56:38 -0500

My opinion is that if you have the money and buy the best quality rockers
available then it's a good thing.  There are some advantages in their use as
they do reduce a bit of friction and also take some of the side load off the
valve guides if the geometry is less than perfect.  The biggest negative to
me is that they don't fit under the stock tractor motor valve cover....   I
happen to like the stock cover!

Steve

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On
Behalf Of John Hasty
Sent: Thursday, October 17, 2013 4:45 PM
To: FOT
Subject: [Fot] Rollers

What is the group's wisdom on roller rockers for a 4 motor.....assume it is
not "stock" & has a billit crank, proper rods etc?????
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From: John Styduhar <[email-masked]>
Date: Sun, 20 Oct 2013 18:17:38 -0400

I have a set of Harland Sharp roller tip rockers with bronze bushings on
the rocker pivot.  They have worked well so far below 6K rpm with a high
lift cam.  Ratio is 1.5:1.

On Thu, Oct 17, 2013 at 5:45 PM, John Hasty <[email-masked]> wrote:

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From: Bob Kramer <[email-masked]>
Date: Sun, 20 Oct 2013 21:23:51 -0500

The word? Illegal! At least where I race.

Bob Kramer
Sent from my iPhone

> On Oct 17, 2013, at 4:45 PM, John Hasty <[email-masked]> wrote:
>
http://autox.team.net/mailman/options/fot/[email-masked]
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From: "Bill Tobin" <[email-masked]>
Date: Mon, 21 Oct 2013 00:00:36 -0400

Legal in SVRA. Also VSCDA. Makes sense to use them.
Bill
----- Original Message ----- 
From: "Bob Kramer" <[email-masked]>
To: "John Hasty" <[email-masked]>
Cc: "FOT" <[email-masked]>
Sent: Sunday, October 20, 2013 10:23 PM
Subject: Re: [Fot] Rollers

> http://autox.team.net/mailman/options/fot/[email-masked]

---

From: Michael Porter <[email-masked]>
Date: Sun, 20 Oct 2013 23:49:35 -0600

> not "stock" & has a billit crank, proper rods etc?????

I suppose it depends primarily on two things--what the roller rocker 
weighs compared to stock, and the intended maximum rpm.  There's 
probably a marginal increase in valve guide life--if they're set up 
properly--pushrod length/pedestal height is just as important as with 
stock rockers.  The roller rockers I've seen, although from 6061-T6 
aluminum billet, actually weigh _more_ than the stock rocker, so the 
advantages of reduced friction are offset by the need for somewhat 
stronger valve springs to maintain the same point of valve float, and 
that latter disadvantage increases with the square of the rpm.

That said, virtually all makes are CNC machined today, so there's a 
uniformity to them that isn't present in the stock rockers.  One can go 
through dozens of stock rockers to get a set that has a uniform ratio 
and weight.  And, beam strength counts as the rpm goes up, and modern 
roller rockers are superior in that regard.  If you're redlining the 
engine at or near 6000, I doubt you gain anything by using roller 
rockers over a well-prepared set of stock rockers, but, if you're aiming 
for stratospheric rpm, roller rockers are probably a necessity, since 
stiffer valve springs are usually required to reach those higher revs, 
anyway.

Cheers.

-- 

Michael Porter
Roswell, NM

Never let anyone drive you crazy when you know it's within walking distance....
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