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Re: Roller Rocker Conversion??

To: 6pack@autox.team.net
Subject: Re: Roller Rocker Conversion??
From: Timothy Holbrook <tjh173@yahoo.com>
Date: Mon, 24 Jul 2000 12:48:22 -0700 (PDT)
Bernard,

It's a dead easy, bolt-in operation.  I bought the roller rockers
preinstalled on a hardened shaft all assembled with pedestals, spacers,
etc from Goodparts.  You just remove the old rocker shaft assembly and
install the new one.  It's available in two ratios, 1.55:1 and 1.65:1. 
I got the 1.65 as I was interested in power.  This increases load on
the cam somewhat, but it's worth it in my opinion.  

I don't know what effect this conversion would have on a stock engine. 
The reason it boosts power is because it opens the valves further and
faster than the stock ratio rockers (1.46:1).  This allows more
air/fuel mixture into the cylinders.  It should boost power on any
engine, regardless of other mods.  I believe Richard Good of Goodparts
claims this is good for a 10% boost in power.

The roller rockers also decrease wear on the valve stems and valve
guides.  The stock rocker tips slide across the end of the valve stem
as the rocker and valve move up and down.  This puts a side load on the
valve stem and wears the valve and guide.  Plus this friction saps a
bit of power.  The roller rockers have a tip that can rotate on needle
bearings and thus they roll across the tip of the valve stem as things
move up and down, rather than sliding across it.  This should greatly
extend valve and guide life.  The rocker arms also rotate on the shaft
on needle bearings, which extends their life and the life of the shaft.
 Of course, this isn't cheap.  It's about $700.  You can save a bit of
money by buying just the rockers and shaft if you want, and reuse your
rocker pedestals and spacers.  But you'll definitely want to get the
new rocker shaft, preferably hardened. 

The roller rockers seem to be easier to adjust for valve clearance than
the stock shaft.  It's a bit quieter too, in my opinion.  I guess it's
smoother in operation, but it's not noticeable from the driver's seat.

Tim Holbrook
1971 TR6 


--- Bernard Robbins <brobbins@wlg.nec.co.nz> wrote:
> Hi Tim,
> 
> I'm interested in your roller rocker conversion...
> 
> What is involved?
> What are the results? (more power, smoother running??)
> Are the roller rockers quieter than standard tappets?
> Is there anything else one needs to modify at the same time to carry
> out
> this conversion?
> 
> Any advice would be much appreciated....
> 
> 
> Regards
> 
> 
> Bernard Robbins
> 
> NEC New Zealand Ltd
> Network Solutions
> P.O. Box 1936
> Wellington
> 
> Ph    (04) 381 6274
> fax   (04) 381 6284
> email brobbins@wlg.nec.co.nz
> 
> 


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