Don,
I'm no engineer, I'm sure that someone with all lot more brain power
will give you solid answers, but it seems to me that the stock TR6 was known
for needing valve guides every 80k or so. So I would think if you push the
lift much beyond stock your looking at much more frequent guide replacement.
I asked my engine builder if Bronze guides would solve just this problem, he
just grinned and said, you wish. I did run a .440 lift cam on cast iron
guides for three years with no problem but I really only put 20K miles on
the car in that time. If It were me and I could stretch my budget I would
get the roller rockers now, that way you could set your nose pressures, bind
clearances and the like to the roller rocker ratio and not have to tear the
head off later, like I did, and reset everything to the higher ratio.
----- Original Message -----
From: "Don Malling" <dmallin@attglobal.net>
To: "6-Pack" <6pack@autox.team.net>
Sent: Tuesday, January 07, 2003 6:53 PM
Subject: Valve lift and lateral forces on the valve guides
> List,
>
> I understand that one of the advantages of roller rockers is that they
> reduce or eliminate lateral forces on the valve guides at higher valve
> lifts.
>
> At what valve lift does this become important? For example, if I have a
> cam with .425 valve lift using stock 1.45:1 rockers, do I have a
> problem? How much valve lift can I have before I start needing roller
> rockers. I understand this is not a binary thing -- If I have a little
> too much lift I will have a little too much wear. Lots of lift, means
> lots of wear. I have no feel for the range -- little problem to big
> problem.
>
> Thanks,
>
> Don Malling
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