I would concur with Larry. I can see where a highlift cam (and the resulting
increase in spring pressure induced by the higher lift) could contribute to
flatten a cam, but all things being equal the roller should be far more
gentle on the lobe than a flat lifter (well, they are not really flat, but
slightly convex to, - yikes "roll" on the cam) .
Now, I have heard (and also believe) that you need to bring a new cam up to
a minimum of 1,500 rpm immediately for about 30 minutes to properly break it
in or you can wipe it out. Thus, the low rpm (idle) issue does come into
play. However, this is for "flat" lifter and I honestly don't know if "true"
rollers need the same attention.
Tom Witt B9470101
----- Original Message -----
From: Larry Paulick <larry.p@erols.com>
To: Craig Wright <cwright@pdghightower.com>
Cc: Scott Hutchinson <shutchin@netjets.com>; <tigers@autox.team.net>
Sent: Sunday, April 06, 2003 7:42 PM
Subject: Re: Subject: 289/302 Conversions - My own biased opinion
> Craig, I don't understand why a roller cam wouldn't work on the street.
> Mustangs from 1988 forward have been using them, and that is a street
> car.
>
> The advantage of a roller cam is that it can ramp up fast, and don't
> have the problem with this steep ramp that a flat tappet does. This
> allows better breathing, without the wear, friction, and heat of a
> non-roller cam.
>
> Check with the cam people, as I have never heard of a roller cam dying a
> quick death with idle speeds.
>
> Frankly, why would it?
>
> Larry
>
> Craig Wright wrote:
> > Hi Scott,
> >
> > Your plans sound good except I would worry about a roller cam on the
> > street. Many knowledgeable people that I have spoken with said that they
> > die quick deaths if they spend much time idling. If you are going to use
> > the same profile as the original 289 hp you won't gain any HP by using
> > roller lifters. You can get a lot of HP out of a solid flat tappet cam
> > and still keep it streetable with a long life. I suggest you do some
> > homework before committing to a roller and make sure that it is what you
> > want. I've got a 289 with flat tappet cam, '69 Ford Windsor heads, and
> > it cranks out 425 hp at 7500 rpm [although it is a little high strung
> > for the street ;) ]
> >
> > Craig Wright
> >
> >
> > Scott Hutchinson wrote:
> >
> >
> >>Right now the 260 is sitting on the floor of my garage, the result of a
> >>bad throwout bearing. It is amazing that such a tiny little part can be
> >>the cause of so much work. Any way while the motor is out I am going to
> >>try some minor work to the motor to improve performance, but more
> >>importantly to increase durability and efficiency.
> >>
> >>The plans are thus.
> >>
> >>1. Screw in rocker studs.
> >>2. New valve seats for unleaded gas.
> >>3. Bronze valve guides.
> >>4. Roller rockers. (Probably CompCams Magnums, maybe promagnums but
> >>most people have said this would be over kill.
> >>5. Custom Ground roller camshaft that is basically a reproduction of
> >>the 289 hp cam. It will have the same firing order as the 260 and
> >>should provide a nice hp boost without killing the low end torque.
> >>CompCams will custom grind it for about $300.
> >>6. Crane drop in roller lifters. (no modification to the block
> >>required.)
> >>7. F4B and Holley 1848.
> >>8. Centerforce Clutch.
> >>9. Roller Timing Chain
> >>
> >>I am quite happy with the performance of the car with the 260. I seems
> >>to me the real limitation of the Tiger is traction. Even if you put 400
> >>hp out of the tailshaft, you just can't get it to the ground without
> >>doing some major mods to the bodywork. Who knows though, I've only had
> >>the car for a year, so maybe in a few I'll get bored and throw a blown,
> >>347 stroker in there, backed up by a Richardson 6 speed, I mean if your
> >>gonna go for gears why not have a few more than four.
> >>
> >>I should have it all back together by the end of the month so I'll let
> >>you know how it comes out.
> >>
> >>Scott
> >
> >
>
>
>
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