DeTomaso Mailing List: February 00, Message #29

I went to the Crane and Crower web sites and found that they also are
showing a similar pattern for spring pressure.  Though the hydraulic roller
and solid flats are using similar springs.

Paul
#9270

----- Original Message -----
From: Paul Timko <thedrol@mediaone.net>
To: Multiple recipients of list <detomaso@realbig.com>
Sent: Tuesday, February 01, 2000 10:36 PM
Subject: Re: Roller vs hydraulic Cam


> I'm not an expert.  This is how I understand it.  The key difference
between
> cam types hydraulic, solid, hyrdaulic roller and solid roller is the
> profile, how fast can the lobe rise and fall.  The idea is the longer a
> valve is at maximum lift (where the best air flow is) the better.  Now as
I
> understand it, a hydraulic (either type) is limited by the oil valves
inside
> and the oil itself.  While a solid is plain old solid.  An easy way to
tell
> how aggressive the ramps are is by looking at the strength of the valve
> spring.  A faster ramp needs more spring pressure.  The valve is moving
the
> same distance, about 0.5" but it is getting there quicker, more valve
speed,
> more valve momentum more spring pressure to keep the lobe on the cam.
> Otherwise the lifter jumps and crashes back onto the cam.  Not good.
>
> Example time.  I only have a Comp Cams catalog so I have to use them as a
> guide.
>
> Hydraulic flat - spring type is 972 or 924
> Hydraulic roller - spring type is 924
> Solid flat - spring type 928
> Solid roller - spring type  947 or 943.
>
> Spring pressure
> 972 - 125 closed, 275 open
> 924 - 125 c, 315 o
> 928 - 160 c, 370 o
> 947 - 340c , 835 o
> 943 - 235c, 635 o
>
> As you can see they sell hydraulic flats that require the same spring as
the
> roller, but even the solid flats require a stronger spring than the
> hydraulic roller.  Now this is a simplification.  Part of the spring
> strength requirement has to do with how the cam lobe is shaped near the
open
> point and closed point.  I would assume that cam manufacturers make their
> cams so that as the lobe is reaching min and max lift, the ramp slows.
This
> helps keep the valve train all touching.  Now I don't have the same
numbers
> available for Crane, Crower and others.  But this is how I judge a cam
ramp.
> There is more to cam selection than this though.  There is the weight of
the
> valve train.  This will limit rpms.  Of course you and I are not looking
to
> turn 7000.  So the weight won't be a big deal in terms of limiting rpms.
>
> Like I said before I am not an expert.  I am a reader.  Which means I try
> and read everything and judge the opinions that I read based on the how
> logical is sounds.  So if I've got this all wrong, please someone let me
> know.
>
> One last thing, for Comp Cams, all of the springs besides the 972 are at
> least double springs (not just a spring with a flat wound damper) and
> require head machining to allow clearance for this extra spring.  It is
> wound inside the other one.
>
> Thanks
> Paul
> #9270
>
>
> ----- Original Message -----
> From: Dennis Antenucci <itbewild@gte.net>
> To: Paul Timko <thedrol@mediaone.net>
> Sent: Tuesday, February 01, 2000 6:14 PM
> Subject: Re: Roller vs hydraulic Cam
>
>
> > Really? No significant difference on power at 5000-6000???!!!
> > MD, who is obviously still learning :-)
> > -----Original Message-----
> > From: Paul Timko <thedrol@mediaone.net>
> > To: Dennis Antenucci <itbewild@gte.net>
> > Date: Tuesday, February 01, 2000 6:04 AM
> > Subject: Re: Roller vs hydraulic Cam
> >
> >
> > >solid lifter is going to be almost exactly the same as hydraulic roller
> > >except for adjusting the valve lash.
> > >
> > >Paul
> > >#9270
> > >
> > >----- Original Message -----
> > >From: Dennis Antenucci <itbewild@gte.net>
> > >To: Paul Timko <thedrol@mediaone.net>
> > >Sent: Tuesday, February 01, 2000 1:35 AM
> > >Subject: Re: Roller vs hydraulic Cam
> > >
> > >
> > >> yea, I'm beginning to think the same thing...I am quickly running out
> of
> > >> cash too....so that will motivate me to live with a simple solid
lifter
> > >cam
> > >> -----Original Message-----
> > >> From: Paul Timko <thedrol@mediaone.net>
> > >> To: Multiple recipients of list <detomaso@realbig.com>
> > >> Date: Monday, January 31, 2000 9:00 PM
> > >> Subject: Re: Roller vs hydraulic Cam
> > >>
> > >>
> > >> >I was planning going the hyrdaulic roller route.  But I talked to a
> tech
> > >> guy
> > >> >at Comp Cams.  He said that it wasn't worth the money (it's like a
> $600
> > >> >premium over a hydraulic flat tappet).  Now maybe I'm wrong, or
maybe
> > >he's
> > >> >not really looking at it right, but it made some sense.  I haven't
> > gotten
> > >> >around to calling the Crane Cams guys yet.  They seem to have the
> widest
> > >> >selection of cams on the market, but it also seems like all of their
> > >stuff
> > >> >is around $1100 for the set as opposed to $300-$400.  This is for
the
> > >whole
> > >> >valve train except rocker arms and valves but including a timing
set.
> > >> >
> > >> >Paul
> > >> >#9270
> > >> >
> > >> >----- Original Message -----
> > >> >From: Tony DiGiovanna <t.digiovanna@mindspring.com>
> > >> >To: Multiple recipients of list <detomaso@realbig.com>
> > >> >Sent: Monday, January 17, 2000 7:25 PM
> > >> >Subject: Roller vs hydraulic Cam
> > >> >
> > >> >
> > >> >> This is a multi-part message in MIME format.
> > >> >>
> > >> >> ------=_NextPart_000_0128_01BF6127.F1942560
> > >> >> Content-Type: text/plain;
> > >> >> charset="iso-8859-1"
> > >> >> Content-Transfer-Encoding: quoted-printable
> > >> >>
> > >> >> I've been playing with Cleveland engine simulations with the
Desktop
> =
> > >> >> Dyno software.  I found a surprising torque increase by switching
> from
> > >a
> > >> =
> > >> >> conventional hydraulic cam to a hydraulic roller cam of low
duration
> > >and
> > >> =
> > >> >> high lift.
> > >> >>
> > >> >> Has anyone made such a switch on their engine and like to comment
on
> > >the
> > >> =
> > >> >> real world results?
> > >> >>
> > >> >> The cam I input is Crane PowerMax Hydraulic Roller
HR-224/339-2S-12
> > RF.
> > >> =
> > >> >> Is anyone running this or similar cam?
> > >> >>
> > >> >> The specs are as follows:
> > >> >>       Degrees Duration @ .050 Int./Exh. Degrees Advertised
Duration
> =
> > >> >> Int./Exh. Degree Lobe Separation Open/Close @.050" Cam Lift
> Int./Exh.
> > =
> > >> >> Lash Hot Int./Exh. Gross Lift Int./Exh.=20
> > >> >>       224
> > >> >>       232 286
> > >> >>       294 112 5    39
> > >> >>       53   (1) .000
> > >> >>       .000 .586
> > >> >>       .609=20
> > >> >>
> > >> >>
> > >> >> ------=_NextPart_000_0128_01BF6127.F1942560
> > >> >> Content-Type: text/html;
> > >> >> charset="iso-8859-1"
> > >> >> Content-Transfer-Encoding: quoted-printable
> > >> >>
> > >> >> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
> > >> >> <HTML>
> > >> >> <META content=3D"text/html; charset=3Diso-8859-1" =
> > >> >> http-equiv=3DContent-Type>
> > >> >> <META content=3D"MSHTML 5.00.2614.3500" name=3DGENERATOR>
> > >> >> <STYLE>
> > >> >> </HEAD>
> > >> >> <BODY bgColor=3D#ffffff>
> > >> >> <DIV>I've been playing with Cleveland
> > >engine
> > >> =
> > >> >> simulations=20
> > >> >> with the Desktop Dyno software.  I found a
> surprising torque
> > >=
> > >> >> increase=20
> > >> >> by switching from a conventional hydraulic cam to a hydraulic
roller
> > >cam
> > >> =
> > >> >> of low=20
> > >> >> duration and high lift.</FONT>
> > >> >> <DIV> 
> > >> >> <DIV>Has anyone made such a switch on
> > their
> > >=
> > >> >> engine and=20
> > >> >> like to comment on the real world results?</FONT>
> > >> >> <DIV> 
> > >> >> <DIV>The cam I input is Crane  >> >> face=3DArial=20
> > >> >> size=3D2><B>PowerMax Hydraulic Roller HR-224/339-2S-12 =
> > >> >> <B>RF. =20
> > >> >> Is anyone running this or similar cam?</FONT>
> > >> >> <DIV> 
> > >> >> <DIV>The specs are as
> > follows:</FONT>
> > >> >> <DIV>
> > >> >> <DIV align=3Dleft>
> > >> >> <TABLE bgColor=3D#ffffff border=3D1 borderColor=3D#000000 =
> > >> >> borderColorDark=3D#000000=20
> > >> >> borderColorLight=3D#c0c0c0 cellSpacing=3D0 height=3D75
width=3D590>
> > >> >>   <TBODY>
> > >> >>   <TR>
> > >> >>     <TD align=3Dmiddle height=3D48> >> >> size=3D2><B>Degrees Duration @=20
> > >> >>       .050 Int./Exh.</B>
> > >> >>     <TD align=3Dmiddle height=3D48> >> >> size=3D2><B>Degrees Advertised=20
> > >> >>       Duration Int./Exh.</B>
> > >> >>     <TD align=3Dmiddle height=3D48> >size=3D2><B>Degree
> > >> =
> > >> >> Lobe=20
> > >> >>       Separation</B>
> > >> >>     <TD align=3Dmiddle height=3D48> >> >> size=3D2><B>Open/Close @.050"=20
> > >> >>       Cam Lift Int./Exh.</B>
> > >> >>     <TD align=3Dmiddle height=3D48><B>Lash
> > >=
> > >> >> Hot=20
> > >> >>       Int./Exh.</B>
> > >> >>     <TD align=3Dmiddle height=3D48> size=3D2><B>Gross
> > >=
> > >> >> Lift=20
> > >> >>       Int./Exh.</B>
> > >> >>   <TR>
> > >> >>     <TD align=3Dmiddle height=3D19> >> >> size=3D2>224<BR>232
> > >> >>     <TD align=3Dmiddle height=3D19> >> >> size=3D2>286<BR>294
> > >> >>     <TD align=3Dmiddle height=3D19> >> >> size=3D2>112</FONT>
> > >> >>     <TD align=3Dmiddle height=3D19> >> >> size=3D2>5   =20
> > >> >>       39<BR>53   (1)
> > >> >>     <TD align=3Dmiddle height=3D19> >> >> size=3D2>.000<BR>.000
> > >> >>     <TD align=3Dmiddle height=3D19> >> >>   =
> > >> >>
> > >>
> >
size=3D2>.586<BR>.609 >> >> ></DIV>
> > >> >>
> > >> >> ------=_NextPart_000_0128_01BF6127.F1942560--
> > >> >>
> > >> >>
> > >> >
> > >> >
> > >>
> > >
> >
>
>

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