From: hotrod@dixie.com (The Hotrod List)
Subject: Re: Solid Lifters?
Date: Sat, 09 Jan 93 08:55:51 GMT
Organization: Dixie Communications Public Access.  The Mouth of the South.
To: hotrod@dixie.com
Reply-To: hotrod@dixie.com
Posted-Date: Saturday, Jan 09 03:55:46
X-Sequence: 3327
X-Gifs-To: met@sunset.cse.nau.edu
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-> So for an application like mine - "329 the hard way" intended for
-> street, low RPM, emissions legal use - that I want to yield as much
-> economy and bottom end grunt as possible....   one of these cams
-> would be a good selection?  I was thinking about the Chevy ZZ3 roller
-> cam as a model.  It has some very impressive torque figures and is
-> smog legal.

 Lessee... the ZZ1 cam is definitely lopey.  The ZZ3 shortened the
intake duration quite a bit and jacked up the lift, right?  For a
torque/mileage engine, it sounds like it'd be on the outer edge of what
you want, assuming you're running a carb instead of EFI.  I think I'd
pick something a bit milder.


-> It has some very impressive torque figures and is smog legal.

 Uh... that's a midrange performance cam for a 350.  It'll perform quite
differently in your 329.  I'd call four or five cam grinders and ask for
opinions, but I bet they'll recommend something around 214-220 @.050,
.450 or so lift.  "Computer cams" generally have 112 to 114 degree lobe
centers to minimize overlap; "RV" and "torque" profiles generally have
110 to 112, and general performance cams 108 to 110.  Closing the lobe
center tends to make more power at the expense of moving the power peak
further up the RPM band.  I'd call for a 110 center, given no more
information than you've given so far.


-> The '82
-> 305 block that I will be starting with does not have hydraulic
-> lifters, so I would have to go the Crane (whoever) retrofit route.  I
-> am trying to get a warm and fuzzy feeling that the roller route would
-> be worth the money and effort to put together.  What do you guys
-> think?

 I plan on scavenging the lifters and the weird finger-tray from the
junkyard when I redo the 262.  I'll make some brackets to mount the
tray in the 262 lifter valley (convenient since I have a roller 350
apart to measure the height needed).  I've even thought about simply
cutting a PVC block and screwing it to the top of the tray, then letting
the intake manifold retain it.  Basically, it only has to be kept from
moving UP; the lifters themselves keep it from moving front to rear or
side to side.


-> I don't understand "quick cam profiles".  I thought the folks at
-> Chevy and the rest have gone to rollers because they *can* get a
-> quick profile. The short duration, highER lift cams can be ground for
-> roller setups where the same specs would be impossible on hydraulic
-> or solid setups. True??

 Theoretically, yes.  However, the standard GM profiles (and Ford, for
that matter) are nearly identical to their flat tappet profiles, and are
very conservative.  Chevy's lifters were just too damned small in
diameter, and premature lifter and cam wear has been a bugaboo ever
since 1955.  Chevy went roller to reduce warranty service.  Ford's
switchover to rollers was to "minimize valvetrain friction" according to
one cam grinder who was in on it.  Like I said, the factory (at least
GM) lifters are very heavy; to get much of a cam in there you'd have to
switch to some *much* stiffer springs, and that's something the cam
grinder can't control.  All it would take would be a few people buying
their Bad Boy Super-Mega-Whoopee Roller, not changing the springs to
save a few bucks, and then floating a valve into a piston top.  Enough
people claiming "Bad Boy cams suck" can hurt sales, plus the stock
lifters have plain old hydraulic guts, which means they'll start pumping
up around 5500 RPM or so.


-> What is the "real performance profile" that you have been waiting
-> for? Do you want a high RPM screamer?  What kind of application do
-> these cams fall short for?

 Well, maybe I'm waiting for a lobe with corners on it.  <grin>  When
someone comes out with a street roller that's about 240 @ .050 with .550
lift and some really bitchen acceleration on the intake side, then I'll
be happy.  For some reason, even the smallest "real" rollers start off
considerably larger than that.  Someday...  it's cost, of course.  You
can get the kind of numbers I'm talking about with a solid lifter, flat
tappet cam for less than half the price of a roller, or even a third of
the price.


-> I had not considered using anything but the roller set designed for
-> the cam - a matched set.  Now that I understand the profile of the
-> cam as it relates to the geometry of the roller better, thanks to
-> your explanation, I now know to *always* keep the set matched.

 You're welcome.  I have a tendency to wander off the subject, mount my
soapbox, and expound at length on random semi-related topics.  I'm glad
you found that one to be of use.  <grin>
                                                    

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Posted by: emory!chaos.lrk.ar.us!dave.williams (Dave Williams)
Newsgroups: alt.hotrod,wiz.hotrod