[DeTomaso] Comp Cam's roller lifters

[Mike Drew]

Dan,

Don't forget that 'carbon poly' distributor gears are available now for the 351C which supposedly are compatible with all kinds of cam materials...do you have any experience with them yet?

Mike

Sent from my iPad

On Oct 6, 2017, at 11:51, Daniel C Jones <daniel.c.jones2 at gmail.com> wrote:

>> Does anyone have any experience with the Comp Cam's retrofit kit's
>   such as this?
>   There are two ways to run a hydraulic roller cam in a 351C.A  The first
>   is to run link bar lifters.A  The other is to run the spider and dog
>   bones arrangement similar to what was introduced in the mid 1980s on
>   the 5.0L Ford V8.A  The Comp retrofit kit is the latter.A  We've run
>   both arrangements and there are some issues to be aware of.A  It varies
>   from block-to-block and depends upon the size of the chamfer at the top
>   of the lifter bore but, on many blocks, the oil feed is exposed at
>   maximum lobe lift on stock base circle cams.A  Some manufacturers (like
>   Comp) will reduce the base circle of the cam so the OEM type lifters
>   can be used.A  As a rule, irregardless of how much lift that a camshaft
>   has, the lifters generally all stop in approximately the same location
>   at the top unless the base circle is deliberately reduced which can
>   cause problems at the other end of the lifter bores.A  With a reduced
>   base circle cam, the OEM lifters will usually be safe at maximum lift
>   but some blocks will have interference problems with the dog bones.A  A
>   local shop which uses the Comp retrofit kit has a fixture to machine
>   the block for clearance but it can also be done by hand.A  Comps link
>   bar lifters have the oil feed (and associated band on the lifter) in
>   the same place as the OEM lifters so have the same problems at max lobe
>   lift.
>   Other retrofit link bar lifters like the Crane, Gaterman (copies of the
>   Crane), Howards (made by Gaterman), Lunati (made by Morel) have the oil
>   feed placed lower on the lifter body and do not have the max lift
>   problem.A A  My favorites are the Crane link bars but they are quite
>   expensive.A  The Lunati/Morel hydraulic roller lifters cost about half
>   what the Cranes do and seem to work well.A  Be aware there are some
>   Chinese knock-offs of the Cranes that should be avoided (tested on a
>   spring load machine and failed).
>   Comps kit comes with pushrods, springs and timing chain set.A  Comp
>   doesn't make the timing chains and gets them from a variety of
>   manufacturers.A  Often (usually) the gears are from one manufacturer
>   and the chains are from another.A  There are some good and some very
>   bad chains out there so you need to verify the name on the chain
>   links.A  Avoid chains with no name or "Rolon".A  The pushrods are
>   shorter for the taller hydraulic roller lifters but may not be correct
>   for your engine.A  Due to tolerance stack up in the cam base circle
>   diameter, rocker arm, whether or not the heads and/or block have been
>   milled, the pushrod length you need may be different.A  Given the
>   angles involved with the canted valve heads, it is important to get the
>   pushrod length and valve train geometry correct.
>   Have your heads been converted to studs and guide plates or are they
>   the original pedestal mount?A  What rocker arms are you using?A  The
>   spring loads required for a hydraulic roller cam may exceed the
>   pedestal mount bolt strength.
>   Another issue is distributor gear compatibility.A  The cam core can be
>   made from a variety of materials, generally either on of several steels
>   or a SADI core.A  Unless you get a custom grind, Comp uses a SADI
>   core.A  SADI stands for selectively austempered ductile iron.A  SADI
>   cores are generally compatible with cast iron distributor gears.A  Be
>   aware the quality of cast iron gears varies greatly.A  Following
>   several cast iron gear failures, a friend Brinneltested several
>   different cast iron distributor gears and found that some gears
>   (especially those purchased from auto parts stores) were softer than
>   the OEM Ford cast iron gear and some were even softer than an
>   aluminum-bronze gear.A  Mallory makes a distributor gear for their
>   distributors that is made specifically for "austempered ductile iron
>   billets" and "proferal billet" cams.A  "Proferal" is a grade of iron
>   alloy that is used primarily for non-roller camshafts because of its
>   anti-wear characteristics.
>> I used the Crane Cams roller conversion kit, with a Crane 351C
>   hydraulic roller cam and lifters.
>   We've used the Crane kit before as well.A  It differs from Comp in that
>   Crane uses an 8620 steel cam core of standard base circle.A  The steel
>   core requires one of Crane's compatible steel distributor gears:
>   A 52970-1 Ford V-8 70-82, Boss 351-351C-351M-400 for 0.500" shaft
>   diameter
>   A 52971-1 Ford V-8 70-82, Boss 351-351C-351M-400 for 0.531" shaft
>   diameter
>   As noted above, the size of the lifter bore chamfer determines whether
>   a standard base circle cam like Crane uses will work in a specific
>   block with OEM style lifters.
>   We've used both steel and SADI cores successfully (with the proper
>   distributor gear).A  The Gaterman/Howards or Morel/Lunati link bar
>   lifters are inexpensive enough that we no longer use the OEM style
>   retrofit kits.A  Rather than buying a kit with parts of unknown brand
>   and specification, I prefer to put together parts of known pedigree
>   that fit the application.A  A custom hydraulic roller cam is around
>   $100 more than an off-the-shelf grind which may not match your engine.
>> When Denny Aldridge built our 351C he used Comp Cams roller lifters.
>   Thank the lord above that he then dyno'd the engine - and found the
>   lifters would not stay up.
>   Plus one on the dyno testing.A  We found a link bar that had come
>   detached on a Crane lifter during a dyno test.A  This was back when
>   Crane went out of business but before they reorganized.A  Someone had
>   bought the remaining inventory and had sold the lifters without
>   realizing they had not been finish machined.A  The specific problem was
>   the link bars had been pressed into place but the ends of the axles had
>   not been peened to retain the link bars.
>   Dan Jones
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