[DeTomaso] Distributor gear Question

SG sdlgibson at sbcglobal.net
Thu Apr 12 12:35:11 EDT 2012


Dan,  TMeyer inc. has the lunati Everwear gear for about $55 if i remember correctly, and also have you ever looked at the Wix 51647 filter?  It's a Nissan truck app. and is listed with no bypass, it's full size, 390 burst pressure, and 7-9 gpm flow rate.  I've used it with no problems.
                                       Shaun G.

--- On Thu, 4/12/12, Daniel C Jones <daniel.c.jones2 at gmail.com> wrote:


From: Daniel C Jones <daniel.c.jones2 at gmail.com>
Subject: Re: [DeTomaso] Distributor gear Question
To: "Pantera REALBIG forum" <detomaso at realbig.com>
Date: Thursday, April 12, 2012, 11:06 AM


> I have spoken to comp cams several times and they say most of their hydraulic
> roller cams can be used with regular steel distributor gears so that is what I
> have done on 2 cars.

I think you are confusing steel with cast iron.  They are not the same
materials.  Comp Cams makes most of their hydraulic roller cam cores (and some
of their street solid rollers) out of austempered ductile iron.  They claim
those cams are compatible with cast iron cam gears.  Cams can be made from
plain cast iron, selectively austempered ductile iron (SADI) or a
variety of steels
(1010, 5150, 5160, 8620, 8660, etc.).  Crane claims their steel gear
is compatible
with all cam core materials for both flat and roller cams.  Note Crane does not
recommend the use of their gears on camshafts that have been
previously run with
other types or materials of gears.

Some engine builders have had problems running cast iron distributor gears
on Comp Cams SADI cores.  Several years ago, Ford engine builder Keith Craft
had problems on both Comp and Lunati flat tappet cores and switched to the
Crane/Ford Motorsport steel distributor gears and it cured the wear problem.
Keith told both Comp and Lunati about it and he said they thought he was crazy.

In addition to Crane, other companies such as Lunati and Mallory have alloy
steel gears but these may or may not be compatible with steel cores.  Lunati's
gear sounds very much like Cranes:

"Lunati now offers the Everwear distributor gears for most popular
  applications.  The Everwear distributor gears were developed with a new
  material that has excellent wear characteristics and uses a special nitride
  process to case harden the gear. The camshaft industry uses primarily 1050,
  5150, 5160, 8620 and 8660 materials for most steel cam cores. Now with
  Everwear distributor gear there are no longer any issues with compatibility
  of material as the Everwear distributor gears are compatible with all of
  these materials."

I checked Lunati's online catalog and don't see a part number for a 351C listed
but am told they do indeed have one.

Mallory's "alloy steel" gear is made specifically for "austempered ductile
iron billets" and "proferal billet" cams.  It is supposed to be compatible with
the Comp Cams austempered iron cam cores.  Orville Burg's Accel distributor
came with a gear and he ordered a replacement gear from Accel that was supposed
to be a steel alloy gear that is compatible with steel roller cams.  I called
Accel (part of Mr. Gasket) and was given the Mallory part number for Mallory's
steel alloy 351C gear (p/n 29420).  Accel said it would do the job with a steel
cam but Mallory's catalog (and Accel's) specifically says heat treated iron cam
cores only (proferal billet and austempered ductil iron".  FWIW, Orville took
the gear to a machine shop that makes gears and they Brinnell tested it.  It
was quite hard.  According to the Mallory catalog:

"Mallory Distributor Gears are precision machined from alloy steel in our
  factory to exacting original equipment specifications. Special attention
  is given to the heat treating requirements of each gear to assure the
  proper hardness, giving trouble free service when used with proferal billet
  (hydraulic and mechanical flat tappet) and selectively austempered ductile
  iron billet (hydraulic roller tappet) camshafts."

Orville went ahead and used the Mallory gear as it was the only one available
for his Accel distributor which has a smaller 0.490" shaft diameter.

The MSD gear for hydraulic roller cams also appears to be for austempered
ductile iron cams but not steel.  The MSD gear is a melonite QPQ coated iron
alloy.  Melonite QPQ is a thermochemical (molten salt bath) case hardening
process that improves wear resistance and lowers friction.  MSD claims they
use a proprietary formulated ductile iron and their advertising says the gear
is designed specifically for hydraulic roller cams.

> Tri-Tec designed their gears by working off of the original Ford drawings for
> the 351C/460 dist. gear, so you can be sure the part is correct.

That does not mean you can simply slide the gear on and use the existing
drilled hole in the distributor.  A replacement distributor gear may or may
not have a holed drilled in it.  Ford cautions that the hole should not be
used for alignment purposes.  Position the gear to the proper location, then
drill a new hole 90 degree to the old hole.  Dykem the contact pattern.  Pull
and inspect gear after a while.  Make sure the gear is not bottoming out and
binding and that the oil pump driveshaft isn't too long.  MSD recommends using
a moly lube to break-in the cam/distributor gears.  They say squirting it on
the gear is insufficient and suggest using a toothbrush to work it into the
pores of the metal.  Some sources recommend that whenever you remove a
distributor, that you mark it so you can reinstall the gear in the same
position to maintain the wear pattern.  You may also want to de-burr the
gear before installation.  You can see the Ford Motorsport instructions
for fitting distributor gears here:

http://www.bacomatic.org/gallery2/v/hidden/dan/dan-cars/album04/album24/FordInstShtM_12390_ABCDEFGH.jpg.html

and the distributor installed heights for various Ford pushrod V8's are listed
here:

http://www.bacomatic.org/gallery2/v/hidden/dan/dan-cars/album04/album24/OHOnews18of38.jpg.html

> Tri-Tec Motorsports (http://www.tritecmotorsports.com) has composite gears
> for the 351C coming out any day now. They've been doing endurance testing
> for about six months, so the gears should be ready for sale.

Don't hold your breath.  I have an email message from Tri-Tec that said they'd
their 351C/460 distributor gears ready by December 2010.  Initial feedback
that I have is from drag racers who say there have been a number of composite
gear failures.

More on the cam gear hardness problem.  A few years back, Steve Grossen
ruined several cams and gears on a 351W which led him to Rockwell (B scale)
test several distributor gears.  A generic auto parts cast iron gear tested
at 70, the bronze gear at 90, and the stock Ford gear was 102.  Note that
the soft aluminum bronze gear was harder than the generic auto parts cast
iron gear.  Steve eventually traced his trouble to a batch of cam cores with
improperly machined gears (Comp doesn't check each gear, only a statistical
sampling).  Comp replaced the cams and eventually gave him one with the
"NASCAR" treatment" (filed, wire brushed on a wire wheel, and bead blasted).

It may be a good idea to run an oil filter without a bypass so the filter
catches any gear wear particles.  On a 351C, consider using Purolator oil
filter number L30119.  It's a full size replacement for the FL-1A Ford/PH8A
Fram filter.  It has no bypass spring in the middle but it does have the
rubber flapper for anti-drainback.  The original application is for a 1978
Nissan 510, 2.0L 4 cyl engine (L20B) which had the bypass valve in the engine
block.  This filter cross-references to a Fram PH2850, a Motorcraft FL-181,
and a Wix 51452.  However, those filters have not been verified and may have
a bypass.  It appears after 1978, Nissan went to a half height filter.
Purolator part number L22167 fits that application and does not have the
bypass spring but does have the rubber flapper for anti-drainback.  Race
engines may want to run dual filters.

In summary, there are a variety of gears to fit a variety of cam materials

1. cast iron gear for flat tappet cast iron cores
2. iron and steel alloy gears for austempered ductile iron cores
(Mallory and MSD)

Mallory 29420 Ford V-8 70-82, 351C-351M-400 for 0.531" shaft diameter
Mallory 29420PD Ford V-8 70-82, 351C-351M-400 for 0.531" shaft diameter
Mallory 29459 Ford V-8 70-82, 351C-351M-400 for 0.490" shaft diameter
Mallory 29459PD Ford V-8 70-82, 351C-351M-400 for 0.490" shaft diameter
Note PD after the part number indicates a gear that is "pre-drilled".
MSD 85813 Ford V-8 70-82, Boss 351-351C-351M-400 for 0.531" shaft diameter

3. steel gears for both steel and cast iron cores (Crane and Lunati)

Lunati P/N?
Crane 52970-1 Ford V-8 70-82, 351C-351M-400 for 0.500" shaft diameter
Crane 52971-1 Ford V-8 70-82, 351C-351M-400 for 0.531" shaft diameter
The latter was also marketed under P/N M-12390-J (1.421" OD, 0.531" ID,
for 351C) in the FRPP catalog.

4. bronze-aluminum gears for steel roller cores
5. carbon ultra-poly composite (Tri-Tec, Comp Cams) for both steel and iron
  cores.  Still in development.

Dan Jones
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