> Comp Cams does have a new polymer type gear out but may not have one for
> the FE.
When I checked a few weeks ago, they only had part numbers listed for
the SBC, BBC, and Windsor Fords (both 0.467" and 0.530" shafts).
> I also know that we use a steel gear on the hydraulic rollers and they
> also do some of the solid roller camshafts with this core.
Comp Cams uses a -8 part number austempered ductile iron cam core for their
SBF retrofit hydraulic roller cams and for some (most) of their street solid
roller cams. A -9 part number 8620 steel cam core is used for the race
solid roller grinds. I checked Comp's website and they list the -8 and -9
cam cores for the SBF and 351C but only -9 cores for the FE. Beware there
may be compatibility problems if you attempt to put a hydraulic roller
profile on a -9 core. I ran into this recently when I attempted to have
some hydraulic roller profiles (Comp 3636 intake and 3637 exhaust) put on
Comp's -9 core. The steel cores they use are rough machined for race solid
roller lobes and grinding milder hydraulic roller lobes will cut through the
cam heat treat. This was for a 351C application but I assume it applies to
their FE cores.
My solution was to use similar lobes from Crane. Crane uses standard base
circle 8620 steel cam cores for their hydraulic roller grinds. The standard
base circle cams are better (less side loading) but require the link bar
Crane lifters (and not the cheaper OEM Ford lifters) in retrofit applications
(blocks without the raised lifter bores). Different roller lifters may have
different diameter rollers so there may be compatibility issues with very
small base circles. Crane says their roller lifters are fine on 1.090"
diameter reduced base circle cams.
> I will do some checking on the cam gear stuff.
> I will see if the steel gear will work on the solid roller cores as well.
Let us know what you find. I recently looked into this when I was doing
a custom hydraulic roller cam for my Pantera. I'm running a 351C-based
engine (Fontana block with C302B high port heads) so the part numbers
below apply to 351C/351M/400 and 429/460 distributor gears. Don't know if
this heps any but here are the distributor gear options I found:
1. Cast Iron Distributor Gears
These are the standard distributor gears used on hydraulic and solid flat
tappet camshafts which use iron cores. Not compatible with most hydraulic
or solid roller cam steel cores. However, Comp Cams claims there -8 part
number hydraulic rollers (which use a cast iron core) are compatible with
standard cast iron cam gears. Note that some cast iron gears from auto
parts stores are substantially softer than OEM iron gears. Also note that
some cam companies use a harder core for certain race solid flat tappet
grinds which may require a bronze (or other material) gear. MSD says its
iron distributor gears are surface-hardened a few points higher than stock
gears because most performance flat-tappet cams are ground on better quality
(harder) cores.
2. Ford Motorsport Steel Gear
P/N M-12390-J (1.421" OD, 0.531" ID, for 351C) in the FRPP catalog.
From page 105 of the 2005 FRPP catalog: "Steel gears are compatible with
billet steel camshafts (hydraulic roller type)". Comp Cams also claims
the Ford gears are compatible with their -8 austempered ductile iron
hydraulic roller cam cores (Comp also uses the -8 cores for some solid
street roller cams). One tech I spoke with at Comp said the Ford hydraulic
roller cam gear was prefered over a standard cast iron gear. According to
MSD, the Ford mild steel distributor gears (as fitted to engines with factory
hydraulic roller cams) are softer than the common ductile iron gears, but
harder than bronze. MSD also claims that Chevy uses a harder cam core for
it's factory hydraulic rollers and uses cast iron gears but that its gears
don't last as long as the Ford gears. Some 5.0L Ford racers have used the
Ford gear on steel cam cores without incident but it's not recommended.
3. Crane Steel Gear
Crane has a coated steel gear which they claim is compatible with induction
hardened or carburized steel roller cores, as well as iron flat tappet cores.
Their website refers to it them as "specially coated and processed steel
distributor gears using either cast flat faced lifter or steel roller
camshafts". They list two part numbers for 351C distributors:
52970-1 Ford V-8 70-82, Boss 351-351C-351M-400 for 0.500" shaft diameter
52971-1 Ford V-8 70-82, Boss 351-351C-351M-400 for 0.531" shaft diameter
Crane does not recommend the use of their gears on camshafts that have been
previously run with other types or materials of gears. Rob at Blue Oval
recommended this gear. Comp Cams did not recommend this gear on their -8
cores. Mike Trusty ran a Crane gear and had it fail in short order. Asa
Jay currently runs Crane's gear on a Crane steel roller cam. I'm told but
have not verified that Crane's earliest steel gears were made like the Ford
gears but their new gears are different. It may be the case that Mike's gear
was the early version and Asa Jay's the late? In any case, I've spoken with
several people who are running the current Crane gears with no problems. Asa
Jay was kind enough to remove his distributor and check the gear and reported
it had a normal contact pattern and wear.
4. Mallory Distributor Gear
Mallory makes a distributor gear for their distributors that are 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. As I understand it, the gear is heat-treated for compatibility.
5. Bronze-Aluminum Distributor Gears
Generally softer than iron. Compatible with most cam cores but wears
rapidly. A bronze distributor gear is essentially sacrificial, wearing
the distributor gear instead of the roller cam gear. Usually specified
for solid roller cams. Note that hardness can vary from manufacturer to
manufacturer. If running one of these gears, you may want to run an
oil filter without a bypass so the filter catches the 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.
6. Comp Cams Carbon Ultra-Poly Composite Distributor Gear
Also meant as a replacement for rapid wearing bronze gears, Comp has a
composite material gear. These are currently only available for Windsor
Fords and small and big block Chevys.
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 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).
> I know that a lot of the distributor gears are just stuck on the
> distributors where the hole is drilled in the gear. This is not always
> the location it needs to be. We have found some on in the wrong place
> and this caused premature wear.
Yes and it's not only the up-and-down placement but also fore-and-aft.
We ran into a problem on an engine that used a front cover mounted
distributor and it had to be bored and bushed to get proper gear mesh.
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.
Dan Jones