| A early 911 owner asked recently
about installing a larger capacity starter on his up-graded 3.0 SC engine to help hot
starting problems. The starter on rare occasions refuses to crank the engine - seems to
happen when you least need it to.
Yes the higher capacity
starters do help spin the engine in cold weather and when they are hot. I have installed
the later 911 starter with 1.5 hp. This evolved from the early 0.8 hp starters that worked
OK for engines up to 2.2 liters.
The factory installed 1.5 hp starters in the beginning of
1972, then in their wisdom reverted back to the 0.8 hp starter in May of 1972, using these
until the beginning of 1974 when all production 911 cars came with 1.5 hp starters.
The 1973 Carrera 911 RS 2.7 came with a 1.5 hp starter and was
available on special order. There are specialty retailers offering even greater hp
starters for the Porsche. Some of these use Japanese starters with a Porsche type frame
mount. These have very small size motors with very high out put from geared reduction.
They are compact and reliable.
The factory 1.5 hp starter also came with another critical
improvement. The battery-starter lead was increased in size from 25mm/2 (cross section) to
35 mm/2, (these had a yellow stripe applied around the cable at approx. 800 mm from the
starter end). This cable enlargement was necessary to carry full battery capacity to the
starter to enable it to deliver full cranking horsepower. While a 3.0 SC engine will need
a 1.5 hp starter it will probably not get 1.5 hp worth of battery power until you have the
correct cable size to transmit it.
Having experienced the need for more power to the starter on
my little blue turbo car I realized the need to up-grade my old starter cable. I bought a
good used cable and started the project by disconnecting the battery (installing a 9 volt
radio code saver in the cigar lighter).
Remove the drivers seat, carpeting on the floor, center
tunnel cover, console, floor board under the pedals, and trans. tunnel cover. The trunk
carpeting needs to be pulled back a little.
Jack and safety stand the rear of your Porsche
to allow plenty of room to access the starter area. Using a good flash light and a mirror
inspect the old cable and pushed away the plastic covered body wraps that hold the cable
in place away from all those pedal controls, wiring, fuel lines, and shift linkage. If you
find other junk in there it is a good time to remove it. Also inspect the throttle rod
plastic bushes. they turn yellow with age and deteriorate. The throttle pedal feels
sloppy-etc. this is a great time to replace them.
The shifter and hand brake need NOT be removed.
Start in the trunk by removing the battery cable end. Solder a
"end lug" onto the copper cable. Next wrap wire through the newly soldered cable
end and the new cable 35 mm/2 starter end, this will enable you to pull the new cable
through the body structure and have the new starter end lug arrive at the starter. You
will need to coach the cable through with a little encouragement. The new cable is
about 11.5 mm in diameter and the old one is 10.2 mm-get it? It takes time but when
the new cable is installed on the starter you can back track forward pulling a little
slack from the front as you go from rear to front to smooth out the cable routing. Secure
the body wraps and work up to the trunk.
The cable may need to be shortened at the battery end, to
avoid too muck extra cable length flopping around. I would recommend a new battery
connector, anti-corrosion felt washers, and dielectric paste on the connections.
Remove the radio code saver 9v battery, and you are ready to
try your full 1.5 hp starter system. I noticed a immediate improvement in the starter
sound. The pitch of the motor was higher, and the starter cranked faster at every start. I
also observed a higher voltage at the voltmeter (an add on), as soon as the alternator was
I have also noticed brighter headlights at night, and the two
fuel pumps run a little quieter. This may not solve a sick starter problem but it is a
must to gain anything from a improved capacity starter and battery.