View Full Version : Avanti engine ground

10-08-2008, 08:44 PM
I have a 63 Avanti R2, with battery in trunk. Negative ground to frame, positive to starter solenoid. No ground to engine. One
melted cable end, negative terminal on battery. I carry a fire
extinguisher in the back seat. I'm thinking about a ground strap
from the engine to the frame. Looking at the wiring diagram in
the shop manual I don't see any connection between engine and
frame. Anyone else have a battery in trunk, I would like to
keep the battery where it is, but not have any more meltdowns.
Any advice would be appreciated.

10-08-2008, 08:54 PM
The Avanti lives and dies by it's grounds. Run a ground from the frame to the engine, battery cable size and also a 10 Gauge from the frame to the white wire under one of the bolts on the starter solenoid.

10-08-2008, 09:04 PM
I don't have my battery in the trunk but I did run a couple of ground straps from the engine to the frame in inconspicuous places.


10-08-2008, 09:25 PM


10-08-2008, 11:21 PM
My 63 has a braided cable connecting engine to frame at one of the motor mounts - looked original when I re-did the car 7 years ago...


1951 Rod
1962 Champ
1963 Avanti R1
1963 GT Hawk R2 4 speed
1964 Daytona Convertible
2006 Avanti Convertible

10-08-2008, 11:27 PM
They did, but by now that wire has become frayed and corroded or left off. That little wire will not take much current and those starters take a lot.

10-09-2008, 06:31 AM
With the battery in the trunk, (hopefully mounted in a Marine box, fixed to the floor)
A) The +12 cable from the battery TO the solenoid and the solenoid to the starter should be around '0000' gauge.
B) The solenoid should be grounded, either to the (-)battery terminal, or the frame with something like 12 gauge.
C) The -12 battery terminal should be attached to the frame (ideally, just below the battery)
D) The engine should be grounded to the frame. I suppose here, you could use the original ground strap, but I'd again opt for the '0000' cable.
E) Sweat the large copper lugs onto the cables. When attaching them anywhere, sand the surface clean of paint/rust and use electrolytic grease.

Bob Johnstone
55 President State Sedan
64 GT Hawk
70 Avanti (R3)

10-09-2008, 01:16 PM
The -12v cable from the battery should go directly to the engine to handle the starting load. The engine to frame grounds handle the balance of the circuitry. With the battery in the trunk, you have to do what Bob says and make sure that extra connection - battery-frame-engine is of the same gauge and zero resistance.

10-17-2008, 04:10 AM
Thanks to all who responded, especially Bob Johnstone, this forum is
a great resource, I'm very happy to be able to participate.