I can't tell for sure from your pics, but it appears that #3 & #4 may be for
distributors, #1 & #2 for six cylinder distributors.
Although rotor center to tip dimensions vary somewhat from brand to brand, the
cylinder rotor usually measures around 1.070" from center to rotor tip. The
measures around .850" from center to tip. Measure this dimension carefully. An
gap between rotor tip & the cap contact would be from .010" to .050". Cap
dimensions also vary somewhat between various caps.
A four cylinder (short) rotor in a six cylinder distributor will cause a much
internal spark gap & consequent insulation failure of the rotor.
A six cylinder rotor in a four cylinder distributor will of course cause rotor
distributor cap contact.
Rotor #2 in your pics would be the best design for the six cylinder as it
appears to have
no rivet & is the correct center to tip length.
Martin Heim wrote:
> As beeing again on the rotor thread I would like to ask the listers which
> which - i.e. for which distributor. I'm still working on my project car BN4
> not yet been able to run the motor, still accumulating parts to chose from. I
> four different rotors that are supposed to be for the Lucas DM6A dist. I have
> pictures of the rotors side by side on my web site to show the differences
> like to know which is which. They all fit on the distributor spindle.
> Is #3 the one with the famous rivet?
> Please have a look and comment on the different rotor types.
> Thanks and regards from Germany!