Melted Rotor Buttons

PSI086 · Running on 1 Cylinder Joined: 12 Feb 2006 Posts: 22

This is the 2nd rotor button I've melted in the past 3 weeks. Was brand new and has done maybe 4 hours driving. The car is a VL RB30 Turbo running an EMS 8860 with a Crane Hi6 CDI and LX92 coil. Is this a normal thing for a CDI or is something like an ecu setting wrong? I'm 99% sure the rotor button has been moved to the correct position

RMS · Posted: Thu Mar 11, 2010 2:34 am Post subject:

High output ignitions can do weird things to rotors, plugs, etc. Have you tried to find a rotor in a different brand that might have a thicker "bridge" of metal from the center to the tip or maybe in brass?

You can usually tell if the rotor is pointed correctly as there will be burnt marks in the center of the outer electrode and the outer edges will still be clean/sharp.

You might be able to cut vents in your distributor cap top and bottom to allow air in there to cool it but it can let water in if its raining and cause drivability issues.

PSI086 · Running on 1 Cylinder Joined: 12 Feb 2006 Posts: 22

Cheers for the reply. I'll try and get a picture of the dissy cap and post it up. I have been speaking to a couple of ignition guys, one being the distributer from Crane in Australia and they both said it would be the indexing in the cap. The button was set up at 20deg btdc as per the EMS instructions

PSI086 · Running on 1 Cylinder Joined: 12 Feb 2006 Posts: 22

Heres the rotor button after 400km after it was cleaned up from those previous pics.

Just wondering if theres any incorrect settings in the ECU set up also?

RMS · Posted: Sun Mar 14, 2010 6:06 am Post subject:

If you have a junk distributor cap you can cut the top open to be able to see where the rotor is vs the dist cap electrodes with the crank lined up at your maximum and minimum timing. This is the easiest way to be sure the rotor is where it should be. When you cut the top off the dist cap, leave the electrodes (besides the center) and hollow out the center with a dremel or cut off tool etc.

You just want to make sure if the rotor to trigger wheel is splined or some kind of step of adjustability you set it more towards the cylinder behind instead of more towards the cylinder ahead to avoid cross spark detonation.

CDI's have different settings. I think MSD wants 2ms or maybe off for dwell, cant remember. Did crane specify any dwell and firing edge when used with standalone?

Its hard to tell from the rotor pic if the oxidation/residue is in the center of the rotor edge or not.

I have LS2 truck coils per cylinder on my setup. They're not cdi but output some serious juice, 120 mA iirc. With NGK copper spark plugs the center electrode has worn rounded edges in about 4k miles. Its possible things are setup right and the rotor just cant handle the current.