Oct 31, 2015
I've been experiencing an occasional misfire when the car has been running. It an ignition problem as often the rev counter will drop to zero when it happens.
The system installed was Superformances Super 4 amplifier system which uses the original points to trigger a CDU system. They no longer make and so I think something in my system was breaking down. In the years since Superformance made this Pertronix developed a kit for the Marelli S127e distributor as used on Ferrari 308's and Urracos so it was time to upgrade for me.
The Ignitor II kit plus coils and new Taylor plug wires came to £500 so a hefty upgrade away from points to hopefully a pretty much zero maintenance system with, as Pertronix claim, adaptive dwell angle as well.
First thing was to check the timing before stripping the old system out which involved getting under the car as the timing marks on the flywheel are visible through a slot in the lower forward area of the bell housing - not a great place!
You can just see the mark on the flywheel and there is a mark in the centre of the slot which lines up at static advance. This was taken with the engine running and my strobe light so I'm impressed it came out.
Next step was to mark the position of the rotor in the distributor just in case and take a few photos of everything for reference. Then strip out the old points.
All went well, but there is a clip which holds the felt pad to oil the points lobs. This is rivited through into the body of the distributor. This has to come out as the Pertronix 9MR-184 kit needs to sit flatt on the distributor. I had to drill out the rivet heads that hold the clip in and carefully knock the remains of the rivets out and into the weights area. Thus I ended up removing the distributor to turn the shaft to I could pick the two rivet remains out with tweezers.
The instructions did note that the clip would need removing but not that it would need rivets drilling out - which really means distributor out. Anyway, it all went to plan and the new kit was fitted in and fixed in place by one of the original points fixing screws. Then place the 4 magnet collar over the original lobe and reassemble the distributor top.
At this point I realised that the plate with the pickups on can be positions at three different angles in the distributor which was a bit a problem. Which position do I choose ? I choose the one where the sets of wires were closest to the exit holes in the body of the distributor.
Then I carefully splotted the distributor back into it's hole in the block. It's driven (like most) by a spiral gear off the auxiliary shaft so when pushing down you have to anticipate that the rotor arm will rotate about 15° degrees. Of course you mark it's position before removing the distributor and so it's easy enough to get it to re-align back to the correct position - if you get the wrong tooth on the drive shaft it's very clear to see as as it will be about 15mm from your original mark so a bit of trial and error works fine.
With the distributor cap back on and the new plug leads also fitted (need to be supression type) and the new coils wired to the ignitor modules and 12v live ignition feed I gave it a go. It didn't start but gave the odd fire which in my experience can mean things are 180° degrees out. I read on Lamborghini Talk about a fellow owner fitting this kit and he said the two coils outputs needed swapping over. I did that on the distributor cap and it fired up perfectly!
Back underneath to check the timing and gave it a tweak. Timing is 18° at static (no) advance and this is identified with your timing gun pickup on No. 1 cylinder (rear bank, right hand plug closest to the timing cover and looking though the timing hole at the appopriate (PMS - top dead centre) mark on the flywheel. If you dial in 18° of advance on you gun then the AA mark will coming into view on the window and should line up with the bell housing mark.
A quick drive out but only a short test revlealed no misfires so hopefully that's now sorted!