MSD timing control compatability with Chim ignition system
Discussion
I need to retard my ignition when running on nitrous due to the faster burn and know racers that use a product by MSD.
The item number is BY8782 and can be seen in Real Steels catalogue here on page 7.. http://www.realsteel.co.uk/section9.pdf
It claims to be universal but its been suggested to me by Trevor at Wizards of Nos that it might not work with the Chimaeras ignition and management system.
Hopefully some guru will know before i make the order.
The item number is BY8782 and can be seen in Real Steels catalogue here on page 7.. http://www.realsteel.co.uk/section9.pdf
It claims to be universal but its been suggested to me by Trevor at Wizards of Nos that it might not work with the Chimaeras ignition and management system.
Hopefully some guru will know before i make the order.
I would have thought if you were adding enough to matter it would be worth replacing the clockwork single coil system with something a bit more consistent - coil packs also result in a stronger spark at high revs and a mapped system would let you optimise the timing everywhere instead of being knock limited. If you really want to do this on the cheap how about just retarding the ignition static timing by the required amount? I assume you would have NOS on while it matters. (The vacuum advance unit does give you a mechanism you could use to frig the timing yourself if you want to get adventurous.)
Im looking for a quick fix for now and will be looking into coilpacks etc over the winter. I would be interested to know what i need and the costs.
Maybe i can raid a modern landrover???
The rule of thumb is to retard 2deg per 50bhp of nitrous added so im needing to retard upto 8-10 deg.
Ive thought about the vaccuum advance mechanism idea and will take a closer look this week.
Maybe i can raid a modern landrover???
The rule of thumb is to retard 2deg per 50bhp of nitrous added so im needing to retard upto 8-10 deg.
Ive thought about the vaccuum advance mechanism idea and will take a closer look this week.
dbv8 said:
The much cheaper option is to just fit a rotor arm with a few mil taken off the leading edge 
That won't affect the timing, unless you take so much off that you start missing the post completely. What it will do though is reduce the range of vacuum advance that the dizzy can cope with.GreenV8S said:
dbv8 said:
The much cheaper option is to just fit a rotor arm with a few mil taken off the leading edge
That won't affect the timing, unless you take so much off that you start missing the post completely. What it will do though is reduce the range of vacuum advance that the dizzy can cope with.If you could put the rotor arm in so that it sat at a different position then that has the same affect as turning the dizzy. Im talking about modifying the arm so it sits 10 degrees anticlockwise from the standard position. This would be a quick fix for me at the track and i would simply swap the rotor arm back to the original for the drive home.
Pupp said:
Why not just mark the current position of the dizzy and then put another mark 10 degrees or whatever further round to equate to the desired setting... bit crude but effective assuming the marks were accurate referenced against a light?
Thats another idea but could be less accurate unless checking with a strobe.Also its a lot less work to swap the rotor arm than fight to loosen the dizzy clamp.
Until i get a proper management system im just thinking of the easiest (laziest) way to reset the timing at the track. Its bad enough having to pack the tent and swap the rear wheels etc after a weekend especially if the weathers on the turn.
Any volunteers to act as pit crew so i can just do the driving?
dbv8 said:
GreenV8S said:
dbv8 said:
The much cheaper option is to just fit a rotor arm with a few mil taken off the leading edge
That won't affect the timing, unless you take so much off that you start missing the post completely. What it will do though is reduce the range of vacuum advance that the dizzy can cope with.If you could put the rotor arm in so that it sat at a different position then that has the same affect as turning the dizzy. Im talking about modifying the arm so it sits 10 degrees anticlockwise from the standard position. This would be a quick fix for me at the track and i would simply swap the rotor arm back to the original for the drive home.
This is the way i see it.
The rotor arm is in a fixed position through the dizzy and driven off a gear on the camshaft which in turn is driven via a chain from the crank.
When you adjust the timing by the normal method the dizzy is turned and therfore the dizzy cap pickups change position in relation to the rotor arm.
Ie if the rotor arms keyway was 90 degrees out then the dizzy or leads would have to be moved 90 degrees to find the correct position of the rotor arm ie the postion of the engine.
Surely all you are doing when movng the dizzy is changing the position of the cap to the arm. Moving the relative position of the arm instead is the same thing.
Why (in my head) does this seem so obvious?
Maybe im missing something.
I will be the first to admit im a fool if i turn out to be wrong
The rotor arm is in a fixed position through the dizzy and driven off a gear on the camshaft which in turn is driven via a chain from the crank.
When you adjust the timing by the normal method the dizzy is turned and therfore the dizzy cap pickups change position in relation to the rotor arm.
Ie if the rotor arms keyway was 90 degrees out then the dizzy or leads would have to be moved 90 degrees to find the correct position of the rotor arm ie the postion of the engine.
Surely all you are doing when movng the dizzy is changing the position of the cap to the arm. Moving the relative position of the arm instead is the same thing.
Why (in my head) does this seem so obvious?
Maybe im missing something.
I will be the first to admit im a fool if i turn out to be wrong
The way it works is that inside the distributor is a low voltage switch that fires the coil at set points, the coil fires and the spark passes to the distributor and then out to the plugs, changing the rotor arm will not change the timing, and as has been said just make the spark jump a bigger gap at the rotor/cap due to the rotor position and the spark not happening at the same time.
A link that might make it clearer
http://auto.howstuffworks.com/ignition-system.htm
A link that might make it clearer
http://auto.howstuffworks.com/ignition-system.htm
Edited by PRTVR on Friday 14th August 09:05
Your are missing the point completely, the trigger point for the spark is set by the alignment of magnetic pickup in the distributor base, the rotor are is purely a matter of pointing the resulting spark down the correct plug lead. The rotor arm tip is wide enough to allow the varing timing differenced to keep the gap the arc has to jump near consistent. It has noting to do with when the spark starts and stops.
On the timing front RPI do an ignition amp for LPG that can be set for 2 timing modes. Although LPG needs more advance (unlike nitro) you could use the thing in reverse so the extra advance is set for petrol, and then set the dizzy for less standard advance for Nitro'.
On the timing front RPI do an ignition amp for LPG that can be set for 2 timing modes. Although LPG needs more advance (unlike nitro) you could use the thing in reverse so the extra advance is set for petrol, and then set the dizzy for less standard advance for Nitro'.
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