Converting To A 90-95 Distributor

[MY1PATH]

I just installed and MSD ignition system with and MSD Blaster coil. I think the sensor on my old dizy may have been out the door anyway but The MSD WITH COIL made it clear that I should replace more than just the sensor...So I just finished installing a distributor from the MPFI wd21 onto my TBI WD21. THere are some good reasons to do this and some of them are a necessity if running the MSD with a hot aftermarket coil.

 

1) the TBI Dizy cap is smaller and the points are closer together. this generates more heat inside the cap and acording to MSD more heat means more chance of arc beteen points. I also know that closer points means more chance of arc and you could hear mine doing so insid the cap evertime it misfired. (I woulda been ok If I stuck with the stock coil)

2)The points Crisscross inside the TBI cap to arrange the plugs yes they are sealed but with heat and age micro cracks can develop and then you have arcs and missfires again. I'd rather just have a traditonal tower cap instead of a flat cap.

3) Once the MSD and COIL were in current kept escaping my NEW TBI cap and zaping me and who knows what else But the MSD spark really packs a punch compared to being zapped by the stock system. I have not been zapped at all by the MPFI tower cap setup.

3)MSD with coil started to Melt my NEW TBI rotor. But The MPFI rotor dispates heat better because it has 3x more exposed tip to release heat and the tip is sandwiched in fiberglass to reduce the heat conducted to the plastic.

4) MSD systems are known to wear out caps and rotors faster and the small points on my tbi cap and rotor were already showing it quickily.

5) the base plate for the newer dizzy has and angled ajustment screw making it much easier reach when making timing ajustments. This is not as big of a deal as the things above but it is definte plus

Edited November 21, 2010 by MY1PATH

[MY1PATH]

The swap was pretty simple

 

1. remove the ajusting screw
2. remove the base plate
3. install the new base plate
4. drop new dizy in and and mark where it hits the valve cover
5. dent the valve cover aprox 1/4" deep along your mark if you (warm up the paint and use rounded wood or plastic tools so it will not chip)
6. reroute the wire harness on new dizy so it reaches you engine harness
7. align rotor and install new dizzy, plug in harness and spade connector on side of unit (this is not a ground)
8. get custom wires or grab a spare #6 wire from another set. 1,3&5 will reach fine. you will use one #4 wire and two #6 wires to make 2,4&6 reach. The MPFI wires will not all fit because the spark plug boots are too long on #2 & #4

Heres some Before, After and clearnace dent pics

Edited November 21, 2010 by MY1PATH