msd pro billet dist question

[Mick]

I'm thinking of buying one but there's two different types with about $100 difference between them. Obviously, i will buy the cheaper one if it will do, the more expensive one is bigger and has the hookup for the vacuum advance which i dont use anyway.
Why the big price difference, i personally think the smaller one looks a better idea anyway.

[Pete]

Can you post part #'s or links Mick

[Guy]

As far as I am aware there are only 2 msd dizzys for the 440


race

http://store.summitracing.com/partdetai ... toview=sku



Street
http://store.summitracing.com/partdetai ... toview=sku

[Dave-R]

The "street" one Guy has there has the spark amp built in. It is a complete "all in one" system where as the "race one" needs a MSD unit to power it.

[Mick]

Of course, i didn't read it properly, i already have an msd so the cheaper one will do fine.
Pete
Is this the one you've got, does it come with the weights and springs.
Mick

[Pete]

I am pretty sure i have the MSD Ignition 8546 (It's at Hausers at the moment).

It comes with mechanical weights that you adjust the timing curve using inserts and different weight springs.

I am running it locked out with a crank trigger Far more accurate

[Dave-R]

You have to make a larger advance stop to get enough initial timing with them though.

[Pete]

Or weld it up

[Anonymous]

You have to make a larger advance stop to get enough initial timing with them though.

Yep , maxed out on the bushings they give an 18* curve , i cut a nut down to get around a 12* curve.

[Anonymous]

I am running it locked out with a crank trigger

Hope you've phased the distributor in conjunction with the crank trigger. .................................@ 5000 rpm the rotor should be phased bang on with the rotor cap terminal.

[Mick]

My old distributor was welded, the reason i want to buy the MSD is to avoid welding the slots to gain initial. Wont the weights and springs give me the advance curve i need.

[Pete]

People's experience would indicate the t it may not work out of the box - what does?

Easier to do than welding up an OEM style one to correct the curve.
Still trial and error to a degree...

[Dave-R]

The curve has nothing to do with the total amount of advance.

To get to my starting point of 18 initial and 35 total I had to wrap adhesive aluminium tape around the biggest advance stop it comes with (the black one).

Once I have found the ideal amount of timing I need i will make a stop that is the right size.

Once you have initial and total start and finish lines decided you can then play with the springs to get the advance curve the engine likes. Starting with a smooth progression from one point to the other and maybe playing with how fast it comes in over the first or second parts of that distance.

[Anonymous]

The MSD dizzys come with various springs so you can tailor the curve pretty easily , they also come with around 4 bushings , the smallest one gives around a 35* curve , the largest gives an 18* curve , i needed a 13* curve (22* initial/35 total) , was an easy fix to file a nut down or similar , you can also lock the mech advance by 'flipping' the shaft in the housing , great distributors.

Mick , i think you pay a lot more for the vac advance , hence the price difference.

[Mick]

My car is getting seriously hot and i need to address this before i take it out again, i dont think it's the timing but i just want to cover all bases. i'm also looking at a viscous fan and cowl which i will use in conjunction with the electric fan.