I have finally decided to do away with the factory GM HEI (already has a MSD 6AL). I purchased a MSD 85861 (slip collar, magnetic pick-up). The MSD instructions show how to connect into a non-computer controlled system. It has two wires coming out of the distributor that would tie directly to the 6AL. Where does the computer connect into the system to control the timing?

Any good sites on the web that show install?

Thanks in advance,
Aaron

 

Aaron,

I don't remember how I did it, but it's pretty easy. I even converted mine from an incap to external coil. Do you have any instructions at all? If not, I can scan mine for my '91 and e-mail it to you.

Tony

 

With a DFI system the magnetic pick up in the distributor is connected to the DFI ECU, then the DFI fires the MSD 6AL by connecting to the White points lead on the MSD Box. In a DFI system you set the ECU for an IPU ignition, the ECU then provides the EST signal to fire the MSD box via the EST circuit wire which is connected to the MSD points white wire.

I would beleive that the FAST box would be very similar seeing how John Meany was instrumental in the design of both boxes

 

You're going to need to have the FAST box converted to an inductive pickup type ignition from the HEI type. Then in the C-com setup you're going to need to change your crank reference angle to 50 degrees from the 6 of the HEI. The pickup wires wires from the distributor are going to go to the cranks sensor inputs of the FAST box. The white points wire from the FAST box will go to the MSD box. When you install the distributor, twist the pickup wires together, and try to run the wires to the FAST box away from your coil, coil wire, and positive wires if possible. The pickup wires can pick up elctrical noise and cause weird RPM readings, and possible timing changes.

 

Thanks for all of the feedback.

It turns out that what was detailed prior is pretty much on target. I had already sent the computer to FAST for the modification to inductive pick-up. The existing wiring harness has a pig tail for both the crank trigger (MSD distributor) and the points feed for the 6AL.

The only thing that remains is the reference angle. I am having FAST's personally selected shop provide a program that matches my combination as a start point, so that should have the refernce angle preset. I should be back up and running next week after return from the East coast.

Thanks for all of the help.
Aaron

 

The BEST place to find out info. on the FAST box is over at http://www.turbobuick.com Those guys are real helpful over there!

 

Absolutely, positively, be sure you compare your timing at the balancer to what your C-com dashboard says. That is what your crank reference angle input in C-com does. It's the lead time telling the FAST box when the distributor pickup gets triggered compared to TDC.

Example : If you have the crank reference angle set at 50 degrees in C-com, your timing map set for 30 degrees at idle, and with a timing light on the balancer the timing reads 30 degrees than everything is right. If the timing at the balancer reads 28 degrees, then you can either move the distributor 2 degrees, or set the crank reference angle to 48 degrees, and either one of those changes will bring the timing at the balancer to 30 degrees.

For your initial set up, bring the engine around to 50 degrees before TDC. Drop in the distributor with the reluctor for #1 cylinder lining up with the pick up - rotor should be coming around to #1 on cap. Tighten the distributor down and you'll be close enough to start the car. You then check the timing with a light. I get the timing within a couple of degrees and lock the distributor down and then get the exact timing by adjusting the crank reference angle.

 

Update:
It seems I do not get to visit / post nearly as often on this forum as one might like. Prior to the MSD distributor install, I had made a trip to the dyno and made some impressive (not!!!) runs. Previous best was 740+ RWHP. The first pass back in June was 69X RWHP, backed up by a 497 RWHP, followed by a 53X RWHP. You will note a bit of inconsistency. Each pass the IC was allowed to cool back to the 110 - 120°F range. Driving on the street, sometimes it would "lay down" to the point of not wanting to break the tires (BFG 335 drag radials) loose except in 1st.

The new distributor has definitely changed the attitude of the car. It seems very consistent and has become quite a challenge to drive. Last night I was out driving with my son running the computer. I was on an open stretch of road with some sort of small Chevy in front and a Dodge turbo diesel at the driver's door. I shifted from 5th to 4th at ~80 MPH and pushed the throttle just past 80% (indicated 6.5 psi at ~3200 RPM), and the back end tried to come around to the right. Not a good feeling at 80 MPH. It will literally light the tires at 80-90 MPH without much thought, not to mention any of the lower gears at will.

One thing that is baffling is that I struggled to get 5 psi boost at 4500 RPM (and 11 psi at 6100 RPM) before the distributor install, yet I am steadily seeing 5-6 psi at 3200, and like 8.5 at 4800. It just pulls so solidly now. I have not gone past ~5200 RPM with full boost, due to the tuning process, but that will happen soon.

I was told by others that the factory HEI will retard the timing, even though the computer shows the timing steady. Before the install, I never showed spark retard even at 36° full boost (52° low load), and now I occasionally show spark retard (due to the solid roller) even though I am running only 26-28° at full boost.

Overall, this may have been what was wrong with this thing for several years. Life is now good. Though I seem to have the oil leaks back again. Maybe it is time to revisit the mechanical vacuum pump?

Thought I would share.
Aaron

 

If your induction delay is not set properly you will lose or gain timing as RPMS increase. Perhaps that was your problem with the HEI. A magnetic pick up versus HEI would have different settings.....

 

Maybe your getting spark scatter with the new distributor. I'd hang a crank trigger off the front of it. I think your fast system can use it. Or maybe a 360 tooth wheel like the electromotive system. Stable spark timing is a must with detonation sensitive blown motors, and having it will allow you to tune real close to the ragged edge.

 

I think some might have misunderstood. The timing is "rock steady" with both the HEI and the new MSD. With the old distributor, the timing did not show any retard, yet would lay down on an incosistant basis. The new distributor does not lay down, yet it does show signs of spark retard. I attribute this to the large solid roller cam. I have now backed the max allowable spark retard down to 2°, wheras before I was allowing it to pull out 24°. It runs very nice now. I do run max of 26-28° under boost.

I will say during some fine tuning last night, I was able to pick a race with a Kawasaki 7R. This guy just could not believe how bad I walked him. Dead stop (even on BFG DRs), rolling, even really bad from about 70 MPH.

As stated before, it runs very good.

As a side note, for those of you running either the D-1R or the F-1R, what is the max boost you are seeing (and with what pulley at what RPM)? I am beginning to think that I will never see 20 psi. Maybe my components (heads, intake, cam, TB) are just too dang big?

Thoughts?
Aaron

 

Dont forget to lock out the distributor

 

Distributor is locked out. Relatively simple process if you follow MSD's instructions.