distributor lock out and MSD 6530 install with pics

[b930]

After realising the stock distributor diaphragm was rusted out to the point of leaving the advance plate in the dizzy flopping around, I decided to ditch the old vacuum and weight timing control for something more modern and reliable. Enter the programmable MSD 6530. Here was the original rust filled vacuum can.



First task: lock out the dizzy. Basically easy to strip down, remove the external screws and clips, remove the circlip above the rotor signal wheel being careful to not to loose the small round keyway pin, pull the lower circlip. Remove the three screws holding the mag coil in place and remove the mag coil. Now you can access the weights. Here are the weights, bit cruddy looking but were working fine.



The idea is to pin the weights in the extended position. I elected to remove the weights and the bushings underneath the posts. Now when you remove the small plastic slider bushings the locating hole is available to use as a pilot hole for drilling the base plate out and popping in a rivet. The slider and post bushes are no longer needed as the weights won't be moving and removing them allows a nice flush fit to the base plate for when you pop the rivet in. This is with the weights removed showing the base plate.



These are the weights with and the bushings / slider that are removed.



The weights are fully advanced and the slider locating holes used as pilot holes for a 1/8" drill into the base plate, clean out and re-assemble and pop rivet in place. I also replaced the springs the circlips for good measure.


Coil and signal rotor wheel going back in.


With the wights pinned at full advance you can pin the advance plate under the mag pick up the old vacuum attached to (or not as is in my case!). Be careful here as you need to access the three screw holes for mounting the coil back in the dizzy so don't pin in too early!. I used part of the old vacuum rod and body, chopping the diaphragm, bending the rod so it sits flush with the top of the remaining bracket and popping a rivet in. I found a setting to give me as much advance as I could dial out with the MSD. That can pull out 25 degrees and I needed 15-17 at idle so was shooting for ~40 static. This the how the advance plate was pinned. Was cleaned up / finished off with a metal cover sealed to the opening.



All back in:


With it all back in and the dizzy at full advance in the retaining slot, I got 42 degrees static verified by measuring from the existing 29degree mark and using some distance into degrees conversion, further verified by dialing back 13 degrees on the MSD to give me a perfect line up of the stock mark.

Install of the actual MSD was easy, with mounting on the existing CD plate and locating a 2 bar MAP near by. The existing vacuum points of the throttle body were plugged and the MAP tied into the line from the TB to the decel valve. No tach adapter was needed and I used spade connectors to go into the stock 6 pin connector for the CD unit.

MSD 6530 installed with MAP sensor just above it:



As far as the mapping, I am pulling out all I can at idle giving me 16degrees, also the resolution on the 6530 allows you to build in a timing ramp just under idle for rock steady idle. Basically I'm letting the full 42 degrees in at light load about about 3500 RPM and ramping out 25 at 1 bar boost for 17degrees. This should give me great fuel consumption at light cruise but more importantly, assurance that things are taking care of themselves when I'm hard on it.

This is the mapping:


Car starts great, revs clean and runs fine. Still to re-gap the plugs. Test drive soon, will report back in the original Aerocharger thread, here:

Aerocharger turbo installed (& distributor question)

[b930]

Oh yeah, regarding the rotor arm, I found that in Australia, Bosch do one that is almost a direct fit with no resistor in it. It just needed shimming up by about 5mm by using a slotted washer under the dizzy shaft (Slotted to allow the index slot to still work). You can get it at any Supercheap auto store.

[smurfbus]

Nice write up. What happens if the MAP fails? Is there a fail safe feature in the MSD?

Can I find that resistorless rotor at any online shop?

[b930]

The rotor is Bosch GB502 made in Aus. Supercheap Auto have some rotors on their website but not that one, they have it in store. I don't know if they ship intl. GB502 is for 70's 6 cyl fords and chryslers sold in Aus. If you get stuck PM me, i'll mail you one.

Also, not sure what the MAP failure mode is in the MSD. Will unplug it and see where the boost retard setting defaults to. I suspect it will not apply full retard and therefore not fail safe but will investigate.

[mark houghton]

Best writeup I've seen on this topic for a long time. Keep the info coming!

[RarlyL8]

Nice write-up. It would be nice to see what this mod alone does for lag and driveability on a stock 930, lots of performance left on the table with the stock US curve.

[JFairman]

If the everything in this year and type distributor is functioning correctly it looks like the stock advance curve could be improved for better lower rpm city driving performance alot by just bending the two vertical tabs I circled in red inwards a little and then advance the static timing to compensate so full advance is the same as it was.

It looks like hose two tabs I circled in red limit full centrifical advance when the weights swing out and stop against them and bending them in toward the center would limit full centrifical advance some more.
Then turning the entire distributor clockwise to advance static timing would bring the full advance back to where it was or where you want it and also advance the idle and low speed timing to wake up the car and increase low end torque getting away from stop signs and improve steady cruise gas mileage.

All it takes is needle nose pliers to bend the tabs and then checking the results with a timing light and road testing.

End result could have idle and steady cruise timing advanced around 10-15+ degrees and full advance and boost retard could be about the same.

I have the MSD 6AL and 8762 boost retard module set to retard timing 1.5 degrees per pound of boost with static timing advanced to around 10 degrees btdc but you never really know if it's working or not.. it's a risk.

[oilonly]

Interesting Idea JFairman.

[JFairman]

When you took yours apart did you have to remove the flat blade screw under the felt seal under the rotor? It looks like you didn't.

Anyway, i'm trying to take mine apart and I've removed every screw and circlip I can see and that includes all of them you mentioned and I can't pull rotor signal wheel upwards to remove it. I see the little round index pin along the side of it and I'm ready to catch it so i don't loose it but I can't get the rotor signal wheel to slide up and off the shaft it's on.

I don't want to pry on it because I'm afraid I'll break something. If I do break it I'll have to get the MSD programmable CDI and ditch my MSD6al and boost retard box. I don't want to do that.

My distributor was replaced by the previous owner around 40,000 miles ago and it's in good condtition with no rust but I hate it's emission based advance curve and I'm gonna change it.

thanks for any help on this...

[Helmsy]

Try to gently pry it upwards with 2 screwdrivers either side of the stator. It should come up without damaging anything but yes make sure you don't lose that little pin.

You can remove the flat blade screw under the felt to clean and lube etc. but don't lose any little washers under the screw or under the rotor otherwise it won't rotate on the shaft like it should. Also put a couple of drops of oil under the felt when reassembling.

[Helmsy]

[JFairman]

Thanks, I'll try that tomorrow, it's dark out now..

I've taken apart points and condensor bosch distributors from BMW's and modified the advance slots and cleaned and lubed them, but first time I'm taking this one apart.

I played with the vacuum advance and retard pots with a mighty vac and mine isn't very old so it works good. When I pressureized the vacuum advance pot like when you're on boost it moved the rod away from it's rest point and moved the opposite direction it moved when vacuum was applied. When I pressurized the vacuum retard pot on the opposite side nothing moved.
That means the 1987 USA distributor has centrifical advance, vacuum advance, vacuum retard during idle and deceleration, and boost retard.

[PrimeMvr]

JF, when I did this mod last year my key pin was basically disintegrated. I wonder if yours might be cracked and jamming the signal rotor.

I had a hard time finding a replacement pin so I cut off a drillbit. 3/32" IIRC.

[JFairman]

I got the reluctor star wheel off thanks.
I put the three phillips head screws holding the stator plate with it's ring magnet and windings back in place because prying up on the reluctor was pulling it up with it and stretching the centrifical advance springs. Once the reluctor is off there is one more snap ring to remove below it.
The fiber shim washer was in several pieces sitting down in the bottom of the distributor housing just like the one in the picture farther up in this thread. I'd like to replace it but I don't have one so maybe thats in the future.

With those 3 screws in place the reluctor wheel pried up easily with 2 flat blade screwdrivers while the distributor was vertical in a bench vise padded with a couple pieces of soft wood to protect the drive gear.
I'm glad people have mentioned watching that pin because it's real small and only about 3/32" long at the most. Very easy to drop and never see again if you are not watching it.

When doing final assembly of the distributor the stator plate is free to move around a little until you tighten the 3 phillips head screws in the bottom holding it in place and the clearences between the star shaped points on the reluctor wheel and the metal points of the stator change and touch at times as it moves around. I don't know what the clearances are supposed so I put .015" feeler gauges in between them until the stator seemed to be centered and close to equal all the way around. Anyway, .014" - .015" clearance worked.


I bent the 2 vertical metal tabs that limit the centrifical advance weights travel inward about 1/16" - 1/8" taking out about the last 1/3 of their total travel outwards to limit total centrifical advance so I could advance the static advance to make up for it.
It was a shot in the dark adjustment guess but it works good and it's easy to bend and adjust them again if I want.

Now my 800 rpm idle timing with vacuum pot hoses connected is at 13* BTDC or halfway between the 0* TDC and 26* BTDC marks on the stock pulley with a timing light. Total advance at 4000 rpms or above with centrifical advance maxed out, vacuum advance and vacuum retard hoses both connected and working is around 38-40* BTDC.
Thats a calculated guess from looking at how far the 26* mark on the pulley moves over to the left of the reference mark on the fan housing while looking at it with a timing light because there are no other timing marks on the stock pulley to know for sure.

Factory Boost retard is working and the MSD 8762 boost retard module is also working and I have the adjustment knob for it mounted to the top of the auto heat box between the seats. If I hear detonation while the windows are up and sunroof closed I can adjust the MSD boost retard.
I drilled a small hole and put a small phillips head screw in the side of the MSD 8762 retard adjustment knob just below the faint little pointer line on the top so I can feel where it's pointed while driveing.

I'll be experimenting more and maybe readjusting those 2 vertical steel advance limiting tabs again and you don't have to take apart the distributor to do it. You do have to remove it from the motor though.
If you pry out and remove the small stamped out oval shaped steel cover thats pressed into a hole down towards the bottom of the distributor it is right at the level of the 2 advance weights and limiting tabs and you can reach in there with a screwdriver or needle nose pliers and bend them inwards or outwards without hurting anything as long as you don't pry against the advance weights which pivot on little nylon bushings. Use the distributor housing to pry against if you try this or take apart the distributor and do it from the top using needle nose pliers.

The result is more advanced timing resulting in more engine torque at speeds below 3000 rpms when there is no turbo boost. Steady cruise timing is advanced at all speeds which will increase gas mileage while ignition advance under boost is retarded back about the same as stock and top speed torque and horsepower is about the same as before.. and it doesn't cost anything to do this.

Stock '86-'89 distributor retarded ignition timing at idle and steady cruise is set for lower exhaust emissions and heating up a catalytic converter faster so the car will pass emissions. That along with the 7:1 compression ratio and slow reacting CIS injection is what makes these cars so lazy at lower speeds in stock from.

Boost retard on an '87 distributor is caused by the vacuum advance pot diaphram being pressurized and pushed/moved the opposite direction by boost pressure. I checked it using a mighty vac.
When you pressurize the vacuum retard pot on the opposite side closer to the distributor body nothing moves so there is an internal stop inside the vacuum retard pot that keeps it from moving the opposite direction when boost pressure reaches it.
Only the vacuum advance pot on the outer side responds to boost pressure and moves the stator plate in the same direction the distributor shaft is rotating resulting in boost retard.

The 1987 distributor rotates counter clockwise and moving the stator or reluctor plate in the opposite direction the distributor rotates advances igntion timing.

The vacuum pots move the stator plate position to advance and retard timing depending on vacuum or boost created by throttle position and engine load and centrifical advance moves the reluctor star wheel to advance timing depending on rpms.

I really wish the stock pulley had timing marks from 0-50* BTDC like this pulley from Supertech but it doesn't. That would really help.
I don't think Supertech makes one with a double pulley for the AC fan belt.

[flat_6]

Guys, I installed same ignition 3 weeks ago and works great. I am planning to lock the dizzy next week and start programming.
Where did you guys end up with your tuning curves? can you post what worked for you, please!
Also, anyone have what the stock timing curve is? I have a '87.

Appreciate any advice for I start tuning.

[flat_6]

Nothing?