: Points Breaker Plate 70 Deville



Cristofo
08-12-12, 05:43 PM
Im having trouble figuring out how to remove the breaker plate in my 70 Coupe deVille 472.

I want to replace the vacuum advance but I have to move the plate to get to the screws holding the advance to the distributor. I've done numerous searches on here and google searches but it seems as if no one else has this issue. Is there a trick to getting to those bolts? Does the breaker plate rotate with the distributor shaft?

Submariner409
08-12-12, 06:38 PM
The breaker plate rotates as the vacuum advance canister lever pulls it - around the distributor shaft. Either use a hand vacuum pump to rotate the plate or simply push it with a thumb - you should be able to just get to the hidden screw.

Drop in a Pertronix Ignitor while you're at it - no more points and faithful, strong electronic ignition.

Cristofo
08-12-12, 07:09 PM
Awesome, thanks for the advice. I definitely want to put in a points eliminator kit...is the petronix unit better than the accel, crane cams, etc?

deVille33
08-13-12, 10:54 AM
petronix was one of the first companies to make conversion kits. The others are all variations of the same design.

1970CadillacCalais
08-14-12, 12:50 AM
I went hei which wasn't difficult in my 70 Calais. Bought a used distributor and ordered a gm hei kit. Only thing I forgot to do was adjust the vacuum advance.

deVille33
08-14-12, 10:57 AM
I have not worked on one of these units in some time. I believe the plate has a small spring clip on the top of the center post of the distributor body. Drive the pin out of the drive gear and check the shaft for burrs at the pin hole. Use a jewelers file to remove any burrs. Check the bottom of the shaft for burrs also. The burrs will cut into the bushings and jamb the shaft on the bushings. Then pull the shaft out of the body. If there is a lot of shellac built up on the shaft under the body, use acetone to break the build-up down and apply WD-40 or another cleaning lube to the shaft and pull out.
If you look at the top of the center post above the plate there is a small spring lock. Use a jewelers screwdriver such as U get for your eyeglass repair kits to remove this lock. Spray the center around the breaker plate with your cleaning lube and pull the plate off the center post.

Cristofo
08-15-12, 02:46 PM
I have not worked on one of these units in some time. I believe the plate has a small spring clip on the top of the center post of the distributor body. Drive the pin out of the drive gear and check the shaft for burrs at the pin hole. Use a jewelers file to remove any burrs. Check the bottom of the shaft for burrs also. The burrs will cut into the bushings and jamb the shaft on the bushings. Then pull the shaft out of the body. If there is a lot of shellac built up on the shaft under the body, use acetone to break the build-up down and apply WD-40 or another cleaning lube to the shaft and pull out.
If you look at the top of the center post above the plate there is a small spring lock. Use a jewelers screwdriver such as U get for your eyeglass repair kits to remove this lock. Spray the center around the breaker plate with your cleaning lube and pull the plate off the center post.

Thanks, I will try this procedure along with using my hand vacuum pump to see if I can get it to rotate first. From your description I should be able to do this fairly easily.

Cristofo
08-16-12, 12:31 PM
Update* I was able to rotate the plate and get to the screws but i have a feeling the bolts have been tight for 42 years (heat plus rust = cement). I broke the head off the one and the other screw head will not budge at all. I'm going to have to grind the head off and use a kit for stripped bolts to back them out. What a pain in the ass!

Submariner409
08-16-12, 01:06 PM
You might be better off trying to find another distributor in the local junkyard - or get into the Performance Automotive Warehouse (PAW) site and find a rebuilt one.

You're not alone - I've had the same thing happen to me with several Olds 455 distributors.

Cristofo
08-16-12, 09:35 PM
Looks like we'll be replacing the distributor. I'm most likely going to get a rebuilt one but let me know if I need to stay away from certain distributors. We're also not going to get rid of the current distributor, the core is only 5 bucks.

Should I just remove the cap, mark the engine where the rotor is pointing, remove the hold down bolt under the distributor and pull out and twist? I realize its probably not as easy as it sounds. Trying to use the easy out kit without removing everything above the base turned out to be a nightmare. I've never seen a more stubborn screw in my life. Needless to say this is not worth the hassle. I'm sure we could drill out and re thread the holes, but it's a pain in the butt and I'm sure we're better off replacing the distributor anyway.

Any tips or tricks are greatly appreciated. Thanks guys.

Submariner409
08-16-12, 10:11 PM
Best bet is to set the engine to TDC on the #1 cylinder firing stroke (harmonic balancer marked with chalk) and mark the distributor rotor and body in relation to the block. When you loosen it and pull it out the rotor will turn due to the helical cam/distributor gears. You want to stab it back in and twist so that all 3 marks are aligned as the distributor bottoms in its bore. Then you start timing from there.

Cristofo
08-17-12, 01:36 PM
Best bet is to set the engine to TDC on the #1 cylinder firing stroke (harmonic balancer marked with chalk) and mark the distributor rotor and body in relation to the block. When you loosen it and pull it out the rotor will turn due to the helical cam/distributor gears. You want to stab it back in and twist so that all 3 marks are aligned as the distributor bottoms in its bore. Then you start timing from there.


Should I reuse the advance weights from the stock distributor?

Submariner409
08-17-12, 02:43 PM
Yes........... although the chances are slim, a different engine might have a slightly different advance curve - use the weights and springs from your original distributor.

......... and you should use the original vacuum advance or the same number replacement unit, too - that unit has a great deal to do with idle advance and WOT ignition retard. (Spark does NOT stay anywhere near fully advanced when you slam WOT - in ANY engine with vacuum or electronic ignition.) Think about it: Vacuum advance, highway, 19" of intake manifold vacuum = Full vacuum advance of 12 degrees + mechanical advance of 28 degrees = total running advance of ~ 40 degrees +/-. You slam the throttle wide open to pass, vacuum drops to < 4" and all vacuum advance disappears - advance now sits at 28 degrees BTDC until you ease off the gas and vacuum advance again dials in.

Cristofo
08-17-12, 06:02 PM
Yes........... although the chances are slim, a different engine might have a slightly different advance curve - use the weights and springs from your original distributor.

......... and you should use the original vacuum advance or the same number replacement unit, too - that unit has a great deal to do with idle advance and WOT ignition retard. (Spark does NOT stay anywhere near fully advanced when you slam WOT - in ANY engine with vacuum or electronic ignition.) Think about it: Vacuum advance, highway, 19" of intake manifold vacuum = Full vacuum advance of 12 degrees + mechanical advance of 28 degrees = total running advance of ~ 40 degrees +/-. You slam the throttle wide open to pass, vacuum drops to < 4" and all vacuum advance disappears - advance now sits at 28 degrees BTDC until you ease off the gas and vacuum advance again dials in.


Huge help, thanks!

Made sure engine was at TDC, then took bolt and hold down off but could not get the distributor to budge. I'm not sure what I'm going to do yet, but I would imagine I need a crowbar.

I feel like there is a hidden bolt holding it on...

deVille33
08-18-12, 10:53 AM
No bolt, but a build up of baked oil sludge below the distritutor mount body. Will the distributor rotate in the bore? Work it back and forth and spray some Knock 'er Loose or a mixture of transmission oil and acetone at the base of the ditributor and the block mount area. There is a square on the distributor body you might be able to put a wrench on, but it is difficult to work in that area. And don't put too much tension on it or you will snap the distributor body.
Keep working the distributor back and forth and spraying the cutter mix at the base. Pull up as you twist. You see a space between the mount flange and the block, spray the cutter then force the distributor back down. Work it, work it, work it. It will pay off in the end.

Cristofo
08-18-12, 04:31 PM
No bolt, but a build up of baked oil sludge below the distritutor mount body. Will the distributor rotate in the bore? Work it back and forth and spray some Knock 'er Loose or a mixture of transmission oil and acetone at the base of the ditributor and the block mount area. There is a square on the distributor body you might be able to put a wrench on, but it is difficult to work in that area. And don't put too much tension on it or you will snap the distributor body.
Keep working the distributor back and forth and spraying the cutter mix at the base. Pull up as you twist. You see a space between the mount flange and the block, spray the cutter then force the distributor back down. Work it, work it, work it. It will pay off in the end.

Wish I read this sooner but I ran into some problems today. I could not get the distributor body to move at all...I've been spraying with PB blaster in between everything I try.

I let it sit overnight drenched in PB and had at it this morning. I ended up breaking the distributor body about 1/4" above the base that mounts to the engine. I tried a oil filter rubber strap and could not get any movement, so I moved on to a hammer and pry bar. I wasn't tapping it hard with the hammer, but did accidentally with the 3 ft prybar.

Let it sit an hr and came back, and focused on the base where the gasket goes. I was finally able to use a flat screwdriver and tap it in many places. After slowly and carefully using this method I now have a 1/4" gap all around. I just keep spraying it in the gap hoping it seeps down. If I can get twisting leverage on the base, I think it will come out.

I was so mad when the distributor broke, I thought the worst.

Cristofo
08-20-12, 09:47 PM
Finally got the old distributor out and installed the replacement. I was able to get my marks lined up after a few tries and buttoned everything up. Will check and set timing tomorrow, but the engine ran really well at initial start with high idle. I really just wanted to get the old distributor out and install the new one and make sure the car started.

deVille33
08-21-12, 10:44 AM
Congrats on that. Sounds like you are headed in the right direction. Too bad about the old distributor, but now you have an engine oil primer once you remove the drive gear.

Cristofo
08-21-12, 03:20 PM
I'm having a hard time figuring out the vacuum hose diagram because it wasn't hooked up this way when we bought the car.

I'm trying to identify where 2 vacuum hoses that run off the carburetor go. One comes from the back center of the carb that wraps around and up the valve cover finally ending around the coil...I believe this vacuum hose goes to the front nipple of the TCS solenoid. The other vacuum hose running from the front right of the carb ends around the back of the TCS solenoid nipple. Do both of these hoses run to the TCS and then the short 4" hose coming straight down go to the C on the ported vacuum switch? D = distributor vacuum advance and then finally MT = the hose that eventually T's and then connects to both nipples of the choke?

Can I run the vacuum directly from the carb (front right) to the distributor advance and plug or bypass the remaining hoses?

deVille33
08-22-12, 10:13 AM
Is the vacuum control diagram on the radiator suport cover? Usually, if you follow that diagram you can get it right. Inspect all the vacuum lines and replace any lines that are dried out, cracked or split. Check the control units to see if they operate properly. If you don't have that diagram, myself or another member can get you pic of it. I have several '79 fleetwoods and devilles'

Cristofo
08-22-12, 03:50 PM
Is the vacuum control diagram on the radiator suport cover? Usually, if you follow that diagram you can get it right. Inspect all the vacuum lines and replace any lines that are dried out, cracked or split. Check the control units to see if they operate properly. If you don't have that diagram, myself or another member can get you pic of it. I have several '79 fleetwoods and devilles'

Thanks! I will check the next time I get a chance.

Currently I have removed the Solenoid with the electrical connection (for withholding advance until 3rd gear?) and plugged the vac line coming from the rear center of the Carb. I then followed the exact diagram for the ported switch so its basically stock again without the Solenoid with the metal plunger inside. Vac 1 coming from front right of carb to switch C, D was hooked directly to advance vac, and MT was connected to the choke.

It ran pretty well and would only ping under full throttle (timing was around 10-11), so I may retard it to around 8. I'm running 93 Octane and have replaced all ignition components along with full tuneup.

Submariner409
08-22-12, 03:58 PM
The solenoid/plunger you removed may be the idle compensator for A/C - that compressor pulls a heck of a load at idle, and there's usually a solenoid that "nudges" the idle cam open a tad as A/C engages.

Advance vacuum may be of several types - manifold vacuum, ported vacuum (depends on throttle opening), or a combination of the above, modulated by a small plastic VDV - vacuum delay valve.

Cristofo
08-22-12, 04:32 PM
The solenoid/plunger you removed may be the idle compensator for A/C - that compressor pulls a heck of a load at idle, and there's usually a solenoid that "nudges" the idle cam open a tad as A/C engages.

Advance vacuum may be of several types - manifold vacuum, ported vacuum (depends on throttle opening), or a combination of the above, modulated by a small plastic VDV - vacuum delay valve.

I currently have both the compressor plug and now the solenoid plug disconnected temporarily until the A/C gets fixed. I will hold onto the solenoid I removed for when the A/C is fixed. This Solenoid was bolted down to one of the ignition coil hold down threads on the manifold.

Cristofo
08-24-12, 06:10 PM
To conclude the breaker plate discussion, I ended up replacing the whole distributor. Car runs very well @ 5 degrees BTDC.

Thanks for everyone's help! On to another part of the car...