Breaker plate/vacuum advance cam

[Zup]

I am trying to find a breaker plate assembly for a ZX dizzy with the E12-80 module. It is a Model D6K82-01 distributor.

I am reconditioning a unit that I purchased in classifieds but, :nervous: , the breaker assembly plastic plate and ball bearings are shot on one side of the breaker plate, so the vacuum advance doesn't work. The diaphram is good, as are all the other parts. No shaft play.

I sure would like to get the advance working.

If anyone has a plastic plate and a few ball bearings from a unit that has a bad shaft, or whatever, please let me know.

I apologize for posting here instead of the classified "WANTED" section, but I don't think many people visit that section.

Any help, or leads, are greatly appreciated!

Jim D.

"Zup" here on www.classiczcars.com

4jim@cox.net

[EScanlon]

Last I checked, this part was still available from the dealer. Don't know the P/N off hand, but check your club microfiche cd and off you go.

E

[jmortensen]

They're always broken. I just JB Weld the two pieces together and run more static advance at idle. One of the nice things about that distributor is that it only advances 17 degrees so you can run 15-20 degrees at idle for a total advance in the mid 30s. And if you can do that, then the vacuum advance really isn't doing much for you anyway. Disabling the vacuum and cranking up the advance gives you the best of both worlds.

[beandip]

jmort , sorry but I do not agree with you about the vacuum advance not being necessary . For a track engine yes ,but not for a street application if you want a smooth performing engine. Zup , the part # 22163-H9501 In Oct of '03 the price was $45.53 . the breaker plate is not rebuildable . After 20 years or so of service the plastic keepers that hold the balls in place , become brittle and brake . This allows the balls to fall out and the vacuum plate cannot rotate as needed . As you have found . Hope this helps . Gary

[HizAndHerz]

I posted this not too long ago on another forum.

Here's what I did to rebuild my distributors.

First, I fabbed up some replacement breaker plate bearing keepers (that's what I call them anyway). The originals are thin plastic (upper right corner). I used a rotary tool to make four out of Lexan. It tricky getting all the holes for the bearings and holes so that the breaker plate screws would clear. The stopping pin was a pain since it can't stick up above the surface of the Lexan plate on one side.

There's a Mitsubishi distributor that seems to have been only available for the Euro market that has a superior breaker plate. It has 16 bearings instead of the Hitachi's 3. A much better design. Good luck finding one of these.

Here's a shot of the whole distributor:

Here's a vacuum canister from an early 1980's Camero that I modifed to fit a Mitsubishi 280ZX distributor. The mounting would need to be different for the standard Hitachi distributors normally found on Z-cars.

I bent the plunger to match the one on the ZX distributor. I cut the end off the plunger of the ZX canister and crimped and soft-soldered it to the end of the new one. Without a agood heatsink, soldering would probably melt the diaphram where the plunger attaches to it inside the canister. The mount would need to change for the standard Hitachi distributors. I did the one below to fit the Mitsubishi dizzy shown above.

[HizAndHerz]

Jim,

I did make a couple of extras so let me check if it is in my Z "inventory". I can send you one with the bearings if you'd like. I got bearings from my local Ace hardware store.

Jorns

[jmortensen]

jmort , sorry but I do not agree with you about the vacuum advance not being necessary . For a track engine yes ,but not for a street application if you want a smooth performing engine. Zup , the part # 22163-H9501 In Oct of '03 the price was $45.53 . the breaker plate is not rebuildable . After 20 years or so of service the plastic keepers that hold the balls in place , become brittle and brake . This allows the balls to fall out and the vacuum plate cannot rotate as needed . As you have found . Hope this helps . Gary

How do you quantify necessary? My Z had 40K street miles on it without vacuum advance, so I think we can say in strict terms that it is definitely not "necessary".

Now if you want to get into the benefits of vacuum advance, I'd be happy to take a stab at that too. The stock ZX advance at idle is 10 degrees BTDC with the vacuum advance unhooked. That plus the 17 or 18 degrees of mechanical advance gives a total of 27 or 28 degrees. When you're WOT there is no vacuum (unless you're WOT for a LONG time) so you'll really be running a max of about 28 when WOT. THAT'S NOT ENOUGH. You're giving away hp by running total advance in the 20's. Should be somewhere in the 35 range + or - a few degrees for best power.

I took mine off for three reasons; one it was broken like all the rest of them, two, I didn't feel like making less power at WOT, and three, an engine will produce some vacuum at WOT after you've been at WOT for a long time, as previously mentioned. The potentially dangerous disadvantage is that if you set the mechanical advance to where you want the advance to stop, the vacuum advance may kick in and add a couple degrees more timing, which could in the right circumstances lead to detonation. This really isn't a factor unless your engine is on the verge of pinging all the time, guys who are trying to run an F54 block with N42 head on 91 octane gas for instance.

What vacuum advance does is it kicks in some more advance when the engine has a lot of vacuum idle, like at idle or throttle slightly open operation. This gives more mpg (when you're driving with the throttle barely cracked open). Slow accelerations will also feel more responsive, as long as you don't punch it to the point where vacuum goes down to the point that it isn't advancing anymore.

If instead of using the vacuum advance you crank up the static advance by 8 or 10 degrees, you still get most of the benefits of the vacuum advance. It is true that the vacuum advance will advance the timing MORE at high vacuum than setting the timing 8-10 degrees higher and disabling the VA mechanism. But when you're WOT the engine will have enough total advance to really make some power.

IMO what you're giving up by disabling the vacuum advance is cruise, and I mean CRUISE mpg. If you don't cruise at 1500 to 2000 rpm then the vacuum advance isn't doing much for your mileage. I don't know for certain, but I'd be willing to wager that at 3500 rpm cruising on the highway the total advance is about the same your way or my way. I might be missing out on a touch of light acceleration responsiveness. What I get in return is a big boost in top end hp. One more thing is when an engine is hot it will theoretically be harder to start with more static advance, especially high compression engines. Hasn't been a problem with mine so far, and I'm running 11:1 on my new motor.

[ez73]

Hi JIm how are you doing? Installed those rims yet? I bought a second dist from that guy in Glendale . My z engineer guru buddy was able to make one good dist. from 2 nots so good. What a difference in the running of my 73 no hiccuping at idle no small miss at speed. I have a extra dist. left over(same number as yours) if your interested let me know . Bushing have too much play,the stator is cracked but all there ,ic module is ok (e12-92) vacuum adv. cannister may or may not be good. There is a guy online that sells the bushing for $15(he says that not always sucessful in replacing bushing) I,m pretty sure all other parts are available Let me know if you want it. d. funk (cant use my name)

[Zup]

My thanks to all of you for your replys and suggestions.My intent is to rebuild the distributor per the "how to" described by Phillip Pilgrim (Blue/Zero) and Wayne Monteath found here:

http://www.atlanticz.ca/zclub/techtips/distributorrebuild/index.html

It is an excellent article.

While John's suggestion of JBWelding the plates together is appreciated, it is my last resort. I agree with Gary that for a good idle and fuel economy the vacuum advance working properly is a must.

The dizzy can be rebuilt, but only if I can find the lower plastic bearing retainer and 1 ball bearing. To me it is more desirable to find just these parts than to spend $50.00 for a new assembly-----not because I am cheap---although I do want to do it inexpensively. So that is my next best choice.

(I don't understand why the lower plate is plastic, when the upper one is made of metal and much more durable. There must be a reason. But why??)

The offer by Jorn is a fine gesture and I can really see that he is blessed with skills and determination by fabricating his own replacement parts! Kudos!!!

So, yes--please, Jorn. Let me know by PM or e-mail and hopefully I can pay you something reasonable for it, or "pay it forward".

I love these forums for the limitless information and the good will to be had here in our persuit of something we enjoy.

You guy's are all "The Best". :knockedou

Jim D.

"Zup"

[HizAndHerz]

Jim, I haven't found them yet. There are buried in the boxes of Z stuff in the garage. I'll look again tonight.