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240Z Distributor Questions

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Posted (edited)

I'm getting close to completion on my first engine rebuild.  I'm trying to set up the timing using the original distributor following Tom Monroe's instructions and I have some questions.  He says:

Quote

Rotate the distributor housing all the way to the left, or counterclockwise. If breaker points are used, check point gap. It should be 0.020 in (0.50mm). Rotate the housing to the right -clockwise- until the points just begin to open.

I must be dense because I just don't get what he's trying to tell me. If the the gap is already 0.5mm when the distributor is rotated all the way CCW, then what should it be when it "just begins to open"? More than 0.5mm or less?  This is my first time setting up a distributor so I'm thoroughly confused.  My points are measuring 0.25mm when the unit is rotated all the way CCW so I'm guessing I should adjust that.

Also, I can actually rotate my rotor around 10 degrees without moving the housing (or crankshaft for that matter). Is that expected, or is my distributor shot?  Here's a video of me messing with it: https://youtu.be/8ve-9dZ30k8

To be honest, I'm terrified of melting my engine with incorrect timing so any advice is appreciated.

Edited by rcv

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the check points gap thing is an aside. I.e. check the points gap before you try to set the timing. it's a pre-requisite of setting the timing.

 

to set the points gap, you rotate the distributor until the points are right on top of one of the 6 lobes, the most open point.

 

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Thanks, Jon.  So at their most open, the points should be 0.5mm apart?  Once I've got that set, then I should rotate all the way CCW and then CW until the points just barely open?

Also, any thoughts on being able able to rotate my rotor a few degrees by hand without moving the rest of the distributor? Is that normal?

 

 

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On 5/2/2020 at 10:29 PM, rcv said:

IAlso, I can actually rotate my rotor around 10 degrees without moving the housing (or crankshaft for that matter). Is that expected, or is my distributor shot?  Here's a video of me messing with it: https://youtu.be/8ve-9dZ30k8

To be honest, I'm terrified of melting my engine with incorrect timing so any advice is appreciated.

There is good stuff in the Service Manual.  You should download it and look through the Tune Up chapter and the Engine Electrical chapter.

Timing is set using a timing light.  It's different from setting the gap of the points.

It is normal for the rotor shaft to turn a few degrees.  That is the mechanical advance mechanism working as it should.

image.png

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yes, that should get you in the right area. As zedhead says, best to set it with a timing light, once it's running.

having watched your video, I don't think that movement is right. it's normal to have some movement again as ZH says, but the mechanical advance is sprung so it should return when you release it. is there more resistance in one direction than the other?

 

 

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Remove the breaker plate and look at the weights and springs.  Sounds like the springs are gone or broken.

Found a good video.  You don't want to lock yours but he shows how to take one apart.  4 and 6 minutes show the critical parts.

 

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Posted (edited)

Great thanks @Zed Head - I'll inspect it in the next few days and report back.  Hopefully the springs aren't shot, as a quick look at my usual online stores (zcardepot / zcarsource/ MSA) don't show any for sale.

Edited by rcv

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Uhhhhhh.... Yeah, that aint right.

If it springs back slightly, I'm guessing that it's rusty cruddy and virtually locked up. I was just messing with one similar a few days ago. Weights and springs had rusted to the pins they are supposed to pivot on. Maybe you threw a spring too, but I bet it's just wear and crud.

The one I was messing with also had wear marks on the sliding components. So now it moves easy, but it's still notch because of the wear.

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38 minutes ago, Captain Obvious said:

rusty cruddy and virtually locked up

Sounds about on-par with everything else on the car. I'll pull it apart as soon as I can and hopefully a little PB Blaster and elbow grease will loosen it up.

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Haha! Welcome to old Z ownership!

This is the kind of stuff I was talking about. The weights and springs were very stiff on the posts because of the rusty cruddy:
P1160593.JPG

I cleaned everything up and now it all moves free, but I can't easily do anything about the wear:
P1160727.JPG

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Posted (edited)

@Captain Obvious you definitely lived up to your name, the distributor was filthy on the inside. I was able to clean it up pretty well, and now it snaps back as expected: 

 

 

There are two pieces of bad news though:

1) One of the springs is completely missing.  Nobody seems to have these in stock anywhere. I suppose I could run with just one spring for a while, but it's not ideal.

2) The breaker plate assembly is pretty locked up.  I didn't try pulling it apart, but I give it a 50/50 chance I lose those little bearing balls when I do. I can also buy a "new" one for $50.

So, my question to you veterans is what's your advice?  My immediate goal is to get the car up and running and drivable so I can have a little fun before I start dumping too much (more!) money into it.  Longer term I've been following @jonbill's speeduino progress which looks like a ton of fun, so I'm not too excited about dumping $600 on any of the fancy new distributors (123, Kameari, etc).  Is it worth retrofitting a cardone 280zx unit, or am I better off getting that new breaker plate and running with 1 spring?  I've heard good things about Advanced Distributors rebuilds but I'm betting they're spendy and the lead time is 6-9 weeks which is a bummer.

Edited by rcv

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AV8ferg just went through the same thought process, almost exactly.

 

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5 hours ago, rcv said:

1) One of the springs is completely missing.  Nobody seems to have these in stock anywhere. I suppose I could run with just one spring for a while, but it's not ideal.

Haha!! Glad to help!    :beer:

Advice? Don't try to operate with just one spring. That will throw off the mechanical advance curve. Too much advance at too low of an RPM.

I think distributors are easy to find. Might be easier to replace the whole thing than to get one spring.

I've got a 240 distributor that came to me disassembled and incomplete... Don't know what year it's from though. What is the number on the side of yours?

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2 hours ago, Captain Obvious said:

What is the number on the side of yours?

It looks like mine is a D612-52. If yours has compatible parts I'd happily take it off your hands. Send me a DM and we can talk details if you're up for letting it go.

I'm definitely in favor of using this distributor for a while until I go off the deep end with something more extreme. Even then I like the idea of having a trusty mechanical distributor in the glovebox in case the electronics breakdown (or someone lights off an EMP ?).

If you're parts aren't compatible I'd still like to try to revive this thing.  Has anyone tried finding the right springs on e.g. McMaster-Carr?  I figure if I can find the specs (k-value, free length, diameter, etc) for the originals I should be able to find a suitable replacement somewhere.

IMG_1066.jpeg

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I have a vague recollection mine has one spring. This could be the "euro" distributor's slightly faster advance curve?

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Well I found the distributor basket case I was thinking about, and it's a D6K82, so I was apparently very wrong about it being from a 240. In fact, the info I have indicates it's at the complete other end of the spectrum and came from an 83 Non-turbo.

But here's the good news... The mechanical advance specs are similar to your D612, and if your distributor is SUPPOSED to have two springs, then I would assume that using one spring from my basket case is going to be way closer to the original design than just one spring. in yours

So short story? Whatever you want from this distributor is yours for the shipping. Just let me know.

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Here's an old conversation about springs and stuff.  You might find a few interesting points to ponder in it.

 

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Here's something interesting.  Somehow, the part number for a spring and a distributor are the same in carpartsmanual.  I found a complete distributor $96.80.  That's what it says anyway.  It's a "from Sept. 71" model.

http://www.carpartsmanual.com/datsun/Z-1969-1978/electrical/distributor/240z/for-manual/from-sep-71

https://www.nissanpartsdeal.com/parts/nissan-distributor~22100-n3300.html

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Nice find @Zed Head!  I just ordered it so we'll see what I get.  It looks like these guys are only a few miles from me in El Monte, so I can storm over there with my N95 on and demand a refund if they just sold me a spring for $100.  @Captain Obvious I'll save you the trip to the post office until I see what arrives from nissanpartsdeal.com - I may come begging again though if this turns out to be a bust.  I very much appreciate the offer!

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I also found the two spring parts (22110-E4602 and 22110-N3300) on concord-parts.com when I was hunting around late last night.  I have no idea if these guys are legit, but they only take payment by "Wire Transfer" which was more hassle than I wanted to deal with at midnight.  I emailed them at least to see if they actually have those parts, so I'll post their response here in case anyone else is in my same situation.

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No problem. Good luck with the parts and I hope they have what they say they do! Let me know if you need a spring or two if the other stuff doesn't pan out.   :beer:

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I have extra springs if you need them. I might even have a breaker plate I got off a 280z. They’re different than the ZX plates but not sure how it compares to a 240z.


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My springs are free no wire transfer required

This is how we roll on this forum!
b90e3b28f704f9aaa573ea87901dbf45.jpg


Sent from my iPhone using Tapatalk

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Welp, I just got an email from "NissanPartsDeal" - I should have known from their generic sounding name, but they basically just list every part ever made regardless of whether they have them in stock. I'm betting I could find a NOS OEM '08 Model-T hand crank listed if I bothered looking.

@Captain Obvious I'll take you up on your springs if the offer is still open.  I'll send you a DM with my shipping info and I'll happily paypal you for the shipping.

@Av8ferg I definitely appreciate the offer - I'm going to go against my pack-rat instincts and avoid hoarding springs for now though.  I'll definitely reach back out if I can't make this other set work.

I'm going to order a new breaker plate from ZCarDepot as well as a new set of points and a condensor and hopefully I can Frankenstein this thing to life.  Thanks for all of the help so far everyone!

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