Weird advance curve

[Babalouie]

Does this look right to you guys?

I've got pretty poor driveability at low rpm, and I think maybe this might have something to do with it. Base timing is 15degs, but you can see that off idle it seems to retard (!) about 3 degrees before going all-in at about 2800rpm.

I think it's a C210 Skyline distributor by the way, looks very much like an E12-80 but has a J-105 Mitsubishi module instead. Vac advance disconnected.

[sblake01]

Judging by the picture, I'm not even certain of that beinig a Nissan distributor. At least, not like any I've ever seen. The screws that affix the module are on opposite sides from where they are on the Nissan distributor. And the body of the distributor looks different from any E12-80/93 distributor I've ever seen. Does the distrubutor have a part number on the body (opposite side from the pictire behind/below the vacuum pot)?

[Babalouie]

It's a Nissan distributor alright, here's a few more angles

Pedestal neck looks like it's the 240Z type rather than the E12-80 type tho.

I think it's from a JDM C210 (78-80) Skyline, with the injected L20 six....

[sblake01]

Looks totally different from any E12-80/93 I've ever seen but we didn't get C210s here. The E12-80 distributor didn't show up here until the 79 model year.

[beandip]

I wonder if this is acting like the modules we have on out later 280 ZX Dists. Does the Skyline have a computer input to the module? When we try a module other than a 12 80 on our Carbed engines the input form the module causes the ignition to retard the timing, with out a signal form the computer. A friend of mine has devised a method to stop this from happening plus he uses a different vacuum advance that has two ports . One goes to the ported source just back of the front carb and the other to manifold vacuum. The claim is faster throttle response and better power and mileage. He has gotten 35 mpg on a bone stock 240Z with 150K. I haven't done this my self, but he is a VARY knowledgeable and respected guy that has been building Zs for over 30yrs. Gary

[Carl Beck]

Kim? in Idaho

[Babalouie]

I wonder if this is acting like the modules we have on out later 280 ZX Dists. Does the Skyline have a computer input to the module? When we try a module other than a 12 80 on our Carbed engines the input form the module causes the ignition to retard the timing, with out a signal form the computer.

Well it looks real similar to the E12-80 module, just 2 spade terminals with B and C on them. No other electronic input...and mine seems to retard the timing just off idle all my itself without any computer input

[Arne]

Kim? in Idaho

Yup. He's worked it all out quite well. I haven't done it yet, but I might at some point.

[Babalouie]

Tonight was dizzy rebuild nite and I thought you guys might be interested in more details on this weird distributor.

First I took off the dizzy and it was pretty grubby inside.

Then I took off the vac advance pot thing

Then the breaker plate

Odd looking advance mechanism....but someone's already removed one of the springs in Japan to get it to advance quicker

Tap out the spring pin with a punch and gently pull the whole shaft and advance mechanism out..

Pretty grubby inside

The old grease has long ago dried up and it was all very stiff

[Babalouie]

The advance shaft didn't spin on the main shaft very easily

Very crudded up

Clean everything with a scotchbrite

Grease me up woman, I'm going in after this the advance mechanism was much smoother to turn by hand, in hindsight I think it was quite notchy before

Reassemble...

Bung back in the car...

I think it advances a bit smoother...still has that little dead spot just off idle, but it seems to come on a little earlier. Timing is 17 at idle which seems to relate to 32 max.

Before:

After:

I'm pretty sure it isn't my imagination, but it does seem to advance a bit earlier and smoother...not a massive difference but I guess we'll see when I drive it next.