SteveJ

Yes, once he finds which end has the voltage, the other end of the resistor should go to the negative post on the coil.

I think something broke in your attachment. The good news is that the BMW mechanic said he could fix it, and it would only cost $5000.

The 74 FSM has a picture of the resistor that is the same as in the 75 FSM. I did a brief search to see if I could find the old part number. So far, no luck. On the other hand, I did buy a bunch of 2.2K Ohm resistors about a year or so ago. They are stashed away in my garage somewhere...

Here is the page from the FSM with the tach schematic. I would say that the resistor matches the photo.

Well, we are going to have a pretty good special guest list for ZCON, too. Just less racing.

Basically the negative side of the tachometer connects to the negative side of the coil through a 2.2K Ohm resistor. The stock wiring has the resistor built into the circuit at a connector.

No, but I know how the tachometer gets its signal from the ignition circuit.

If you're curious about the Mitty schedule and entry list, they are online. Go to http://hsrrace.com/classic-motorsports-mitty/ and look for them. There are about 45 Nissans and Datsuns entered, including a D21 Hardbody and a C110 Skyline. Most of the Nissans and Datsuns are in group 3A.

When you did your modification, you probably did not leave the tachometer connected to the negative side of the coil. The best way to do that mod involves leaving the stock wiring on the distributor, adding the additional wire for the HEI to trigger the spark, and disconnect the TIU from the wiring harness. I'd offer to fix it at my house, but you're 5 hours away.

Bring it down to ZCON in October. @240260280will be there.

I can find 4 people nearby easily who could set up triple Webers for me. That's the advantage of living in God's Country.

It doesn't seem so weird to me that the problem is happening at higher RPM. It's likely a combination of the amount of current and frequency of the pulses. Splitting the circuit as Zed suggested may not be enough. It may also require a small resistance in the tach side of the split. If I were to test, I would start with having a potentiometer in the tach side to see how much resistance is needed and replace the potentiometer with a fixed resistor of the value in the test. ZKars does have a point about adapting the tach. It may be easiest to use a 260Z/280Z tach and the faceplate from the 240Z. Either way will require some wiring mods, though.

That's impressive getting the award seeing that there's a 2000GT parked next to you. You faced some stiff competition there.

He was living in Brunswick, GA. My friend was hoping to get him up here for the Mitty and maybe even ZCON. My friend received a few red BRE polo shirts from Pete Brock for the Mitty. I told him that his team has to wear the white jeans, too.

I saw on Facebook that Mac Tilton founder of Tilton Engineering and former engineer for BRE passed away on Saturday. Not being as well versed in Datsun history, I only learned a couple of years ago about Mike's role in BRE after I made friends with a BRE fanatic. This just compounds the loss of John Knepp last year. I'm glad I get to go to the Mitty and to ZCON this year so I can meet some of the old time Datsun greats. I hope you guys on the west coast pack the Monterey Historics for the same reason.

What year is your Z? Assuming it was imported from America to you, is it a Federal or California car? California had stricter emissions standards in the late 70s.

Reach out to the Connecticut Z Car Club (http://www.ctzcc.com/ and http://forums.ctzcc.com/). There's probably someone in that club that can put you in the right direction.

I forgot to mention that it will be sporting some new tires, too.

It looks like I'll be parking my car at the BF Goodrich tent in Vendor Village.

Randy Jaffe also gave us an update at the GZC meeting on Thursday. The Amelia Island winning GTP car will be at the Mitty along with some other Heritage Collection cars. There will be a Nissan/Datsun touring lap session among other things. We are going to have a special weekend.

More news from GRM on Mitty events: Adam Carolla is bringing his Bob Sharp 610 to race at the Mitty along with BRE Roadster to display. We are having the Classic Motorsports Saturday night party in our tent starting with John Morton autograph session at 6:30 pm and free beer from 7:00 to 9:00 p.m. We will also be showing some old Nissan/Datsun race footage Racing Against All Odds along with the Paul Newman documentary with Adam Carolla and John Morton doing some commentary.

For people coming to the Mitty, here's the layout for the car corrals.

I suppose I have to since I was foolish enough to volunteer for the organizing committee.

ZNationals will be part of ZCON this year. Instead of two days, there will be 5 days of events. http://www.zcon.org

Isocyanates are very common for coating military aircraft. @Namerowis correct about having either a powered air purifying respirator or some other supplied air respirator, and you have to make sure the air is being drawn from an area where the paint vapors will not contaminate. I became quite familiar with this from trying to protect people's health in the Air Force. A couple of years back I was talking with a fellow club member, and I found out that he was in the Air Force and had been responsible for painting aircraft. He said how they didn't bother with the proper protection because it took too long. He also happened to mention that he became sensitized to isocyanates, so he can't be around them anymore. Unfortunately it seems like a lot of material safety data sheets are written more to satisfy lawyers than to advise users. On the other hand, chemicals that cause respirator sensitization (and anaphylatic shock) will always cause me to be cautious.