A Distributor Question

[txvepr]

I have read all the posts I can find on this site, and the manual for this answer. Some are close, but maybe not exactly my problem.

My newly acquired 78 280Z has a problem where at around 3000 rpms, the tach starts to jump wildly. At the same time, I detect that the engine is either missing or starving of gas. Voltmeter does not change. This problem has only just started to show itself recently.

It starts up great, and idles smoothly, so I don't see this happening at all driving ranges either. Slower speeds I have not seen it yet.

1 more observation, the rotor seems to have some play in it when I checked the cap and rotor. Like I can wiggle it maybe an 8th of an inch or so. Does your car do that?

So, would this be the dreaded Ignition Module failure(where I would do the HEI retrofit?) or would it be something related to the distributor being worn our or bad?

I am girding myself for your opinions.

Thanks.

[Zed Head]

My newly acquired 78 280Z has a problem where at around 3000 rpms, the tach starts to jump wildly. At the same time, I detect that the engine is either missing or starving of gas. Voltmeter does not change. ......

It starts up great, and idles smoothly, so I don't see this happening at all driving ranges either. Slower speeds I have not seen it yet.

This part here is about exactly what my 1976 car did when the module went bad. You can wire in an HEI module without cutting or permanently changing anything to verify the old one is bad, for about $20. The technology is of the same level and it's cheaper in the long run, than buying used modules or expensive new ones.

Thinking about it, someone could make some money by wiring GM HEI modules in to old Nissan module boxes and selling them for $100, for a plug-in replacement.

[txvepr]

Yup.

about the rotor wiggle, have you ever noticed how much a good one has? I just never took note before.

[Walter Moore]

Side to side play indicates bad bearings. I am not sure that 1/8th of an inch would hurt anything, but if it is a stock 78 distributor, which I think may have had a single pickup, it might cause a problem with misfires. By the way, isn't the control module on that car bolted to the fender instead of on the distributor (aka the S130 style)?

[txvepr]

I did the switch! Got a Ignition Module from Autozone part#DR100 and wired it up per the instructions found on this site.

I was a little unsure of it until I cranked her up and it runs Great. Highway test shows no Tachometer jumping at any RPM's I ran it at.

I don't know if this will give me better mpg yet. I wish, but I'm only seeing 17mpg combined daily driver. Might be something else I haven't found yet.

I used the mount for the coil wire as the Module mount, it was well grounded already. Just needed a slight bend to make sure it didn't hit the hood when closed.

My 78 had the module on the pax side footwell inside the firewall.

Awesome!