Cam timing or ignition timing?

[StrokinIT]

Hey everyone,

 

I have a 1976 280Z with a few problems right now that I'm trying to sort out before I start upgrading. I bought the car a few years ago and just finally got it on the road last year, sort of. We bought the car from CT and trailered it back to NH. We hadn't registered it or anything due to it being late fall, winter was coming, and we were going to begin the restoration on it that winter. So the only driving we did with it was in the neighborhood in mostly first gear. At the time I knew very little about cars, and we had a "reputable" shop look over the engine and they gave it a clean bill of health. Fast forward to last spring, and the car was finally ready to get on the road. It went back to the same shop to diagnose why it was idling poorly and sputtering under throttle. $350 later and the invoice says "check fuel, make adjustments" and it is still running as crappy as before. So I finally took it to a Z specialist who fixed a few vacuum leaks, replaced some of the fuel lines with actual fuel hoses, and then told me that he thinks the cam timing is off. Since I didn't have the money to shell out for him to do any more investigative work, we were unsure of whether or not it was the timing chain needing replacing or that the head was shaved and the cam towers weren't shimmed properly. Also, my headgasket leaks a small spurt of oil out of the front passenger corner whenever the car is shut off, but my compression seemed fine. Well, relatively low across the board (which could be due to the cam timing being off?) but it is consistent.

 

Sorry for the long backstory, I just wanted you guys to have enough information to help without guessing and wasting your time. Anyhow, my goal for the car is to replace the factory dished pistons with flat tops, but keep the 2.8L displacement. I have an N42, with unknown amounts of headwork, I'd have to sort through some old paperwork from the previous owner. I believe he had a 3 angle valve job, aftermarket cam, new valves and valve seats, possibly rockers and springs. I will check on that tonight or tomorrow and post up that information. Of course, doing any sort of head/cam work on the stock ECU is somewhat pointless, so I was going to go with megasquirt.

 

My question is this: I've heard that you want to get your car in proper running order BEFORE you set up megasquirt or other ECU systems, reason being that you already know your engine can run properly so you know when your tune is good. Does it make sense to get a stock N42 head to try and get my car running properly, then get megasquirt? Or should I go ahead and do the timing chain, new pistons and headgasket, then install megasquirt?

 

Thank you all in advance, I've been stressing out about which way to go with this for quite some time now.

[Leon]

Download the FSM at xenons30.com

 

Go to atlanticz.ca and look in the tech tips section.

 

Diagnose your problems first before throwing parts at it.

[letitsnow]

Absolutely fix it before megasquirt, you will chase your tail for months if you don't. Ask me how I know.