Zmanco

You really haven't told us anything about how the engine management is set up and configured, so it's hard to make educated suggestions. Also, did the engine run with this configuration before the rebuild, or did you change things? We're not mind readers so you need to give us an idea of what's going on for us to help. One general suggestion: measure the timing with a timing light while cranking.

FYI, I have a 25 row oil cooler as well but run 10W30. I'm sure thinner oil makes a difference, but 1 sec vs. 5 makes me wonder if there's some other difference.

I too have a mechanical oil pressure gauge on my L28et and the gauge begins to read pressure in about 1 full second (say "one thousand one" out loud). Perhaps you have a larger diameter hose between the gauge and engine which takes longer to compress and move the gauge? Otherwise, I'm not sure if that's a clue or not, but even 5 seconds seems too long compared to my setup. BTW, regardless if the Fram filter is the culprit, you might want to change to a better brand. There's a great writeup on the web by a guy who got curious about what's in filters so he cut them up and posted pictures. The Fram filters use the cheapest materials and are poorly made. Since I've seen those pictures, I've never bought another Fram oil filter, at least not their orange "extra guard".

Looks like it's 155966.

I can't easily get to the engine right now but the car was built in 2/73. Let me know if you want them and I'll clear things out of the way and get the serial number for you tonight. BTW, were is the serial number on the block? This one is so dirty that it's probably not going to be obvious.

I still have the original L24 from my '73 sitting in the garage and have been looking for a good excuse to get rid of it $125 + shipping.

On a Z with the sloping hatch and the poor aerodynamics that causes, a small wing like that will have very little aero effect. You need one that sticks up much higher. If you're doing it for looks, well then have at it

Follow SleeperZ's advice if you have no idea of the position of the cam with regard to the crank so you don't land up with a valve hitting a piston. However, if you know they're close, but not more than a few teeth off, then do this: Don't forget to put the spacer down into the timing cover before you remove the cam gear!!!! With the crank turned so piston 1 is TDC and the chain off the cam gear, rotate the cam so that the little wedge shaped cut on the back of the cam gear lines up with the short line (dash) on the cam tower behind it. You can see this by looking from the front of the engine back at the cam gear looking through the holes in it. This will make more sense when you look at it on the engine. When you have the cam gear in the correct position, pull the gear off the cam, put the chain back onto the gear and re-attach the gear to the cam. Double check that the dash is still centered on the wedge, or at least pretty close to it depending on chain stretch, tolerances, etc.

It depends on which tire you use. I have Hankook RS-3 in 225/50-16 on the XXR531 16x8 (same size rim I believe) and even with the fenders rolled the tires rub in the rear. I'll add that these are the widest 225 tires I've seen, but the point is you can't assume that all tires with the same size on the sidewall will have the same width.

In case you haven't done the math, the diameter of that tire is nearly 3" smaller than stock.

You need a gear puller. If you don't have one, your local parts store (Checker/AutoZone etc) usually has a loaner program where you can buy it and return for refund after you're through. When you reassemble, be sure to use blue loctite on the crank bolt threads. But I have to ask why you're taking the timing cover off to replace the head gasket...

Just took a quick look at one of the dead tachs in my bone pile and there's a metal strap that wraps under the plastic guide around the studs on the back of the tach. Because the polarity is opposite for the 3 wire (vs. the 4 wire), you have to move that strap to the other stud.

As you can see, the Webers don't get much respect, but it's getting hard to find SUs where the throttle shafts aren't worn and leaking, and that makes it hard to tune for both idle and light throttle cruising. Rebuilding the throttle shafts is a few hundred dollars, so unless you have a car worth it, the Weber DGVs (assuming they are in decent condition) aren't a bad alternative. I ran them early on and from the seat of the pants on a stock engine, they're the same as SUs. They're easy and cheap to rebuild as well if they need that. And they're not any harder to tune, assuming you have the correct jets to start.

TS displays the AFR tables properly for me as well, not sure if the x100 display in MLV is important or a red herring. I'm still curious if the voltage rises due to RPM or boost. Other than that, I'm out of ideas so would suggest you post on the megasquirt forum and/or email DIY Autotune. Matt Cramer is super helpful and hopefully will have some insight. BTW, you're running 2.1.0q. Once you resolve this, you might want to catch up to 3.x as there are many enhancements as well as some bug fixes.

Reading your post reminds me that I think the polarity of the two posts are reversed for the 3 wire vs. the 4 wire? Take a closer look to see if that's the issue.

- What is CLT/MAT/Battery Lag factor set to? - Are you sure you have the alt completely disconnected? Don't mean to insult you with such a basic question, but nothing should be connected to the output stud. - I believe in the MS assembly instructions there are test and trouble shooting steps for the voltage regulator. IIRC, it's one of the first portions of the board to be assembled. You might follow the test measurements and see if that provides a clue. - What is the history of this MS unit? Did you build it? Has it ever been run successfully before? Did this problem recently begin to occur or is this a new MS install? - The Target AFR values all appear to be 100 times too large. Instead of 14.7, it shows as 1470.0 in MLV. Check the Target AFR table. Perhaps your MSQ file is corrupted? (I don't know how that would affect BATT V though). Where did the MSQ file originate? If you created yourself, did you start a new project while the laptop was connected to MS powered up? - Might be a good idea to post your MSQ and let us know which version of firmware you're using.

I used to run a Pertronix on my 73 with the stock tach with no issues. It has been a long time now, but I think Beermanpete's instructions should work. You do have to make sure you get the 2 BW wires connected properly otherwise as he says, the car will run, but the tach won't work. If you're going to replace your tach anyway, I'd recommend you switch to a later 3 wire. They are easier to find, and you can swap the internals to keep the stock faceplate and needle. After buying 2 used 4 wire tachs that had issues, I swapped to a 3 wire and haven't had to touch it since.

You really need to get this resolved before you can worry about the cut out under boost. If the alt output is really rising to 16+ volts, then you're going to damage the battery and perhaps other components. If the problem is with MS reading inaccurately, then you're going to have other problems with tuning e.g. PW is compensated based on battery voltage. Good luck and let us know what you find.

I was able to look at the log. Looks like the AFR begins to rise when the bat voltage hits 15.5V. I would not be surprised if the EDIS controller had an overvoltage protection mechanism that shuts it down - although this is pure speculation on my part. In any event, you need to resolve the battery voltage rising - is it tied to boost or simply rpm? I'd guess that it would be the latter, which you may be able to verify reving the engine while parked. I'd focus on fixing that first and the rest of the issues may go away. Then get on with tuning - AFR <9 will kill the O2 sensor.

I never experimented with advancing it when I ran that cam so can't answer that one, although I don't think so - I only tried retarding. I was running a 4.11 with an 81-83 5 speed so only cared about power at higher revs.

I'm having a problem with java on my work laptop so can't see your log, but keep in mind that without combustion, the O2 sensor will read full lean regardless of how much fuel is present. Remember, the O2 sensor measures how much oxygen remains, and without combustion, it's all still there. I think you're headed in the right direction looking at the ignition. What is controlling EDIS - perhaps the Explorer module? I ask because that has a fail safe mode such that if it loses the signal from MS, it defaults to 10 deg adv. Hence it's not possible if it's working properly to implement a spark cut. So if you're losing spark, the problem is probably with the EDIS components and not MS. All that said, I'm not able to imagine how it would only fail when under boost ...

I would not have recommended that cam for an auto. It makes good power between 3500 and 6500 rpm, but there's not a lot of torque at low revs.

Unless the clutch isn't fully disengaging ...

Save yourself some time and go straight to 3. If the power peak becomes too low in the rev range for your taste, then go back to 2, but I doubt you will. 4 deg (one hole) isn't that much of a difference.

It's up to you how you want to approach this. I tend to have more time than funds for these types of issues so using the existing cam gear to at least verify that advancing the cam improves this would be my next step. But if you're paying for labor, then it might be worth having an adjustable cam gear installed so you can do it yourself from then on. Again, there's a proper way to do this as I mentioned before - I believe BRAAP did a great writeup for setting cam timing showing it step by step.