New World Datsuns...

Didn't even mess with the EFI today. Did clean the garage and inspected my dual SU setup and perused which cylinder head I want to use. I have a P79 280 head which has a bit bigger intake valves than the Maxima head, other than that it's the exact same. However, it came off a milkshake motor, so I'm not sure I trust it. Think I'll use the original Wynona head or Ugly Betty head. We shall see.

I truly believe that the SUs would be the most reliable in the long run. If the car was bone stock and had 35 years less age under its belt I'd say EFI all day long. The only thing the SUs give up is a little mpg. My Z ran great in all weather and the only adjustment I ever made was a half twist to the knobs when I would move from Walla Walla in the summer to Portland in the winter. It always started easily in any weather.
Sounds like you're close and I commend you on your efforts. I know you'll eventually make it run right but I wouldn't blame you a bit if you ended up with carbs on it.

Yeah, I'm just fighting a lot of unknowns. If I didn't have the other race car to put an EFI system on, I'd do it on the wagon, but either way I look at it, I'm 1500 into EFI roughly, whether it's time or learning. Whereas, carbs and low pressure fuel pump I have. And that eliminates old wiring/components that were great when new, but not so much now. I think for the ease of dinking with carbs and the performance potential, I'll be worlds ahead. We'll see. My Datsun guru suggested maybe I have an electrical problem such as an igniter, but in my experience, they either fail on low circuit, or high circuit, or both, they don't cause a miss at 2/8 or 3/8 light load. I do have a GM igniter I could patch in for testing. I'm about 99% sure I'll still have the lean miss, but it wouldn't take long to check.

Either way I'll be headed to the garage in a bit for some more testing and then likely yanking the head.

So I changed out the matchbox to the nasty factory matchbox with the extra plug. It ran like shit. Unplugged the extra plug and it ran ok, but not great. But then had hesitations everywhere. So parked her back in the garage. Might try to wire up the GM one and test for one last hurrah. It would be really nice if this was a new car where I could plug in a scan tool to it and watch the feed from the ignition unit. I'm almost debating the light load miss/lean issue may just be spark dropping.

I suppose testing the GM module would tell me that. But the car runs so darn perfectly well for the most part with the original matchbox, I find it hard to believe that one little 3250 rpm hitch is the matchbox. But it could be the wiring going to it I suppose. Or something in the ecu.

Either way, I remember Ugly Betty doing the same thing when I had her near stock. With the big cam I was always in the throttle so it just went past it and it didn't matter. The wagon, on the other hand, ran perfectly until I killed #6. Granted it was automatic, so there was usually a shift point right about there. I would have thought that was it, but I've changed the ECU to the manual (verified manual) from Ugly Betty. So unless there's some sort of shift module hidden somewhere (which there isn't as far as I know) then it's just something else. Probably just going lean and pissed off because flappy afm and higher compression makes it unhappy.

I like the idea of subbing in the GM module just to see. You also might try pulling all the plugs and closing up the gap by .005-.010" just for kicks.

I decided the GM module is going to be my last test and I will leave it hooked up most likely whether it solves the problem or not. that way I'll have a cheap replacement ignition module for the carburetors since the matchbox is getting harder and harder to find.

Damn. Thought I had a GM module in the garage, but I've either lost it or I think I might have returned it a while back because I never did the project and the matchbox was working. Balls! Tomorrow I guess.

https://youtu.be/tri0MtGdbvs

Good stuff.

Well crap I haven't had much time at all lately, but I did finally install the GM ignition module, which works well. Then I had an off-day and cursed at the wagon for two hours as I tried to simply adjust the cam gear as I have 8 million times before, except this time I used the wrong tool to block the chain and the tensioner came out, then I dropped a cam dowel down the timing cover. After extracting that and finally weaseling the tensioner back in, the chain was only off my mark by two full links and I finally put it back together only to confirm 2 hole was way too advanced and the car ran like dog poop. Yes, you read that correctly. Advancing the cam makes it come on lower, retarding it raises the rpm range. Anyway, the 3 hole I had with the offset bushing in Ugly Betty is indeed the sweet spot for that motor.

So now I'm debating trying to either snag an 86-88 Maxima efi system and put it on since most everything is the same except the CAS distributor, which I can make work, OR just doing carbs in the first place. I'm leaning towards just doing carbs again. I'd really like to do a nice EFI system, but the race car needs that and it's 1200 to get a megasquirt assembled with a bunch of wiring to make my job easier and I'd rather save up for it. The wagon is much more low tech and honestly, I remember the 510 with carbs vs. EFI and the only thing different was gas mileage was better with the EFI, and it idled nicer for such a lumpy cam. Given my cam isn't that aggressive, I think carbs will still be a major improvement.

Of course, I'm still going back and forth. EFI if I can get an older system to work, is much easier since I don't have to yank the head and have the injector holes welded up, and I don't have to swap the fuel pump for carbureted application.

But, pulling the head isn't that hard, and I have everything needed to do dual SUs other than welding the head. Much cheaper when you have all the parts. Plus, I have no guarantee the 86-88 Maxima VG30 system will work happily on the 2.6 liter Maxima motor. And it has some funky air bleed stuff for IAC control also, though it shows a solenoid. The air stuff may just be for the cat, can't remember. I just don't want to go to pull and save, yank the stuff, and then find after I get it all hooked up that it runs less than perfectly and I'm back to square one because I can't tune it.

What say you guys?

Told you you'd never go carbs. Yer too yeller.

Double dog dare ya.

Lol, I came to a conclusion in the shower this morning. While I suspect the maxima 86-88 system will work, I don't know. So I'm trading one unknown for another just to avoid pulling the head.

That said, I take your double dog dare and I'll triple dog dare you! Updates to come.

Dare me to what? My wagon runs great.

So will mine. Soon. Need Rose to help me get the hood off after she gets out of the shower.

Ok, no turning back now! I did find a slight clean spot on #6 piston, which makes me wonder if I had a slight water leak. Upon inspection of the head, I did find the water port I'm pointing to full of sand nasty. Not a lot, and it dead-heads against the block there, but I'm going to have the head pressure tested while it's out. Also, some of the valves are pretty white from the leanness. Definitely don't like that, but they should be ok.

Either way, SUs should be a vast improvement in response and performance. Not to mention look how much less crap will be on the intake side! Keep in mind the EFI intake is missing a giant fuel rail and fuel injection harness on it.

^^^This guy doesn't fuck around^^^

For L motors, I only use ARP fasteners anymore. Had two "good" head bolts break on one I put together, and I called it quits due to 30 year old hardware. And if I'm spending $80 on bolts, might as well spend double and get stuff that will last and not have head gasket issues.

Think I may just take the other original head up there and that way I can take my time taking out all the Schneider springs and retainers for use after the head has been refurbished. I'll just have them pay close attention to #6 since it had the piston issue. Should be fine though. Going to have a lot of little peripheral things to hook up. There IS a working dashpot on the SU carb set though, so I'm thinking I'll be able to have an "idle-up" feature when the A/C is on. Figure a vacuum switch that gets turned on when the compressor gets signal, should help a bit. We'll see.

I use ARP head studs on all my L blocks now, no more issues after that, had to put a heli coil on one block because the stock head bolt pulled the threads out.

I'm toying with ideas for personalized plates. So far:

DEDSQRL

SIKBRIK

USDM910

Anyone else got any ideas?