jvandyke

alright, thanks, I think I might just chase the signal converter then, I should consider getting a copy of that book, although it's not my car (my kid's) and he may or may not be in it for the long haul, I 'should' just buy it from him, I freak'n love this thing. I"ll be along in a week or so with rear suspension questions, maybe later today.

This one? https://www.amazon.com/Datsun-Z-V-8-Conversion-Manual/dp/B0006EVOAK/ref=sr_1_2?keywords=jtr+manual&qid=1548178839&sr=8-2-spell $263.84 (I've seen it for $40ish elsewhere) Care to share what you did?

So all you do is add a resistor and the 6 cylinder tach reads correct for the 8 cylinder?

Here's what he says, I hope doesn't mind the re-post. He seems knowledgeable and quick to respond, that's two ++ already. Yes, but you'll also need one of our voltage boosters to drive the tacho (see our listing# 142171581596). Tachos on all pre-300 Z's were back-EMF types that needed the "spike" from a coil discharge to trigger. The 12V square wave from this BTA adaptor won't drive them, so you'll need to add the BTAC2 booster on the adaptor's output. The adaptor and booster can mount together and share the same power and ground (most of our customers use piggyback fastons). For an HEI distributor, you'll probably also want a filtering resistor (free, but you'll need to request one with purchase). Lastly, since the tacho has been out of use, we recommend you test it first to make sure it's working. If the HEI is an OEM type, the HEI tach output should trigger it (albeit with a wrong reading), since OEM HEI outputs use an internal connection to coil-negative. If it's an aftermarket HEI with digital output, you can test using a different vehicle with an external coil by jumpering signal and ground between the vehicles. We do bundle shipping, just pay full postage at checkout and we'll refund the excess to your PayPal when the items ship. In this case you'll pay $10.50 with $3.50 refunded. Thanks for your interest!Best Regards,Gene K

I did see the dakota one too. I contacted the "widget man" ebay one linked above, he responded immediately and said it would work but only if I also added a widget to increase the voltage: https://www.ebay.com/itm/TACHOMETER-SIGNAL-BOOSTER-3-16V-Input-48-63V-Output-compare-to-MSD-8920/142171581596?epid=3012319916&hash=item211a162c9c:g:d9kAAOSwjoFb~Mao So that's about $80 in his stuff, whereas if the Dakota works, there ya go. Can't really get a whole tach for that anyway, let alone one that already fits the car and looks correct. I'm leaning this route but I should probably try to see if the stock one still reads, it won't be correct but it should read something, which means another few hours crammed under the dash trying to decipher the rat's nest nightmare of wires 40 years of hackers have built up, it's something else, my turn!

i've searched, honestly. The aftermarket tach in our '72 is junk. Is it possible to make the OEM tach work with the V8? I see some "adapters" out there. The 350 has an HEI dizzy. The OEM tach is still sitting in the nacelle and it would be so nice just to make it work with the V8, ya know? Something like this? https://www.ebay.com/itm/UNIVERSAL-TACH-ADAPTER-CONVERTER-COP-1-2-3-4-5-6-8-10-cyl-to-any-4-6-8-Tach/141931549970?hash=item210bc79512:g:wqgAAOSwNX1b~MNz:rk:1:pf:0

I agree, great color.

Yes, we should try to figure it out. There’s a slew of receipts from the initial build back in ’95-’96 but not much since. It used to have a little higher cfm carb, who swapped it out when and why I don’t know but they didn’t do it very well. My kid has been driving it for a few weeks now. We got some heat going and she’s running decent. We have to go after an exhaust leak at the header. He’s content to be going to high school in a 48 year old classic hot rod. So am I. I think we’ll get it sorted better over the winter, clean up the interior, tweak the tuning. We have to do something with the suspension, it rubs. Maybe even do a little dragg’n. It's a hoot to drive as in but I think we should tame it down a bit, make the fuel pump quieter, weather stripping on the windows, maybe even get the A/C working again.

Really? I have lots to learn apparently. I assumed that was the A/C blower. Okay so there's a flap inoperative. I think it maybe right behind the center vent (well, deeper in near #6 here: That would totally make sense. Which lever is supposed to close that dude off?

trying to help my kid get some heat in the cabin, '72 240. Chevy 350zz4. Has some flavor of dealer installed A/C. So, turning on the fan we get air through the center and two side vents but nothing to the floor or defroster, I assume the A/C system's fan replaces the OEM one? So what directs air where?

So what went wrong first I don't know but in the re-re-rebuild I put the wrong meter block gasket on and that induced serious flooding. That sorted it out. Then we starting battling the choke, long long story but the end is a manual choke and I had to modify it. End result is we're running strong again. Now try to get some heat as it's getting cold around here.

working on my kid's '72 240, he has one broken heater control knob. $25/pop? I quickly modeled one while watching UofM kick Wisconsin's butt last night and printed one off. It might work, pretty ugly so far, needs tweaking. I don't have set screws to see if it will catch but hey, it's easy and might work. https://www.thingiverse.com/thing:3154591 could make clear and embed one of these into them, I've seen it done on other stuff https://www.amazon.com/Tritium-Self-luminous-15-Years-1-5x6mm-COUNT/dp/B0784BDV3Y?ref_=fsclp_pl_dp_6

It was carb related, I still don't know what happened but the Holley was flooding the left bank of the dual plane intake, flooding 3/5/2/8 (by memory) which are fed by the left side of the intake. I stole the Edlebrock 1407 off my '62 Galaxie and she fired right up and ran great. I've been through the Holley 4 times and can't figure out what is up, warped metering block, something crazy, I replaced every part to no effect. Might get one of these if I can't find what's up with Holley https://www.summitracing.com/parts/sum-m08600vs I think the spark issue was just the plugs starting to foul. I always assumed the timing light would fire when on a wire even if the plug wasn't sparking, someone set me straight on that. All ignition efforts were unrelated but we have a new cap and rotor. The Holley is messed up that's for sure. The old girl wants to rip it up with the Edlebrock on there, although I suspect it's too much for this motor being a 700cfm carb but it'll get the groceries home anyway until we can either sort the holley or find a replacement.

I think I agree. Not firing (or weakly) to every other cylinder in the firing order is just too weird. I'll swap coils around, triple check static timing and all else ignition related. We'll get there.....again.

I've got the Holley manual, practically memorized by now.

No, I don't. There's a brass plug. Test fire, no joy. Pulled primary bowl, can't see anything amiss. 2,5,3,8 still not operational. Spark was weak with timing light. Then gone. ??? I STILL don't know if it's carb or ign.

So I went out again last night, after finding other guys with a 2,5,3,8 no fire. Most claim carb issues. I had already checked for spark on those with a timing light and we had it. I went to check carb settings and found the primary dumped gas as I opened the inspection port so I reset that float but didn't have time to check operation. I think we introduced a lot of little issues as we went after the initial rough running, dying on acceleration. Cautiously optimistic that the flooded primary side was a major issue. I had checked it before and it seemed fine but that was during the intermittant fuel pump saga so, well, lot's of factors ganging up on us. Manual: they make them for crate ZZ4s? Heck yes I'll hunt one down. I assumed I would have to fumble about in the dark on that.

poked around a bit tonight, interesting findings; fuel pump circuit: one of the two wires on the oil pressure sensor had fallen off (probably due to us messing with the distributor) fuel pump works steady 7psi of fuel now feeling exhaust after brief test fires and several cylinders are obviously not firing, every other cylinder in the firing order: 2,5,3,8, they have spark and compression so, bad coil? We swapped in a new one off some random HEI distributor I had bought 2 of (for an old Ford) and never used the one. I went to put the old one back on but it's center button totally fell apart. Hmmmm, I did a compression test on #3 it was fine, didn't do the others but can go back out in a bit, weird. After some googling: one side of the carb isn't putting out.....maybe.

great stuff, much appreciated

I'll try to grab some pictures of ignition and carb fuel/vacuum later tonight. Fuel pump is some orange wire to + and the - runs to chassis mount. Not the stock green. I need to trace it back to it's source and see where they wired it in. I'm pretty sold on the idea we have electrical issues at this point. It was not wired very well. Fuse block is hacked up and broken, we've already had to clean up the mandatory melted connection (I cleaned it and it stopped blowing fuses and getting hot). I'm thinking a good winter project would be to rewire everything, or at least investigate every circuit and clean connections, grounds and rework as needed. Of course, with a month of driving left here in Michigan we want it on the street for a bit yet, if possible. A 355hp 240z, really? Who wouldn't want it roll'n!!

agreed, we need to dig deep to figure out how this beast was built, I suspect electrical issues at either the pump and/or the ignition system, if we're not getting a consistent 12v to critical systems all carb work is wasted (well, good to do in any event). Maybe the ignition switch is flaky and circuits on "run" or "start" aren't seeing what they're supposed to see. thanks for bouncing ideas off me. We know it was all good so it can be again, the street avenger 670 with our recent re-jet and choke linkage work was good so back to trouble shooting electrics. It is a cobbled up mess of wiring. How would an electric pump "normally" be wired in? I suspect off the oil pressure sensor circuit but who knows.

had 7psi on crank and crappy idle but then I noticed it dropped to nothing....??? so you maybe onto something, if fuel pressure is all over the map.....voltage test at pump we had only 4v intermittently during crank, then I rigged up a different source, pump worked well, back to 7psi but no love running, could have flooded it by then. I don't know if this pump is hooked to oil pressure or what even....

yes, pressure gauge present at carb and was okay, headed out to check level and pressure, the pump (some old Holley type) is loud but seems to put out sufficiently, gunna turn towards ignition again soon, I do have to recheck valve clearance, i haven't done a hydraulic lifter like these before. I think I'm doing it wrong. Problem predates my messing with clearances though.

I did not yet. I know I have to but since the car ran the same after I was done it "shouldn't" be the issue.

carb rebuilt, must be ignition?, starts and idles, rough like it's missing, (exactly like before) so thoughts?, rebuilt carb, checked filters, checked fuel supply (pump works fine) new distributer cap/rotor/plugs, tickled the timing a little we also tried to snug up the valve clearances a tad, FWIW Is it possible the cam jumped a notch?