demo243

Car is back on the ground and on the road! For the moment…. Busy few morning last week during the heat. Lots of 4 letter words were said but new fuel and return lines were run. There was no way I was going to be able to match the originals without taking a whole lot off the car… I ended up terminating them at the firewall and just before the rear diff mount. Moved the regulator to the firewall and flipped the fuel rail fittings around. Also changed up the fuel rail mounting- moving it from the manifold to the back of the carbs hoping to isolate it from heat more- should also allow me to pull the carbs and make changes without removing all the fuel lines. Fuel routing isn’t my favorite but it will do. Got the new Vintage tank solutions tank prepped and ready to go. It seems to be slightly larger than the stock tank but pretty close. Working with poly was nice- super easy. Pick up and sender unit mounted up easily and plumbed cleanly. I ditched the vapor tank since there is only one vent on the pick up set up and tank. It now runs though a roll over valve. Then I got to work on the manifold. With a fresh set of calipers I measured the two flanges which are close but not… the TWM manifold is actually fairly disappointing… some parts of the flange were a perfect match others were off by almost 1mm… the 2mm offset washers were far too big of a difference so I ditched those. Ended up spending a bunch of time filing the “stock” fat washers to get them to sit nicely. They contact both manifolds but won’t rule them out as a possible vacuum leak issue… I mounted up the manifold with out the carbs which definitely was easier. Carbs mounted up pretty easily as well. Testes the fuel system and everything held tight- then fired her up! No fuss firing it up. As for the smaller pilot and larger main jet- smaller pilot seems ok at idle, still only 3/4 turn out from full rich. Larger main is definitely to big at WOT as in 10-11 afr. Going to bump back to the 142.5 mains. As for the pilots- it’s a tough call.. 20 seems good or better… but it’s still very rich at low/no throttle cruise- I’ve been told it could actually be better with a richer pilot and leaner air screw setting… considering bumping to 25. Seems counterintuitive but I’m told the air screw makes a big difference especially at low throttle cruise. Lots to think about… back on the road briefly but carbs to come off to make some jet changes. Still have a slight rev hang issue-although better- that points to a possible vacuum leak issue too. Heres the photo dump-!

Committed now! Already regretting it… but it will be for the better. Going to switch things up a bit to make it a little easier to run the lines. Going to swap the connections on the fuel rail and have the fuel enter from the firewall side. Then will mount the regulator to the firewall and it will pick up the fuel line right from the tunnel. Saves a couple tricky bends, and also cleans up the front of the engine bay. Trying to think of something to replace the isolators without spending $100 on a whole set when I only need a few… also probably going to have to zip tie a couple clips since the screws snapped off and I can’t get in there to get em out

Best deal in hauling cars! I’ve taken to do “local” round trips too- usually cheaper even including the extra gas to empty haul it down, and nice to not have to drive around for your trailer where ever you go. Good to see that Frontier putting in work! That bus is pretty cool too!

sorry nothing right now. Hopefully I’ll get her out this summer. Just need some time to push it out and swap the wheels over. The Z has been a big time suck and always in the way. Runs great though! Prime the fuel system and it starts right up. Always a blast to run out to 95 and rip up and down a few on ramps- got some big double sweepers that are really fun.

I’ve already grabbed a VTS poly tank. Lucky for the Z cars there are a few options out there. sending unit and pick up mount on top. Never have to worry about rust again! Just need some time to try and pull the fuel lines. Not looking forward to that job… but if I’m doing the tank I might as well do the lines too so the whole system is fresh

Well this would definitely be my problem…. The inside of this tank is NASTY!!!!

Carbs are back off the car- Working on a few things --- Plugging the idle adjustment screws Main/Pilot Jet Swap Hopefully solve what is I believe to be a vacuum leak... On the vacuum leak front - it is likely from the manifold- when I pulled the manifold I found a couple things. For starters the intake flange is about 1mm thinner then the exhaust. Ive got some stepped washers coming, but will need to file/grind them down since they are a 2mm step... Also there is quite the interference between the oversized washer I was using (came with the MSA stud/hardware kit) and both the header and intake... That combined with the offset seems to have bent a couple of the shared studs... There is so little room next to the weld... guess Im going to have to file the washer down Same on the intake - can see it was connecting on all runners... but I'm guessing not tight enough to prevent a leak I picked up some new functioning digital calipers - but this give an idea of the thickness difference. MSA header and TWM manifold. Also - upon opening up the float bowls to drain the remaining fuel for the jet replacements I confirmed that I definitely need a new tank and lines. I found rust sediment in all of the bowls. Will probably pull the trigger tonight, but I am leaning toward the VTS poly tank for long term rust prevention and simplicity of less places for a future leak out of the tank - pick up and sending unit both mount to the top so much simpler. Will order up lines to replace the feed and return lines as well - planning on Nickel Copper 5/16 for feed and 1/4" for return.

I really like the idea of the poly VTS tank, but needing to buy a sending unit and pickup - then deal with drilling and installing them... along with the overall cost of it is putting me off. But... I new sending unit and simple pick up/return/vent on top sounds pretty nice... I have already dealt with a leaking sending unit o ring and am not stoked on the old sending unit anyway... S30world is so much simpler since it is "plug and play" but the big question remains- do I keep the vapor tank or delete it...? I had originally planned on deleting it but with no good way of plugging the vents on the tank I ended up replacing all the lines. Now I can order a tank with out the extra two vents... Im torn... I already did the hard work of replacing the lines, but don't really want to do it again. VTS would delete it... so I lean toward deleting it with the S30world too. Hmmmmm

I did work on and drive the car a little bit today. I had an exhaust leak before the o2 sensor so tried to fix that. The gaskets I ordered weren’t right so didn’t fit… but I had an extra from the header so I used that. Had to double up on the header to pipe gasket as neither flange looks straight…. Again my displeasure with MSA…. Should just pony up for a Zstory exhaust… I just want a nice stainless header!!!! Didnt notice any real change from that… Had a wierd very lean idle at initial start up, but that quickly dropped down with a blip of the throttle or 2 and the idle coming up. I dropped the needle clips all the way down (rich) the other day and now part throttle (and cruise) are VERY rich- part throttle in the 10s! So need to raise that clip back up and test again. Still trying to wrap my head around how the needle jet and needle work together- it seems the jet and needle diameter should influence 1/8-1/4-1/2 throttle most and the needle clip does 1/2+ mostly. Needles are much easier to change… but if I’m opening em all up then the jet can be changed at that time too- but not much info on the jet… WOT is in the 13 dropping to 12.5 range which seems pretty solid. I might try one richer main to see if it doesn’t go to rich. Still thinking about going leaner on the pilot- mostly to help with “idle”/“no” throttle cruise … but everything says the opposite…. At ~14 I am 1/2 to 5/8 turn out from full rich which indicates I should go to a richer pilot jet- but no one is running that rich of pilot jet on their twin carb set ups- and im afraid of that making it richer at low rpm cruise… on top of that pilot are a pain to remove since I need to pull the carbs and bowls… I really need a weekend where I can just tune it all weekend but unlikely to happen so I’ll just have to keeping hitting it in sections and pieces… Still - all things said the car drives pretty well. Has its quirks… but still fun to drive! I would argue it drives better with these carbs in this state then it did with the SUs. More ramblings in the future.

It’s definitely a frustrating problem. Hard to recreate and tough to diagnose on the side of the road when it randomly happens. But everything else checks out and the tank is pretty much the only thing left… the filter confirms that it’s nasty🤮 I’m considering that as well. The radium is sweet! But $$$. The ATL one is interesting but a bit small I think. The biggest thing is I don’t really want to have cell hanging out back there… and want to keep the stock fuel door fill. If I could hide a cell there - even slightly smaller I’d be down! I’d even consider cutting the spare tire well out. But really just after a simple easy solution right now, and since I already re did all the fuel tank lines I’m leaning toward the s30world tank

Still have my fuel issue…. Same as before. Went for a run on the highway after making some small tweaks as I try to decide what additional brass to order… and sure enough went super lean and lost power. Managed to limp it off the next exit. Shut it down, fired it back up and was fine. Must be something in the tank intermittently blocking the pick up. I still find it surprising that the car will still run… Only thing left in the fuel system is the tank and the hard lines. All vent lines were replaced and the vapor tank is currently vented to the atmosphere so I don’t think it’s a pressure thing. I almost picked up a used tank a couple weeks ago and kicking myself now… Looking at the S30.World and Vintage Tank Solutions tanks now. I like the poly and simplicity of the VTS one… but also complicated as you need to source a pick up and sender unit… S30.World is more reasonable and basically just a bolt in replacement… I don’t have the time or patience to deal with cleaning and repairing the current tank…

There are a couple of us North of Boston on here. With @mainer311 and @Crashtd420 both having 521s around. Hopefully we’ll see you around! There is a nice little cars and coffee that goes on at Cafe Nero in Andover. Lot can fill quick but sometimes there are a couple Datsuns there. Japanese day in the fall at Larz Anderson is always a good time too. I’ve been meaning to check out Sea Coast and Southern NH cars and coffee but haven’t made it up there yet. Nice looking truck! Let’s see some more of it.

45 If you are making new lines I recommend the nickle copper stuff as it’s much easier to work with

Played around a little more the other night. Dropped the needle clip a couple notches raising the needle- making it richer- and it definitely helped partial throttle. Cruise was really rich though- 11-12. Pulled the clip up one notch and seems to give a real stumble when getting on the throttle during highway cruise. Raised the idle up to 14.5 with the filters on, which seemed to help cruise a bit but still in the 12s. I need to check a few thing before I order any brass. - vacuum leak - definitely have an exhaust leak, possibly before the o2 which would be screwing everything… Then I’m going to drop the needles back down. Really need to pull the carbs and pull the idle adjusters, but want to wait till I decide what jets I’m going to try so I can do it one less time. Based on my plug check my idle is good- afr shows 14.5…- but I’m not sure I believe it… still smells rich… but the pilot is 7/8 of a turn out which is on the rich end of the jet - meaning I might need a richer pilot? But that doesn’t make sense… and leaner would likely help lean out cruise, but not sure it will work since I’m less then a turn out on my current 22.5s…. Im thinking I may bump to a richer main 145 from my current 142,5 as I could use a touch richer at wide open ie on ramp pulls. With that I may try a leaner needle jet paired with the richer setting on my current needle. But need to do some more reading. Trying to figure out my idle/rev hang… seems some people say a lean condition… but car smells rich… and afrs so mostly rich too. I’ll tag @datzenmike maybe you’ve got some thoughts? I think you’ve messed with some slide carbs before? Still happy overall- pulls hard on highway on ramp runs. Feels faster in the butt dyno but stiffer suspension I’m sure plays into that too… Back to reading ….and researching… Busy weekend so probably won’t get anything done till after the holiday.

I dig it! Sweet little truck. In case you are after a decal- “heartbreaker” - https://importbible.com/shop/decals/heartbreaker-decal

Cleaned up the heat shield - not as fancy as my original design, but seems to work quite well; can actually touch carbs 3 and 4 now. Made a few other small tweaks with out much change. Did notice something interesting this evening. When cold it will fire up and idle @ 900. Fires nearly instantly! Way easier then my old SUs. But as soon as I rev it, it gets hung at about 1200 rpm (LED charge light doesn't provide enough draw; so I need a rev to ~3500 to awaken the alt which is needed to get the AFR gauge working). Then as I was driving it around I was having trouble with I'll call it rev hang - getting caught around 2000rpm. My first thought was slides getting stuck, but that doesn't seem to be the case since the shaft rotates fully closed which would force the slides down. Then I noticed that it seems to be more apparent during light throttle applications - think backing out of the driveway, parking lot speeds, neighborhood cruising. But if you give it a good romp and let of quickly it will drop right back down to ~1200. Could be a vacuum leak maybe? AFRs are looking decent but it is definitely popping out the exhaust at idle a bit- I figured this was do to its high idle. Pilots seem to be good - although a very small change (think 8th of a turn) makes a big change in AFRs. Then add the filters on and it richens up (expected... UNI filters are restricting). Ive been basing my tuning on AFRs for the moment since it "easier" but maybe time to try the high/low idle method.

Snuck a few more minutes in today. My progressive throttle lever showed up so I made a few tweaks to the the cable set up and mounted it up- definitely not the final version of the cable set up; but much better. Also managed to re-bend my heat shield mounts and utilize two of the old holes on the DSI shield to get a quick shield thrown together. Seems to make a difference on the quick test tonight, need to let the car run longer to be sure. Short term will probably just trim the excess mount and run it. Threw the filters on too for the test which helped richen it up slightly. On quick initial pull this evening it feels stronger then before. No lag or lack of lowend. Super happy overall!

Thanks!!! Really truely happy it worked. And super excited about them. Haven’t tallied the total recently, but definitely less then a set of triple PHH 44s and probably even 40s. Ill try and get a driving video one of these days, although they never seem to come out well.

Can’t describe how happy I am that it works! Still a number of kinks to work out. - Idle is stuck at about 1200; I believe this is due to the individual adjusters bottoming out on the carb next to them. These truely aren’t needed, but I will need to replace them with a screw to seal the opening. Unfortunately means I need to pull the rack again to get them off - Still having a throttle cable issue, including a very slow return to idle. - Heat shield is definitely needed as carbs 3/4 are getting hot from their very close proximity to the headed. Might need to re- think the fuel rail mount too to separate it from the manifold. Overall pretty close on the tuning. Carbs are close to sync without even touching it them- 1-4 @ 3.5, 5 @ 3, 6 @ 5. Need to pull the fuel gauge to adjust the 6th carb. Currently at 1 turn out from seated on the pilot and ~14 at a high idle. Quick pull down the street at wide open showed ~14 as well. May need to bump to 145 mains from the 142.5 in there now. Im sure there is more but really just excited it works!

Waaaahhhhoooooo!!!!!!!

I do have a plug for it- and was thinking about doing that once I get it dialed in.

Verdict is - Floats! Drained em all and pulled the manifold. Lo and behold every single float was below level- ~14-15mm when spec is 18mm… -so I guess I got lucky on the front 4. Pretty disappointing that they were all off from the factory… and dumb on my part for not double checking them when I had them open to install the new jetting…. But anyway got them all adjusted and back on and now it hold perfect at 3 psi on the gauge. In other news… this new header while the same? Definitely seems different… pipes feel larger and the collector definitely is- but it sits much higher in the body which gives me some much needed ground clearance…. BUT it is very tight to the manifold… so I suspect heat may become an issue… The header is ceramic coated, but I will need to sort something out with the heat shield… quickly. The carbs are atleast isolated from the manifold with a composite spacer and rubber mount.

Through process of elimination… I have an issue with the rear two carbs. First installed the regulator, but no change. Then using the super fancy shop towel check it seemed like only the rear one was leaking. So I pulled that line and plugged the rail and tried again. Leaked again, this time showing the second to last carb. Pulled and plugged that one; gave it a shot and we are good- happily holding 2.5 psi (think I need to swap back to the smaller jet in my in line restrictor to raise the pressure up a bit). This leads me to believe there is a float or needle valve issue on the rear two. I couldn’t potentially get to them while on the car but would be hard to make adjustments… biggest downfall of these carbs… so I think the whole rack will come off. Thinking it’s just going to be easiest to pull the whole manifold, hopefully the gasket will be ok. Going to try tonight to atleast get it off

Grabbed a couple of the wrong fittings yesterday so still waiting on plumbing in the regulator. The bigger issue I am dealing with currently is the throttle cable. Given the heavy return spring on each carb it there is a lot of tension on the cable causing the housing to flex. I re worked the set - going back to a rod off the gas pedal to the pivot and then to the cable- which drastically shortened the cable, but I am still getting so much flex in the housing that I only get about 1/2 throttle at the carb… I have ordered a progressive throttle lever, skillard cable mount, and real Lokar cable. Hoping this will solve the issue…. Here is the current set up

Lots of teething issues right now as I prepare to fire it. But that’s to be expected with a “new” or under utilized carb set up. Have to rework my throttle cable set up. Going back to a rod and link but since I already drilled the pedal I need a new attachment rod. Also having a fuel issue- attempted to test the fuel system with the pump on and gas started pouring out of the over flow vents. Could be a few things- 1)To much fuel pressure- HSRs are sensitive to fuel pressure (2-4 is ideal) and the Carter pump is 4-7psi- I was hoping with a return I may not need a regulator but that seems maybe not case 2) Bad needle/seat or float adjustment needed - hoping this isn’t the case since they would really need to come off to fix this. Picking up a regulator this afternoon and hopefully get on too and go from there.