Stanley

'73 240z with stock 240 bottom end, and head with round exhaust ports. AT so MSA 6-1 headers won't fit. Wanted equal length with 1 3/8" primaries to maximize already good mid-range torque but Stahl NLA and custom out of price range. Thinking MSA 6-2-1 for 77-78 280z but that collector pipe they supply looks a little crappy and the muffler guy would need to fabricate something to hookup to my 2 1/4 exhaust pipe anyway. Also want to extend the secondaries to equalize the unequal lengths somewhat and maybe help at midrange. Need some photos to show the boss at muffler shop. Found one online but the merge collector looks bad, see below. Anybody have photos in and/or out of car of something like this?

Looks good as is. I'd use aluminum polish and elbow grease, toothbrush to work polish into difficult areas, and a polishing attachment on a drill for final buffing. Need to shine it up now and then to keep it looking great. Maybe easier when it's on the car except for fuel rail area. A year since I shined mine and it needs it. Maybe I should try wet sanding mine or using some rubbing compound before polishing, cause that one looks better. Racers used thin black paint for better heat transfer. I saw a beautiful grey one at a car show, owner said it was powder coat. Keeping mine as is, though.

A good bit of educational information in various locations at the site. I don't know enough to comment on it, but lots of interesting reading, technical but easy to understand. Helped to clear up some concepts I didn't understand previously. They don't make headers for 4 or 6 cylinder cars, they sell parts though, for anyone making their own headers. http://www.headersbyed.com/index.htm

That empty space in front of the engine doesn't look just right. Maybe something like this would help.

What's the fuel pressure now ? 5 psi to 9 psi is a pretty big spread, so maybe your fuel pump is adjustable. The better regulators use a bypass (return). If you're using the stock fuel rail, it has a restrictor before the rubber hose that goes to the stock fuel return line. You'd have to block off the return end of the stock fuel rail, and plumb the regulator's return line to the stock return line. The return line is supposed to be the same size as the inlet line but the stock return line should be OK if your pump isn't pushing too much. You'll need a good F.P. gauge to set any regulator. The better ones all have a port to attach the gauge. I read about some problems with the cheap deadhead regulators on this site and elsewhere. Mallory or Aeromotive are probably way better. Don't need one myself since my stock mechanical pump puts out the right pressure. If I wanted an electric pump I'd probably use the stock one, or get a Mallory 4070LP, which is adjustable and set at 4.0 psi from the factory (but I'd still check it with a gauge). Anyway, here's a link for some regulators. http://aeromotiveinc.com/products-page/regulators/subcat/Carbureted

The gas gauge was on empty, but I figured I had enough to go to the grocery store first, then to the gas station. So I'm heading to the store when the fuel pressure gauge starts going nuts. No engine stalling or other indication except from the gauge. I guess there was enough gas in the float bowl to keep it running although it was intermittently sucking up air. Went to the gas station first instead, put some gas and no more problem.

Yeah, my battery crapped out couple months ago, same time as the VR. Should have guessed the connection.

My auto electric book from the 90's says buy alt / VR as a set so they "match". Does it matter ? They don't sell sets, and there's a generic photo of the VR's used for different makers and part numbers. I think I have a 60 amp alternator, all they seem to sell are 50 and 60 amp. Same alternator part numbers for 240, 260, and 280z. Want to get a spare VR to keep in the car. Had both kind, mech. and elect., go belly up so don't know which. From the original look of the one on my car when I bought it, I guess they lasted longer previously. Maybe the new mechanical ones are made by older children, since they're more complicated. My new elect. one is working OK I guess. Test and adjustment per FSM for mech. type only, though.

Better question would be what type of braided hose to use. You'll need to figure out how you want to set it up and carefully measure everything in advance. That filter probably uses NPT fittings, so you'll need AN to NPT adapters, and an AN Tee fitting to branch out to the 2 carbs . The AN fittings won't make your car go any better, they are for safety, for racing or just a safer road car. They are much less likely to come apart in a wreck. I used AN fittings and cloth-braided (1000 psi rated) hose for a fuel pressure gauge in the cockpit, for safety. Sure, they look nice too. You'll also need AN banjo bolts, or NPT or metric with AN adapters if you want to take it all the way to the carbs. No personal experience, but I've read some horror stories about using cheap stainless steel braided hose, like the stuff at PEP boys. If the rubber inside is crappy it will supposedly leak gas like a sieve after a few years, especially with fuel injection, so better get good stuff that can stand up to gas, heat, and ethanol. Maybe someone can suggest a good brand. There are some newer braided hoses made with space-age materials like teflon. Fire-rated, USCG approved fuel hoses with fuel injection type hose clamps (needed because the hoses are thicker and more rigid) are a good compromise for safety IMO, somewhere between AN braided everything and ordinary fuel lines. Not as pretty as stuff from Earl's but way cheaper. I've got some cloth-braided covers from Wirecare on a few hoses mostly for looks. If you decide on AN cloth or steel braided, I suggest you get your hoses and fittings and take them in to a company that makes up hoses for trucking, air-conditioning, etc. They can make them up in a few minutes while you wait, instead of you trying to figure out how to do it yourself without the right tools, and they'll have tons of fittings and stuff in case you forgot anything. I like that filter, too.

Thank you, some good ideas. I researched the tach in 2014 and came to the conclusion it was current-driven, don't remember how I got the information. Build date for my '73 is 9/72. Attached is a pdf photo of my tach. Wonder what all those wires are and where they go. The TachMatch TM-03 looks pretty cool. They mention using for early 70's Datsuns, it does voltage and current driven tachs, and you get your money back if you can't make it work. A lot to like. My electric skill/confidence level is fairly low (I was boy radio genius - what happened ?) but looks like this little box could make it a lot easier. tach reduced pdf.pdf

After reading a recent thread here that included so information about the Crane HI-6 installation, I did some more search online. I think a cleaner burn at idle and mid-range might do my ride some good, especially with the SM needles. I might try running it with points. According to the instructions, and other sources, it can be done. I saw on MSA catalog that HI-6 is triggered by points, etc., but they don't recommend it. Crane doesn't recommend it either, see attached, due to points float and wear. However, I read some stuff that recommends the points trigger, as it's cheaper, no issues installing a retrofit trigger or different distributor, easy to switch back to stock, and no issue with trigger wires moving when driving. The last one might not matter depending on the trigger. Also, read that points wear (not the contacts, the spring and the piece that rides the cam) and float aren't a big deal if you keep it under 7000 rpm (posted by drag racer on Ford site), because point gap can and should be reduced with the CD box, which reduces both problems. Also, I could always upgrade to xr3000 later. A few questions, though. First of course is the tach. My 73 has the current-driven tach which works fine. Keeping it for now. Also keeping the new (7 years ago) stock 240z euro distributor. About a year ago I posted a thread to see if anyone made the stock tach work with MSD and 240z distributor. Apparently not. The HI-6 instructions seem to imply most tach's work, but I'm not going to waste my time and money if I don't know. A diagram or photos of a setup that works with a stock tach and distributor would be way better than the generic diagram (fig. 2 in the instructions). Also, what coil to use, and ballast resistor or not. Fig. 2 shows a "ballast resistor, if used", but doesn't explain. Maybe the stock tach will work if ballast resister is used ? Seems like it might be different with points but I'm guessing (again). Last, will the stock (I use Japanese parts) cap and rotor be OK with more energy going through ? Seems like it could be regulated by ballast, coil, and plug gap, if so how much is OK for daily driver ? Crane HI 6 instructions 2.pdf

"somebody with 2 hammers hitting the bottom of the car" is exactly how mine sounded when my driveshaft U-joint self-destructed. Happened at odd times though. New driveshaft fixed it instantly. Mechanic I trust said needle bearing was loose in there. I was sure it was something about the right rear wheel but no. Jalex, maybe install a new trans mount and new differential mount ? If that doesn't fix it, it's OK, they were probably about shot anyway. So then do the expensive stuff if necessary. Or if you can afford it, replace rubber at all eight points of contact per post above. I got my car cheap because it was clunking. Thank you worn out trans mount !

Black Dragon has 70-71, 260z, 280z, 280zx. $150 plus $35 core. Didn't know there were all those different ones. When mine went out you could hear it wheezing. http://www.blackdragonauto.com/icatalog/ZR/full.aspx?Page=37

I see K&N has these http://www.knfilters.com/search/product.aspx?prod=E-3190PL for those with the round chrome air cleaners and velocity stacks. They look a little cheezy for the price, but after reading this I might get some anyway. Don't know if they do much.

Ask Kats, probably got his in Japan though.

Vacuum leak at brake booster or elsewhere is obvious thing to check, but it's been done according to previous threads. Sticking choke is possible but easy to check. Pull the choke lever and push it back. Then see if you can push either of the nozzles up. If so it's sticking and probably just needs some carb cleaner and spray grease. Item #3 in the FSM carb tune procedure, is setting mixture adjusting nuts to 2 1/2 turns down (only if you're driving near sea level and the ambient air temperature is 68F, otherwise adjust preliminary setting according to the graph in the FSM) . Items 5 to 8 usually need to be repeated. When you're done, item #11, you check it with the Uni-sen (the "flowmeter" shown in FSM) or Synchrometer again, and if the air flow doesn't match you need to repeat items #5 to 11. So if you just do item 3, that's not it. Observing the tachometer at several stages is also part of the procedure. I thought you had to ask for the SM needles with the ZTherapy carbs, don't know though. N-27's are right for stock engine with stock air cleaner and exhaust. Modified engine (or just using K&N's, see official SU publications for in-depth discussion) may require different mix settings and/or needles. My car has some minor mods, and N-27's, even modded N-27's, didn't cut it. It's doing OK with heavier springs and SM needles, but it's a bitch to tune. The problem is the SM's (as stated in post above) are lean at idle. This is because they are British needles, and the first station is 0.099 inch instead of 0.095 inch like the Hitachi SU needles. So they have to be set richer to start, idle, or run at low RPM. This makes them even richer at mid-range and top end. There is a very narrow range of mix settings where my car will idle and not foul the plugs. 1/8 turn one way or the other can mess it up. I may try modding the SM's by making them thinner at stations 1 & 2, after I buy a spare set in case I it doesn't work. Turn idle adjusting screws clockwise to increase idle RPM.

Courtesy Nissan sold me a Hitachi "made in Japan" dist. cap for 240Z last year, maybe they have Japan cap for 280zx, if it makes a difference.

Right ! No Guessing ! Leave the guessing to the experts. You aimed the new IR gun at the radiator and got 185F when the gauge showed 3/4, correct ? So that's OK. Overheating won't turn the plugs black. Maybe the gauge or sender is bad. Changing gauge is a hassle, but changing sender is easy. I have a few questions: 1. Do you have a digital copy of the FSM ? Blue uploaded it a couple months ago, it's all divided into sections so you can find the section with the carb tuning and print it, or put it on a flashdrive, and take it to the printer. You can't tune the carbs without instructions. There are other instructions, but FSM is almost complete and easy. You need to follow it exactly, and you have to have it printed so you can put it on the fender and refer to it while you're doing the tune-up. 2. Do you have a uni-sen or synchrometer ? You can't tune the carbs without one or the other (unless you're a expert with SU carbs). I prefer synchrometer, because it has numbers that you can write down for reference. FSM explains how to use it. It's almost fun. MSA sells both. You need to raise the nozzles to lean the mix, not lower them. When the mix is set according to FSM, you can fine-tune it with street tests. The IR gun is also useful to see that all cylinders are getting the same air/fuel mix. I point it at the same area near each spark plug, and write down the temp. Then do it again and average the readings for each combustion chamber. The gun needs to cool down about a minute between each reading. If the front 3 are hotter than the back 3, then the front carb is set leaner than the back carb. It's fun to watch the temperature readings change when you make a small adjustment of the mix nuts. Now I have a question for the experts. Could a bad vacuum advance cause the change in RPM at idle ? I suspect a combination of problems.

You could also test the manifold heat control thermostat you have now. It looks shiny and fairly new. Maybe the previous owner bought a new one and installed it. They were available until a few years ago. Your car's symptoms aren't related to the cooling system, and the temperature readings you got with the IR gun were normal, but it doesn't hurt anything to clean it all out. I thought they always cleaned out (hot-tanked) the block when rebuilding an engine, but maybe not. When my father-in-law helped me rebuild the engine in an old Chevy, under the shade tree years ago, we didn't bother with that. You could do a DIY flush. Buy some radiator flush liquid, put it in according to the instructions, and drive it on the highway for a hour or so. Then drain the radiator into a container while it's still hot. If the old coolant comes out looking gunked up, then repeat the DIY flush or take it in for a major flush. Otherwise, you can forget about it.

Good investigation, guys. I'm also puzzled about the "direction of flow" issue. Since the water pump normally sends coolant through the engine, thermostat, radiator, and back through the water inlet, I thought with the thermostat closed the coolant would go through the manifold, manifold heat control thermostat, and around to the water inlet, in that order. Where does the coolant come from if it's going the other way? Seems like position of heater valve might have something to do with it, if the heater's in the loop. Regarding the cavitation issue, seem to remember seeing a little metal tube going around the front of the engine, connecting to a barb on the water inlet, on 280 Z's. Don't think there's a hot=closed thermostat in that line, but wondering if it's to reduce cavitation when the thermostat's closed. I planned an experiment (after reading the HybridZ thread a couple years ago) running a clear line from the outlet on the rear of the head to the lower outlet (OK, inlet) on the thermostat, just to see which way it flowed, but the "clear" high pressure silicon tube that I ordered wasn't clear enough to see flow direction, so I abandoned it. Perhaps a beer will clear my thinking....

Yep.

He's got the little NLA manifold heater thermostat. You can see it in the second photo posted in this thread, on the rear intake manifold. Whether it works or not is another question. It's probably a good idea to have it in the system. Maybe I'll get one someday, but it's way down on my list. Problem is the tube that goes through the manifold rusts out and leaks (mine was totally shot), no easy way to fix it then. Doubt if it's necessary in Panama. FSM says (about) 3.3 to 4.3 psi is acceptable range. I get 3.9 to 4.0 psi with stock mechanical pump and no return line. No problems. No telling what his aftermarket electric F.P. puts out without testing it, though. 1/4 turn of the mix nuts can make a big difference.

It's very easy to test for plugged radiator, as posted previously. But you tested it yourself, saying temp was normal running on the road. If the radiator is badly plugged, how could it possibly run at normal temperature on the road, on a warm day? Besides, 185F is normal. Sounds like your thermostat, water pump, and radiator are fine. Blocking heater bypass loop will bring temp down somewhat, but won't fix your problem since 185F is normal. A car running too rich will sputter and stall at idle or low rpm, but run OK on the road at medium rpm. Plugs will get black. Vapor lock or water temp can't make plugs black. According to ZTherapy video (hidden in the British SU section) fuel pressure can affect the mix (more = richer) so that could possibly cause rich condition, as posted by others. Otherwise, I guess something to do with carbs: they look new, so probably mix setting. The caps are freeze plugs. They look new. Digression: My mom hired a guy to fix her truck. It was driving really wonky. I crawled underneath and saw that he had loosened the bolts to the cross member under the transmission. I tightened it up and told my mom but she wouldn't believe me, and she paid him soon after for even more useless repairs.

Maybe try temporarily installing a set of points (set dwell per FSM with dwell/tach meter) to rule out a possible problem with the Pertronix.

I have the same radiator, runs cool even in very hot conditions. There are engine flush chemicals at any auto parts store, and many auto mechanics will do a flush where they circulate chemicals through the engine for several hours. cost about $50 to $75. Did you try the test I suggested (start engine with radiator cap off, and let it idle until the thermostat opens. You should be able to see a vigorous flow of water) ? If so what was the result? There's another test for blocked radiator. When the engine is warm and thermostat open, place your hand on various parts of the radiator core to feel for a cool spot. Did you replace thermostat with genuine Nissan? Nissan parts man suggested 180F thermostat.