Today I tune a Datsun 240Z with dual SU carbs that would not rev past 4000 rpm. Don't forget to visit my website for more updates: www.thisweekwithcars.com This Week With Cars - Episode 0010 #datsun #datsun240z #classiccars
Very methodical approach and it yielded a great result. Not only fixed the problem but got some tuning out of the deal. Thanks for sharing. Nice Z too!
I was stationed in Wichita Falls, Texas in 1971 and met a fellow Staff Sergeant who owned a 1970 "Fairlady".....this was the Japanese Datsun 240Z .......the only markings on the car was the script "Fairlady" on the sides of the car (behind the front wheels) ...... it had right hand drive - five speed - and had a race engine of, I believe, 2000cc (none of these options were available in the US)..... He purchased the car in Japan and brought it back on an Air Force transport (not an uncommon occurrence back then)..... really fun car to drive and was a real sleeper ................... ;-p
Really enjoy your tutorials. I especially like the videos about starting up cars that haven't been run for a long time. I like how you just dig in and start from the most basic, common-sense items, then follow the process very thoroughly till you solve each issue as it emerges. I like how you're not slamming and banging parts and tools and shouting as you work. I have a 1971 Ford that I want to get running. I'll be watching your vids before I start this process.
Thank you & I really enjoy your videos. You diagnose without throwing parts & hoping it fixes. You are a true mechanic. You make SU’s look easy. Owner of a 64 AH Sprite.
1st principles mechanical thinking is a RARE find today - it's also refreshing to hear an American conversant with British terms, like bonnet and boot for example. I'm really gladI found your channel Steve, You are my go-to for car maintenance process. Thank you Sir 💯 ⭐️⭐️⭐️⭐️⭐️ 🇬🇧
Wow this is a great helpful video Steve on the 240z! This issue sounds like something I’m dealing with now on my 72 240z. You really went over each section very well and explained them all carefully. Camera position’s were spot on with being able to follow your instructions! Thanks for making this video!
You are a decent, humble,good person, and it reflects in your work, and passion of doing things the right way , there are very few people like you, thank you so much, people see the goodness in you .👍🚕🔧❤️
Great stuff and it's so nice seeing someone sticking to the basics 4 strokes of suck,squish, bang and blow. I do Triumphs and so often the problem is so simple. Focus the diagnosis on the technology of the time...
My first car was a '76 280z back in 1980. That car was bullet proof and I loved it. I will watch any video working on a vintage z car because it takes me back to that experience. Although my car had fuel injection, everything else was pretty much the same as the 240 and 260. These were simply awesome cars and should be preserved as much as possible. Thanks for taking care of this nice example!
I run those exact air cleaners on my 240Z, and they work well. Add another nut inside the air cleaner on the long bolts. Done ✅. Also I run the float vents back into the back of the air cleaner. You can put both wires on the same side of the ballast resistor to bypass it. Leave it there, no need to trace out wiring.
I had a 1992 240Z. At 92,000 miles it developed a coolant head gasket leak that corroded the aluminum head around the 6th cylinder. I had it tig welded and then the shop planned it flat. The original cam and cam towers went back on without needing an align bore! Finally in 1989 the rust fairy took out enough of the subframe members and body sections to send it to the junk yard (:-((. A Brock Spook solved the cross wind sensitivity problem and a dented hood replaced wirh a fiber glass one. Also installed a Delta II CD ignition system. I previously has a 59' MGA and a 61' Austin Healy 3000.
Before any fuel adjustments a basic tune should be performed, valve adjustment comp test , ignition test including vacuum and mechanical advance, you also failed to check carb dashpots.
Susan anderson # its an old car , acording to the mechanic by replacing the regular plug its run good , and the owner is happy about it .., is it bcoz using the unsuitable plug it lost its rpm ...? The present plug is mainly for car which are using computer .... did you agree on it ...? regards from kuala lumpur.
@@noorzaidi220 At higher revolutions the spark was getting snuffed. out, because the wrong spark plugs had been fitted. Older points operated ignition systems are producing 12,000 V at the plug, where as a modern engine management system 30,000 V at the plug. Never handle modern H.T leads while the engine is running!
Great point. In this day and age with posers, fakes and imposters claiming to be experts about almost anything, it’s refreshing to see someone who knows what the fuck they’re doing. Sadly, this type of extreme competency is rare.
If it hasn't already been mentioned...those float bowl overflow/vent hoses are supposed to go into the back of the air cleaner (on a stock airbox, if I'm not mistaken)...those aftermarket air cleaner plates look to have open ports on the back that just need a bung for the hoses to connect to (overflow fuel recirculation into the carb, again, if i remember correctly)...
It's wild how much a difference the correct spark plugs can make for your car. I had a supercharged Miata that the previous owner plugs in that were 3 levels colder than stock. Super fouled up but ran ok. I replaced them with one level colder than stock. But now the car misfired on cold starts. After doing some reading I checked the gap and it was 5thousanths too wide. Made a considerable improvement afterwards.
Before tuning SU carbs, Ideally, you should remove the dampers in the dashpots and make sure they're not sticking (it's often worth removing and cleaning them anyway), then checking they have the correct amount of oil. Unless there is an obvious issue with the fuel system, carbs should be tuned after any ignition work.
i love these cars and still want one...I had a '76 280Z 2+2 about 28 years ago, didn't care for the 2+2 option, but even though it had a shoddy suspension, body full of rust (owner lived close to salt water), no A/C or radio, that thing was QUICK!!!
Good video. As the old saying goes many carburetor problems are really electrical. I was guessing no vacuum advance for a while but I suppose that would still allow it to rev but slower.
I worked with a woman in the mid ‘90s who owned a 240Z that was BONE STOCK. It had the original hubcaps and everything. It was orange and, without driving it, appeared to be in fantastic condition. To her credit, she knew what she had and was not willing to part with it. LOL!
I drove one of these a long time back when they were new and I was stunned at how good it was compared to what i'd driven up to then, fast, handled well, and looked fantastic, shame Datsun didn't believe in rustproofing cars until they became Nissan, In the UK they had a thin coat of paint on the underside which after a few years did nothing to stop the salt on our roads rotting them away, Never did understand Datsuns lack of rustproofing,
When a ballast resistor is fitted there is one 12v lead from the starter solenoid and another from the ballast resistor which reduces the voltage when current flow, so you will have a 7v or 10v coil, so you get a good voltage for starting when you are cranking the engine.
another thing to check with those carbs is the floats, since they are rubber and kinda heavy they tend to bend down over time, really the floats are the only thing you need to do with these carbs after they are set right. Also if the car is running points its always good to check the spring for the points if it is weak spark can break up at higher rpm as the points start bouncing around. Another thing is always make sure your engine is running properly before any carb balance/adjustment, these hitachi SU carbs dont need to be adjusted hardly ever, just make sure they are clean, have the right oil and set them on a healthy engine then forget them.
I ran my 280 for about 30 miles with a bad oil pump and it didn't brick the car but it ground down the cam a lot. Even when flushed and repaired, with the old cam points and valves worn down It could never rev and make power like it should. Hope this isn't the issue here and I will keep watching.
I own the exact same year and model with similar issue. So was the timing bad? Did just replacing the plugs cure the limit on revs? A nice verbal summary conclusion would have been good. Would be good if you explained more in how you sorted the timing. Thank you!
I’m wondering what you ended up doing with the Ballast Resistor. Did you bypass it? I’m trying to figure out what multiple mechanics have done with my ignition system.
I was taught to tune SUs by ear not with a gauge. All you need is a pipe. Say a heater pipe. Put it to your ear then listen to the noise both carbs are making. Once they sound the same all is good in the world.
What do you think was wrong with that spark plug? I don't think a short would stop the test light from flashing, so busted resistor perhaps? I would expect the non-resistor plugs you put in to interfere with the radio. Did you test the radio with the new plugs?
Just throw away the awful SUs and throw on triple side-drafts. night and day, the throttle response is transformed, and the weber warble is such a lovely sound! plus without moving parts the damn things stay in tune .
Man I got a similar problem. The car idles fine but when I press the gas pedal it stumbles and I have to feather the pedal then the RPM’s will pick up. It doesn’t like pedal inputs at all.
Well what can be said for an import 6 that refused to hold a tune up 10 sec or as far as the curb, whichever came first. It was a beautifully styled car powered by an unreliable engine on a less than average chassis with poor weight distribution. Little wonder that the Toyota 4 cyl Celica could run rings around it. Not to mention a USA pickup truck. I was filling my gas tank at Biggs Jtn.OR On I 84 while on the other pump was a 240Z complete with attitude. We were both E bound He was telling me how he would get to Idaho hours before me. I took it as a challenge and we pulled out tanks full Down the road we went with me in the lead. '71 Chevy farm PU, and for miles across N OR he could get beside but couldn't complete a pass. Gas mileage was apparently similar at over 100 MPH so we both stopped in Pendleton to refuel. He's bragging again........"It's gonna get crooked in the Mts"............I tell him "right" but leaving here there be 6 MI of 6% grade and no way that 6 cyl is gonna beat a 350 Chevy smallblock up that hill. Lost him in my mirrors less than 2 Mi up and never saw him again. Could be he accepted defeat. could be he couldn't catch up. I never took my foot outa the carb till I reached my Baker Or. destination.
R or no R on the plugs doesn't matter, but whatever floats your boat. Good catch on the coil, some folks don't take the time to read and get the right coil. Pertronix also makes a 1.5 ohm coil if someone just insists on keeping the ballast resistor.
If Needles to Carbs Are Scoured,Repl.Them,Effects Power,According to Another App.on U Tube.If Headers Are Used & Manual Fuel Pump,Gotta Either Wrap Headers or Ceramic Coat Them.Under Reving Power Was A Big 280 Problem W/ Lousy Lucas Ignition Modules.My Former Mech.in ATL.is Udo Kosche,ONE OF BEST INDEP. Older Z Mechs.in So.East..If U DON' T Get It Figured Out.
Do you have any videos on tuning a 68 Datsun 2000. I have been working on one several years. The carbs have been rebuilt, but I still cannot get the engine to run smoothly and reliably.
Can I remove water from my bowls Without removing my carbs? Hope it's from ethanol. I start it once in a while/never drive it? Pumped from my fender filter into a measuring cup then milk jug. Maybe palm full of water.but no more. Drain ed 3 times at the tank corner. Maybe 1.5 gal. In all.looked good. They said they lost my stock plug. ??? Created a new drain. Oh well.
Yes I removed it completely from the ignition system but if I remember the tachometer might have needed it to read correctly so the resistor itself was there for the tach only.
@@ThisWeekWithCars The tachs on the early 240's get their signal from the positive side of the coil (BW wire) vs later year Z's the negative. I swapped out my 240Z stock points distributor for a 79 280ZX electronic distributor & an MSD Blaster coil. The ballast resister is completely bypassed by connecting its 2 wires together. This must be done because with the ignition switch in the run position this is the positive wiring. In the start position the ballast is bypassed to give a little extra juice. A positive wire from the coil to the B terminal of the 280ZX distributor box is also needed. Negative wire to the C terminal. Rock solid stable even at 7500 rpm's.
Wiki says that Prince licensed the design, and of course Nissan would have gotten the rights when Prince (including the hakosuka Skyline) was brought under the Nissan umbrella. Apparently by the time of the merger the engine was changed enough to not warrant licensing. Great sounding engine for sure.
@@SvenDansk7 I used to work next door to a car yard back in 63 and that was when I first saw a Prince Skyline GT with Triple Webers, they also had the 4 pot short hood version, same body from the windshield back, It may have been called the Gloria?.
@@adoreslaurel Gloria was a different Prince model, but used the same G-series engine back then. Absurdly rare these days, and back then probably the same!
