monster Posted June 21, 2011 Report Share Posted June 21, 2011 hey all, Ive lurked here a bit before picking up my first roadster and now i need ur help to get it running right. This is my first datsun and only my second carbureted car ive worked on. It starts up, runs good at idle but when I try to get into 4th gear speeds or after ive been driving it for a while it seems like the gas just cuts off on one carb. theres no smoke from the exhaust and no response from the choke to try and keep it running. If I don't turn it off, the engine eventually dies like it runs out of gas. The carbs seem in good clean condition and many of the hoses are new. there is spark, distributor , plugs and plug wires seem new(er) . There is no visible leak in the fuel lines, I will continue to investigate but it is hard to replicate that condition in my driveway. My intuition is telling me maybe a vaccum leak somewhere. Anyway, thought Id post up here and in 311s.org to see if some of the datsun gods could chime in . all comments or suggestions are welcome Quote Link to comment
Skib Posted June 21, 2011 Report Share Posted June 21, 2011 are your carbs tuned? is there oil in your domes? Quote Link to comment
datzenmike Posted June 21, 2011 Report Share Posted June 21, 2011 Change the fuel filter. Quote Link to comment
Skib Posted June 21, 2011 Report Share Posted June 21, 2011 Change the fuel filter. ya that too :lol: Quote Link to comment
motavated Posted June 21, 2011 Report Share Posted June 21, 2011 I give you a 1000 for it. AMERICAN! Quote Link to comment
datzenmike Posted June 21, 2011 Report Share Posted June 21, 2011 ya that too :lol: 'so kay, I knew you knew that. :) Quote Link to comment
80datson Posted June 21, 2011 Report Share Posted June 21, 2011 fuel pump, get carb rebuilt? Quote Link to comment
monster Posted June 21, 2011 Author Report Share Posted June 21, 2011 the PO said he tuned them and the look clean but I havent opened them so i don't know forsure. I just adjusted them to get the idle near 1000. Oil in domes? the breather line from the head seems to be leaking a bit near the carbs... i will change the filter soon. would a bad filter clog one carb? it seems like when the car chokes it is only running on 2 or 3 cylinders...btw i only take soviet russian money. serious face Quote Link to comment
Skib Posted June 21, 2011 Report Share Posted June 21, 2011 on the top of the each dome theres a black screw top. you unscrew it and put oil in (ATF works good) to dampin the piston. bout a cap full is a good amount if there empty (the screw top has a dipsick on it so you can check) start with the filter tho Quote Link to comment
monster Posted June 21, 2011 Author Report Share Posted June 21, 2011 (edited) awesome, ill check that and pick up a new filter tommorow, thanks skib! also, should I be worried about oil leaking out of the carb end of the pcv hose? it happens more when the motor runs rough. is there anyway or reason to delete or not delete that hose and just put a breather filter on top of the valve cover? Edited June 21, 2011 by monster Quote Link to comment
Skib Posted June 21, 2011 Report Share Posted June 21, 2011 awesome, ill check that and pick up a new filter tommorow, thanks skib! also, should I be worried about oil leaking out of the carb end of the pcv hose? it happens more when the motor runs rough. is there anyway or reason to delete or not delete that hose and just put a breather filter on top of the valve cover? if your top and bottom PVC hoses are run to your airbox like factory than just leave it, there fine there. the only real reason to put filters on each is if you dont have an airbox to hook them too. I personally run them both to a catch can Quote Link to comment
monster Posted June 21, 2011 Author Report Share Posted June 21, 2011 yea its setup like factory but its leaky on the carb side, I tightened the hose clamp but its still leaking...hard to tell if its through the air filter or hose itself. I don't think it should be enough to build a pool of oil after a short drive...could this be a concern or clue to the problem? Quote Link to comment
Skib Posted June 21, 2011 Report Share Posted June 21, 2011 where is the oil pooling? this is un related to the problem as far as causing it goes but your original problem could exacerbate the oil leaking there. having some is normal, but it depends on how much there is, it may or may not be something to bother with. change your fuel filter and then check back in, take it one step at a time. Quote Link to comment
monster Posted June 21, 2011 Author Report Share Posted June 21, 2011 hey so, replaced fuel filter...it was a little grimmy in one hose so I eliminated that hose and used a shorter new hose just to test. Drove it..it ran well..but when I brought it back in i believe i found the problem. There is slack in the front carb linkage. I believe it is the choke. I believe there is slack and that causes the linkage to stay shut so it suffocates the air and causes it to die. I will pull it apart, clean it and re oil or regrease it. Feel free to correct me if im wrong but the pic shows the linkage im talking about:also the next pic shows where the oil pools when it is running rough...it is along the whole flat rail below the carbs: Quote Link to comment
Skib Posted June 21, 2011 Report Share Posted June 21, 2011 There is slack in the front carb linkage. I believe it is the choke. I believe there is slack and that causes the linkage to stay shut so it suffocates the air and causes it to die. having slack would mean its not closing all the way. and even if it was staying all the way closed it should be when its warmed up. if the choke (on the very bottom of the carb) is pulled out (down) then its on if its pushed into the carb (up) then its off. also the next pic shows where the oil pools when it is running rough...it is along the whole flat rail below the carbs: the heat shield? Quote Link to comment
monster Posted June 22, 2011 Author Report Share Posted June 22, 2011 yo long story short, i played around with pushing the choke into and out of the carb and that seemed to replicate the roughness i experienced when driving. I proceeded to check out the linkage and the bolt holding the linkage together fell off in my hand. The PO seemed to have over torqued and snapped the bolt. After looking around the rest of the carbs for surprises I noticed the bottom of them is a mess of leaking oil. with this and the snapped bolt I just decided id pull them apart and clean them to make sure they are in proper working condition. thanks skib for your patience and im sure there will be more questions but I owe ya some beers man! O ya, heres a pic of the grim on the heat shield: it looks worse in person Quote Link to comment
monster Posted July 6, 2011 Author Report Share Posted July 6, 2011 (edited) YO! sorry I haven't been back here but I got the car running well and havent been inside since then. I've been stretching the cars legs since the day I got it and now that it was running well Ive been making freeway trips. Well, a couple days ago something finally gave out. Here's what happend: I was at freeway speeds, went to accelerate to get into a lane and the motor just died, no sputtering, just shut down. I was able to start it back up while rolling and it died again before I got to the side of the road. The lights and gauges still worked and read ok without dimming. Nothing was leaking and the only thing that was unplugged was a wire to what looks like the voltage regulator: The battery is new, the alternator looks to be a new replacement that is the one wire type but I have no clue when it was replaced. To check the charging system, I have tried to jump the car and also tried a fully charged battery with no luck. also, the grounds look to be ok but I will be going through and cleaning them up anyway. can anyone chime in on where to go from here? I will continue to track it down but any experience would help! also is this another voltage regulator? it was bolted onto the harness for the coild but nothing was hooked up to it. The back has a spring embedded into the plastic and goes from one side to the other. Thanks! Edited July 6, 2011 by monster Quote Link to comment
ppeters914 Posted July 7, 2011 Report Share Posted July 7, 2011 That's the ballast resistor. Ballasts change resistance with current as they heat and cool, and thus provide a sort of buffer for the coil. Coil current will be different at higher and lower RPM. The ballast resistor reduces the current flow thru the coil at low speeds and keeps the coil from overheating. However, the main reason that a ballast resistor is installed in a points-type ignition system is to let the coil receive 12 volts during cranking providing a fatter spark for easier starting. When you crank the engine for start, the switch bypasses the resistor. Once the engine is fired, the ballast resistor is back in action, and the voltage to the coil is reduced to about 9 volts to make the load on the coil lighter. Quote Link to comment
ggzilla Posted July 7, 2011 Report Share Posted July 7, 2011 Yep, that loose wire will cause the engine to stop Quote Link to comment
monster Posted July 8, 2011 Author Report Share Posted July 8, 2011 That's the ballast resistor. Ballasts change resistance with current as they heat and cool, and thus provide a sort of buffer for the coil. Coil current will be different at higher and lower RPM. The ballast resistor reduces the current flow thru the coil at low speeds and keeps the coil from overheating. However, the main reason that a ballast resistor is installed in a points-type ignition system is to let the coil receive 12 volts during cranking providing a fatter spark for easier starting. When you crank the engine for start, the switch bypasses the resistor. Once the engine is fired, the ballast resistor is back in action, and the voltage to the coil is reduced to about 9 volts to make the load on the coil lighter. should I wire it up to the coil then? It was just on the coil mount with nothing going to or coming from it. Yep, that loose wire will cause the engine to stop I plugged it back in and tried but there was nothing not even a crank or sign of spark. Tried a new coil and nothing either. I have not had the time to go back out there yet. Thanks for the help! Quote Link to comment
ppeters914 Posted July 9, 2011 Report Share Posted July 9, 2011 If you're still running the stock points-type ignition, then, yes, the ballast resistor should be connected. 12V wire with key on ---> ballast resistor ---> + side of the coil. The wiring should already by there; just reconnect 'em. If it don't start, then time to check the ignition. Is there spark at the plugs? If not, work backwards until you find the problem. You don't say if the starter turns over or not. If not, double-check those connections. One that a lot folks miss is the grounding strap to the frame: Since it was working, then just quit, I suspect a loose/disconnected wire and/or an electrical part just up 'n' died. Quote Link to comment
monster Posted July 9, 2011 Author Report Share Posted July 9, 2011 yea its all stock, I hooked it back up...just wondering why the PO had an extra one mounted on the coil. There is no spark, there is not even a click. It seems there is no signal to the starter to start cranking. I am also thinking it is a wiring issue somewhere. Just to keep it clear to read, here are some questions I have: If it was a bad ground would nothing work ? or since it is just for the starter it isn't a ground for the whole motor. If it was a starter wire or something from the ignition, would it die while driving? I was thinking possibly it needs to be a complete circuit even when the motor is already running. On the last VW I owned, there is a way to bypass the signal to the starter and just give the starter voltage from the battery so you can rule out the ignition switch. Could bridging the positive to the starter hurt to try? when I get a sec, I am going to try to trace the wiring. another thing to note, It shut off at highway speed, and I was able to restart it twice while i was pulling over but it just died suddenly a Thanks for your help!!!! Quote Link to comment
monster Posted July 10, 2011 Author Report Share Posted July 10, 2011 YO! turned out it was near the key end of the ignition switch. Some of the solder became brittle and cracked through. I guess my knee hit it while driving and took it out! so back on the road she just completed a 20 mile run yesterday. Thanks guys!!! Quote Link to comment
monster Posted October 25, 2011 Author Report Share Posted October 25, 2011 I need help again!!! ahah sorry but I'm totally lost on another issue I got going on. When the cars fully warmed up it begins to miss fire and it sounds like its running on 3 cylinders. If I try to limp it to a safe spot it dies eventually. The coil was old so I got a new msd one and the problem was solved for a couple miles and then it came back. A friend of mine suggested it may be getting flooded so I attempted to re-tune the carbs when the motor is warmed up and having the mis fire. I couldn't tune them though because the idle kept surging. If anybody has had any similar issues or can point me in the next direction itd be awesome. Quote Link to comment
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