JW360 Posted January 20, 2015 Report Share Posted January 20, 2015 Hey everyone I just joined. I love this truck, but it has been really frustrating getting the idle right. I have capped vacuum lines cleaned the carb just gave it fresh oil. Cleaned the spark plugs and changed the PCV valve. I have messed with the mixture and fast idle screw and when i get it to a good idle in the next couple days it does something funny and will either die and wont start or give a high idle. Also another weird thing is if I fill up the gas tank it will die after I start it and get back on the road. Then it deffinately doesnt start for at least 30 min while im stuck in the midle of the road. 1 Quote Link to comment
datzenmike Posted January 20, 2015 Report Share Posted January 20, 2015 Well first, welcome to Ratsun Mr. 360. Lets get down to it... Lets eliminate some easy to fix items and move onto the more difficult ones later.These engines work best with everything working including the vacuum lines. So what vacuum lines did you cap and why? Does the choke open fully when the engine warms up? Just take top off the air filter and look in. 2 Quote Link to comment
Charlie69 Posted January 20, 2015 Report Share Posted January 20, 2015 Welcome! You have the best man here already helping you! This sounds like you deleted something needed. Post some pictures of what you did and describe each picture please. This will help Mike help you. Mike is great with Datsun/Nissan problems. Quote Link to comment
JW360 Posted January 20, 2015 Author Report Share Posted January 20, 2015 Ok ill try and get some pictures during my lunch break, while we try and set the timing. We are having trouble finding the mark on the pully. 1 Quote Link to comment
]2eDeYe Posted January 20, 2015 Report Share Posted January 20, 2015 Once you find it, drop a touch of yellow or white paint on it. Makes it easier to see when the motor is running. 2 Quote Link to comment
JW360 Posted January 20, 2015 Author Report Share Posted January 20, 2015 I will! Quote Link to comment
JW360 Posted January 20, 2015 Author Report Share Posted January 20, 2015 Setting the timing is the first notch on the left TDC? And i just plug the light up and go? Quote Link to comment
datzenmike Posted January 22, 2015 Report Share Posted January 22, 2015 I believe the 720 has a small v notch in the pulley. On the timing cover is a saw tooth timing plate with numbers 20..10..0. This is further divided with a line at 5 and 15 degrees and further into 2.5 degree notches. Check the emissions sticker under the hood for the correct timing. (5 + -2 degrees I think) Pulley notch should be aligned with the correct timing on the scale. To help find the notch Take the distributor cap off and crank engine until the rotor is pointing at about 9 and 4 o'clock when viewed from the driver's fender. This should be roughly under the intake (9) and the exhaust (4) pug wires. This will in theory put the v notch at the 0 (zero) mark on the scale. Naturally nothing is that perfect but it should be withing 10 degrees before or after the 0. 2 Quote Link to comment
JW360 Posted January 22, 2015 Author Report Share Posted January 22, 2015 yes awesome picture. Sorry I didnt update I did find that booger notch. My buddy has a timing light, but that didnt work. Since we where already there though we kinda adjusted the timing by ear and now she is purring like a kitten at a good 800-900. I know probably not the best thing to do, but I plan on taking it to another buddy this weekend who has a timing light. He says it works. Quote Link to comment
JW360 Posted January 22, 2015 Author Report Share Posted January 22, 2015 testing photo 2 Quote Link to comment
datzenmike Posted January 22, 2015 Report Share Posted January 22, 2015 Yes definitely time it. The NAPS Z engines are very tolerant of too much advance and they won't run right. Some things to check... Valve lash. Has to be done. Too tight exhausts will burn them. Too tight intakes will affect intake vacuum and idling. If you don't know the history on this truck they may not have been checked in years. Check that both coils are firing. Important. Replace or at least check the transmission oil GL-4 and the differential oil GL-5 1 Quote Link to comment
JW360 Posted January 22, 2015 Author Report Share Posted January 22, 2015 Awesome I got a busy weekend ahead of me then. Mike you are awesome! Quote Link to comment
JW360 Posted January 22, 2015 Author Report Share Posted January 22, 2015 Is it pretty difficult to check and set the valve lash? Quote Link to comment
Draker Posted January 22, 2015 Report Share Posted January 22, 2015 No, you will need like 4 tools and some spare time. Also retorque the head bolts if you have the valve cover off. 1 Quote Link to comment
JW360 Posted January 22, 2015 Author Report Share Posted January 22, 2015 Awesome thanks and the timing should be set first before I do this right? Quote Link to comment
Draker Posted January 22, 2015 Report Share Posted January 22, 2015 Really you just need to have both valves closed on the cylinder your working with. My suggestion would be find one of the many posts that cover this topic. Quote Link to comment
datzenmike Posted January 23, 2015 Report Share Posted January 23, 2015 Is it pretty difficult to check and set the valve lash? No, you will need like 4 tools and some spare time. Also retorque the head bolts if you have the valve cover off. A head re-torque must never be done on a warm engine. Do first thing in the morning. Loosen one bolt at a time and immediately torque to spec. (about 60 ft. lbs.) You can do in any order but only one bolt at a time loose. It won't hurt to torque the Z22 but it's the Z24 that really needs this to prevent the head gasket form failing. This can be done quickly and easily enough to finish before the engine cools down if you prepare and are ready with all tools. For valve lash, start and thoroughly warm the engine. (about 15 min) Set the timing mark to TDC on the compression stroke of #1 cylinder. A quick look at the valves will show both #1 valves closed. If not turn the engine ONE turn completely. Adjust the following valves to 0.012" (better check) In. = intake, Ex. = exhaust In. #1 Ex. #1 In. #2 Ex. #3 Turn engine exactly one turn to TDC and adjust... Ex. #2 In. #3 In. #4 Ex. #4 You're done!!! 1 Quote Link to comment
JW360 Posted January 31, 2015 Author Report Share Posted January 31, 2015 Im going to be honest I have not done the valve lash yet. It is in the works. it was supposed to happen this weekend, but its raining all weekend. Any way I have timed it and replaced spark plugs and wires. It runs like a dream now, except for a few times driving on the high way it seems like there is no power at all. I will go over a small hill or overpass in the high way and she putters and drops MPH down to 40 with pedal all the way down. It has happened about 3 times since replacing spark plugs and wires and times. Quote Link to comment
datzenmike Posted January 31, 2015 Report Share Posted January 31, 2015 Well we can probably eliminate the ignition as the cause but replacing components to fix something is very expensive. Setting the valve lash may not fix the problem but it won't cost anything. The timing is next . Probably not the cause but costs little and eliminates them. Still sounds like the secondary jet is blocked. Quote Link to comment
JW360 Posted January 31, 2015 Author Report Share Posted January 31, 2015 Timing is set. I have noticed it does this when its cold outside. The truck is warmed up, but doesnt have any power like other days when its warm outside. It will also not idle well at all. Quote Link to comment
JW360 Posted January 31, 2015 Author Report Share Posted January 31, 2015 But if its a nice day out it runs great. 1 Quote Link to comment
datzenmike Posted January 31, 2015 Report Share Posted January 31, 2015 Yes definitely time it. The NAPS Z engines are very tolerant of too much advance and they won't run right. Some things to check... Valve lash. Has to be done. Too tight exhausts will burn them. Too tight intakes will affect intake vacuum and idling. If you don't know the history on this truck they may not have been checked in years. Check that both coils are firing. Important. Very important... the ignition timing relies on the assumption that both plugs are firing. If only one side firing the engine will be running retarded and lack power. 1 Quote Link to comment
JW360 Posted January 31, 2015 Author Report Share Posted January 31, 2015 Oh I knew I forgot to check something thanks ill do that soon and let you know. 1 Quote Link to comment
JW360 Posted January 31, 2015 Author Report Share Posted January 31, 2015 Both coils are firing 1 Quote Link to comment
datzenmike Posted January 31, 2015 Report Share Posted January 31, 2015 Good. Also it doesn't cost anything to find out. 1 Quote Link to comment
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