Daryl Posted August 23, 2015 Report Share Posted August 23, 2015 Picked up a real fugly and nasty dats from my grandpas field. It's got the J13 motor in it. Went through and did a full motor check up. Cleaned up spark plugs, spark plug wires, fluids, carb clean up, and put in a new battery. Squirt some starting fluid in it and keeps cranking over but doesn't start up. Motor so far sounds good, no weird noises. she's nasty but a good looking one! 2 Quote Link to comment
DanielC Posted August 24, 2015 Report Share Posted August 24, 2015 Step one. Check compression. I do not know what is OK for a J-13. Step two. Spark at the plugs? If spark is good, make sure it is at the right time. Step three, pour a little gas down the carb, and see if it will fire. I would disconnect the gas line from the tank. Remove the tank, clean it out. Whatever stuff is in the tank is not gasoline any more. 1 Quote Link to comment
Daryl Posted August 24, 2015 Author Report Share Posted August 24, 2015 Ok, so this is what i've now got so far: Cranking over. Coil has power going to it, but no spark is coming from spark plugs. New plug wires, new cap, new rotor. Points are clean not burnt. So far no firing up :/ 1 Quote Link to comment
DanielC Posted August 24, 2015 Report Share Posted August 24, 2015 If you have no, or low compression you are wasting your time. Check it! 1 Quote Link to comment
Daryl Posted August 24, 2015 Author Report Share Posted August 24, 2015 I'd Imagine compression is good cause im getting 163-168 psi on all 4. 1 Quote Link to comment
Charlie69 Posted August 24, 2015 Report Share Posted August 24, 2015 Set the point gap and check the timing. Check each plug wire with a grounded spark plug in it for spark. The yellow wire you ask about is possibly the temp sending or the oil sending wire. 1 Quote Link to comment
Charlie69 Posted August 24, 2015 Report Share Posted August 24, 2015 Gene Knight has a grill for your truck. Nice score. Quote Link to comment
DanielC Posted August 24, 2015 Report Share Posted August 24, 2015 OK, compression is good enough. That leaves ignition, and fuel. A quick test for those two problems is this. Crank the engine for about 20 seconds. Go and smell the exhaust. If you smell gasoline, probably an ignition problem. If you do not smell gasoline, probably a fuel problem. If this is the case, the engine should still fire briefly, by pouring a small amount of gasoline down the carb. 1 Quote Link to comment
datzenmike Posted August 24, 2015 Report Share Posted August 24, 2015 Take the coil wire off the cap and check for spark first. If no spark the coil may be bad. If spark then it may not be getting past the rotor to the individual plug wires... maybe the dizzy is out of time and firing between the wires on the cap. 1 Quote Link to comment
Daryl Posted August 24, 2015 Author Report Share Posted August 24, 2015 Ima try different coils out of my other running dats. My knowledge is growing but how would I go about setting the timing on it? 1 Quote Link to comment
datzenmike Posted August 24, 2015 Report Share Posted August 24, 2015 It's simpler and easier to test the coil rather than to go to the trouble of replacing something that may be fine. In addition, you may be putting a bad coil in, wiring it wrong or break something and adding to the problem. You can only set the timing close enough to get it started. Timing is set with the engine running. Turn the engine to TDC on the number one cylinder compression stroke. Now look at the rotor on the distributor. It should be directly under the #1 plug wire on the cap above it. This will be close enough to get you started. 1 Quote Link to comment
banzai510(hainz) Posted August 24, 2015 Report Share Posted August 24, 2015 dont swap coils!!!!!!!!!!! I never seen a coil go bad myself, seen wrong ones installed then causing proplems put the org back in. see if sparks then ck the points and ck if the coil is even seeing a signal to fire. Meaning points closing on/off. Last J motor the dist was grounding out when dist cap was on. it was condensor or point grounding out. not hard to ck to see if gas is being squirted in the carb by looking down and cycle the gas linkage. if squirt then you know your fuel pump is good and carb is full. Try pour a tiny amount in carb. But ck spark first maybe you sucked 15years worth of rust in the the carb and now bad 1 Quote Link to comment
Daryl Posted August 24, 2015 Author Report Share Posted August 24, 2015 Put the original coil back in and found with a testing light that the two connectors on the coil (negative and positive) have positive power, there's no ground going to it? Should I ground it with another cable? Did the timing on it and got it to TDC and #1 is perfect on the Cap. Got timing good. Now I've got no spark even though there is power at the points. Quote Link to comment
DanielC Posted August 24, 2015 Report Share Posted August 24, 2015 The ignition coil is grounded by the points in the distributor. The points are closed as the cylinder is on the compression stroke. This builds a magnetic field in the coil. About 10 degrees BEFORE top dead center, the points are opened. The magnetic field in the coil collapsesimmediately, and this is what makes the high voltage spark. It takes time for the magnetic field to build up. This is where the point gap is critical. If the point gap is too wide, there is not enough point closed time. The spark will be weak. If the point gap is too close, the poins will not open far enought to prevent a small spark in the points themselves, and this will wear the points fast, and the spark will be weak. Adjusting the point gap affects the timing. You have to adjust the point gap, then set timing. You can time an engine with points pretty close, just with a test light. This is how. You take a test light, and ground one end of the test light. put the probe on the test light in the negative, or distributor side of the coil. You can also make this connection on the distributor connection that goes to the coil. Take the high voltage lead from the coil out of the distributor. This is the center one on the cap. Lay it on a valve cover, or close to some metal on the truck. Turn the key on, or supply power to the positive side of the coil. Rotate the engine by hand clockwise. Sometime way before top dead center the test light should be off. This is when the points are closed, and building a magnetic field in the coil. At about 10 degrees before top dead center, the light should go on. Just when the light goes on, the points just open. Rotate the distributor to make the light go on just as the 10 degree before TDC passes the timing indicator. 1 Quote Link to comment
Daryl Posted August 24, 2015 Author Report Share Posted August 24, 2015 How far apart should the points gap be? 1 Quote Link to comment
banzai510(hainz) Posted August 24, 2015 Report Share Posted August 24, 2015 say .020 1 Quote Link to comment
Charlie69 Posted August 25, 2015 Report Share Posted August 25, 2015 You have the best help here. Good info gentlemen. 1 Quote Link to comment
datzenmike Posted August 25, 2015 Report Share Posted August 25, 2015 say .020 About the thickness of a paper matchbook folded in half if you are ever in the woods and need to set it. :lol: . 2 Quote Link to comment
Daryl Posted August 25, 2015 Author Report Share Posted August 25, 2015 Got the points checked and got that straighten out. As well as the coil checked and works too. What are the chances of the distributor condenser going bad or failing? I also checked out the timing and got that right. I grounded the distributor from one of it's screws to an engine bolt just to have it better. Haven't gotten it to give out spark at all as of now. Hummmm?? : / Another night, another one of those odd datsun mysteries. haha. 1 Quote Link to comment
banzai510(hainz) Posted August 25, 2015 Report Share Posted August 25, 2015 bypass the points. place centor coil wire near ground. then take a wire hook up to minus side of coil. ground then unground the the center coil wire should spark. if yes then dist inside it grounded or soemthing shorting to ground. 1 Quote Link to comment
Daryl Posted August 25, 2015 Author Report Share Posted August 25, 2015 Got it RUNNNNNINNGGG!!!! Hel* ya! Shorting out in the distributor. Took it all apart to find a thin wire had come loose inside. Got it removed put back together and dam she runs! Thanks a bunch guys :thumbup:. Going to go out for a spin. :rofl: 1 Quote Link to comment
thisismatt Posted August 25, 2015 Report Share Posted August 25, 2015 Check your brakes immediately...haha 3 Quote Link to comment
Daryl Posted August 25, 2015 Author Report Share Posted August 25, 2015 I got some breaks. haha, I'll rebuild them as soon as I get back. Down the road we'll do the adjustments needed to get up to spec. 1 Quote Link to comment
DanielC Posted August 25, 2015 Report Share Posted August 25, 2015 Good job! Trust us when we say check your brakes. Most of us, including myself, are speaking from experience. Compared to a 521, 520 parts are rare. A little time spent on brakes may prevent a lot of time spent repairing body parts. 3 Quote Link to comment
banzai510(hainz) Posted August 25, 2015 Report Share Posted August 25, 2015 I think Pertronix makes a electronic conversion for those distributors also. 1741 pn last J motor I worked on had this same proplem 1 Quote Link to comment
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.