November 21, 200420 yr comment_102718 My '70 240Z sat for about 8 years in a garage before I got it. It did much the same as yours. 1) The first thing I did was remove the plugs and put a little oil in the cylinders incase the rings were stuck. Then I turned the motor by hand. I guess you're past that now. 2) I removed the carbs and gave them a good cleaning. That helped but it wouldn't run for very long. 3) I drained and removed the tank and took it to a radiator shop to be cleaned out. I also changed out all the rubber fuel hoses. 4) The rubber brake hoses were rotten so I changed them out and purged the old brake fluid. The old car now runs and stops just fine. However, I think it would benefit from a complete tune up. I let my 17 year old son drive it today while I was in the passenger seat. He got a real kick out of it and so did I. Link to comment https://www.classiczcars.com/forums/topic/14052-first-drive-in-the-z-backfiring-and-sputtering/?&page=3#findComment-102718 Share on other sites More sharing options...
November 24, 200420 yr Author comment_103091 Ok, heres the update. I've checked the compression seems to be about 160 across the board, that seems in check.I have checked the points, they are clean and the gap is correct.I ran the car out of a gallon of 93 octane. No luck the car ran exactly the same after all of this, no different at all.The car is still suffering from a lumpy idle, almost if I had a cam. While reving the car its still missing and hesitating, If I had not run the compression check by the sound of the motor I would think the compression is down. When I rev the car to about 1500rpm and hold it there, it runs pretty rough.Help Me!!!Thanks again-jared Link to comment https://www.classiczcars.com/forums/topic/14052-first-drive-in-the-z-backfiring-and-sputtering/?&page=3#findComment-103091 Share on other sites More sharing options...
November 24, 200420 yr comment_103093 I know it's a long shot, but I wonder if the capacitor might be "nearly" shot?It's been the solution for many "strange" problems. Being a buck part its an in-expensive long shot.Good luck and keep us informed..MOM Link to comment https://www.classiczcars.com/forums/topic/14052-first-drive-in-the-z-backfiring-and-sputtering/?&page=3#findComment-103093 Share on other sites More sharing options...
November 25, 200420 yr Author comment_103100 By "capacitor" do you mean the one in the dizzy? Link to comment https://www.classiczcars.com/forums/topic/14052-first-drive-in-the-z-backfiring-and-sputtering/?&page=3#findComment-103100 Share on other sites More sharing options...
November 25, 200420 yr comment_103102 Yes, reading back over this thread, I'm pretty convinced the problem is somewhere in the dizzy, may even be the advance mechanism. If the plate mechanism fails then it gives symptoms similar to this.Give the cap a try. Link to comment https://www.classiczcars.com/forums/topic/14052-first-drive-in-the-z-backfiring-and-sputtering/?&page=3#findComment-103102 Share on other sites More sharing options...
November 25, 200420 yr comment_103110 Yes, reading back over this thread, I'm pretty convinced the problem is somewhere in the dizzy, may even be the advance mechanism. If the plate mechanism fails then it gives symptoms similar to this.Give the cap a try.Hmmmm, I wonder where I've heard this before...... (reply #4).......Enrique Link to comment https://www.classiczcars.com/forums/topic/14052-first-drive-in-the-z-backfiring-and-sputtering/?&page=3#findComment-103110 Share on other sites More sharing options...
November 25, 200420 yr comment_103111 Hmmmm, I wonder where I've heard this before...... (reply #4).......Enrique Oh well.... at least we concur..... MOM [ps try the capacitor]! Link to comment https://www.classiczcars.com/forums/topic/14052-first-drive-in-the-z-backfiring-and-sputtering/?&page=3#findComment-103111 Share on other sites More sharing options...
November 25, 200420 yr comment_103117 Oh, no worries there. I wasn't referring to your repeating something I wrote as much as that Messenger (the original poster) hasn't yet posted whether or not he has checked that part.As we all know, there are many "minor" problems that can be erroneously interpreted as being something else, and then repairs attempted that can really bollix the whole car up.So, Messenger, as Carl has posted, you need to get at least 1/4" inch of MOVEMENT (if not more, I'm not sure). If you are NOT getting that movement, then it is very possible that the plate has returned to it's proper position SOMEWHAT, but not necessarily to it's proper position, and your timing is off. That's what the advance plate does, it literally adjusts your timing under heavy acceleration to allow the car to rev up. If it doesn't, then you'll experience everything you've listed.Voice of experience here. My car went from a joyful ride to a handicapped, coughing turtle in the middle of a ride. Took it to a specialist mechanic and although he also did a tune-up and valve adjust, he told me it was the advance plate that had gone out.2¢EnriqueP.S.: I must be out of touch, but what does MOM stand for (no wise cracks guys)? Link to comment https://www.classiczcars.com/forums/topic/14052-first-drive-in-the-z-backfiring-and-sputtering/?&page=3#findComment-103117 Share on other sites More sharing options...
November 25, 200420 yr comment_103119 P.S.: I must be out of touch, but what does MOM stand for (no wise cracks guys)? Look below my sig. MOM Link to comment https://www.classiczcars.com/forums/topic/14052-first-drive-in-the-z-backfiring-and-sputtering/?&page=3#findComment-103119 Share on other sites More sharing options...
November 25, 200420 yr comment_103126 I had signatures turned off, it's all clear now.Enrique Link to comment https://www.classiczcars.com/forums/topic/14052-first-drive-in-the-z-backfiring-and-sputtering/?&page=3#findComment-103126 Share on other sites More sharing options...
November 25, 200420 yr Author comment_103160 Ok, the inner workings of this distributor are very foreign to me. I have it all apart, i looked in the distributor no sign of any ball bearings in there. Anything else I should check in there while it is all apart. I have it all apart other than the cam and counter weights those are still in there.How can I check the "vacuum capsule" as hayes reffers to it, for the neccasary 1/4" of movement? Just by pulling on the spring? Link to comment https://www.classiczcars.com/forums/topic/14052-first-drive-in-the-z-backfiring-and-sputtering/?&page=3#findComment-103160 Share on other sites More sharing options...
November 25, 200420 yr Author comment_103161 Sorry to post again but I just made some progess. I have figured out whast going on here and roughly how the system works. Im pretty sure something is screwy with the vacuum advance plate. It is very hard to move or twist it is very notchey, I don't think that a little bit of vaccum would be able to move it very easily it was probally jammed. Im going to give it a nice cleaning and lubing. Now to figure out where to set it? Link to comment https://www.classiczcars.com/forums/topic/14052-first-drive-in-the-z-backfiring-and-sputtering/?&page=3#findComment-103161 Share on other sites More sharing options...
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