Perfect240z Posted March 10, 2011 Share Posted March 10, 2011 So I drove the car to the gas station the other day. I fill up the tank and go to start the car and she won't start, it was weird since she was fine driving around the block. Anyways after trying a few times I basically emptied one float since I had no tools and the gas station didn't have any tools as well I yanked one tube open and drained it. Tried her again and she started right up, but then started making this weird winy noise. Anyways I recorded the noise, if anyone knows what this could be please let me know. Quote Link to comment Share on other sites More sharing options...
Pharaohabq Posted March 10, 2011 Share Posted March 10, 2011 Dunno, you checked your oil levels in your engine and in the carbs right? You're talking about the metalic pingin noise right? Quote Link to comment Share on other sites More sharing options...
Perfect240z Posted March 10, 2011 Author Share Posted March 10, 2011 Dunno, you checked your oil levels in your engine and in the carbs right? You're talking about the metalic pingin noise right? Its sounds like a low whistle OOOOoing noise if that makes sense. its harder to hear in this video, I'll try to take another one. Quote Link to comment Share on other sites More sharing options...
clutchdust Posted March 11, 2011 Share Posted March 11, 2011 (edited) I think I heard what you're describing, but it is hard to make out on your video. It sounds like it might be a vacuum leak, and a pretty major one at that. Have you checked all your vacuum lines? Odd that it would start up after you drained fuel from just one of the floats. Not sure it matters but which carb did you drain? Why did you pick that one and not drain the other? Is it down on power? Does it backfire? What have you done so far to troubleshoot it? If you rev the throttle does the whine speed up or go away? Just need as much information as possible since we can't actually be there and put hands on. Know what I mean? [EDIT] OK, just reread and caught the part where you say it sounds like a whistle. Whistles typically indicate a vacuum leak. So here's what you need to do. First get some carb cleaner. And just for safety's sake get the hose on stand by. I have not tried this with a Datsun engine where the header is right by the carbs. So get the engine running and reasonably warm. Now spray the carb cleaner around the carbs. You want to spray it on any of the joints, like where the base of the carb bolts to the manifold and where the manifold bolts to the head (although this is the part that worries me). Carb cleaner has notoriously low volatility so itshouldn't catch fire but that's where the hose comes in. Spray on all of the vacuum connections on the carburators and intake manifold. If the whistle goes away, even for just a second, you've found your vacuum leak. Make sure you check that big, fat vacuum hose that goes to the master cylinder brake booster. Your brakes feel OK? Edited March 11, 2011 by clutchdust Quote Link to comment Share on other sites More sharing options...
clutchdust Posted March 11, 2011 Share Posted March 11, 2011 Dunno, you checked your oil levels in your engine and in the carbs right? You're talking about the metalic pingin noise right? It does sound rather tinny, doesn't it? Quote Link to comment Share on other sites More sharing options...
Perfect240z Posted March 11, 2011 Author Share Posted March 11, 2011 I think I heard what you're describing, but it is hard to make out on your video. It sounds like it might be a vacuum leak, and a pretty major one at that. Have you checked all your vacuum lines? Odd that it would start up after you drained fuel from just one of the floats. Not sure it matters but which carb did you drain? Why did you pick that one and not drain the other? Is it down on power? Does it backfire? What have you done so far to troubleshoot it? If you rev the throttle does the whine speed up or go away? Just need as much information as possible since we can't actually be there and put hands on. Know what I mean? [EDIT] OK, just reread and caught the part where you say it sounds like a whistle. Whistles typically indicate a vacuum leak. So here's what you need to do. First get some carb cleaner. And just for safety's sake get the hose on stand by. I have not tried this with a Datsun engine where the header is right by the carbs. So get the engine running and reasonably warm. Now spray the carb cleaner around the carbs. You want to spray it on any of the joints, like where the base of the carb bolts to the manifold and where the manifold bolts to the head (although this is the part that worries me). Carb cleaner has notoriously low volatility so itshouldn't catch fire but that's where the hose comes in. Spray on all of the vacuum connections on the carburators and intake manifold. If the whistle goes away, even for just a second, you've found your vacuum leak. Make sure you check that big, fat vacuum hose that goes to the master cylinder brake booster. Your brakes feel OK? The float I drained was the rear float closest to the cabin. The only reason I drained that one was because when the car did't start back up at the gas station I didn't have any tools on me since I was right around the corner from work. I tried listening to the motor yesterday and it stopped making the noise :/ So i'll have to look today while on my lunch break. I actually know for a fact I have air leak in my carb joints on the front carb, it still works but not well, they need to be replaced with some ztherapy carbs. I did the carb cleaner spraying on the joint and it actually almost stalled out the motor each time I sprayed it on the leak spots. But it never made that noise since i got the car running. Brakes feel good, I haven't checked them yet but, I haven't driven the car really out of the work parking lot except for a couple days ago to get gas, and they work great actually. Quote Link to comment Share on other sites More sharing options...
Perfect240z Posted March 11, 2011 Author Share Posted March 11, 2011 Dunno, you checked your oil levels in your engine and in the carbs right? You're talking about the metalic pingin noise right? I just checked them when I had help trying to sync the carbs. They should be good, even though the carbs are on there last leg. Going to order some ztherapy carbs soon. Quote Link to comment Share on other sites More sharing options...
clutchdust Posted March 11, 2011 Share Posted March 11, 2011 If I understand you correctly, the car almost died when you sprayed the carb cleaner at the mounting flange between the carb and manifold. Is that right? If so, holy hell, you have a big vacuum leak! Do not drive that car until you get that fixed. A small leak will just seal up for a couple seconds when you spray the cleaner until the vacuum pulls the cleaner in. What you're describing, if I'm reading it right, is a leak so big that it's like shooting cleaner straight into the carb. As bad as your carbs may need rebuilding, you should pull them off and replace the gaskets between the intake and blocks and the blocks and the carbs. One time, many moons ago, a guy I knew had this old Buick or Olds something or other and he was complaining to me that it was running like crap. Would idle OK but had no power and ran like garbage when ever he gave it throttle. I took a look at it while he revved the engine. The carb had come apart internally. While the carb's base was still bolted to the manifold, the main body had come loose and would separate from the base, showing a good 1/2" gap. Stunning that car ran at all. I don't even think he replaced the gaskets, just bolted it back together and ran it like that until he got transferred and I never saw him again. Crazy. Quote Link to comment Share on other sites More sharing options...
Pharaohabq Posted March 11, 2011 Share Posted March 11, 2011 From what you've said, it really does sound like you've got a bad vacuum leak. you might try just getting new gaskets before replacing your carbs. Vacuum leaks can easilly cause it not to run well. As for the noise, it does sound a little tinny to me, though that could very likely be the video since it's hard to make an engine sound that way unless something is rubbing. I would guess that you flooded the carb (why it wouldn't start) and the noise was probably something imbalanced between the two amplified by the vacuum leak. I really don't know for certain since I can't see the car. Check your levels and hoses would be my advice. Quote Link to comment Share on other sites More sharing options...
clutchdust Posted March 11, 2011 Share Posted March 11, 2011 At the very least, you should grab both carbs and rock the motor. You can give it a pretty decent tug. I'm betting that something is loose. You can make your own gaskets too, by the way. Especially with the way the factory carbs are it's super easy. Go to your parts store and get some of the thin gasket material. Take off one of the phenolic spacers (the brown insulator between the carb and mainfold. Trace it out on the gasket material and use an Xcto or similar knife and cut out new gasket. Now, as I reread your post, it almost sounds like you could have sprayed the carb cleaner into the carb inlet. Please clarify. Quote Link to comment Share on other sites More sharing options...
Perfect240z Posted March 11, 2011 Author Share Posted March 11, 2011 At the very least, you should grab both carbs and rock the motor. You can give it a pretty decent tug. I'm betting that something is loose. You can make your own gaskets too, by the way. Especially with the way the factory carbs are it's super easy. Go to your parts store and get some of the thin gasket material. Take off one of the phenolic spacers (the brown insulator between the carb and mainfold. Trace it out on the gasket material and use an Xcto or similar knife and cut out new gasket. Now, as I reread your post, it almost sounds like you could have sprayed the carb cleaner into the carb inlet. Please clarify. I actually took off the carbs and the intake manifold and gave them a good cleaning, made new gaskets and bought float gaskets from ztherapy. She runs really good aside from that leak. For that reason she cant be synced properly. I have to take her to the dmv to be verified as a 1970 this month so I can finish up the registration and transfer paperwork. After that I can garage it and start the real work. There isn't any leaks on the connections from carb to intake, its the throttle linkage where theres free play at. Its all original, I have a video on youtube to show where the leak is at. I'll try it again today after work to see if it makes the noise. Quote Link to comment Share on other sites More sharing options...
Perfect240z Posted March 11, 2011 Author Share Posted March 11, 2011 From what you've said, it really does sound like you've got a bad vacuum leak. you might try just getting new gaskets before replacing your carbs. Vacuum leaks can easilly cause it not to run well. As for the noise, it does sound a little tinny to me, though that could very likely be the video since it's hard to make an engine sound that way unless something is rubbing. I would guess that you flooded the carb (why it wouldn't start) and the noise was probably something imbalanced between the two amplified by the vacuum leak. I really don't know for certain since I can't see the car. Check your levels and hoses would be my advice. Maybe it did flood, I have no idea, Lets hope I flooded it cause I have to drive it home about 40 miles lol Quote Link to comment Share on other sites More sharing options...
clutchdust Posted March 12, 2011 Share Posted March 12, 2011 I actually took off the carbs and the intake manifold and gave them a good cleaning, made new gaskets and bought float gaskets from ztherapy. She runs really good aside from that leak. For that reason she cant be synced properly. I have to take her to the dmv to be verified as a 1970 this month so I can finish up the registration and transfer paperwork. After that I can garage it and start the real work. There isn't any leaks on the connections from carb to intake, its the throttle linkage where theres free play at. Its all original, I have a video on youtube to show where the leak is at. I'll try it again today after work to see if it makes the noise. If you have that big a vacuum leak you really need to find that thing and get it fixed. Running very lean does really bad things to pistons. Where's your video? And how soon do you need to drive it the 40 miles? Quote Link to comment Share on other sites More sharing options...
Perfect240z Posted March 12, 2011 Author Share Posted March 12, 2011 Well the pistons on this car might be bad anyways since the motor seems to never have been rebuilt. Well I need to get everything done by the 31st of this month. So I can finally get a license plate and make sure I don't have to smog. Shoot I freakin forgot! I went outside and tried her around the block and she actually did great, no noise today. I'll be heading to work on a sat tomorrow so Ill do another video tomorrow. One going down the street too Quote Link to comment Share on other sites More sharing options...
clutchdust Posted March 12, 2011 Share Posted March 12, 2011 OK, all I can say at this point is make sure you take a small tool kit with you. Seems to ward off the mechanical gremlins. Quote Link to comment Share on other sites More sharing options...
Perfect240z Posted March 13, 2011 Author Share Posted March 13, 2011 Yeah, I was off from work today so I didn't drive all the way to work, might go tomorrow afternoon to see how she does around the block again. Quote Link to comment Share on other sites More sharing options...
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