robox

Oh... And it also says 0125A on the block.

Looks like I've got an N42 block and an N42 head. Does that make sense? So... What have I got? (I've got pictures too, which I can post a bit later...)

OK, thank you. I will take a few more pix and would be super-appreciative if you guys could chime in and let me know what it looks like I've got. The damper has 3 pointers, space 120º apart from each other. And also those weird looking sprocket teeth around it.

OK, thanks guys. I will look carefully at the pulley (and try to find the rubber you are referring to) in order to see if it looks like I've got an imminent failure around the corner. Regarding the possibility that this is an L28 engine: It wouldn't surprise me. A convincing argument could be made that the purchase of this car (by me) was somewhat impulsive. I bought it without ever having seen it in person... from two guys who in retrospect have been proven to be shysters, liars, swindlers... whatever. The car had WAY more problems than I was led to believe. The selling points for me were that it was a Series 1 car with a basically straight body and an intact interior, and a reasonable price (although I quickly came to feel I'd paid too much). Mechanically the car was on the verge of falling apart from neglect and/or uninformed tinkering. I was told that it was not the original engine, but if it's an L28 that is news to me. It's a project, and obviously a big part of that project is learning about what I've really got.

MYSTERY SOLVED! I enlisted the help of a friend to hold a piece of 3/32" welding wire in the #1 spark plug hole while I slowly rotated the crankshaft with a ratchet handle and socket. We worked together to find absolute TDC on #1, and.... The timing pointer points at 30º when cylinder #1 is at TDC !! So 5º past the end of the scale is actually 5º advanced. When I first timed the car it was somewhere between 35º and 38º, so 5º - 8º advanced. Sounds about right. Maybe the damper (I guess that's the name for the pulley that carried the timing pointers) was installed incorrectly at some point in the past. Or maybe the little scale with the degree markings was installed incorrectly. If (when) I rebuild the engine, perhaps I will figure out what happened. I guess the next step for me will be to put the Pertronix ignition module back into the distributor, armed with this new info, and see if it was really defective, or if my lack of knowledge about the quirks of this particular engine invalidated the earlier tests... if you know what I mean Oh, and also... I did the "rotate the crank one way, then rotate it the other way, while watching the distributor rotor and also the timing marks and degree scale" test to determine the dead space, and it was about 6º-7º. Seems like probably not a source of concern. C

Here is the timing degrees scale on my engine: It's slightly hard to see, but the scale does go up to 30º. I am getting the 30º reading, with attendant good engine operation, at an idle rpm of about 800-850 (tachometer broken, so I am guessing). When I rev the engine, the timing light shows the pointer going up to about 45º (off the scale, obviously, so guessing on this one as well.) Regarding the idea of the distributor being off one tooth... My thinking was that maybe, just maybe, the drive gear might be 10 teeth. If it was off one tooth, or off by 36º, then maybe when the timing light shows 36º it's actually at 0º. If it showed 40º, that would really be 4º advanced, and so forth. I wasn't advancing this as a theory about why the engine wasn't running previously, but rather as a theory to explain the weirdly advanced timing settings that the engine seems to need to work properly. Thanks, as always!

Thanks djwarner. To answer an earlier question of yours that I never addresses... no my car is not an automatic. I will read your thread about timing, and probably several others. Yes I know that a re-jet for my altitude may be in the offing. Might help with the super-stinky exhaust!

Thanks... yeah, that makes sense. I did in fact play with all sorts of timing settings, with no results... but that was when I had the Pertronix inductive ignition module installed. It was not until I re-installed the original set of points that the engine decided to work again. All the info stated above regarding engine performance respective to timing is pertinent only to using the points. With the Pertronix module, the engine simply would not work, regardless of timing. I will start reading. I would like to get a better idea what it really means when a car will only run happily with such ridiculously high advance. I don't yet understand what that means. Maybe a badly stretched cam chain? Just a guess.... Thanks

OK, so..... I re-installed the old points and there was a marked improvement. Suddenly it sounded like it was running on 3-4 cylinders instead of 1-2. I noticed, however, that opening the throttle produced no increase in engine speed, whatsoever, even at WOT. Then I put in new plugs, which did not seem to make much of a difference. Then I started playing with the timing, and the car came back to life, albeit only when the timing was put back up around 30º, where it used to be when all this started. Here is how it behaves with regard to timing: 0º: engine will not start, no matter what. 5º - 10º: engine will start and idle poorly, opening the throttle produces no increase in engine speed. 20º - 25º: engine idles pretty well, but throttle response is slightly sluggish. 30º: engine idles well, throttle response is nice and crisp. What does all this mean? I haven't got a clue. I know some advance can be called for due to high elevation (I am at 7000 ft) but I do not know how much is appropriate. For now, I am just happy it's running again. Seems like the Pertronix pickup was crap. One other thing to note... on top of each float bowl is a nipple fitting, and there are hoses which attach there that join up and appear to go back to the tank. I am guessing they are overflow lines. Anyway, if I attach those hoses to the nipples, the engine appears to fuel-starve and dies pretty quickly. I need to leave those nipples open for the car to run. Also, the exhaust is really unpleasant... makes my eyes tear immediately. Seems rich... although the "briefly lift the carb pistons and observe idle speed" test indicates that the mixture is close to right. C

Thanks Zed Head. I've been thinking the same thing. The situation did NOT improve with starting fluid. Still nothing more than occasional burping on cylinder 6. header pipe 6 is the only one that got warm. To be honest I am getting a bit discouraged. I will try reinstalling the points. If that does not work I will tow the car (which drove itself in a week ago) out and put it in storage, I guess.

I can't really speak to the proper method of timing these cars, as I am something of a novice (which is probably quite obvious by now!!) But anyway, I also would like to know the answer. It does seem to me that the vacuum advance should probably be disconnected... but hopefully someone else more experienced on the topic will chime in. Just to re-visit a question that seems to have gotten lost... Is it even possible to have the distributor shaft installed one gear tooth off? I am gonna go work on the Datsun for a few minutes now, before I get to what I am really supposed to be doing today. I will see if starting fluid reveals any new information.

Thank you, madkaw and everyone else, for reading and re-reading my post and giving it some thought. I agree that it makes a lot of sense to conclude that the problem must be related to when I screwed with the carbs. The problems with this theory are that A) I am actually reasonably familiar with the carbs, and I did not do much to them. When I first bought the car in SoCal it was not running too well, so I gave myself a crash course on the carbs on the internet and then rebuilt them with good results. The car ran better. What I did last weekend was simply remove the domed tops, piston springs, and pistons, clean them, and replace them. Also I checked the number of turns on the butterfly adjuster (idle) screws and then returned them to their original positions. That's all. AFTER it became clear the car didn't want to start, I then did some other things such as fine-tuned one float level to give a fuel level of 23 mm from bowl top and also replaced the oil in the dashpots with 10W motorcycle fork oil. I'm familiar with the drop test and the pistons are dropping and clunking well... if anything better than before. Thanks, Christian

Also, all timing right now is being done by just cranking the engine over with the starter (which I am doing with a rigged push-button) as I obviously cannot get the engine to run right now. I don't know if that makes much of a difference. In the past I have had to use liberal amounts of starting fluid to get this engine going, and as I pointed out in my opening post I am currently out of it. I'm gonna buy some more and see if I can get it to run on that. If it does... Maybe that would mean I'm having a fueling issue???

Yes, but choke kills it immediately.

Thanks Zed Head. Plug wires are definitely installed as per manual, and as you said. I originally timed it with vacuum advance intact, although then I disconnected it and saw no difference in the timing.

Also, to be clear... the engine did run for a minute or two AFTER installing the Pertronix items. Although it might have been warm already at that point... I can't quite remember

One other idea... Is it possible that the distributor shaft was installed one gear tooth off? If the gear is 10 teeth, then one gear off would be 36º off, which is close to what it was at before. I do not know the number of teeth. With this thought, I did pull the distributor, but found that I couldn't pull the actual shaft with the gear, as I am sure you all know. What I do know is that the car did not run well with the timing closer to 0º. It seemed to want to run better around 35º. Just a thought

Hi guys- Thanks for the replies. First off, in retrospect it seems like it was a dumb idea to post this same post in two different places on the site, so I killed the other thread (the one in the HELP ME! section) and am moving the discussion over here. One member over in that other thread suggested that i might be having fuel starvation related to the altitude and the fact that I am only using the mechanical fuel pump, and suggested I go with an electric pump near the tank. It's true that I only have the stock pump. I have thought about this possibility and considered getting an electric pump. Although it's also true that the car worked at this altitude previously. Also, just now I replaced the tubes going from the float bowls to the nozzles at the bottoms of the carbs with clear tubing, and there is definitely fuel getting into them. Maybe not enough??? I don't know. Regarding the coil- I bought the two Pertonix items together in a kit from Motorsport in California. They sent me the 3 ohm coil. From what Madkaw says it may be the wrong coil. I don't know enough to say. I did try hooking up my old coil, with no luck. I am getting a spark at each plug, as shown by testing the plug against an engine ground, and also by putting the timing light on each plug wire. Sparks all around. Also put in a new fuel filter, which is clear. Good fuel flow into the filter, still no start. I will post the part number for the coil later. Definitely 3 ohms, though. Thanks

Thanks guys for the replies. In retrospect, it seems like a dumb idea to post this same post in two different places on this site, so I am going to end this thread and move the discussion over to the other place I posted it, which can be found HERE. I will reply to you guys over there. Thanks again!

Hi folks- This is my first post here. By way of introduction, I am not new to forums and I'm also not new to working on cars. Although I will say that working on gasoline engines is not really my strong suit; I'm a bit more familiar with diesels. I owned a 1971 240Z in my 20's, and I bought another one about a year and a half ago. I bought this Z in southern California and drove it home to northern New Mexico. The car is in decent condition, although it took a lot of tinkering to get it back here.... new plugs and a few filters along the way... but it did make it. It's been basically sitting for the last year and a half. I drive it every once in a while just to keep it alive. Well, about a week ago I decided to give it some attention and get it to run better. I drove it into my workshop (yes it was drivable a week ago) and installed a Pertronix Flamethrower coil and replaced the points with a Pertronix Ignitor. After that, the engine fired right up. At that point I decided to do the timing, and I observed that the pointer on the crank pulley was showing at about 35º on the little scale (which only goes to 30º). My old Chilton manual said it should be about 5º, and I'd read online that it should be around 10º, so it was way off. I moved the distributor and got it to be about 15º, which caused the idle to go way down, but the car was still running. At that point I shut the car off, and pulled the tops of both SU carbs to clean them up a little (I could see some oily residue on the round slides which I wanted to clean.) After cleaning up both slides and reinstalling them, the car would not start. Almost a week later, after doing lots of work, I still cannot get the engine to start again. Things I've done: • Adjusted valves (twice) • Put timing back to 35º, and every other setting you can imagine • installed new plug wires • Cleaned and gapped all plugs • Checked fuel levels in the float bowls with the 23mm clear tubing method • Verified good fuel pressure out of pump (visual verification only; watched fuel squirt out of float bowl tops into plastic container while float bowls were disassembled) I also checked compression, which came in between 122 and 132 for all 6 cylinders. I understand these are fairly low numbers, although I have a mechanic friend who assures me they are not TOO low. In any case I'd have a hard time believing that compression was my problem, as the car ran OK before I (minimally) messed around with the carbs and the timing. What I can get the car to do occasionally is run VERY poorly for a minute or less. It typically dies on its own. Also it does not respond to throttle, throttle usually kills it. From feeling the headers after the engine dies I can tell it's usually only running on 2 cylinders, typically 1 and 6. Sometimes I will hear what sounds like detonations in the exhaust pipe. Also when it does run, it frequently coughs big spurts of air-fuel mixture BACK out of the carbs. Other info: I am at 7000 feet elevation. It frequently seems to me that the carbs are too rich. I currently have the mixture nuts turned down about 1 turn, although I have played with settings between one-half turn, and two turns. Also, it got quite cold here right around the time the engine stopped starting, probably averaging in the 20's in the last few days. I did put some work lamps on the engine for a few hours this evening in an attempt to warm things up, but the car still would not start. Also, the engine seems to want to run on starting fluid, although at the moment I am out of it. Also, right around the time the engine decided NOT to start again, I filled the fuel tank (but I can't see how that could be significant). It's a mystery to me.... as well as to my mechanic friend. Any insights would of course be appreciated. I am going to post this in both the HELP ME! section as well as the general engine section, because, not being too familiar with this site, I'm not sure which is really the right place. Thanks again, Christian

Hi folks- This is my first post here. By way of introduction, I am not new to forums and I'm also not new to working on cars. Although I will say that working on gasoline engines is not really my strong suit; I'm a bit more familiar with diesels. I owned a 1971 240Z in my 20's, and I bought another one about a year and a half ago. I bought this Z in southern California and drove it home to northern New Mexico. The car is in decent condition, although it took a lot of tinkering to get it back here.... new plugs and a few filters along the way... but it did make it. It's been basically sitting for the last year and a half. I drive it every once in a while just to keep it alive. Well, about a week ago I decided to give it some attention and get it to run better. I drove it into my workshop (yes it was drivable a week ago) and installed a Pertronix Flamethrower coil and replaced the points with a Pertronix Ignitor. After that, the engine fired right up. At that point I decided to do the timing, and I observed that the pointer on the crank pulley was showing at about 35º on the little scale (which only goes to 30º). My old Chilton manual said it should be about 5º, and I'd read online that it should be around 10º, so it was way off. I moved the distributor and got it to be about 15º, which caused the idle to go way down, but the car was still running. At that point I shut the car off, and pulled the tops of both SU carbs to clean them up a little (I could see some oily residue on the round slides which I wanted to clean.) After cleaning up both slides and reinstalling them, the car would not start. Almost a week later, after doing lots of work, I still cannot get the engine to start again. Things I've done: • Adjusted valves (twice) • Put timing back to 35º, and every other setting you can imagine • installed new plug wires • Cleaned and gapped all plugs • Checked fuel levels in the float bowls with the 23mm clear tubing method • Verified good fuel pressure out of pump (visual verification only; watched fuel squirt out of float bowl tops into plastic container while float bowls were disassembled) I also checked compression, which came in between 122 and 132 for all 6 cylinders. I understand these are fairly low numbers, although I have a mechanic friend who assures me they are not TOO low. In any case I'd have a hard time believing that compression was my problem, as the car ran OK before I (minimally) messed around with the carbs and the timing. What I can get the car to do occasionally is run VERY poorly for a minute or less. It typically dies on its own. Also it does not respond to throttle, throttle usually kills it. From feeling the headers after the engine dies I can tell it's usually only running on 2 cylinders, typically 1 and 6. Sometimes I will hear what sounds like detonations in the exhaust pipe. Also when it does run, it frequently coughs big spurts of air-fuel mixture BACK out of the carbs. Other info: I am at 7000 feet elevation. It frequently seems to me that the carbs are too rich. I currently have the mixture nuts turned down about 1 turn, although I have played with settings between one-half turn, and two turns. Also, it got quite cold here right around the time the engine stopped starting, probably averaging in the 20's in the last few days. I did put some work lamps on the engine for a few hours this evening in an attempt to warm things up, but the car still would not start. Also, the engine seems to want to run on starting fluid, although at the moment I am out of it. Also, right around the time the engine decided NOT to start again, I filled the fuel tank (but I can't see how that could be significant). It's a mystery to me.... as well as to my mechanic friend. Any insights would of course be appreciated. I am going to post this in both the HELP ME! section as well as the general engine section, because, not being too familiar with this site, I'm not sure which is really the right place. Thanks again, Christian