Stanley

It has the individual K&N's on each carb. I put a little catch can at the low spot in the middle of the hose from the crankcase vent to the PCV valve. It picks up a spoonful or two of oil in a year so there is some blowby.. I emptied it a month ago. Keeps oil out of the PCV valve. PCV valve was new couple of years ago. It ran OK except for the smoke the two blocks from the store, surprising with all that oil in there. Yep.

No. Can't get a wrench on the pulley nut without removing the fan shroud, and have to pull the fan to remove the shroud, so it's a bit of work. I don't see how something that happens in one cylinder gets oil in them all. Didn't lose any coolant. Didn't see any oil floating in the radiator. Lost oil though, in just a two block drive. I'm trying to come up with an idea but I've got nothing. I don't think anything was rattling around in a cylinder. I've heard that before, a small nut that my Chevy inhaled; it was loud. Been using the truck for storage. Hadn't driven it for about a year and a half but put in some gas and it started right up. Header is shot, rust hole got bigger since I looked at it last.

Pulled the plugs. All six had a liberal coating of fresh engine oil. That seems to make my idea of a broken ring unlikely.

Should have thought to check the plugs but I'll do it tomorrow. Been cleaning out the panel truck so I'll have something to drive. If the cops get behind me I won't be able to turn. No turn signals. Can't go on the freeway in the truck until I rebuild the front end. Steers like a boat over 50 mph. Runs good though.

I've been planning to refresh the engine since I bought the car. This seems like a good time to do it. I'd rather not even start the car and have possible debris moving around in there that could make the rebuild more expensive. If I had a garage or if the management here didn't care if I worked on the car (beyond tune-ups) I might do something different.

I could use some advice on this. Need a first-rate shop in LA South bay, San Pedro or Long Beach to do the R&R. Also a engine builder, preferably in the South Bay or at least Southern California, but engines can be shipped so not necessarily. R&R and engine builder could be the same. Also wondering what I should do with this. I've got a stock '73 240 with SU's, and a small-port Y-70 head and cam from Japan that doesn't let it rev very high but makes amazing mid-range torque, which is very good with the automatic transmission. I only get to the drag strip every few years but it does good there.The tech's were amazed at the flat torque line when I had it dyno'd. So keeping that setup seems good. On the other hand I could buy a L-28 and have more horsepower for about the same money. They could swap the Y-70 on a 280 block but something would need to be done to reduce the compression which is already high with the stock block. Using California 91 octane here. Think I want to stick with SU's, since I've learned a little about them, but I'm concerned they might be hard to tune with a higher-displacement engine. Not trying to build a race car, just fast and dependable for around town and the freeways.

It's possible. Didn't have it on the freeway though, and the temp never got over 175F. When I first changed the needles and installed new points a couple weeks ago had the mix very lean, took a drive and noticed extra heat in the exhaust manifold area. Had to stop several times to re-adjust mix and idle and it was almost too hot to adjust the mix. It was only like that for a half hour of driving but maybe it cooked something. More recently it was only slightly too lean. Took the mix down another 1/12 turn yesterday and the 5 mph burbling was barely noticeable and didn't affect driving. Been planning to rebuild anyway though. Wanted to take it around to some shops and figure out who I wanted to the work, and get it done it in the fall while I'm on a long camping trip in a rented minivan. But once again reality has reared it's ugly head. It's my daily driver so I need to deal with it even though I'm swamped with work right now. Don't want to pay $1200 or so to fix a broken ring or whatever it is, and then do a complete rebuild or buy a new motor 4 months from now.

Sounds right. The weak one was only slightly weaker though. Test will have to wait.

Coming back from Torrance, stopped at the grocery store. Didn't notice any problems. Came back and started it up, big cloud of whitish smoke from the tailpipe. Drove home, just a couple of blocks. Less smoke while driving but still a good bit. No loud clunking noises but heard some intermittent rattling like gravel in a can that seemed to come from the bottom of the engine. Pulled into the parking spot. When I turned it off, saw smoke coming from under the hood. Popped the hood and saw it was coming from the air cleaners. Oil was down a quart, but it was about right last week and it doesn't burn oil. Don't really know, but my guess is it broke a ring and a piece went down in the oil pan. The smoke smelled like oil, not steaming coolant. Coolant temp was below normal. I'd be bummed, but I'd been planning to rebuild it or get a new engine soon anyway. No point in paying to fix a broken ring or whatever it is now and then rebuild it later.

I first noticed the difference in pressure required to push the pistons up a few years ago. I've been "fixing" it by putting less oil in the front one for a while. I also noticed that pressure required seemed to vary by how tightly the plunger caps are screwed down. Maybe, maybe not, but I want to test that again too. Maybe with both full of oil it wouldn't make a difference. With no oil they're both the same, very little resistance with just the springs. Don't remember if the plungers were installed and screwed down when I checked that, so that's another thing to test. Another question is how fast does the oil go down, and so how often should it be refilled. I have trouble seeing the oil level, both down in the hole and on the plunger rod which makes getting an accurate measurement difficult. I recently tried using a rolled-up piece of paper as a dipstick. The oil soaks in making in easy to see. This ain't particle theory but "uncertainty principle" applies: when you wipe off the plunger rod to re-measure and see the oil level, the level is reduced a little. That's how I reduce oil level in the front carb, by wiping down the front rod and plunger a few times until both pistons feel the same. Crane ignition on my do list BTW.

I've got them, also have a new set of yellow springs to try when I feel like experimenting, so maybe. It's running the best it has in a long time though. It would cream its former self in a drag race. It ran mid-16's a few years ago at S.I.R. (with a lucky perfect light) which beat Car & Drivers test of a 240Z automatic by 2 secs, and it's not a race car by any means. Now I've got better size tires for the quarter mile and it's running much better so I think I can get to the mid-15's if I have a good light. That's what C&D got with a 4-speed and they may have burned up a clutch on the borrowed car to do it. Maybe next spring in Tucson. If it goes much faster they'll make me wear a helmet. Now I've got to replace the alternator before it eats a bearing, and get a new radio installed. Oh yeah, and work. Next time I have the air cleaners off I want to test those plungers. I expect there's something going on with at least one of them.

You could put red tape over the green tape. Would that be too much red tape ?

Yes I was on a thread about springs. I had a lean miss when accelerating from cruise at about 4500 rpm. Couldn't tune it out without being too rich at low end. Installed red springs and the miss went away, maybe I changed the mix too, maybe needles, at that time. I got the idea from reading the "Just SU's" book. It says using slightly stiffer springs will increase performance but reduce gas mileage. Counter-intuitive I know. It also says using very stiff springs will reduce performance but increase gas mileage. Blue, red, yellow and green springs are available, with stiffness increasing in that order. Called APT and they recommended red springs for the 240Z. Car is running good, except as described from stop to 5 or 10 mph. I don't think it's too lean at cruise as is. I'm experiencing better acceleration than before when it was running well but on the rich side. The head is higher compression than stock which might have something to do with the best A/F ratio. I will set the nozzles a bit lower lower to tune out the burbling at the stop signs though. Last week we had a very hot day, a record-breaker. I had it set a 1/12 turn leaner than it is now and there was no burbling. Next day it was foggy and cool and the burbling was back. Previously I've often noticed better performance on cool days, indicating to me that it was too rich on average days. If I leaned it out, the top end miss came back. Installing SM's eliminated high end miss but due to the profile at the first couple of stations I had to set it extra rich to run at idle, which resulted in fouled plugs. I don't miss the SM's, don't think they're right for a stock-displacement 240Z, except maybe if it's snowing at the coast when 3 1/2 turns down is correct per FSM.

Seems like the difference could also be caused by one damping too much due to a blockage. I gave it a good blast of carb cleaner, though. Didn't do anything.

I gotta look at my book. Didn't know there was a check valve. If I take those plungers apart, wonder if I'm more likely to learn something, or mess something up, or both ?

Thought I had them both full to start with but not sure. Maybe one jiggly bits functions different than the other. Next time I'll try swapping the plungers with oil levels topped off and see pressure required to lift the pistons changes.

Yes, the dampers were the same and hard to lift two weeks ago when I balanced the carbs. I had to put a few drops less oil in the front (IIRC) one to get them the same.

Yes it's lean at idle, intentionally. Just wondered if it would hurt the engine. If I pull the choke a little the burbling instantly goes away. In fact, I've been driving with a hand on the choke when there's a lot of stop and go, until it warms up. It doesn't do it once I'm going 5 or 10 mph so I push the choke back in. Using straight 30 wt. in the carbs per book and red springs that are stiffer than stock. I could easily tune it out by dropping the nozzles a little more but it accelerates great at all other conditions and the gas mileage is incredible. The needle profile is richer than stock in the cruise and top end zones so there's no miss when I stomp on the gas like with the stock N27's (and no fouling the plugs at low end like the SM's). Plugs look too lean though, so it's bye bye 35 mpg I guess.

After running too rich for months put new points and swapped the SM's for modded N-27's. I balanced the mix and set it lean, then set it 1/16 of a turn richer every few days. Now it goes lean when first leaving a stop sign, burbling a little except on very hot days, but runs well otherwise. I could easily richen it up but I love the gas mileage around town. I can drive for an hour and the gauge doesn't move. I've read that these engines like a rich mix but I seem to have more power when it's a little lean, especially on hot days. The N-27's are polished down at the mid-range, cruising, and top end stations so there's no lean miss or burbling when I get on it. No overheating at all. I do have to pull the choke now to start it. I plan to richen it slightly to the point where there's no burbling, but no richer. Does the danger to the engine from running lean still apply if it's lean at low RPM only and engine temp is normal or less ? Also, the plugs are showing leanness. Will a little light gray stuff on the plugs hurt performance ?

Used one length from the start of the hard line in the engine bay almost to the tank. It wasn't easy even with the drill. It keeps getting stuck every bend in the line. I think the wire rope works better than a solid wire since it won't stay bent when it hits a curve or other obstruction. Maybe having a reversible drill helps too.

I ran the main fuel line not the return but it's similar, just bigger. Got a length of small stainless wire rope at ACE hardware. Wouldn't go very far until I put one end in my portable drill. Finally got it to the elbow by the tank that hooks to the rubber line, but no further. The spinning wire end cleaned it pretty good. Filled the hard line with with injector cleaner and let it sit a while before flushing it out with gas.

There's nothing in the FSM that says both mixture nuts should be set the same. It has a graph that gives preliminary settings dependent on altitude and temperature. 2.5 turns down is about right for 70 F near sea level. Hotter ambient temperature and higher altitude require a leaner initial setting, richer for cold weather, but that's just the starting point. If the engine or carb needles aren't stock then the initial setting should probably be different. Then the mix is set per FSM or other more advanced or simplified methods. It's important to use syncrometer or similar and adjust balance screw to get them balanced. Since it's difficult to get the floats set exactly right, and since the carb pistons move differently depending on the oil level in each one, and maybe other differences, it's unlikely that the best mix would be where both mix nuts are set exactly the same. But if they're way off when it's running the best something's wrong, probably the float levels, and needs to be corrected. Correct me if I'm wrong, but I think once the carbs are balanced and a test drive shows it's a little lean or rich, the carbs can be adjusted by moving the mix nuts of each the same amount, say 1/6 turn before re-testing, without rebalancing them. Since you can't adjust them with the air cleaner(s) on, and air cleaners make it run richer according to British SU documentation, I set them a little lean and richen them up according to test drive, plug color and paper towel test. Air/fuel gauge would be better.

My car is 9/72 so 50 amp is stock then. Wonder if the Canadian 60 amp alternators had exterior regulators. Internal regulator seems better but ammeter needs to be swapped for a voltmeter, right ? Might go to 60 amp later but putting something in there Monday since the noise got worse. I'm getting a new radio. Not a monster system by any means but might increase the requirement. I'm used to seeing the charge increase on the ammeter when I use a turn signal. If I stick with external regulator I'll buy a one to keep in the car. Last time it went out with no warning. Was in Santa Monica. Triple A got it jump started and I made it to Autozone in the South Bay on the run-down battery and installed a new regulator. Wouldn't start of course so bought a new battery too.

Use of DIY stethoscope showed "box of rocks" noise during warm up is coming from the alternator. Guess a bearing is shot. Stock alternator is 40 amp. The two from autozone were 50 amp. I see RockAuto has 50 and 60. A couple of voltage regulators have gone out in 7 or 8 years. I plan to get a 50 amp, any problem with that ? Any advantage or problem with 60 amp ?

Thermostat is fine, it's a 180 degree IIRC Nissan. Temp climbs to a little to the left of the middle of the gauge where the thermostat opens and stays there. If I'm going up the hill from Palm Springs to Chiriaco Summit in summer for example it will go to a little right of center. Glad it's 180 not 165 degrees or it wouldn't get to correct operating temp with the oil cooler. Should probably cover the oil cooler with a blanket or something in winter. It does have a bypass that's supposed to work until the oil heats up, though. Don't remember what temp it's supposed to kick in. High-jacking my thread: noticed that the cam follower on the old points was quite worn down, decreasing the point gap and apparently causing the points to wear down. Gonna keep the points cam greased with correct grease from now on. Pep Boys, Autozone and O'Reilly didn't have it but my local independent auto parts store got me some.