Jetaway

BTF/PTM, I can't really take photos right now because I have the front end in the air and their just ain't that much room left under the backside. I am attaching a photo of the offending bracket. Note the slightly squarshed looking rubber bushing. Didn't realize the significance of it at the time, but this is what I eventually took a small sledge to. I loosened maybe ten to twelve nuts or bolts in all. Any and all of the bolts that attach the differential carrier to the body, including the indirect attachment through the "dog legs." Nuts and bolts attaching the differential to the carrier, I did _not_ loosen. One of the dog legs was bent, but only because it was forced out of position. Once I whacked the bracket into place, the dog leg straightened out and hung nice and perpendicular to the ground. Chris

It _never_ bottoms. And I think I know why now. Thanks for the advice, I would not have known I was missing bump stops. And very much for the link. After posting I gave a run at figuring out the spring rate on those bad boys. I bought a cheap household scale ($9.99, thank you K-Mart!), removed the wheel from the other side, taped a cardboard scale with 1 inch of compression measured off to the top of the coil, put a floor lift under the car and lifted him up. I slid the scale under the tire and slowly lowered the car until the spring had compressed one inch and noted the weight. 305 pounds! Stock is around 90 - 100 lbs and my first thought was that this couldn't be right. I thought that maybe the sway bar and compression rod were exerting a downward pressure as well, so I removed the former and disconnected the latter and repeated the measurement. 270 lbs. I removed the wheel, slipped a small bottle jack under the strut end and used the jack to lift the wheel assembly up the inch. 275 lbs. I haven't disconnected the steering knuckle, but since it isn't designed to control up and down motion while the sway bar is, to some extent, I don't think it can be having much of an effect on the measurement. Here is where the link to Beta Motorsports proved very interesting. In the description of the Tokco HP shocks (I assume these are the "blues" you have on your car) they call them great shocks for springs up to 200 lbs / inch. Yikes! The Tokcio HTS shocks, at $180 a shot are the only one of the three types listed for springs over 250 lbs. being rated for 200 to 375 lbs. The doubts I had about my lbs. / inch measurement methods have been relieved by finding these statements. Rates of 270 lbs / inch aren't out of the realm of possibility and are, in fact, right around the midpoint for race-equipped early Zs. The relief I have in not being completely nuts is someone nullified by thinking that the Tokico HPs might not be a good fit for my car. Is this mismatch between recommended spring rates and my actual rates something to be concerned about or am I worrying too much about something that would have, at most, a small effect that I may never experience? Although at a little under $100 for the pair, picking up a new set of progressive Tokcio springs with 140 lb rate might not be the worst idea in the world. Hmmmm.. Thoughts? Chris P.S. On the really bright side, all the bolts came loose without much argument after an overnight hit of penetrant. Well, one of the sway bar to control arm nut required a bit of the blue torch, but nothing went up in smoke.

Happy New Year Zcar-ers! My 1972 recently developed steering wheel shake, its way of telling me its time to work on the front suspension. Since it's going to be dissembled anyway, I've decided to: 1) replace all the bushings and: 2) replace the struts. There is, of course, a possible complication. I sure hope not, but I'm pretty sure the coils aren't stock. The attached photo is from the left front suspension. There is no compression on the spring when unweighted. It turns easily in the holders, though it won't quite rotate 360 degrees. Maybe it would if I tried harder, but that seems like a pointless exercise. I'm not quite sure how to count the turns, the spring continues at the bottom and ends within an inch of where the top of the spring can be seen to end. I counted this as 7 turns, starting with the hidden turn "zero" at the bottom. The spacing is consistent except at the top and bottom where the spacing is tighter so that the a reasonably level coil end is produced. I measured 10 and 3/4 inches from top of the spring to the bottom of the spring (which is just about where the top of the date-stamp is). The wire is 1/2 inch in diameter. I haven't seen any markings but I haven't had it off the car yet. The ride does _not_ seem to be lowered. It looks stock and ground to body measurements seem right in line with what expected distances based on the tire diameter. Probably rides stiff -- I haven't ridden in any other Z so I couldn't say for sure, but my 150 lbs doesn't seem to make the slightest impression on it when pressing down on the fender. The first question is about the bushings: rubber (stockish) or urethane? I understand that the urethane bushings are stiffer and more durable, what I don't have a grasp on is how the stiffness will affect ride and handling. Well, handling should be a bit crisper, but what about the ride and noise levels? I don't race it but it does get a lot of use, 15,000 miles / year is not out of the question. Would the stiffer urethane bushings be something that would be noticeable at all times or only when driven hard or on, for instance, rough roads, of which we are becoming increasingly well supplied with here in California? The second question is what brand of strut. I don't need adjustable struts, so it seems to come down to KYB or Tokico. Prices seem pretty consistent regardless of source, I'll use Black Dragon's prices here: $60.00 for the KYB and $90.00 for the Tokico's. What am I getting for the additional 50% over the KYB price? I wouldn't mind spending more if I got a smoother ride _and_ better handling characteristics but I'd have to think about it quite a bit if the Tokico's only either rode smoother or handled better but not both. And I'd certainly like to hear about other options, though at $220 I do think I'll pass on the Koni's. First, will stiffer than stock shocks make urethane bushings intolerable for regular street use, or make little difference? Second, will the non-stock coils mean I have to use a non-240Z strut? I have no idea what kind of strut is in use now. Thoughts, tips, and experiences appreciated. Chris

My Z (1972) developed over time two different wheelbases with the driver's side ending up an inch shorter than the passenger side. It took me a year, a lot of head-scratching, research, and measuring, before I got it doped out. Hope I have that terminology correct here. The rear mounting bracket on one of the transverse links had loosened and was not in parallel with with the frame crossmember. It wasn't much off, hell I had looked at it several times before, but a close inspection did reveal that it indeed was off. Loosened up the differential carrier frame bolts and whacked it a few times with a small sledge. The bracket moved at most 1/10th of an inch to line up and that brought the wheel back an inch into parallel with the other wheel. Chris

That's one sharp looking car. It's also a good example of the influence of GM stylists on Japanese design at the time. Chris

Yeah, I know that a centrifugal pump run considerably more than a thumper, but man, that thumpa-thumpa annoys the heck out of me. Chris

No question this time, just something that may help someone some time. My gauge works, and seems at least consistent, however, the markings on the gauge don't correspond with the needle. That is, it never shows (F)ull and I remember going pretty far once when the needle had hit (E)mpty. The gauge was registering "E" so I thought it would be a good time to drain the tank and measure then resistance of the sender after adding a known quantity of gasoline to the tank. I'll be posting pictures of the gauge and resistance measures in another thread in the next day or two. My fuel pump is a generic electric "thumpa-thumpa" type installed at the tank, with a filter between it and the tank. The mechanical pump has been removed and replaced with a cover plate. Drained the tank, all 3 and 1/4 gallons of it (With the gauge on 'E!'), measured the resistance, snapped a couple of shots of the gauge and poured the gas back in. Started right up but by the time I had it out of the garage and down the driveway it coughed and died. Wouldn't restart. My first thought was that the slight incline of the driveway had moved the gas away from the pickup, though my 2nd thought was 3 gallons was a heck of a lot of gas to have unavailable in the tank. I rolled/pushed it onto the level street and tried again. Nope. Took the other vehicle down to the corner gas station and bought 2 gallons, put it in the Z and tried again. Nope. Thought about what I had done while draining the tank -- that was it, all I did was drain the tank, measure the resistance, then refill and measure again. Maybe inadvertently knocked off the hose to the tank? Nope. A vacuum in the tank? I took off the gas cap and tried again. Nope. Arggh.. Wasn't planning on car work today. Pulled the fuel hose at the rails, seemed a bit dry, put the hose into a container and turned on the ignition. Thumpa-Thumpa, but no gas. Connected the hose back up, pulled the hose at the entry to the engine bay fuel filter. Plenty of gas there, but when I turned on the ignition, again, no gas. Went a got a big-arse (2 oz, to be technical about it) syringe that I picked up at a scientific supply store, stuck it in the fuel hose and pulled the plunger. It filled with gas. I pushed the plunger back in and was going to ask my wife to come and put her ear to the gas tank to see if she could hear anything but instead decided to test the pump again. Put the line into a container, turned on the ignition and TA! DA!, it had started filling with gas. Connected the gas lines and I was on my merry way. What I found really interesting about this was that last spring I drained the tank to clean the sending unit and replace the leaking sender gasket. I didn't have a large enough gas can at the time so I had put a couple of gallons into the other vehicle and as a result put, at most, 3/4 of a gallon back into the Z. Started up and ran with no problem, with the same fuel pump. When I installed the pump three years ago, I didn't have to prime it either. Just replaced the old one and was on my merry way. The only change that has occurred is that the pump has aged a year. (I replaced both fuel filters last summer) When newer, it didn't require priming, now, a little older and no wiser, it does. Seems like a good excuse to get a quieter centrifugal pump come spring. Chris

It would have been useful to at least know about the discount and how to find it. I thought I remembered seeing that we get a discount at MSA but when I looked around the site I couldn't find any mention of it and figured that either I was mistaken or it was no longer offered. I don't know how large the discount was or is, but a 10% discount would have covered the shipping and then some on my last order. Chris

Just found where it went. Looks like the original owner has taken it back and is willing to let it go, still for six figures, but with an asking of $100,000, might be able to get it down into five figures. http://www.classyauto.com/v/Datsun+Scarab/+240Z+Rare+Find/105934 Chris

Just checked in on the subject car. Was put up for bid shortly after the sale ended with a buy it now price of $150,000. Top bid was $34,101 with the reserve not met. Not sure if it is up for sale elsewhere or if the owner has decided to try later. http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=290615356547#ht_8027wt_1026 Chris

Classy looking car needs classy wheels. I like the look you have now, so I'd say repaint in the same color. Chris

Sure, now you tell me. Sounds like that method beats the hell out of scooping up the oil in my hands and shoving it in the hole. Actually, never did that. Close, though. I just go through the engine compartment on my 1972. Chris

I'm an hour south of you and while my 1972 sounds like it may run a bit smoother than yours when chilly, your symptoms don't seem out of line to me at all. I've bypassed the intake water passages, so that can't be the difference. Instead of going through the mess and bother of draining coolant to hook up what might very well be clogged passages anyway (mine were) why not try using the heat riser? $5.00 -- $6.00 for the flexible tube and no possibility of a drain **** snapping off or getting sticky cold liquid on hands or shoes. Chris

Maybe. Depends on which bar you are referring to. The large, well-lit curved bar immediately above the drain plug? No. Not sure what it is called, rear transverse link bracket perhaps. The hidden in shadow, wouldn't know it is a bar unless you are looking for it thing that the differential attaches to with two bolts? Yes, that is the "mustache bar." Chris

Steve, Lee. Thanks. Sounds like it if looks the same, it is the same. May seem self-evident, but it's not always the case. Chris

When I got my 240Z three years ago it came with a brass bolt in it. A month back it started to weep so I thought I'd replace it. The store didn't have a sizer, but a 20mm seemed to match the diameter. The pitch, which I don't remember, alas, did not and I ended up wrapping the old one in teflon tape and reinstalling. So, it could be a 20mm with the pitch I don't have. Not real helpful, I know. I also seem to recall that I read somewhere that it's something odd like an American plumbing size. I couldn't tell you where I read that to save my life, but since I've never had a dream about plumbing, I likely did read it somewhere. Whether the source knew the difference between well, two different types of holes, I haven't a clue. Chris

While tracking down a pesky vibration recently I took apart the half-shafts figuring that 50,000 miles or more had gone by since their last servicing. The driver side shaft did not extend or compress as smoothly or as far as the passenger side shaft. On dismantling, I discovered that a couple of bearings and spacers had migrated to the other side of the "fence" at the differential side and the fence was itself wandering along the shaft. In short, not good. My question is quite simple: Can I use the half-shaft from a stock 260Z or a 280Z on my stock 1972 240Z? I have the R-180 differential, it appears that at least some of the latter Z's have R-200s. I figured I could but then started researching and somewhere around a discussion of longnose vs. shortnose R-200s and Cardon vs. tripod shafts I sorta lost any idea of the answer. Chris

I suggested timing chain because apparently it hadn't been checked and the problem existed before the recent upgrade / rebuilds. I believed you when you said a worn timing chain would produce a bit more power at the high end, what I am still curious about is why, or how. Is it because the factory position is a compromise between low and high RPMs? That a slight delay, for example, in the intake valve opening puts the valve opening during a period of higher vacuum created by the intake stroke than the original factory setting? Which would seem to explain variable cam timing found on some newer cars. So, just for reference, what are the symptoms of a badly worn timing chain or badly worn sprocket teeth? Really poor low-end with a strong high-end? Chris

Or extreme crustiness in the switch. Get a good spray contact cleaner with lubricant, one that is not safe to inhale and is enthusiastically flammable (not De-Oxy, which is fine stuff for its intended uses, de-oxidizing lightly corroded signal-carrying connectors) and spray the heck out of it. Remember to pull the fuse or disconnect the battery. Chris

You're right about ignition timing as even with a worn timing chain the dizzy will match up with the crankshaft. I am aware that the actual physical measurements of lift and duration are unchanged, what I was trying to suggest was that because the cam would become slightly out-of-synch relative to the crankshaft as the engine was designed, the retarding effect on cam timing, minus any jittering caused by wear, would be duplicated by an engine with a unworn timing chain but an altered from stock cam grind. A worn timing chain is somewhat like a mis-installed cam and to take an extreme example, if the cam were installed sufficiently out of phase, the measured lift and duration would have no effect on engine operation as the opening of the intake valve during the power stroke won't cause a fresh air-fuel mixture to enter the cylinder. Interesting that you say a worn timing chain would produce a bit more power high and less low. I would think the opposite. Why would retarding the cam produce more power at high RPMs? Chris

Hmmm. I must have yet another non-stock item. My steering wheel has metal spokes/arm with a wood rim. Be gentle! As gentle as possible with a sledge. Chris

Oh, and I assume the symptoms of a worn timing chain would become worse with time. Chris

Don't know if carb heating could cause the problem, but I'm very sure that lack of carb heating won't cause this problem. The line was clogged when I got the car and I've since bypassed the intake manifold coolant pass through and in a climate slightly cooler (not much!) don't experience these symptoms. Timing Chain? I don't know what symptoms a tired, stretched, worn timing chain produces, but it would make sense that they are most noticeable at higher RPMs when the timing of events become more critical. Thinking about it, a loose timing chain has a direct effect on ignition timing and have also, in effect, altering the cams lift and duration. By the latter, I mean that, say, the maximum lift is designed to occur when the piston is at position X and if play in the timing chain causes maximum lift to occur at position X + Y, less air will be able to enter (or leave) the cylinder than designed. Altered duration would be even worse -- it couldn't possibly be a good thing if an intake valve hasn't fully closed when ignition occurs or an exhaust valve remaining open longer than designed during the intake stroke. Chris

Assuming that the steering wheels are the same on your and mine 1972, you should be able to find a puller that can hook around to grab the spokes while centering the driver on the column. If not, you could try this less elegant method. Remove the fascia around the steering column. I recommend also removing the combination switches, if for no other reason that to get the out of harm's way. Get a piece of lumber, a 2*4 or a 2*6 about one foot long. Position the wood as close as possible to the column to catch two of the wheel arms. Somewhat fancier would be to carve out a bit so that the wood catches a bit of the flat lip and the arm. What you are trying to do is have the impact as close as possible to parallel with the steering column. Start with a force that you are sure couldn't possibly loosen the wheel. You'll probably be right but then you can gradually escalate with each round. Take a small sledge (I have a 4 pounder) and using the _underside_ of the sledge head pull the sledge towards you striking the lumber. Do that 2 or 3 times, then move the wood to the other arm and repeat. Give the wheel a tug. If it still doesn't budge, repeat the wood and sledge routine. You want to start gently and escalate force gradually because the one thing you _don't_ want to happen is having a mighty whack dislodging only one side, which in the course of its forward motion will pivot on the stuck side, causing all sorts of havoc on the splines and in the worst case, producing a force-fit made in hell. Chris

Thanks, Zed Head. Fear of snapping the reservoir off had my relying on a reading of the hydraulic fluid level through the translucent plastic. It was only when the clutch action rather suddenly changed that I took off the top and discovered: 1) essentially no fluid left and 2) what I thought was the fluid level was formerly fluid turned black gunk. Cleaned out the reservoir and bled the lines till the fluid ran clear. Clutch pedal height and play spec'ed out so I'm thinking I should be OK. And adding yet another level to the weekly under hood check. Chris