mdbrandy

I give up. Nowhere can I find the freezing point of pure ethylene glycol. Even the handbook of Chemistry and Physics only lists the freezing point depression to 60% glycol. The only thing I did find was a very bad chart that indicates that the freezing point decreases to 67% and then rises again, which supports Daniel's contention. I stand corrected. The (very, very poor) graph is attached. The graph on the left seems to show the freezing point on the bottom curve, and the boiling point on the top curve as a function of the % glycol. Note that the article that I got this from was comparing ethylene and propylene glycol, and I think the left curve is ethylene, and the right two propylene. Anyway...

Sounds like a challenge to me. FYI, heat transfer is not a chemical process. Mass transfer, maybe. A little data on glycol/water mixtures: At 180 degrees F %glycol specificheat thermal conductivity 20% .974 .318 30% .914 .288 40% .880 .261 50% .866 .241 60% .801 .220 All in English BTU/lb etc units. The actual values aren't that important - it's the trends I'm after. Obviously, a glycol mix has a lot lower specific heat than pure water, and can thus hold less heat per unit volume. It also has a much lower thermal conductivity, which will lower the heat transfer coefficient at the boundry layer (i.e., the metal/liquid interface). I haven't found freezing points for pure ethylene glycol yet.

According to the tech article that bambi posted, pure water is actually a better heat transfer agent than a antifreeze water mixture. I don't know if this is because the antifreeze lowers the heat capacity of the mixture as compared to water, or because the heat transfer coefficient is decreased by the antifreeze in the water. Pure water has a very high specific heat, and designed correctly, a heat exchanger (radiator) using water alone would be very efficient. However, then your cooling system would corrode away, and your block would crack when the pure water froze. I'm somewhat skeptical that pure antifreeze would freeze at a higher temp than an antifreeze/water mix, but I'll reserve judgment until I look it up.

I'll try to turn the fan when I get home from work tonight. If anyone knows what SportZ issue the fan clutch article is in, I'd appreciate it. I have all but 3 or 4 issues - it'll probably be in one of those! If I remember, I used to buy little prestone "kits" that had a "T" that you inserted into the middle of a heater hose (permanently), and that had a garden-hose attachment on. A screw-on cap sealed it off when you were done. I wonder if I still have one of those.... It's amazing the odds and ends that I've carted around the country for 15 years during my "Z-less" period. I guess I always knew I'd have one again. :classic:

Just finished reading it. Thanks! :classic:

Thanks Carl. I'll be lookin' for that article ...

Did you ever track it down to a single source? I am currently having the exact same problem. While running down the road, the car's temp is rock steady just under the half-way mark. I sat at a ATM for 3 or 4 minutes this morning, and the temp started creeping up to somewhat over the halfway mark (this is at an ambient air temperature of about 35 degress F). As soon as I started driving again, the temp dropped back down and settled into it's normal place. I figured inadequate thermostat opening or fan clutch (coolant level is fine). A good flush couldn't hurt either, since it probably hasn't been done in 10+ years (the car sat most of the past 10 years - only 2000 miles, and most of that before 1997). So, for the experts: Are there any obvious ways to check the fan clutch? Never had one fail before. What is the best way to flush the coolant system? Been a while since I did that too. Thanks.

I was interested enough to send the seller a question about where he got his info, and he said: FWIW

There's an elephant oil cap on e-bay right now, where the seller purports that: "This was made to celebrate Datsuns South African Safari Win in 1969." Any ideas of whether this is BS? oil cap link

Actually, the ones in both my 280Z's (the good one and the parts car) are "collapsable", but not "dinky". When you fill them with air, they are full-size tires with a 3000 mile life (according to the paperwork I have). An inflation canister does come with them. When inflated, the tires appear to be about the same size as the normal 195/75-14 type tires that come on the Z's. In the parts car, the tire has been used, and the PO did not do a good job of deflating it - just let out some of the air and stuffed it back in. Seems to be ruined after 10 years of being deformed pretty badly. In my new, good 280Z, the tire has never been used, and is nicely compressed there in the shallow spare tire well under the elevated deck. To answer ozlime240Z's question about where to put the jack and stuff, they go under the elevated rear deck, next to the tire. Envision a fiberboard deck, propped up above the real rear deck of the car about 4 inches throughout the rear deck area, and hinged about where the shock towers are so you can lift it up to get to the spare and jack. Hope that's clear

Interestingly, in the '78 280Z I am currently tearing apart, the tool box compartments on the rear deck are still there, even though you couldn't have used them due to the elevated fiberboard deck over the top of them. No lids either. Just the holes.

Paint? What paint? We midwesterners don't need no stinkin' paint! We like floorboard air conditioning! Not.

Here's a pic of the rear mount on my '70Z before I disassembled it...

:dead: Ouch!

Except for the reservior cap and the pushrod, everything looked identical. Bolted up perfectly, body length is the same, reservoir looks the same, etc. Just the pushrod length. I took the rubber boot off the pushrod from the old one, and it isn't obvious how it comes apart. The pushrod seems to be an integral part of the plunger assembly. On the new one, that doesn't feel true - it seems like the pushrod floats inside the rubber boot and just seats on the plunger. I hesitated to take the new one apart in case I have to return it. Which looks likely. I did not see an easy way to switch pushrods.

Ok, so I installed new clutch master and slave cylinders today. Was very happy that I could get both locally on a weekend. However, when the master came in today, the pushrod was almost an inch shorter than the one on the car. Even after adjusting the fork out all the way on the pushrod, it was about 1/4" shorter than the original. Other than that, it looked identical to the stock part. To make a long story short, after installing and bleeding the system, the slave pushrod pushes out, but I guess not enough, since I still can't put the car in gear. Would 1/4" on the master cylinder pushrod cause this kind of problem, or is it more likely that I don't have the system fully bled? There doesn't seem to be a lot of clutch travel now. Much less than before. Thanks.

The NOS assembly I bought a couple months ago is 18410-E4601. Pic attached. It has square knobs.

Interesting. That's just what the mats in my new 280Z look like. Deep grooves and a big "Z" on them. Have to pull one out and look at it closer. Unfortunately, tonight is "fix the new car" night, since I blew the clutch slave cylinder last night on the way to a local watering hole, and have to replace it now. Actually found a local parts store that had it in stock! But that's another subject...

Here's the rear deck on #215 before I tore it all apart...

No, I looked, and there are no manufacturer or brand markings at all. Interesting that yours don't have any either. Chris, you seem somewhat familiar with AMCO; do you know if they marked their products?

Now that's a cool idea!

Maaaaayyyyyyybe....:devious:

I'm a master at accumulating stuff. Need to work on that getting rid of stuff thing...maybe I need to learn to SELL on e-bay instead of just buy!

That's for sure. I'd rather buy new poly bushings than a hatch window seal! I'll try the pouring water and/or hose suggestions friday or Saturday and see what it looks like. It is probably a fairly small leak, considering that it rained for 4 days, and only enough water got in to soak the carpet, but not to flow into the tire well (bone dry there). It is probably a drip, drip, drip sort of leak, but we'll see. Thanks for the suggestions.

And that's why I have divots down the side of my Camry, and the parts car is banged up on the drivers side side. I don't know what I'm going to do when I get the good 280 in the garage in place of the parts car, but the bikes do have to stay in the garage somewhere. Maybe I'll hang them from the ceiling? :classic: