Stanley

I put about 4 layers of electrical tape on the frame under both terminals and used those plastic terminal covers, but that looks better. No unintentional welding.

Mine have thin aluminum washers on both sides. Seems like rubber or something would be better.

That valve looks longer than the other corroded hose barb. Looks like the tube would work with the rusty one, but it's about shot. You could get a 1/4" maybe BSPT hose barb at M-C and run the little heater hose to that. Maybe the control valve can be plumbed in line on the other side of the motor before the tee. Nice water tube. Maybe it's the wrong tube. Can you bend those? Wouldn't want to wreck it, about $80 for those. Heater hose there wouldn't look as good.

Looks like your new setup has the manifold heat control valve. It's the (hot=closed) thermostat for the water tube. A good thing to have since it lets the carbs warm up and also provides a bypass for better flow to the water pump while the main thermostat is closed. once it's warmed up it shuts off the water so you're not recycling hot coolant. Maybe a short piece of heater hose and a couple of clamps. Seems like you shouldn't have to bend that new rear water tube or the clamp. Maybe a spacer under the rear water tube bracket.

$450 wow. Did yours have those nifty clamps? Too bad part of my plastic box is broken and the compressor is missing, or I'd have enough for some nice headers, or an MSD. And I was going to toss it all in the dumpster. Where it belongs, IMHO.

Pulled my AC (the stuff inside the car) a few weeks back. Planning to sell or trade it (cheap to club members, way less if anybody wants to pay cash and pick it up). Saw a used evaporator (core only) for $235 recently on e-bay. Ridiculous. Don't want to lose a potential buyer but I'd go with new or late model used components instead. The two clamps on mine are Ideal stainless w/ stainless screws and a stainless guide to get the correct distance from the hose ends. They are beautiful and I haven't seen anything like them at McMaster-Carr or anywhere. I want them for my own car unless somebody needs them for a period mod resto. The connections to the core are hydraulic type fittings.

How hot is hot? 180? 200? 210? Don't know FI so I better not try to diagnose it. Hotter air to the intake means less power. On the other hand, my 240 makes more power when it's thoroughly warmed up: 3700 rpm = 78 mph (AT in high gear) when cool (but operating temp) in the morning; 3700 rpm=84 mph on a warm afternoon.

Fighting the same problem this afternoon, after fixing another leak a few days ago. after a drive I felt wet coolant at the water outlet for the heater, at the back of the head. My heater's bypassed, the hose looped, with a restrictor. The hose was leaking at the clamp. Cut an inch of the hose and clamped it back - no more leak. The clamp had cut the hose. Helped to have a plastic bag over the starter, and the bottom half of a one gallon plastic water bottle sitting on the starter to catch the coolant that comes out. Also helps to have a rubber cap to pop on the hose barb for a minute while cutting the hose. Better to put new hoses, but had to fix the leak fast.

Not sure how to fix that knob extraction/drain hole. Do I use a shop rag, or go hi-tech and use duct tape?

My 240 doing the same thing. Air pump and AC compressor gone, Stock radiator changed to aluminum, banged-up stock bumper replaced with lighter temporary one. Adds up to about 1/2" rise at the front. On the plus side, gives me 1/2" clearance for the spook at the average parking lot curbs.

Read a post here that said if the windshield fogs up it means the core's leaking, but I don't really know. Here's a shot on the corroded valve on my 240 - don't know if the 280 one is similar. Also a shot of my heater loop, with a restrictor (hose clamp with piece of radiator hose for a cushion) I put a couple days ago. The restrictor cuts down the amount of hot coolant recycled to maybe 25% of what it would be without it. Just temporary. Don't know if this helps.

Helps to spin the lid 90 degrees to remove/replace it. Also, if there's fuel in the bowl it helps to drain it.

Looking for the knob that fell off the radio. Got to be there somewhere. Unless it fell through the round hole under the driver seat. WHY is there a HOLE under the seat?

Right. Also, since the tube is lower than the coolant level in the radiator, when the engine is shut off I guess the coolant just gurgles it's way up there, by the principle of water seeking it's own level. Anyway, plugged the lower thermostat outlet with some caps from pep boys. The 1/2" cap fit it but looked flimsy so I put a 5/8" cap over it. Also capped the pipe that goes behind the motor. Have a hose and some BSPT stuff on order - at least it's not leaking and I can drive it for now. Also put a restrictor on the heater loop (a hose clamp with a piece cut from radiator hose to cushion it) that should cut down the recycled hot coolant by about half. Later I'll put the "real" restrictor - a washer. Here's a few corrosion shots...

Got some rubber caps to temporarily plug the pipes, pulled the short hose off the lower thermostat housing. Now, my coolant is new and green, but what came out was a few drops of brownish corrosion. The 1/2" hose barb was corroded. Pulled the other end of the hose off at the intake manifold. That hose barb was totally plugged with some grey-green gunk. Looks like no water flowed through there for a long time. I'm guessing the gunk is stop leak put in by the PO (flushed the engine three times when I got the car a few years ago, to get rid of the gunk) , plus coolant residue and rust. Then I cut the short rubber hose that connects the rear of the intake manifold to the steel water tube that runs around the back of the motor. Plenty of corrosion there also, and some green coolant. So where's the coolant come from that keeps dripping down on the exhaust manifold? For sure it's not coming from the thermostat housing (like the arrows in the FSM). So it's being pushed up into that deadhead tube from the other side of the engine somehow. Coolant's not supposed to flow that direction. A puzzler.

Thanks darom, I was looking for a small heater. Extra space behind the dash would be good for a hidden sound system. But now that I see it's just the hose connection that was leaking, and that big useless evaporator (that I thought was the heater core) is gone, I'll just get some new hoses and a heater valve, and stay with the stock heater. Maybe some wd-40 will free up that heater valve....

No problem, this is good stuff. Probably doesn't make much difference for me - don't have a high power motor, and there's a big difference between 15 seconds down the strip and running above the yellow line for an hour or more on the track. The z never overheats anyway (Aluminum 3-row, oil cooler, shroud & spook). Just doing some plumbing work anyway so figured I'd do the mod while I'm at it. If I do, I'll put a restrictor in the line, they're cheap. Rather than plug the thermostat housing, I plan to run a hose around to the tee, like the stock system, for better circulation, maybe. Will put a restrictor in that line too, between the tee and the water inlet (after the heater return branches in), so as not to recycle as much hot coolant.

Not to complicate the issue - but it does... my intake manifold heater (hard) line is shot. Was going to just plug the outlet at the lower thermo housing and the end of the tee on the other side of the block, but been reading a number of sources that you need that circulation (while the thermostat is closed) or hot spots will develop and the water pump will suffer. Dunno if it's B.S. At the dragstrip it may take an hour to get through the staging lanes. Last year a dragster blew up and the lanes sat still 45 minutes for the clean-up. So the runs might be with the thermostat closed. Don't want to sit there idling a long time and maybe foul new plugs (with a slightly richer mix for the evening). I like to get the z over a hundred at the strip (though it happens after the light). I'm thinking run a new heater hose around to the back of the tee on the other side. But then I'm putting more hot coolant back into the intake, raising temp after the thermostat opens. Damn. Maybe a restrictor in it?

Interesting. I'm no expert either. Checked the head temps with the IR thermometer - #6 was hotter than #1 (by about 10-15 degrees) even though the exhaust temp was a little higher at #1. So it appears to confirm the theory that some extra cooling is needed at the back of the head. The point about flow being diverted makes sense too. Maybe use a restrictor or a smaller hose? A restrictor could also be used inline when the heater hose is bypassed (looped) from the head to the water inlet.

Yep, now that I see where the leak is I'll fix it. Just need the valve and hoses. That cheapo set of little stubby screwdrivers will come in handy again. And plenty of liquid wrench. Also plan to do the mod that runs a hose from the heater outlet on the head to a tee on the upper radiator hose, so I need a tee and valve (to run it when needed) in the line before the heater. BTW, saw an AC evaporator like mine on e-bay for $235, without the enclosure or thermostat line and control. Is that for real? When you could probably put a complete system together from much newer used parts for about the same?

Using the hammer and dolly is way easier than bondo and hi-build primer to even out those tiny dents. Five minutes versus five hours for one slight dent. If you're going to clear coat it the body needs to be sort of flawless. Eastwood sometimes has kits with various hammers and dollies on sale.

Exactly. Seems "obvious" but that's key to understand it. For the same reason, as a post here stated a while back, the car needs to be level to set the float bowls (or the slope compensated for). If the car has a raked stance, or the driveway isn't level, it will change the setup.

On the 3-screws the front carb has "long ears" that are 2 mm longer than the rear. The measurement to the holes is the one that matters. The long valve goes in the front. If you measure the tilt of the engine and the distance from the center of the bowls to the center of the nozzles, and do the trig, you see that 2mm is the difference in fuel level between the front and rear carbs (lower in the front one) needed to have the same relative fuel level in the front and rear nozzles.

It's normal to need to let the car warm up for a minute or two with the choke on, unless it's set too rich. You can pull the choke just enough to keep it running well, not necessarily all the way, then ease off on it as it starts to warm up. The needle valve in the float bowl has a little conical rubber tip. If it doesn't have a sharp point at the tip it's worn out and can leak. The right carb kit should have some new needle valves and gaskets. The little spring in there likes to jump out and get lost when you're inspecting the needle valve. The piston looks a little grungy. It's not a big deal to take off the domes and hit it with some carb cleaner. The FSM says to do that every six months. If you spray a bunch of carb cleaner on the linkage on the side of the carbs and follow that with lithium spray grease (also on the outside of the nozzle) the choke is unlikely to stick.

This nice 280zx at the supermarket last Saturday.