Mark Maras

Zed Head, I agree with all of the possibilities except the f. pump. Can't figure out why a bad pump would cause black plugs. Jai, Possible success? We won't know until you try again several times. It may be just a normal glitch in the EFI cold to warm-up process. Do you remember it happening in the past? I really don't know squat about EFI, I remember RossiZ mentioning a similar symptom with his EFI. When he switched to SUs, the temporary rough running, when cold, went away. How long has the tach been bad? Was it dead before the problems started & does it ever show any life?

Jai As I understand it, the car now starts & runs OK. If it were me, I would start her up, let her warm & start making trips to the mailbox & back keeping the RPMs up around 3000rpm. If it does start to crap out, push in the clutch & give it full throttle. I've had a moderate amount of success forcing small amounts of water to pass through the engine and managed to keep the engine running til it passed. You'll know if & when it has passed. The engine will start running normal again. If it doesn't crap out, you'll gain some confidence in her ability to be reliable. BTW the gas drier is still a good idea.

rcb280Z I've been wondering about the frequency of the smoke too. I don't have an answer yet. But as far as the "smoke" lingering, if the car was under an open canopy, there must have been no breeze & if the relative humidity was high & if there was a lot of condensation in the exhaust (a lot of ifs) a cloud of "smoke" could & would hang around. I've seen this happen when the conditions are just right. Jai On the Tues. morning of the "smoke" , you started the car. How long did it idle before driving it? You saw a cloud of smoke, drove the car 1/2 mile & turned it off. Did it run OK, & was it still smoking when you got back from the mailbox? I'm beginning to wonder if the smoke & the engine crapping out are unrelated. The smoke being condensation & the engine being water in the gas. A bit of a stretch but possible if the engine ran OK when smoking.

Not loony at all. Water does settle at the bottom of the tank. The underground 100% gas tank could have a lot of condensation in it. Probably is not a big seller. Also pure gas, no alcohol. Not a chance of mixing the water with the gas. There are a number of alcohol based products avail. to rid your tank of water. Alcohol is one of the few solvents that will mix with water and petroleum. Most are less than $10.00. Or you could drain the tank either by siphoning or pulling the plug on the bottom. If it has a full tank, I'd siphon it. You won't waste the gas, you'll be able to see the water in the bottom & avoid it.

Jai Do you remember the smell or the feel of the smoke? Coolant being somewhat sweet and humid, oil being, well, oily & greasy smelling & feeling. Generally, a coolant cloud dissipates a lot faster than oil depending on the relative humidity & if the car is in a closed space. I was leaning toward water in the fuel but anytime I've experienced it, It only took a mile or two before it crapped out. Was the soot that came out of the tailpipe oily? Judging from the pics, it wasn't. On Wed. when the car was towed, was it parked uphill, downhill, level when it wouldn't start?

Was it always the same one? Might have been owned by someone in the cast or crew.

Jai, Did this latest gremlin arise shortly after refueling? If so. how far did you drive until RB started acting up?

I think that much fuel pressure, without a regulator, will soon over power the needles & seats filling the bowls to overflow. Keep in mind, those float bowls sit over the hot exhaust manifold. 4 psi should be the MAXIMUM pressure. IMO There is no maybe in getting #4 and all the others adjusted & burning properly. Honestly I would change direction temporarily and leave the carbs alone. Fix everything else and make sure it is right. These are things that you can do and should learn if you are able, however your mechanic should have taken care of that before tackling perfectly good carbs. I question whether your mech. is ignorant, incompetent, or milking you for money. Your choice.IMO, As long as he doesn't quite fix it, he gets paid for yet another attempt. The only way you will know is to try to find a better mechanic or learn to do it yourself. I doubt very much if you need a new pump. You could test it yourself & know for sure.

I don't know what it's called and as far as I know there is no replacement part available. If you found a donor chassis to cut that section out of, you'd be better off rebuilding the donor chassis. IMO, that boxed section is the stiffest portion of the whole chassis. Remove it and you'll open a Pandora's box. The body on that side will sag unless it's mounted on a chassis jig. Not worth the time & trouble.

Jai Stick your finger in the tail pipe & tell us how much carbon, if any, is in there. Doesn't have to be running.

The bent upper lip in their pic is bent to conform to the edge of the sheet metal in the rear hatch opening.The weather strip glues over the top of both of them. I doubt that the extra section of sheet metal would improve the sealing but the bent section of the panel does reinforce the lower hatch opening & it needs it. If you do fab your own (I did) I would include the upper & lower lips for strength. Just reread your post. Is the sheet metal on the bottom of the opening gone or just the cover?

Get rid of it? NO, NO, NO, Not yet. IMO I haven't seen one solid reason to give up on Redbird yet. Let's back the tow truck up for a little while. First is the cooling system losing coolant? Jai, A compression tester is avail. at Harbor Freight for $22.99. If you are able to remove spark plugs, you can use this tester by yourself. If $s are short, I'll send you mine. PM me. I'm a bit perplexed at the intermittent nature of this problem but I'm with Zedhead. Head gasket seems like a stretch & is easy to verify. I'd want to know what the problem is before I parted ways with her because I'd know in my heart that I hadn't given it my best shot. Regret is a bitter pill.

I don't remember having to do much twisting on four screw carbs. I've been told that three screw carbs require rotation to remove the tops. Unless there is considerable resistance, I doubt that the float setting will be changed. By removing the suction chamber and piston you can see the fuel level in the nozzle to double check the height. I have never used this method & I don't remember how far below the top of the nozzle the fuel is supposed to be. Anyone want to chime in and add some info?

IMO It's not necessary to separate the float bowl from the body unless it's leaking fuel from the connection.

My first question would be, why the valves & pistons are kissing each other?

How big was the spark? Did the wrench hit grounded metal when the spark jumped? I'm assuming something that you did caused it & it wasn't random. Anyway, I'd look at the fusible link(s). Unfortunately, I don't know the location on the 280s but the info should be avail. in any manual or on line.

The right firewall is usually worse because of the battery location. Corrosion from the battery wipes out the battery holder, fender well, firewall and often the frame. After looking at the pics, it's not practical to rebuild it. The seams that you will be attaching to, on these cars, were spot welded and rust creeps between the layers & just keeps going. You'll have trouble finding solid metal to weld to. I don't know what the market is like in your part of the country but around here you can pick up a repairable Z ( floorpans & rails & lots of work) for $1500.00 - $2500.00. The more money the less rust but there is ALWAYS rust. The good thing about your situation is you already have a good parts car.(Sorry). Your new one can be & will be a hybrid of parts from both cars.

Jalex. I'm quite sure the pump you have will work just fine. The pressure specs. on the pump are exactly what you need.You don't even need the FSM flow test specs. Just disconnect the coil wire, pull the f. line after the pump, insert into a fuel proof vessel & crank the engine with the starter. You'll know immediately if it's pumping enough fuel to idle & rev the engine. As Patcon said, these engines don't need much fuel but it does have to be at the proper height in the bowl.

When you order the kits, assuming they're coming from ZTherapy, get the "SUs only" DVD too. The knowledge shared in this DVD will take any guess work out of the rebuild.

Ok, Had to check your "Level of Desire." You do have a reasonably realistic view of this project & I like your motivation. Just realize that the Z will be torn apart for quite a while & getting discouraged is an unintended consequence of taking on a rustoration. That said, Keep your dream alive & have fun.

If #s 4 & 5 were getting black but not #6, I would suspect there is an electrical problem in 4 & 5. Check the rotor, cap, plug wires & plugs. The front carb. feeds #s 1, 2 & 3. The back carb #s 4, 5 & 6. There is a balance-equalizer tube between them, but it has a limited effect on plug color. There is another possibility however. It could also be that the rear carb is set rich & there is an air leak into the #6 cylinder, maybe an intake manifold leak. That scenario would give you the same symptom. Black #4 & 5 plugs but not #6.

Anything over 4 psi will overwhelm the needles & seats. 2.5-4 psi is OK. What color were the plugs the last time you pulled them? In fact I'd like to see a pic of them & a description of what it was running like when you shut it off. There are still other things to confirm. I've read the many threads about your build but refresh my memory, what have you done to ensure the basic tune-up procedures were done properly? Such as valve timing check, valve adj, ign. timing, & vacuum leaks. You will be chasing your tail trying to find the problem in the fuel system if any of of the basics are wrong. So, give us more info, pics.of the plugs, & any changes to the carbs you have made except mixture & normal tuning.

I don't know, maybe we're overthinking this. If anything draws attention to your car by the driver behind & keeps their attention, you've got less of a chance of getting rear-ended.

I'll have to agree with ksechler. Think of the visible rust as the tip of an iceberg. Well, maybe not quite that bad, The problem I've had is when I have removed any panel to be replaced, I have found the rust just keeps going, requiring even more material removal & replacement than I had planned. This gets very tricky when you start removing critical strength areas. Yes. you'll find rust in those hidden areas too. Unfortunately, The fact is you will end up spending A LOT MORE TIME & MONEY fixing this car than buying a better Z & using the current car for any parts you may need. It is very easy to get discouraged after starting a "rustoration". Honest. That said, Should you go looking for another Z & find more rust, IMO you don't want to have to repair much more than floors & rear frame rails. That is a PITA job as it is & is considered an easier job than the rest. Sorry for the Rain on your Parade. Don't let the disappointment get to you, you'll have plenty of time for that later.

As i have always understood it, backfire thru the intake indicates the mixture is too lean, ASSUMING everything else is fine, valves, timing, etc. IF the mixture screw IS being adjusted & the backfire is still happening there is only two possibilities. Not enough fuel or too much air. Not enough fuel? I would check fuel pump volume & pressure. Float level, if you've changed it from ZT settings. In fact, review anything you have changed on the carbs since they came back from ZT & return to their settings. Too much air? Vacuum leaks, intake manifold leak, loose carbs, brake booster, anything that can pull air into the intake. Mixture adjustment mix-up. If you are looking down at the top of the carbs, the mixture screws turn anti-clockwise for less fuel. They are being screwed into the carb, leaning the fuel mixture but the manuals want you to adjust the m. screws as if you are looking at the bottom of the carbs. Now, clockwise is the direction for less fuel.