Captain Obvious

I'm stuck at the same question and I'm not endorsing the KD needles thing. ZT put your carbs on their car and they said they were fine. Why would your car need so much more fuel than theirs? Also, about your piston springs. Why would you, just you, and no other Z owner need to run stiffer springs in their round tops? Why? Why? Why? I'm just not buying it. So what about your results with grabbing a handful of choke while it's popping and having the problem go away? The results clearly indicate that your car runs better with more fuel being supplied, but does that absolutely guarantee that the root problem is in the fuel system? By that, I mean... Is it conceivable that the problem is ignition on the hairy edge of not working and the reason the problem goes away with a handful of choke is that the richer mixture burns so much easier than a leaner one? Ignition isn't my stong suit... Leon? Conceivable?

What did the original factory key look like for the Z's? I'm mostly interested in the later 280 years and I know the blanks changed over the years with earlier years being different than later 280 years. Anyone have a key that they know was the original key to come with a 280 when new? I've been working on the locks for my 280 and I'm nearing completion and I've been thinking that it would be nice to have a fancy factory looking period original key to go along with my nice reworked locks. I've already got aftermarket keys that work great with my locks and I know it's completely esoteric and unnecessary, but I think it would be a nice touch to have an original factory looking new key. I'd be willing to spill a few unnecessary bucks for the feel good effect. I've been through ebay, and can't find anything truly conclusive. So, anyone got pictures? Links? Anything?

Glad you've got it licked and I wish you good luck with the smog. So... What's your plan with the original flat tops? I'm going to be putting my 74 up for sale and I'm not sure I want to saddle any new owner with my modified flat tops. I mean I think they're better than original, but it's not like you can open up the manual anymore and have everything look right. It's a labor of love, and I'm just not sure it would be a good idea to pass those mods on to someone else unless they know what they are getting into. I don't want a future owner taking his car to someone for work and having the mechanic go "What the heck is that? That's not right!!" Haha! Does that make any sense at all? Anyway, it sounds like your flat tops are in pretty good shape and if so, I could give them a much better home than the bottom of the lake. If they're going to end up as boat anchors, send me a PM instead.

Bummer. Well it was worth a shot. I've not tried opening the glove box by removing those 4 screws, but it really wouldn't be that secure of a compartment if it were that easy, right? Anyway, don't force anything, and I agree with Unkle... It's time for a locksmith. Something to think about though as you are talking with the locksmith... I suspect the real problem is more complicated than you've described. I've taken apart all of the locks on my Z and I've found the glove box lock to be the least used and best condition lock on the entire car. I bet that yours is the same. So what does that mean? That means that if you're having problems with the glove box, I bet the problem isn't with the glove box at all, but with the key and other locks on the car. Your previous owner has vouched that it used the same key when he owned the car, so maybe the owner between the two of you had the ignition lock re-keyed or replaced. Or, maybe they are still the same key, but the key and ignition lock are both so badly worn that they work together, but the worn key won't work in the unworn glove box lock. Bottom line, is I suggest you talk it over with the locksmith and explain the situation to him and see what he suggests. The real solution might be to replace the ignition cylinder using the original tumbler sequence and have a new key cut to work with the original code. Then that new key should open the glove box just fine. Does that make sense?

olzed, Thanks again. I appreciate the attention. I'll let you know how it turns out when the new pump arrives.

So the bottom line is that you cannot put the drive shaft in from the top, so the only way to prime the system is to drop the pump a second time to install the dizzy drive shaft from the bottom when you're done. No magic bullet. I was wondering about that... I have not drained my oil and my filter should still be full from the last time I shut the motor off. Except for what has drained from gravity and siphon effects, all the oil passageways should still be full as well. I plan to do an oil and filter change when this is all said and done, but I was planning to wait until after the pump replacement was done. So you're thinking that if the filter and passageways (and hopefully bearing journals) are already full, then there's really no reason to prime the engine at all. It's already done. Just fill the new pump before I put it on and be done with it, right?

BGM, You are the man! I don't know how you find this stuff, but you are the Jedi Master of topic appropriate pics.

Wait a minute... Are you saying that I can drop the distributor shaft in from the top? It doesn't have to go in from the bottom?

Another option to be able to separate idle from the rest of operation... Flat tops! (Haha! Someone has got to come up with a "poking the hornets nest" smiley.) :bandit:

Just started a priming specific thread.... http://www.classiczcars.com/forums/showthread.php?45440-Priming-New-Oil-Pump-How-to&p=392008#post392008 Let's hope that all the priming wizards catch wind.

I've got a new oil pump on order for my Z and it should be here soon. While waiting for the pump, I've been searching the forum for info about how to prime the new pump after installation, and I've found some threads that talk about it, but I'm not sure I get it. I got the general procedure: Bolt the oil pump to the block and then spin the pump with a drill from above down the distributor hole. But... It's my understanding that the distributor drive shaft has to go in from the bottom before the pump is bolted into place, right? And if that is the case, if you try to spin that shaft with your drill, you would be trying to spin the engine with your drill, so... Of course, I could install the new pump without the distributor drive shaft, prime the system, and then drop the pump again to install the drive shaft. But is there a better way? Has someone got a magic way to prime the new pump without having to take the pump back off again to install the distributor drive shaft? :bulb:

Well I'm still waiting for the new pump to arrive, so I'm not time critical yet. Unless there's a Saturday delivery, which is doubtful, I've still got a few days to gather thoughts on this. Maybe I'll start a specific thread to priming the pump and see if that attracts any more input.

madkaw, A nozzle adjustment will make a difference everywhere. You can't confine a nozzle adjustment to idle only. That, IMHO, is the biggest drawback of the round tops. If you make a nozzle change it will affect the entire operating range. beerman, that's an clever idea. It would have a small effect on idle, but the effect at higher flow rates would be much more dramatic. Points! Points! Points! Points!

I lost a surprisingly small amount of oil. Obviously, I lost whatever the capacity of the full pump was, but other than that, It didn't seem to drain much. I truly expected it to weep and weep and continue to drain for days until the entire pickup tube assy was empty, but it didn't. Don't know if it's just me, but once I dropped the pump, it was pretty much over. It did not continue to drip.

Yes. Duh. :laugh:

siteunseen, Yes, I remember that post. Unfortunately, it's a "proof is left to the student" moment. Jeff, That all depends on your definition of sense. What would really make sense would be able to put that shaft in from above after the pump has been installed. I know... Not your fault. I'm not sure what would gained by bolting the pump on, spinning it until oil starts to flow and then taking it back off again. I mean, I took this pump off a running engine, and I have not yet drained the oil or pulled the filter. The filter should still be full, the oil passageways should still be full. I can easily pre-fill the pump itself... Is my situation different than starting a rebuilt engine for the first time where everything is bone dry?

So today's question is are you truly lean or are you simply getting a lean indication on the wideband because of a misfire? You ought to be able to test this by dialing in a turn or two of fuel on your nozzles. Assuming the carbs are working properly (ZT says so), if you take them two turns down from where they are now, you ought to be running pretty rich, right? Maybe try that and see what your wideband says? I still suggest you try an old school OEM non-Pertronix distributor. Something with...... ewwwww.... points? I know they're old, ugly, and unreliable, but the fewer variables, the better.

Well I feel a little better at least that I'm not missing some completely obvious. (After all, I'm Captain Obvious). My engine is assembled. I could pour a half quart of oil over the cam lobes right before I try to start it, but I'm not going to pull the cam or crank to smear assy lube on the journals. Options that I've come up with: Pop the drive gear off the shaft - Works if the gear is pinned onto the shaft, but from what I've seen, some of the pumps press the gear on without a pin and I don't want to mess with that. Also, since the shaft cannot be installed from the top, this means you would have to pull the pump back off to get the shaft out to put the gear back on. I think I read a post somewhere that said to put the pump on without the shaft at all and use a long screwdriver to turn the pump directly - Again, I believe this means that you would have to pull the pump back off to put the shaft in. So what's the secret? Anyone?

Gotcha. was just getting a little ahead of myself. So now the round tops are on and it's running OK. And your timing numbers are back to reality. Sweet! I fully believe that the carbs weren't the original root of the problems as all evidence points to ignition, but if you're happy with the round tops, it would be a completely academic exercise to find out for sure. Sounds like you're not that curious, and I don't blame you. I agree with your assessment about resale value and the round tops... Whether the flat tops reputation is deserved or not, it's just so prevalent and has existed for so long that there's just no way most people will ever believe otherwise. Without getting into the design details, I went back to the flat tops because I believe that the flat tops are inherently a better carb design than the round tops. IMHO, the single biggest advantage of the round tops is the ability to make large adjustments to the mixture by cranking the nozzle knob while the engine is running, and not only that, but you can do front and rear independently. The air bleed style mixture adjust on the flat tops works too, but it's range of adjustment is much smaller than the round tops which means that you must have everything else working just right, or you won't be able to get the flat tops mixture right no matter where you crank that screw. And you only have one adjustment for both carbs. Other reasons? I've made a bunch of improvements to my flat tops to improve some of what I consider shortcomings, and I have so much time invested that I refused to lose that battle. Also, there's some sick satisfaction in being able to make work what everyone else says is impossible. I assume it's the same thing for the people liking Gremlins or Azteks, dome houses, Brussels sprouts... An "underdog" kind of thing. All that and the simple "stockness" of the flat tops on my 74. Anything else in there just looks wrong to me. You didn't ask, but it makes sense to explain the other side of the question... "Why did I put round tops on then?" Because before all of my carb work, I bought into the "flat top boat anchor" hype and picked up a set of round tops. My flat tops clearly weren't working right, and I used the round tops to keep my engine running while my flat tops were under the knife, and also to see how my engine "should" perform with the "good" carbs on it. Kind of a baseline for proper performance. Now that I'm done, I think my performance is about the same between the two designs, plus I get all the improvements of the flat tops. It's probably off the direction of your original topic, but if you want details about design improvements, etc, LMK.

Yes, when he says "leaning out" he means that at certain RPMs and throttle positions (4500-5000 RPM and light to medium throttle position) his wideband indicates that his mixture is lean. Details are in post #229 (page 10), but here's the Reader's Digest version: You can see from the results that at the same RPM, he's running leaner at part throttle, than he does at WOT. The recent interest in ignition timing details isn't because it would do anything to add fuel to the mixture, but it might reduce the effect. In other words, the root problem is that he's lean, but it might be OK to be that lean, if it weren't for the fact that it's causing performance issues.

Cool, thanks. But when that shaft is installed, the gear on it meshes with another gear on the crankshaft, right? So then what is it that keeps the oil pump shaft from having to backwards drive the entire engine through the crankshaft gear while you're spinning it? Seems like a pretty heavy load on a shaft that small. What prevents you from turning the entire engine over with your handheld drill? What do you do? Pull all the plugs to reduce the load and just go ahead and let the engine spin? Still seems like an awfully large load for that shaft... I'm assuming I'm missing something simple here, but I don't see it.

I ordered a new oil pump a few days ago and I've been waiting for it to arrive. siteunseen, thanks for the recommendation for the Melling pump. While waiting, I've been thinking about that priming the pump process I've seen mentioned. Sounds like a great idea, but I've got a couple questions. I got the general procedure... Put the pump on the block and then spin the pump with a drill via the distributor hole. But... I'm assuming that the priming operation has to be done with the shaft between the pump and the distributor removed or the drive gear that normally spins the pump would try to turn the motor over, right? My shaft is currently out, but it came out the bottom with the old oil pump. Does that shaft have to go back in from the bottom, or can I slide it in from the top after the pump is bolted into place?

Excellent! So it's working well with the flat tops and as soon as the round tops are done, you'll toss those on and see how they work? Here's a starting point for you... The flat tops are the same thing as round tops with the nozzles three turns down and then an air bleed around them to lean the mixture back out some. Keep that in mind when you're tuning the round tops. If you find you need three turns or more down to get it to run right, you've most likely got a vacuum leak somewhere. First time I tried this swap, I reused the same insulating spacers and associated gaskets. Problem was, however, that the bulges in the gaskets from the water passageways in the flat top carb bodies didn't seal perfectly against the round top bodies. It ran OK for a proof of concept test, but I needed more turns than I should have to account for the extra unfueled air leaking past that insulator gasket. So, the next time I had the round tops off, I replaced those gaskets and everything got better. Then the next time I had them off, I pulled all the studs and replaced with longer and went with the thicker insulators and all new gaskets. Then, I pulled it all back off and went back to the flat tops. I've not yet messed with the ZX ignition module, but I've heard good things about them. Mine (fingers crossed) seem to be working fine and I'm inclined to leave sleeping dogs lie. So... Are your timing numbers back to reality?

In my opinion nothing is less appalling than a vinyl top on a Z.

Wait..... So does that mean that the problems you were having have been fixed? It was an ignition problem? Haha! Nice. Yeah, my modified round tops turned out pretty well. I bought a spare set of flat tops and they were damaged in shipping so by the time they got to me they were parts only. I didn't feel too bad about them giving their internals in the name of experimentation.