LeonV

DGVs and SUs are both carbs, but that's just about where the similarities end. They operate with different principles. The SU is a variable venturi carb with just one jet, or circuit, to work with and uses a tapered needle within a moving piston to meter fuel correctly. The DGV is a fixed venturi, air-bleed carburetor and uses multiple jets/circuits to meter fuel. With that said, if they are currently jetted rich as the current owner postulates, then they may work fine at your altitude. In order to really tune the carbs, a wideband O2 sensor and gauge are highly recommended. Otherwise, you're just guessing and getting within the ballpark of where you want to be.

Thanks! I'm not 100% sure, but if I had to guess I'd say they're 0 offset (or very close to it). Next time I remove a wheel I'll have to look to see if it's in the casting somewhere.

A set pops up every once in a while, you just have to be patient!

:tapemouth

Get Panasports, you won't regret it! I am a bit biased though... 16X7 Panasports with 225/50-16 tires. Lowered by 1 to 1.5", no rubbing at all. Got them on Craigslist for $800 with tires included.

A stock P79 head on a flat-top L28 will not yield over 9:1 compression. It should be about 8.7:1 if I remember correctly. The exhaust ports are not restrictive as some like to proclaim, and will flow better than an E88. The 260Z E88 is not as desirable as the earlier E88 (yes, there are different castings of E88 heads) because the 260Z E88 is an open-chamber (poor squish) head. Also, if you do the math, the compression will not be over 10:1 but in the mid-9s. There are tons of threads on building up L-series engines, search around, especially on HybridZ. Spend the time to read the countless threads on the topic and you'll be rewarded with having that knowledge within yourself. Take a month or two to read and soak in information. Take a look at datsunzgarage.com. While some of the information is not 100% accurate, it's a good resource for basic Z-car modifications.

Welcome Bill, from another early 260Z owner!

The Z gods thank you! I smell a resto coming on. Just get those wheels off ASAP and send them to the crusher...

Sounds like lean-popping on decel, which is not a big deal. You'd have to adjust the mixture in order to get rid of it, and since you said the engine supposedly has extensive work done, we can't help further without more info. Post a video, and at the very least describe your modifications and the popping that you get in more detail.

I'm with them, fuel comes to mind for me, as well. Check all filters and replace as necessary. You can put in a fuel pressure gauge in-line for diagnostics.

It won't change how long you crank at all, not by even one-tenth of a second.

Can you please elaborate on the physics of this phenomenon? How are you going to increase vacuum at startup by extending intake length? This is a rhetorical question. Air horns will aid in decreasing entrance losses, but more importantly, they tune the powerband by varying intake length. This has no effect at startup. Your cold start issues most definitely lie elsewhere.

Sounds like a bad ground somewhere. When you turn on the headlights, you are activating a ground. This may be helping to ground another circuit that is involved in running the car (e.g. ignition, fuel pump, etc.).

Buy "How to Restore Your Datsun Z-car" by Wick Humble, it should be the perfect resource for you.

At the very least, it should be vented to atmosphere. It would be better to devise a PCV system on the triples, as others have before (e.g. stonehenge from Zcar).

Did you check the differential strap which goes over the top of the diff nose? Make sure it's in good shape and not stretched out. Put in an RT mount for extra insurance.

That's exactly what I did on my 260Z. I'm using poly in front and the old rubber in back for the TC rods. I also don't have rubbing issues, but I have a lower air dam and not the factory valence. I was pleasantly surprised that I had zero rubbing with my setup, which is similar to your car: 16X7 Panasports with 225/50-16 rubber and Eibach springs. The ride is stiff and harsh, but that is mostly due to the very small amount of bump travel available before hitting the progressive bump stops and also the valving of the Tokico HP dampers. Some NVH analysis would be cool, I haven't seen that done with a Z!

Okay, that makes sense, regarding the subframe bushings. As far as putting in the rubber TC bushings, you'll notice a reduction in harshness which would be proportional to the spring rate change. You'll get a bit less noise, but I don't think the change in actual ride harshness will be drastic. I would try to devise a way to measure harshness and do back-to-back tests (accelerometer(s) perhaps).

Exactly. If the manual recommended 91 RON then 87 at the pump (AKI) will be fine. All the octane rating is, is a measure of knock resistance, meaning resistance to self-ignition under high temperature and pressure. It has nothing to do with burn rate, energy, etc.

So I take it that the engine always cranks over when you turn the key, but doesn't always start? My triple Weber start routine is this: Cold: pump pedal 3-4 times, crank over and hold at high idle for a bit (start enrichment not hooked up) Hot: ever so slightly hold the throttle open when cranking over, it starts in one crank when I do this You may have other issues, but try the simple stuff first.

Agreed!

I'll agree that stiff TC rod bushings add to ride harshness, but it's more to do with the fact that they limit vertical movement (adding to spring rate). This effect is exacerbated as TC bushings get stiffer. However, I disagree that all cars are designed to have the wheel move backwards much in bump. If this were true, all cars would have terrible bump-steer as rearward movement of a steered wheel leads to an effective change in tie-rod length. It is true, and I agree that passenger cars have some "compliance" built into them and if that's the give you speak of then I'll alter your analogy a bit. It is akin to catching a baseball with a stiff arm, with a glove on. If the glove has "give" or "compliance", then it will deflect more when catching that ball. When using a stiffer glove, you will "feel" the ball more, since there is less deflection in the glove (less force absorbed at impact). Maybe I'm just rephrasing what you meant, but I just wanted to be more clear on what I wanted to convey.

Don't bother, unless a head port is blocking off an intake port (opposite of your situation). Unless you plan to hog out the rest of your intake to match, you're not gaining anything.

I changed all of the bushings on my 260Z to polyurethane. Install was not bad in retrospect, but a big PITA while you're in the moment. Blue's Tech Tips has a nice guide on bushing replacement. As far as ride, I'm fine with it. The spring and damper choice has much more to do with harshness than putting in slightly stiffer bushings then stock. It's not like you're using metal bushings or heim joints. You'll probably get a bit more noise, but ride harshness shouldn't change much when compared to new rubber bushings. You are a lucky guy! I was looking to buy an M Coupe for months before finally going with an S2000 (my other top choice) recently. Those Coupes are awesome cars, but don't expect that a Z will corner and ride like one. A Z that corners flat will feel harsher, louder and more raw than an Coupe, even if it has coilovers.

Not a problem. I'm pretty busy these days, but I could probably manage to stop by sometime if you're having trouble. Feel free to PM me, or give me a call if you still have my number.