260pos

Sounds like a blown diode in the alternator, I had a PL620 truck with a similar problem once

How many miles are on it? it may be time to rebuild. to change the valve guides, you'll want to pull the head, "and while you're at it" steps in if you redo the head with a lot of miles on the bottom end, you will most likely begin to get excessive blow by at the rings. And more smoke! The year of the car means that you have one of the better block / head combos. Do what you can to save it, and good luck.

Are you sure it’s white? White (steam), Blue (oil) Black (fuel). Personally my car does an impression of the country of Estonia’s flag, but he colors are what the colors are. You have to figure out what the source is. As it doesn’t do it at idle, get someone to follow you with a good nose. Most likely you are losing a head gasket. Do you get a lot of white smoke at start-up? Valve guides smoke generally at start-up too, rings smoke while decelerating, and an over-rich condition smokes when you have too much fuel.

Oh! The reason for the hole is to vent the cap (tank) after the evaporative emission canister was removed and pluged.

EFI requires a higher pressure than carburetors, the stock pump won’t cut it, and so it really doesn’t matter whether you leave it or pull it. The pump it only there to help the mechanical pump out, as 260’s don’t have a fuel return to prevent vapor lock.

So John, how do we properly setup the stock system?

Olderthan, Well… 3mm is not really 3mm, by the specs Hitachi’s are 46mm, and the difference (dia x pi) is almost 12.7 mm squared or 8½% bigger. So you can figure at least 8% more flow considering Tony D’s observation that a carburetor HAS to restrict airflow to draw fuel. Rebello is boasting a 46% CFM gain in there advertising, but that is using an unrealistic 25” of vacuum. Fluid dynamics confuse the hell out of me! But by the link in my original post, 220 Hp should be a supported with a 2” 50mm carburetor. The most Nissan ever pulled out of the L26 was 162 hp gross, well within the working range of the 46mm carbs. If GM can get 71 hp per liter out of a pushrod crate engine with a 10.5:1 CR, we should be able to easily get 195 hp from a L28 engine, as a smaller engine is more efficient. **Some applications may not be emission legal; check state and local ordinances** At that power, the bigger SU’s should be just the ticket, without the complications of side draught tripples.

Sure PM sent -Jim

Absolutely, Post the pics. I need new pads on my car and I might as well to do the early Toyota caliper conversion. (Justification; I’m in there anyhow…) There is nothing to fear but fear itself, correct?

Check this site, there is a lot of good info on the different heads. It gives the benefits and drawbacks of the different castings.

I was under the impression that the threads weren’t NPT, but that they were BPTT (British Pipe Thread Tapered). Think of all the money I could have saved on rubber plugs! Might want to check that, I will too.

Well switch the tires back to start, then check the bolts that my skinny a$$ tightened...

I just checked out Rebello’s Big bores are $850.00 a piece plus parts. They say they flow 365 cfm, my SWAG of the 2†SU’s cfm must be way off, or Rebello really bores these beauties’s out! (Speed is money, how fast do you want to go?) Thanks for the insight Randy. -Jim

As far as the world of Google, there aren’t any HIF8’s. I know Ztherapy can hog the Hitachi’s out to 46mm. But the 2†SU is almost 51mm, which would give you quite a bit of flow. I imagine at least 575 – 625 cfm, quite a bit less than the 1086 cfm triple Weber 40’s will give you. But keeping that all important velocity up and less trouble than going to triple SU’s that most likely wouldn’t give you much more power. Thanks for the reply Tony, you have lots of insight on the little Z-monsters, we all appreciate it.

Definitely get the Hitachi's going first! As I have mentioned in previous posts I’m building a “paper†car first. I’ve build to many vehicles that just weren’t thought out well enough before I started modifying them. I’m going to make a plan… Mwah hah hah!!

So, how does it go? Did the 4:11’s get you into the powerband as hoped? I appreciated the comradely and of course the wisdom you so freely gave to me. I’m working on my kid’s little Honda XR80 right now. I’m trying to source a long travel swingarm for it. Going a bit nuts with it, another hybrid. Love the Japanese’ interchangeability! But when I get the Z parts together, we will tune those SU’s and we can bench race some more! Thanks Russell Jim

A few things could be giving you grief. You daid that you have a multi-meter, see if you have voltage at the coil. If not does your car have the dual point setup? If so, there is a control box for it. It has been *cough* 20ish years since I had this problem but the control box switches points while you crank. I replaced a whole engine trying to figure out that one, so don’t feel bad!

If you find a balance tube from a ’70-’71 240, it won’t have the big honking EGR, water, and exhaust passages on it. ztherapy has a nice solution, but it is kinda pricey.

Ditto, unless this car was your late grandfather's or you had your first encounter on the hood. Other than that, I would advise getting a new car to start with. Take a trip to the southwest United States; there are still Z’s here with minimal rust. Thanks for reminding me of what the Snow Belt does to a car. I need to change my signature!

I thought of that, I figure I’ll just take the old rotary file and hog the runners to match. It all has to get down to the size of the intake ports on the head. I feel that the triple su setup would decrease the velocity too much and lose some throttle response, that’s just a SWAG, I could be wrong…

Yes, I am a pain! I have a question about SU carburetors, the real ones. I found that there are 2in su’s. Model no’s are H8, HD8 & HS8. I was speaking with “Dtsnlvrs†(He has one sweet 240, IMHO. Off the subject) Russell said that the SU carburetors won’t cut it at high RPM’s in a modified engine. Now he runs triple Webers, I have had experience with them, duels on an old 510, but I’m looking for that stock look with less maintenance. From what I have found on the net, I think that the big SU’s could support about 220 horsepower. (Link) Not that my motor will put that out, but I’m hoping to exceed the >170 HP that this graph states 1 ¾ SU’s can handle. Oddly, I can’t seem to find much information on this swap. (Hybridz link) Would I need to modify the flanges on my stock N36 intake manifold? What about the linkage, and would the stock (I’m sure modified) air filter choke off any gains? Any Information would be helpful. Thanks, Jim

Oh, as far as carbs, I think I have round tops. I havent been able to find a photo of Z flat tops yet, but I did see a photo of a single SU on an A12 that looked very wierd (like a coffee can), I'm guessing that is what a flat top is.

AH! The front carb has oil up to the first line, the rear carb doesn't! dang newbie... Marvel Mystery oil eh? Sounds fitting with my SU experiance! How do i drain the old mystery fluid out, as what is in there is a mystery (30 wt, atf, dog urine- Who knows?)

Ok, so I’m going to show off my lack of knowledge! SU’s. Might as well be Greek. My car runs like cr@p, but it does run. It idles fairly smooth, but has such a huge flatspot coming off idle, I have to feather the throttle to get it to accelerate. Last night I was out freezing in the garage smoking, I decided to pull the air filter off. (I know, I’ve had the car for three months now, and I haven’t even done this yet, I suck!) I stuck my finger in the front carb and the slide? (looks like a motorcycle carb) lifts about 3/8’s of an inch, go to the rear and it lifts about 7/8’s of a inch (before any resistance, both slides will lift all the way up). This can’t be normal! How do I “rough†adjust these carbs? Or is my motor just that jacked that they are synched like this? The motor cranks steady, so the compression must be close, and I sprayed a can of carb cleaner around looking for vacuum leaks, and fixed a few. No dramatic change.

Here’s a nice little toy I found while I’m building my “paper” 260z. I hate running out of gears before redline almost as much as I despise not being able to redline in top gear! http://www.rbracing-rsr.com/aerohpcalc.html Lot's of great info on this site, I just love this place...