Stanley

If raising the idle and richening the mix made it run better, doesn't sound like it's the fuel pump. Sounds like it needed more gas and the F.P. is providing it. Hot weather and high altitude (Hot summer day in Denver) needs a leaner mix; cold plus low altitude (couple weeks ago at sea level on the East Coast) needs richer mix. There's a table for that in the FSM. But a non-stock engine might need more gas, if it moves more air. In that case it might be better to change or modify the needles instead of richening the mix. Otherwise the mix that works best when going WOT from 70 mph to 90 might be too rich at idle and for ordinary driving around town. Maybe the mix where it runs the best at all rpm without fouling the plugs is OK. Does higher compression engine need a richer mix? Wondering about that one. Seems like it would need leaner mix but I'm guessing.

That site is bad, very bad. I need to go to work and it won't let me. Love that 65 Silvia though.

Carbed intake is different of course, but I did the same way: hit it with a small wire brush on the electric drill, small hand-held wire brushes where you can't reach with the drill. Apply aluminum polish with rag and toothbrush. Rubbed it out with rags and a cone-shaped foam buffer in the drill, got it at O'reilly. Off the car would be better and easier, looks much better though.

I read the 4 psi Mallory has a adjustment screw that takes it up or down about 1 psi. Don't have the FSM in front of me but I think it says about 3.3 to 4.2 psi for SU's. 3 psi might be a little low unless you drive slow. In Ztherapy video it does say fuel pressure affects mix (maybe higher pressure keeps fuel level in the bowls steadier?). I had a fuel starvation problem when getting on it and thought it was the fuel pump but it was a combination of other things. Using modded needles and slightly higher than stock float height seems to help. My stock rebuilt mechanical pump puts out 3.5 to 4.0 psi (usually 3.9) while driving, depending on temperature, amount of gas in the tank etc. Pressure nice and steady, no vapor lock in severe conditions. No return line. Some cooling system cheats though. I have the float bowl vents going to a catch can so I'll know if they overflow. So far OK. Don't like the new tin-hat mechanical fuel pumps though. They look crappy and they don't have screw-in fittings, so you can't adapt it to AN.

Thank you Mr. K for your personal efforts to expand the Z car market in the USA. Otherwise they might be as rare as Skylines, Cosmos, and GT2000's are here, and most of us would probably not be driving these cars today.

I called ProFab again, still no answer. So I Emailed Stahl, got this back yesterday: Stahl Headers Tome Feb 19 at 1:31 PM I don't know the situation for ProFab. All I know is that they bought our jigs, prototype and sample pipes to be able to reproduce them. You best option is to find someone in the Z community willing to take their car to ACP in Harrisburg, PA. Greg is the one who built them in our shop. Judy So there you have it. From what I've read, from John Coffey and many others, these headers are among the best; also they do 1 3/8" primaries (and other sizes), and equal-length 6 into 2's that don't seem to be available elsewhere. And they look great. The only ones that look better IMO are those pricey works of art from Japan, and I don't think they work with LHD or carbs.

Had a local muffler shop install a 2 1/4" pipe and "turbo" muffler, with the stock exhaust manifold and down pipe, on my '73 automatic. I made a bunch of zero to sixty mph runs, timed with a stopwatch, before and after. The new pipe improved it from mid-nines to low eights with no other changes. Definitely noticeable. Cost about $400. I gave the installers some rattle cans of prep spray and hi-temp exhaust paint; after they welded it up they painted it, before installing it. Might help prevent rust.

I also use the IR thermo gun to fine-tune the mix after getting it close with the FSM method. I aim at the head near the spark plugs since that seems to give more consistent results than aiming at the stock exhaust manifold (that might work better with headers). I take three or four measurements at each plug and average them since the readings aren't exact (the IR gun needs a minute to get itself together after a reading, or the previous reading throws it off). Interesting to watch the readings change when you adjust the mix. My question is, is there a way to use the IR gun or EGT meter to get the best mix for racing or everyday driving? Do racers tune that way or are the EGT's just a warning system to prevent losing an engine? Obviously you can't use an IR gun while driving. In FSX, flight simulator, you have to set the mix depending on altitude (or use automix). The manual says to adjust mix for highest EGT and then bring it down 50 deg.(F). It's a video game, though. If you have EGT's would you use them like that? It's an issue for me since the non-stock head assembly needs more gas at upper mid-range and top end (I guess it's pulling in more air), improved since having the needles modded. Also, if the temp gauge is in the middle, about 180F, while driving, wouldn't that mean that there's no need to worry about cylinder head temps due to overall AF ratio, if they're all about the same?

I looked at RHD Japan site, it seems a little scanty on information. It says the Fujitsubo Super Ex headers for S30 are 4 into 1. Wonder about 76000 yen ($637), seems low for good SS headers. According to thread on HybridZ, Fujitsubos won't fit LHD. Kameari has LHD headers. They look very nice, should work OK with your triples if you really want 1.75" primaries. Kameari USA site lists MSA as dealer. 187000 yen ($1569 w/o shipping) at RHD Japan may be OK price for them but if you have to send them back to Japan then not. Might be legitimate reason ProFab in Aurora doesn't return calls; maybe they're moving, retooling or something. Otherwise maybe the new Stahl Headers by ACP could buy the jigs back from ProFab or start from scratch (if enough interest from Z community). They sound like the right outfit to do it, anyway. Maybe next year.

At http://www.stahlheaders.com/ it says Datsun headers now made at ProFab in Aurora Oregon, (503) 678-2948. Tried two weeks ago, and last week, there's a message but no call back. I called the other number listed on Stahl site, for Stahl Headers by ACP, (717) 232-2800. Greg got back to me today. He knew about the Datsun headers, but said the jigs etc. were sold to ProFab in Aurora. I told him about calls to them not returned. He said he might have stuff for the 510 headers only, would know when they had everything moved. He said if there was enough interest in the Datsun headers he might build them in the future; he would need a car to work with (I guess a set of the old headers might help too). I saw another ProFab in Woodburn, OR, called the number thinking it might be the place, since it's only a few miles from Aurora. They don't make headers, but he knew the person who owns the Aurora ProFab, but thinks he may have retired. Still looking for some 1 3/8" headers.

Maybe it's a coincidence, but I've seen a number of posts in the last few years where the left turn signals work but the right ones don't. I had the same problem a few years ago, repaired it by cleaning the contacts in the little teeter-totter switch. Then the right side went out again, took it to the shop and it was ok for a while. Now the right side is out again. Is there anything about the wiring that would make only the right side tend to go out?

I was mostly concerned about rust, but temperature control might be more important than I thought. Hadn't heard of Swain before but checked it out. A bit pricey with the shipping but looks like it's a different process with much thicker ceramic, probably the way to go for performance, especially racing. I see a lot of dragsters with those white pipes, it's probably Swain's. I don't race, except occasional test & tune, but do take road trips in the desert where it gets over 110F. Seems like Z's wouldn't have as much of a problem with engine bay temps as newer cars that don't have much room for air to circulate. However, headers have a lot more surface area to radiate the heat, so it would be good to do something to keep it cool near the carbs and intake Maybe the problem with wrapping is it works too well, keeping those pipes extra hot and eventually causing the metal to deteriorate. I'd like to wrap just near the intake but that's the hottest area; I've read that hot spots are bad for headers.

Paint vs. ceramic vs. jet-hot etc. or other finish for new headers. Price, corrosion protection, temp reduction near carbs? Twenty years ago got some nice Clifford headers for my Chevy truck. "Saved" $150 by not ordering them coated, now they're shot. Don't want to repeat that for the Z. Don't know about coatings, though. Seems like using spray cans would be cheapest, but how long would that last?

Congrats on the brazing, and nice write-up by zKars. For someone else with a similar project I would recommend a machine shop if they're not comfortable with brazing. There is probably a machine shop just about anywhere where machinists are standing around hoping someone will bring in a project, and the cost may be way less than you'd expect. A couple years ago a client needed some 45 degree bolted steel timber connectors; the contractor said it would take two weeks to get them. I made some calls and found an old machinist in Watts who made them from my drawings the same day. The cuts and welds were beautiful, and it cost about half what the mass-produced items would have cost.

Bypass originally provided heat to intake during warm-up and bypass when thermostat closed, with cold=open thermostat connected to back of stock intake manifold. I figured flow in that bypass when from lower thermostat housing but after reading post #155 on p. 8, looks like it might flow the other way. That discussion on Hybrid Z goes 24 pages, didn't finish yet but here's an excerpt from #155. A comment about the port above #6. When the t-stat is closed, water will probably be routed from the lower t-stat housing into #6. The pressure in the t-stat housing will most likely be higher than #6. Remember, the water in #6 is most likely stagnating due to the pressure differential between #6 and #1. When the t-stat opens, water will then reverse flow, as the t-stat opening is now the lower pressure zone. The pressure through the t-stat and into the hose will most likely be lower than the pressure at #6, thereby allowing water to flow from #6 to the t-stat. Seems like it would be easy to run a hose from the heater outlet on the back of the head over to the lower thermostat (without a restrictor or the cold=open thermostat in line). Could put a tee at the heater outlet if you want the heater, otherwise block off the heater return to the lower radiator hose water inlet. I bought the hoses and fittings to do that last year, about $50, haven't got around to it though.

Here's a shot of that one at Pierre's shop, from last summer.

http://www.zcar.com/members/6796-nismoz-albums-jdm-stuff-picture3977-s30-lhd-header.html Kinda like these, but maybe I'm dreamin...

After seeing ProFab's number on a recent thread in this forum (and getting the same no-answer) thought I'd better ask before spending much time trying to find them (the headers). So, did the Stahl 1 3/8" headers fit a 240Z with AT? Or, is there another source (other than OZ or Japan, expect RHD headers won't fit around the brake and steering stuff) I should try? Running 1980-81 small port head on stock '73 block, figure 1 3/8" primaries would give best mid-range torque and maybe extend top end a bit.

From what I read at Mallory site and some hot rod chat sites, the return line should be same as the supply line for their regulators. I'd guess they're talking about setups for big dual 4-barrel guzzlers, but it might still apply. On my '73 at least, the return line is smaller than the 5/16" supply hose barb at the tank (and the vent line comes out of the evap tank). You might want to hook up a fuel pressure gauge to check; on the other hand, if there's way too much pressure the bowls will probably overflow so you'd know anyway. Maybe the other 5/16 outlet would work as a return, but you'd still need a vent. BTW, the vent line on mine didn't work (per the test in FSM) until I took it out and blasted it with carb cleaner.

Not sure if those are very safe. They can leak where the hoses clamp to the hose barbs (like any filter), also where the hose barbs screw in to the filter. There are O-rings at each end, they can leak too, especially if they're made of rubber that's not ethanol- resistant. If there's a fuel pump before the filter it can leak gas. If it's a mechanical pump after the filter it can let in air bubbles.

Came home the other night, put the car cover and on smelled gas. There was a steady drip from the fuel return hose where it attaches to the tank. Got a flashlight and some cardboard to lie on, saw the clamp had cut the hose. After getting some gas in the eye, decided on a quick fix, took off the old clamp, pushed the hose farther on the barb, past the cut, and clamped it with a #10 F.I. clamp (needs a #8 or #9). When I redid the fuel hose to the tank couple years ago, didn't change the return hose; figured I didn't need to since the return line's not hooked up. Dumb. The hose is thin and not ethanol-resistant, don't know how old, and the clamp was too big, not F.I. type, so it tightened out-of-round and cut the hose. Noticed my gas mileage is worse lately, maybe this will help.

The link didn't work for me but I went Amazon books and searched L6 Engine Tuning and there it was. Tried to order the kindle version but I have "Kindle for PC". Yes if you have the free "kindle for PC" app you can download a book to hard drive and read it offline whenever you want. It's great. But it didn't work for this book. I could only order it for my Cloud Kindle (didn't know I had that until today) but not the PC app. Don't know why. My ISP isn't very reliable so I need it to work offline.

A little off topic, but IMO the main thing is to change or clean the filters frequently. A few years back, a friend had a 90's Nissan SUV that was running crappy. A "mechanic" had done some stuff and charged him money, but he still couldn't keep up with traffic on the freeway. We pulled off the air cleaner, shook about a cup of dirt out of it. After that it ran fine. I have K&N's with the round chrome housings (carbs) and clean and oil them about every six months, always get a fair amount of dirt out of them.

Just an observation (no experience with either one): I see most of the pro drag racers have Mallory stickers on their cars. Don't think I've ever seen one with a Holley sticker.

I planned to install an electric fuel pump (or hook up the stock one for drag racing) because I had a fuel starvation issue at WOT that I thought was due to some weakness of the fuel pump. Why did I think that ? Because I was not really thinking. Installing a quality fuel pressure gauge in the cockpit verified that my fuel pressure was fine (3.5 to 4 psi) at all times with just a stock mechanical fuel pump. The problem turned out to be due to a combination of low float bowl levels and the fact that stock needles were not providing enough fuel at WOT for the non-stock head assembly I'm running. Good to see that the original electric fuel pumps are still available though. They should bolt right up if you have the original bracket. In the Just SU's video, there's a statement that fuel mixture depends on fuel pressure to some extent. If you hook up clear tubes as sight glasses and watch them while the engine's running, you'll see the levels go up and down slightly as the valves open and close. Maybe with lower pressure that variation would increase, causing a slightly leaner average mix.