240260280z

Great! Good luck today...here I am checking my daughter's 98 Rav4, P0171 (Lean code) but plugs are pig rich sooted.... now to investigate

Hoses are inexpensive. There are not many on a 240z. You can see them here: Datsun 240Z-260Z-280Z Parts Manual As well as in the 1972 factory service manual: http://www.xenons30.com/files/FSM/1972%20240z%20FSM.zip You can change all of the engine compartment and under dash hoses for under $100. (Cooling, fuel, overflow, washer fluid, evap) There are a few fuel lines hoses to/from the gas tank that will be under $5. There are also emission/vent hoses to the tank that could be expensive if you purchased from Nissan, however you can use alternate methods and do the job for $50. There is also a drain hose for an electric radio mast/antenna if your Z has one. It is $1.

What chokes are on the webers?

I would set the floats for fuel level at 27mm down. I think Frank Keith's 25mm is too high. When you look at the configuration tables in the back of the Weber books, you can see where part of the carb set-ups includes varied fuel levels (even for 2 litre 4 cylinder engine applications, fuel levels can vary) ...I am sure this is for the reason why I see problems at 25mm for 40mm's on a 240z. 1 size does not fit all. I hope to plot A/F against float level tomorrow on a 510. I'll share the data here

The interior is great too!

btw only the later DCOE's run at 2-3 turns out on the idle enrichment screw. The early ones run 1 turn or less due to a different taper in the screw.

The off idle/cruise is the first thing to address. It is primarily the progression holes that are operating then. The two interactive parameters are fuel level and idle jet selection. I have found that the fuel level at 25mm down will cause the mains on a 240z to come in too early and cause an overly rich progression (40DCOE with 30mm chokes). Try removing the mains and plugging the (spill jet/pump exhaust jet/ pump bleed) with a bolt then try to get an idle jet and fuel level that works. Also inspect the throttle plates sealing and their locations with respect to the progression holes.... you know the drill Have fun! btw closing the throttle plates at high rpms (over run) should draw only fuel from your idle enrichment hole. The symptoms you mention above may be caused by the choke circuit (if you have one).... sometimes the plungers do not seal properly.

That's only part 1... now you have to compare on the road

I concur, the sway bar was #1 for me too for best bang for the buck for street driving. The t-c ball and sockets were next but you need to a/b without/with to see this. I think your full upgrade masked it. The weak link(pun) with sway bars are the end links. If they are not tight then some of the effectiveness of the bar is lost. Poly's work better as the insulator pucks in the links. Of course the mount points for sway bar to the frame is a common rust point on the Z. The sway bar mount often pulls free. Bad Dog parts make plates to reinforce this area.

Something with distributor and timing? What is your timing light showing at idle and at 3500rpm

So sad.

Clean toe nails too!

Nice stuff! It will help a lot of people. You should also post in technical articles. It is great!

Hey guys, I'm about to start profiling weber's a/f ratio's vs configuration changes. I'll try to do the same for EFI systems this summer and measure what the A/F ratio changes for teeth changes of AFM and resistor changes at the temp sensor as well as idle and WOT enrichment. May even pull out the scope and measure injector pulse width changes.

The chain guides and chain tensioner are adjustable. If you shave the head and take the front timing cover off, you can easily take up all of the slack from the shaving. An adjustable cam will let you dial in the mechanical valve to crank timing. In my case I shaved 2mm off an N47 and did not bother taking off the timing cover. I correctly assumed the tensioner would take up the slack. I had to rotate the cam 1 link CW closer to get the mechanical timing close enough to use the hash mark/triangle alignment marks. It was a quick and dirty ghetto mod thought experiment that I implemented. FYI it is a common improvement mod to use a larger chain guide bolt(s). Check the How To Modify.... book for the details

Holley boosters are better than Weber Venturi's however fuel in air does not like 90 degree turns. It is not desirable for air to do this in a design but it is much worse for fuel in air to take a 90.

Nice catch!

Nice to see your observations matching theory. You are now F183 to R151 so only 17% weaker in rear compared to 30% for the last setup so the gap is closing.

Denso/NGK price brakes to Nissan? CO, for experimental fun, I would try to pick a day where you can advance the distributor to just get the projected plugs to ping going up a hill... then swap in the regular plugs and see if the ping stops...this may prove the flame front theory.

P79/90 head vs N42/47

"Pain in the butt" beats brake cleaner blast Here are some rates: http://atlanticz.ca/zclub/techtips/springs/index.html Most seem to have rears at ~ 13% stiffer than fronts. You are now at front: 212 lbs/inch and rear ~ 151 lb/inch (approximation with the 2 ring cut factored in). So you are skewed with rears ~ 30% weaker than the front. It would be good to correct as this may make the car twitchy.

I find that eliminating the roll makes the car move like a shark finning on the surface. Glad it all worked out. Good luck with the rack bushings!

After more thought I think the WOT fuel enrichment circuit in the ECU has a bad component that kills the pulse shaping when activated.

I think it is an interference fit. You could probably get by with a skim of high-temp gas resistant sealant/adhesive however if it ever came apart while driving, fuel will go everywhere.

good stuff! The suspension will settle after some driving.