'72 240Z quit...

[Curtis240Z]

Thanks for all the help on the ignition system' date=' the more info I get the better off I'll be when I get back. Where do they sell the O2 gauges you're talking about? What exactly will I need to do for it? I've been looking at switching to an electronic ignition system, the XR700 seems nice and I'm looking into a Mallory Unilite distributor, does anyone have similar setups?[/quote']

I got my O2 gauge from Summit Racing http://store.summitracing.com/partdetail.asp?autofilter=1&part=AVM%2D30%2D4100&N=700+0&autoview=sku you will need a muffler shop to weld in the bung fitting for the sensor. Other than that all you do is mount the gauge and wire it up.

I have the XR700 in both my wife's and my daughter's 240Zs. I am using the Crane HI-6. My friend was trying to use a Mallory Unilite distributor but I think he was having some trouble trying to get the tach to work because the 240Z tach is voltage triggered instead of the more common current triggered tachs. I believe Mallory sells a tach adaptor though.

[Mr.Woof's72z]

Thanks again for the info on the ignition, looks like I have a nice list of parts to look through. Do you like the Crane HI-6 more than the XR700s (is it worth the extra money)? I'll see what they do for adapters, hopefully all the problems I've been having will be taken care of when I get back to CO. If anyone else wants to give me info on ignition that would be great (something I'm lacking knowledge in...) and thanks again.

[Mr.Woof's72z]

Thanks again for the info on the ignition, looks like I have a nice list of parts to look through. Do you like the Crane HI-6 more than the XR700s (is it worth the extra money)? I'll see what they do for adapters, hopefully all the problems I've been having will be taken care of when I get back to CO. If anyone else wants to give me info on ignition that would be great (something I'm lacking knowledge in...) and thanks again.

[Curtis240Z]

The HI-6 has a rev limiter in it which is primarily why I switched up other than that the XR700 is fine.

[Carl Beck]

Hi Brendan:

Since the Triple Webers do not provide for the use of the Vacuum Advance, you have to dial in a lot of initial advance at the crank. Because of that you also have to have a timing curve in your distributor that limits total advance to something around 34/35 degrees.

Replacing the points with an electronic trigger will not address the above issues. Nor will adding a CD system.

You could - take your distributor to a good Automotive Ignition Shop - and have them set it up such that at 1500 PRM you have 0 mechanical advance and by 3500PRM you have an additional 14-15 degrees (crankshaft degrees). With the vacuum advance mechism removed. Once that is done, you set your initial advance at the crank to 18-20 degrees.

The question then becomes - do you rework your stock distributor, by adding the XR700 or Pertronix to replace the points, and having your distributor timing curve adjusted - or do you switch to an HEI ignition etc. One option is to switch to the later 280ZX electronic distributors/coils, or spend the big money on something like a Mallory UniLite distributor and their HyFire VI CD...

I've been running the Mallory UniLite with a Pro-Master Coil for about 15 years now - with the triple webers.. and ignition has not been a problem.

Your biggest problem with the triple Webers is - like someone else said - finding a truly competent tuner - that really knows not only the Webers, but how they have to be set up to run on the L6. Most of the time the 40DCOE's are delivered with primary chokes too large for the L6 on the street, and to make things worse they usually have the wrong combination of primary jets, emulsion tubes and accel. pumps.

By the time you buy new primary chokes (28mm to 30mm at most), and all new jets etc for 6 individual set-up's... you'll have several hundred dollars in parts and postage. Plus the time the mechanic will need to work everything out... So you can set $600.00 to $800.00 aside to get the Webers set up to run right... Short of that you can dink around with them for years yourself and spend twice that amount.

If you want a good running Z at a reasonable price, with very little hassle - get a set of rebuilt S.U.'s and sell the Webers...... If you have plenty of time and lots of money to throw at it - you can get the triple Webers to run just fine (but you won't have any better performance because of them, unless you do a lot more to the engine in total).

Just my opinion...

FWIW,

Carl B.

[Mr.Woof's72z]

Wow thank you for the detailed response. "Big Money" to me is over $1,000 so by stepping up to the Unilite and something similar to the HyFire VI (I say similar because the HyFire is a little overkill for what I would like) in my opinion is worth it. My car is the only place I'm spending my money which helps quite a bit. As far as tuning Webers, from what I've read online and been told by different mechanics in town here is that with enough background knowledge on how the system works I can get a good idea of what needs to be done. Fortunately I've been able to find a huge amount of info on different jet sizes, venturi sizes, emulsion tube sizes, etc to get a good idea of what sizes will work best for the setup I currently have.

So far all I have for the engine are headers (3 into 1s) and for what its worth the Targa Exhaust from Motorsport Auto. Are you saying I won't notice a performance difference between the Triple Webers and a rebuilt pair of S.U.'s? I've got quite a good book on S.U.'s (How to Build and Power Tune S.U. Carbs, bought it because I was going to buy a 1976 280Z with S.U.'s before I found the 240Z with Webers). If I were to go back to S.U.'s...what is the asking price for used Weber carbs with K&N filters (I will get sizes of jets, etc when I get back)? I'm assuming I would come out ahead of the game, which would be nice if I were invest in the ignition, and since you're saying I won't notice a difference in performance without serious $ and time spent on the Webers I see no reason not to.

I'd really love to hear your opinion on this since you are the first one to recommend going back to S.U. carbs since I won't notice a difference in performance (and I'm assuming/hoping there won't be...) Thanks again for your input, hopefully you can help point me in the right direction.