Duffy's 1/71 Series 1 240z build

[duffymahoney]

Well test run didn't go well, I have a strange crack sort of sound when I got from stop to forward and back and also a slapping sound at higher speed. Trans seems to shift fine.  It's a little too modern feeling, I am thinking it might be better without the short throw shifter.  Hopefully it's something dumb.  

 

Noise doesn't seem to be coming from the trans or the rear end.  Rear end doesn't whine.  Which I think is good.  

Edited June 14, 2019 by duffymahoney

[moritz55]

Hey Duffy... congrats on both getting married and testing your car....

Just one observation on your noises....

Crack Sound - maybe be a U-joint / Drive shaft or side axles ... maybe add some grease?  rotate when car is on the ground check for play..  

Good luck.... keep us posted....

[duffymahoney]

30 minutes ago, moritz55 said:

Hey Duffy... congrats on both getting married and testing your car....

Just one observation on your noises....

Crack Sound - maybe be a U-joint / Drive shaft or side axles ... maybe add some grease?  rotate when car is on the ground check for play..  

Good luck.... keep us posted....

Thanks! Gosh I hope it's a u-joint.  Nothing is loose.  I did remove them all when I did the last round of zinc.  So that is a thought.  I am just hoping its not something super important or hard to repair.

 

I bought an portable o2 meter, I think my carbs aren't happy.  I have a feeling i have them too rich.  

[moritz55]

Regarding your Carbs running possibly rich....   until you get your O2 meter hookup (for each Carb?) I'll share what I did becuase I didn't want to install two O2 sensors for each SU.

1) I used Colortune 14mm plug and this technique for fine tuning Carb A/F mixture on cylinder #2 & #5 for twin SU's .  At Idle and 3000 rpm ... plenty of Youtube videos on this...    https://www.amazon.com/Gunson-G4074-Colortune-Single-Plug/dp/B0012MB4VE/ref=pd_sbs_263_1/139-8508085-4072005?_encoding=UTF8&pd_rd_i=B0012MB4VE&pd_rd_r=0c081181-9cc0-11e9-b500-9959ee5ce66b&pd_rd_w=6PqYJ&pd_rd_wg=arPBD&pf_rd_p=588939de-d3f8-42f1-a3d8-d556eae5797d&pf_rd_r=R68MTQD1GKPP7VZV8M3G&psc=1&refRID=R68MTQD1GKPP7VZV8M3G

Video : 

2) Then used this manual page (attachment) referring to page 11 "Testing Procedure" .  Under load so it gave me a good indication that my "SM" needles were too rich during pickup/cruising... so now I am running "SR" needles which are closer to N-27 stock needles and the car runs great.  Page 45 has the needle profiles for comparing "SM" vs "SR".

I know you have Triple Carbs... but thought this approach may add to your fine tuning approach...

Good luck....

SU Needles - Tuning_SU_Carburetors.pdf

Edited July 2, 2019 by moritz55

[duffymahoney]

I should get the o2 meter today.  Hopefully the tailpipe reader works well enough, or it will be time to get the welder out.  

[duffymahoney]

Happy wats day!!

[duffymahoney]

Looking snazzy.  I went with stainless black lug nuts.  I also have the raw stainless, it's a hard choice.  

[duffymahoney]

I got my Innovate LM-2 AF meter.  I was around 9-10 at idle with my jet settings, so I dropped it to the lowest jet i had.  Still reading right around the same at 9.8 or so.  

 

Could spark/ dizzy issues be causing the AFM to read real rich?  I tested the LM-2 against my other cars and they are all in the high 13's and 14s.  So I think its right, also my z smells real rich and it has some carbon build up.  Any reason why the jets wouldn't change AFM?  

I have some smoke now as well, which I am real hopeful is just excess gas.  It dissipates quickly.  Hard to tell what color it is.  

[240260280]

It usually is fuel level too high or jets too big.  9-10 will foul your plugs quickly.

[duffymahoney]

I checked fuel level and adjusted, also went down on the main jets.  Didn't change anything.  

 

I ordered a 123 dizzy.  So hopefully that gains me some adjust ability  I didn't have before.  

[240260280]

Hmmm, normally you can do both and drastically raise the air/fuel ratio. Something seems odd?

[duffymahoney]

Odd in deed.