Jughead

Hi all. Since my last post, I have done the following: 1) Installed a replacement cam “oil sprayer tube” that I got from Yoes Racing heads (See picture below) 2) Installed the new old stock (NOS) distributor shown in my previous posting. 3) Set the points gap. Reconnected the ballast resistor and put the 1.0 Ohm coil back in. 4) Started the engine & adjusted the timing. Result: It started quickly and ran about the same as described above, BUT… As we were adjusting the carb mixture, the engine started to sporadically shake, with a corresponding metal-on-metal “clunking” sound - similar to the sound a carb piston makes when lifted and dropped in the carb body without the damper rod in. We shut the engine down to check under the valve cover and make sure cam oil bar was OK, which it was. Then, using a remote starter switch we turned the engine over in short “bumps” to watch the valves and cam operate, and to locate the “clunking” sound. We found the “clunking” sound to be coming from the timing chain slapping against the timing chain guides/timing cover as the engine rotation come to a stop. Depending on where the rotation ends up after bumping the starter, the chain can be very tight, or pretty loose. Is this right? Or should the chain tension be constant - no matter the position of the cam/crank? The clunking sound is pretty noticeable, but it might’ve been there the whole time and I just never noticed it. Don't know, but now I'm wondering if this is what was causing the tuning issues described above... Thoughts?

Here's a better picture of showing the model number. Also below is a picture form my Haynes manual where it's referenced. Good to go? My only concern is that it's for a car "with emission control systems" and I've removed most of my emission control components (air pump, non-return valve & flame trap). I'll triple-check for air leaks (again) around these components, but other than that, any issues with running this distributor? 'll

Gents, I'll check all those connections out this weekend. (I won't be able to test this weekend though, because I'm waiting for a cam oil tube from Yoes Racing. In the meantime, here's a distributor I bought on ebay (see pics) . It came from Kuwait(!). My plan is to swap it with the old distributor as-is - with the points, so I have some more questions: 1: What do I need to do under the hood in order to revert back to points from a Pertronix set up, other than a) Reconnecting the Ballast resister and b) Reinstalling the condensor on the coil bracket? Question 2: Should I leave the 3.0 ohm flame thrower in or re-install a 1.0 ohm flame thrower that I have? (I'm guessing the latter.) Question 3: Is there good wiring diagram anywhere that would help in this process? (I have a Haynes and the FSM.) Question 4: What am I NOT asking that will get me in trouble?! 🙂 Gracias, Amigos.

Will do & thanks Terrapin! 😉

BTW: Is the that little (~ 3" braided) wire the only thing that grounds the points? Where (on the distributor) would you attached a secondary ground? Thanks!

@Zed Head: Thanks - I'll do it. Is there a comprehensive list of grounds to check for a '72? I'll definitely check out those you called out above .

@Zed Head /All: Here's my complete history with this car so far... First of all, about me: I’m no “expert” mechanic, but I’ve done many repairs over the years, including replacing a tranny & a cylinder head, starters, suspensions, etc. – simple stuff mostly though. I bought my Z car about 2.5 years ago. The previous owner told me that he & his mechanic “could never get the carburetors adjusted right”. (Hmmm). It had been under a tarp and not driven for at least 10 years prior to my purchase. Most of my time with the car has been spent doing body work (in all the usual places). Last summer, after changing all the fluids and filters, I started her up and had a couple weekends with the car running awesome. It was great! Initially, there was some crap in the fuel lines, but that cleared up after a couple fuel filters. I put 50-100 miles on it, but then it started to run poorly (ran rough, low power - thought it was running out of gas.) It turned out that one of the chokes was stuck down, so I cleaned it and it ran great for another 50 or so miles. Then I had similar problems with the other choke which I fixed as well. Soon after that though, I had it running smoothly in my driveway, and as I was looking looking down at the exhaust, it suddenly just stopped running. Dead. Turned over, but wouldn’t start. I checked the chokes – they looked fine. So, just to get it started, I put in new points, plugs, condenser & coil. Wouldn’t start So I rebuilt the carbs – very carefully - using the Z therapy videos and LOTS of coaching from Steve Epperly at Z Therapy. I’m 99% confident that they’re rebuilt & set up correctly. I’m on the list for rebuilt carbs, but Steve’s skeptical that carbs are the issue. (HUGE shout out to Steve by the way!) Last year around Christmas time, it was getting too cold to work on it, so I brought it into the local shop. They were trying to diagnose it, when I got a Pertronix system for Christmas. They suggested they install it to see what would happen. They installed it, and got it to start, but it’s had the symptoms described above ever since... A couple of other potentially interesting details: 1) When I changed the points, the distributor was pretty dirty, so I pulled it to clean it and bench-install the points. The distributor slipped into a shallow tub of EvapoRust and was partially submerged overnight. I blew it out with air, and it seem to spin ok, so I forgot about it. I haven't taken it apart yet... 2) At one point I replaced the ignition switch with an old, used one that came with the car. I can’t remember exactly why I did that, but as I recall, I was not getting enough voltage to the coil, so I tried it. (This was around the time of, but prior to, replacing the ignition parts.) It ran fine for a while after I swapped out the ignition switch, but I’ve wondered if this might be part of the problem… 3) Based on many conversations with Steve Epperly, he recommends swapping the distributor with one with points as a test, which I’m currently trying to source. So, that’s my story. Other than swapping the distributor and rechecking the manifold gaskets, any thoughts? I WILL figure this out, but I want to do it while I'm young enough to drive it! I’ll take all the help I can get…Thanks Y'all!

Zedhead: Does this apply to a '72 240Z? Do I even have an AFM?

Gentlemen, Here's the latest update: 1) I redid the compression test using with better tester and throttles open. The readings look good (to me): 1=165 2=160 3= 174 4=170 5= 160 6=165 2) I removed valve cover again to recheck cam sprocket position @ TDC on compression stroke. Please see new pics below, and give me a sanity check on the following: a. The notch on the sprocket is directly below the groove, on the camshaft locating plate. (This is factory setting, per Haynes). b. The distributor/oil pump shaft “tongue” seems to be positioned correctly. (I did confirm that distributor shaft was NOT installed 108 degrees off!) c. The #1 cylinder cam lobes are in the “bunny ear" position d. I used a zip tie to verify TDC, and checked that the rotor was in #1 position to verify I was on the compression stroke. e. Question: Should I be concerned that the #1 mark on the cam sprocket is not on the “bright” light. (It looks to be on the adjacent one.) I have no idea whether the other bright link is correctly positioned on the Crank sprocket.) Everything else seems to be spot on... 3) Hooked up vacuum gauge and, after adjusting timing and mixture, I got between 19-20 psi of vacuum. The engine "purred" at these settings (at idle). And yet, when I test drove, I got backfiring & sooty plugs (again). And (again), when I adjusted to lean out, I got backfiring (i.e. "front-fire") out of the carbs. I've sprayed starter fluid on the manifolds and didn;t notice any reaction. So now I'm focusing on the distributor. I'm looking for a new/rebuilt dizzy to swap in & see what happens. Anyone have a solid distributor they'd like to sell? I also need a cam oil spray bar ("oil distribution tube"). Thanks all, for hanging in there with me!!! Jughead

@240260280z: Can you clarify something for me? In the picture below (it's also in your September 22, 2012 posting above), are the numbers running clockwise (1, 5, 2, 4, 3, 6) the cylinder firing order? I ask because the Haynes manual shows 2 diagrams that both show the order as being 1, 5, 3, 6, 2 4. (Haynes pages 73 & 74.). I'm working on setting up my ignition, so very curious about this! Thanks!!

I need to redo test - forgot to open throttle. What does "choke open" mean? Full choke? I wonder why that would make a difference... I'll update compresion test results tonight. @Zed Head's is a good question: Should the carb pistons be lifted/roved for the compression test?

Update: 1) Yesterday I bypassed the ballast resistor. (I disconnected the wire from one resistor terminal, and connected it to the other terminal along with the other wire.) It helped a little. I set mixture with lift pin method again & test drove. It still backfired out of exhaust, but was better. So I adjusted with Colortune, and as soon as I left the driveway, it “front-fired” out of carbs right away. (Same ol’ same ol’...) 2) Then, I took the plugs out, cleaned them (once again) and watched them all spark. They were all pretty much the same. The color is "white-ish blue" – almost purple. I was in a dark garage & I really had to look hard to see BLUE. Not sure how to gauge the strength of the spark. (Is there a way to measure this? If so, what should the reading be? I’m running new NGK BRR6ES plugs and new NGK leads (the blue ones). Plug Gap = .8 MM (Is that correct for Pertronix set up?) 3) I also checked the compression in all cylinders. Readings are below. Seems like a wide variance…thoughts? Cylinder PSI 1 152 2 149 3 154 4 179 5 152 6 179 BTW: I did spray starter fluid on the manifold/gaskets and carb bodies. The manifold/gaskets don’t seem to be affected. When I sprayed starter fluid on the carb bodies near the shafts, it decreases the RPM by ~ two hundred RPM at idle speed. Is the consensus still leaning toward the manifold? Is there a recommended thread on testing/interpreting vacuum on a '72 a40 anywhere on the board? I have ZT Carbs on order...are they likely to help? Thanks much for hanging in there with me...keep those thoughts & ideas coming!! JH

Update: 1) Today I bypassed the ballast resistor. (I disconnected the wire from one terminal resistor and connected it to the other terminal along with the other wire.) It helped a little. I set mixture with lift pin method. It still backfired out of exhaust, but was better. Then I adjusted with Colortune, and it “front-fired” out of carbs right away. Same ol’ same ol’ 2) Then I took the plugs out, cleaned them (once again) and looked at the sparks. They were all pretty much the same. The color is "white-ish blue" – almost purple. I really had to look hard to see blue. Not sure how to tell if sparks are strong, as I have nothing to compare them with. (Is there a way to measure this? If so, what should the reading be? I’m running new NGK BRR6ES plugs and new NGK leads (the blue ones). 3) Checked the compression in all cylinders. Here are the readings. Seems like a wide variance…thoughts? Cylinder PSI 1 152 2 149 3 154 4 179 5 152 6 179 BTW: I have sprayed starter fluid on the manifold/gaskets and carb bodies. The manifold/gaskets don’t seem to be affected. When I spray in on the carb bodies near the shafts it decreases the RPM by a few hundred RPM.

I got the Pertronix set up from Motor Sport for Christmas (2.5 months ago), so whatever Motorsport was selling then, that's what I have. I chose the 3.0 Ohm flame thrower coil with it, and I just realized/remembered that the 3.0 Ohm coil has a built in resistor. The shop that installed it to left the Ballast resistor installed, so maybe that's the issue...? Regarding the experience: It starts with a bit of effort with full choke. Once it gets warm, it runs without any choke. I start the mixture nuts at 3 turns, and adjust using piston-lifter pin method and/or Colortune. It needs to be around 4+ turns to sound good. Then I take it on a ~ 1.5 mile test spin. It'll run "OK-ish", until I put the pedal to the metal. Then, I'll get exhaust backfire. If I then lean out the mixture, I get "front-fire" out of the carbs. I check the plugs when I get back to my place' and they're all sooty. I've done this test repeatedly - always with same results (and yes, I'm going crazy!!) See prior notes in this thread and you'll see I've rebuilt carbs with ZT kit (set floats, installed new jets & needles), adjusted valves, checked for cam chain stretch.... The next steps I was gonna take were 1) verify ignition set up is OK, then 2) replace intake & exhaust manifolds. What do you think? Am I getting close? Could it be as simple as bypassing the ballast resistor?!

Here are my answers to @madkawquestions: Q: When you checked the mark on the cam sprocket at TDC - was the #1 mark on the sprocket where it should be ? A: I didn’t check, but I will. Where should it be? Q: Sure you have the needle jets seated correctly?. A: I think so. I set up per the ZT video, hear good “thunk” sound from the piston drops.when I remove the damper pistons Q: Verified good strong spark from the plugs ? A: What’s the best way to do this? Q: Verified no vacuum leaks ? Taken a vacuum reading? A: Not yet. Where’s the best place to get a reading on a ’72, & what should I look for? Q: Compression test ? A: Not yet, but will do & report back, Q: Was Pertronix set up properly based on ballast resistor used or not? A: I paid a shop to do it. The ballast resistor is still wired in. Should it be? BTW: I hear "whistling" & a ticking sounds coming from between the carbs. Could this be a intake or exhaust manifod gasket? Both are original-looking - especially the exhaust. COuld my issues be manifold gasket-related? Thanks Gents!!! JH

@Siteunseen: I get it! You're saying that the distances are NOT the same for front and rear! (This is the first time I recall hearing this!!!). At what distances should the respective valves shut off (front and back)? BTW: Since my last post I've adjusted the valves. (Some of the valves clearances were fairly tight.) I also checked for timing chain stretch. As you can see in my pics below, the "notch" is exactly aligned with the "groove". I'm told that's the factory setting - is that right?

I measures from the bottom edge of the float chamber top 9/16 inches (not 22mm). I've told Steve the year. Is '72 unique in this regard?

Anyone know where I can source center caps for my Minilites? (See pic.) Thanks! (Not sure yet what the inner diameter of the hole is...)

I just reset the floats. Here's the procedure I used (which I got from Steve @ Z-Therapy): 1) Removed float chamber top and held with float on bottom. 2) Blew into fuel banjo fitting while slowly lifting float and holding 9/16" spacer between top of float and bottom of float chamber cover. 3) Adjusted (bent) the float adjustment tab so that airflow thru the banjo just stops at 9/16", and air flows with any downward movement of the float. After doing this, I checked the levels with Float Syncs. The levels are exactly the same in both carburetors: ~ 1/2" above the top of the metal bases of the Float Synchs. Thoughts?

I'm running the needles I got as part of the Ztherapy rebuild kit. And I used the "blow method" to set the floats. I've tried SAE 20wt, but Z- Therapy suggested ATF, so that's what's I'm using now. I need to screw the mixture "nuts" ~ 4.5 turns, otherwise it front-fires and runs like crap. Around there I get a decent sounding idle, minimum smoke out of the exhaust & the lift pin test seems right. I have NOT gotten a decent bunsen blue ColorTune reading yet. It kinda goes from yellow to white-ish blue to white... Steve @ Z Therapy has told me that since I live @ sea-level (Seattle), the 4.5 turns wasn't surprising.

Thanks for that clarification. Actually, I've experienced both backfire & front-fire, depending on mixture setting. Just couldn't get the right mixture, which is why I yanked the valve cover. In order to get it to run right i've had to enrich the mixture to the point where it fouls the plugs. Then, when I lean it out, it starts to front-fire.

Thanks Zed Head. The pointer is pointing to the first notch in this picture - the furthest to the left, when they're on top & you're viewing from the front of car. There are 5 notches. At idle, under the timing light, it points to the 3rd notch from to the left (10 degrees). And I've double / tripled checked the wires. However, I haven't started the car since adjusting the valve clearances. Do you think that might make a difference?

OK, hopefully the 7 pictures above are worth 7,000 words!. I think I found the mark @siteunseen indicated above. It looks to be right above the notch. All these pictures were taken without turning the engine. Does this indicate the need to reposition the cam sprocket? The damper pic is blurry, but the 2 white marks are (from right TDC & 10 degrees). Let me know if a clearer pic would be helpful

I'll provide a picture. Dan you clarify where/what the "damper" is?