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Leon's Other 260Z

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Haha yeah, I would imagine they're relatively short! It's something I'm actually thinking of doing in the future when I start to become really serious with the engine. Funny enough, I found myself grabbing a complete E31 head not too long ago. Still deciding whether to hold off the head for when I acquire an F54 block, or just slap it on my existing L24 block. Decisions, decisions.


On that note, I'm living a lot closer to you these days. As a matter of fact, I just live a couple of minutes away from Yoshi, and I see him nearly every week. So seeing the car is actually a pretty good possibility  :lol:


Sweet man, I haven't been at Yoshi's in a little while. I need to get this Z put back together... :)

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Small dowel pins also work for locating the intake on the head.


Sounds/looks like a great job was done. Enjoy your newfound flow and det resistance.


Thanks Brady!


The head is back on the block as of last night, I did end up using a gasket for the intake/exhaust (had already bought a Nissan gasket) and trimming it around the locating pins. I even installed an L28 head gasket this time! :P


I'll be doing my best to work on it in the evenings this week. There shouldn't be much left to make it run, just need to reassemble the carbs, put a few odds and ends together, fill with fluids, prime, and do my third break-in in about 1500 miles.


There are some other things I'd like to do but that can wait until it's back on the road. :D

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  • 2 weeks later...

Worked on the car after work during this past week, culminating in a final push on Saturday night to have it ready for Blackhawk Cars & Coffee (why does it always happen this way... :rolleyes:). Finally fired her up at 12:30am, fixed some minor issues, and synced the carbs!


Got in a few hours of sleep and made the hour-long drive up to Blackhawk early this morning and just got back a few hours ago with no issues. I need a weekend of fine-tuning and then I should be ready for some dyno work. :D


I didn't take any photos at C&C but snapped one at a buddy's house just after a light sprinkling of rain.


Edited by Leon
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  • 2 weeks later...

The time has come, I finally made it to the dyno today! Tuning was done on the Dynapack at the shop I used to work at, Works Motorsports at Sonoma Raceway. :)




Swami joined for the day, driving in on my old 260Z which he's done a great job cleaning up! We did some carb-sync work on it while he was there and I took a test drive for old time's sake. That Z is so dialed!




I played with various combos of jetting along with the crappy F11 e-tubes and ended up at 135/F11/110 (main/tube/air). This was the best combo I found from my Weber stash but far from perfect, as there is a big rich spot that's causing the torque dip in the midrange that I minimized but could not get rid of. The F11 tube is to blame, I'm planning to alleviate that...




Once jetting was done, I played with timing. First using the ZX distributor and then the 123ignition tune-able unit. I optimized timing with the E12-80 before swapping to the 123. Interestingly enough, I didn't get any appreciable peak gains from the 123. I have a feeling that if I clean up the midrange fueling, the 123 may make more of a difference. All said and done, peak timing was 34 degrees.


Needless to say, I was very happy with the results and surprised that I could run at 11:1 compression with 34 degrees of advance on 91 octane! Guess I have the P90 to thank for that. :D When I originally build this motor, I was hoping for 200hp at the crank and I almost hit it at the wheels!




The yellow line is with the mesh filters and the red line is without. Looks like those filters are worth about 6hp.


I'd like to do another dyno visit in a few months to address the mixture issue and play with cam timing, either with the stock sprocket or an adjustable one (which I'd have to source).

Very happy with this! Videos to come as Swami was the videographer for the day. ;)

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Nice numbers . I guess there's something true about that squish stuff :)

I plan on at least 11:1 on my build but will be using the mn47 . I can get 93 out here so sounds like I'm good . Making that power with 34 all in also confirms my research . Congrats

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Thanks Ryan, you should put it on the dyno and find out! Bring your jets... :)

In the Spring I hope.  Winter storage is looming large at the moment.  My biggest concern in dyno'ing the car is with finding a shop with someone familiar with Mikunis.  I know a bit, but having a tuner that understands the carbs and can make educated recommendations based upon prior experience would be ideal.  I might have to drive do to New England or Virginia to find that though.  


I will be interesting to compare numbers, since we should both be running the same camshaft, but with different heads, ignitions, carbs, and so on.  

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In the Spring I hope.  Winter storage is looming large at the moment.  My biggest concern in dyno'ing the car is with finding a shop with someone familiar with Mikunis.  I know a bit, but having a tuner that understands the carbs and can make educated recommendations based upon prior experience would be ideal.  I might have to drive do to New England or Virginia to find that though.  


I will be interesting to compare numbers, since we should both be running the same camshaft, but with different heads, ignitions, carbs, and so on.  


Gotcha. I'm not familiar enough with Mikunis but maybe you can find someone that does remote tunes, i.e. rent a dyno and have the tuner on-call via phone/email as you tune. You can email graphs and they recommend changes. I did this for a few customers when I was the tuner at Works.


It would definitely be interesting to compare, although unfortunately comparing numbers on different dynos is pretty much useless. I've seen as much as 50hp swings between dynos with the same car. Looks like you'll have to make a trip out to Northern California! :D

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  • 5 months later...

It's been a while and there's actually not too much to report which is a good thing! I drive the Z once every week or two. However, there are a few annoying things to take care of:


Rev-hang when shifting and blipping the throttle. This does not seem to be a linkage problem but a fueling or vacuum leak issue. The car idles well but sometimes hangs at 3k RPM before dropping. The bigger issue is that there just needs to be more fine-tuning done with the idle/transition circuit. I get pops out the carbs during highway cruise once in a while and have a tip-in stumble. Looking forward to sticking in Keith Franck's jets once I have some more time to tune.


I also feel the engine leaning out at high RPM even though the dyno showed good AFR at high RPM. This indicates a weak fuel pump (O'Reilly-special thumper) which I'm looking to upgrade.


Otherwise, I've still got the 3.9 CLSD waiting to go in whenever I get to it. That should wake the car up quite a bit although I do enjoy the long gearing of the 3.54 for cruising. :)

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  • 1 year later...

It's been long enough! The car has been on the road for a few years now and I needed to catch up on some maintenance and upgrades this past Friday. On the to-do list was some maintenance, mainly diagnosing a clunky front end, as well as a new speedo cable and the long-awaited LSD and fuel pump install. 


There were wins and losses on this day! But first, the wins...


It's always nice to have friends help out to make things go quicker and today was no different. We got the rear end out without much trouble, it's nice to work on a freshly put-together California car.




The LSD is on the left, along with some cruddy old axles I had lying around. Those will be addressed later...




While the diff was out,  we thought about how to tackle my rear toe issue. The chassis doesn't look like it's ever been hit but something is definitely off. Here are the rear toe numbers from a while back:



For the sake of on-car adjustability, we decided to slot the transverse link brace. I calculated, based on rough measurements, that we'd need ~1mm slot so we milled off 2mm.




Slotted vs stock




And a major win, we're finally at zero thrust angle! Goes to show that it doesn't take much to have the rear toe go out of spec, especially considering a stock Z has no adjustment back there. (The amount of cross-camber is annoying and I plan to find a way to fix that as well)




The LSD install went smoothly and we finished up late that night. It's clunkier than my old diff, yet to be determined whether it's the backlash or the u-joints in the axles. There's also a bit more gear whine but not really in cruising RPM ranges. Filled it with Redline GL-5 diff fluid which has friction modifiers in the formulation, the clutches are nice and quiet so far. Acceleration is definitely peppier but it's not quite the 80mph cruiser it used to be. I haven't had a chance to push the LSD much yet but that'll come!


Now for the other stuff...


After a quick investigation, the clunky front end turned out to be a loose FR gland nut. We snugged up the rest as well. Channel locks did the trick without any drama or disassembly. However, that wasn't the only clunk. Grabbing the wheel at 9 and 3 also revealed a lot of play in the steering. We initially thought it was an inner tie rod but it turns out the play is internal to the steering rack (!). I plan to see whether I can make any adjustments to fix that. If it's too far gone, I have a spare rack I can toss in. If that happens, I'm curious to measure the rack ratios to see if there's a difference considering my spare is a 240Z rack and I have no idea what's in there currently.


The speedo cable went in without much fuss but the speedo is still non-functional. Haven't probed further. I did put a matching 19T (white, 3.9 diff) speedo gear into the tranny so the speedo should be accurate once it's actually working.


We didn't have time to do anything about the fuel pump so that's been postponed.


The major annoyances left with the car is the lack of bump travel causing the suspension to bottom out when it shouldn't and the rev-hang issue. We'll be sectioning a spare set of struts in the coming weeks to deal with the former. Once those are dealt with, the refinement level and enjoyment will go way up. :2thumbs:

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Forgot to mention, I threw the wheels on the tire balancer and they all had borderline-to-excessive road force (14-28lb). That explains the slight vibration in the steering wheel (combined with the excessive play in the steering rack). Unfortunately, looks like the tires have all been flat-spotted from sitting stagnant for a few years when the car sat. There are no issues with driving on them but the slight steering wheel shake is annoying. I'll have to accelerate the wear a bit, I think. :D


I'd like to get some 15X8 Wats as the 16" Panasports are just a bit too big for my tastes but the tire options are unfortunately limited to either some cheap no-seasons or R-comps. Might just go for the 15s and just send it with some R-comps since it's a fair weather car.


If anybody's interested in some 16X7 zero-offset, almost brand-new Panasports let me know and it may just send me over the edge... I'll also have to find a good source for Wats.

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