duragg Posted April 11, 2013 Author Share Posted April 11, 2013 A little update. I switched to some big-daddy DCOE45-152 carbs with 40mm chokes and now my L28 pulls easily to 8000RPM.With this higher RPM my 2nd gear crunch is back if I rush the 1-2 shift. Remember I did not do the modification to the 1-2 synchro, just the 2-3 and 3-4. I was not able to get any crunching on the 2-3 and 3-4 shift even when pushing hard at extreme RPM. I am pretty confident that if I pulled the tranny and modified the 1-2 synchro key spacing I would fix that crunch. But that ain't happening anytime soon... Tj Quote Link to comment Share on other sites More sharing options...
duragg Posted April 15, 2013 Author Share Posted April 15, 2013 A long track day this past Saturday. 3rd and 4th gear with the modified synchro timing were flawless at all RPM and all amounts of force. 2nd gear crunches if the lever is pushed too hard and not patiently waiting for the speed to equalize you can push past the synchro and crunch, where no amount of reasonable force could do the same in 3rd and 4th despite some serious abuse and RPM. Will fix 1&2 this summer. Quote Link to comment Share on other sites More sharing options...
Tony D Posted April 16, 2013 Share Posted April 16, 2013 Cool Beans! "Klog" got a bunch of my tools over the years as well. Usually at Union worksites where I now make clear these are MY tools, and not "company tools" which Ford employees feel entitled to cob at their discretion. Piece of advice: if they ask "are those your tools, or company tools" GUARD THEM WELL AND TAKE 'EM HOME NIGHTLY!!! Quote Link to comment Share on other sites More sharing options...
duragg Posted May 6, 2013 Author Share Posted May 6, 2013 Finished my last event of the season thrashing the holy crap out of my Z at the amazing Inde Motorsports Ranch in Willcox, AZ Every single 2->3 and 3->4 shift was perfect, even with some 8000+ rpm sprints beyond the end of the tach . Any inpatient use of 1->2 or 3->2 would crunch (please reference thread history as to why). More confident than ever in the need for synchro timing correction. My next rebuild will fix this and swap out the low OD for something racier. Quote Link to comment Share on other sites More sharing options...
duragg Posted May 21, 2013 Author Share Posted May 21, 2013 We rebuilt a friends tranny this weekend (83 FS5W71B) and did all the key slots in the synchros. New Nissan Brass rings all had about .165" meat from the bottom of the key slot to the face of the brass ring flange. Trimming those all down to about .150" seemed to create the desired alignment. Hopefully he gets it installed soon for testing. Tj Quote Link to comment Share on other sites More sharing options...
duragg Posted November 16, 2013 Author Share Posted November 16, 2013 Tranny is back out. 3rd and 4th are still shifting flawlessly even when abused. Disassembling this week to cut the 1st and 2nd Syncros to the right depth and reassemble. I also finally cut a new holt in the shifter thing and lengthened the selector below the pivot by an equal amount. Throw seems shorter (I think I measured 3" throw at the top from 3rd to 4th? But i had a beer by then and wasn't scientifical much). Hmmm, I should have ordered that rear extension bushing which aligns the driveshaft. Forgot about that. Read in another thread. Back to NPZ.com Quote Link to comment Share on other sites More sharing options...
duragg Posted December 2, 2013 Author Share Posted December 2, 2013 Took tranny apart (again) and machined the slots in the 1st and 2nd gear synchros. I took about 20 thou out of the slot making it that much deeper. Visually looks correct and so now should have solved the shifting issue for good. I find a triangle shaped file about 3/8" width on sides works good. But the cut differently pushing / pulling so I used a die-grindr to cut it in half and used both directions to make the slot base even. I can do that tranny in my sleep now. Trick... to the left and right of your work stations affix 2 rods to the left (top and bottom) and 2 on the right. As you take parts off the shafts you can keep them in order and just hang on the rods. Quote Link to comment Share on other sites More sharing options...
duragg Posted December 31, 2013 Author Share Posted December 31, 2013 Some fail... Drove the modified 1st and 2nd gear tranny tonite. I was able to get a crunch in the 1-> 2 shift while pulling hard. Not as bad as before tho.. For the record, I HATE the "short shifter". Stock throw was just fine. Quote Link to comment Share on other sites More sharing options...
inline6 Posted January 3, 2014 Share Posted January 3, 2014 Man, that is a bummer. I've been hoping that this would take care of it once and for all. I hate the 1st to 2nd crunch. Any chance that you don't have the timing spot on? If that is right, then what is left to look at? Could the dog teeth be worn a bit too much on second gear? Quote Link to comment Share on other sites More sharing options...
johnc Posted January 3, 2014 Share Posted January 3, 2014 If you are building a track only car, the first to second shift is generally only used when exiting the pits onto the track - if you're gearing is correct. There may be one 2nd gear corner on the track but if you've got the car geared correctly and handling well, you shouldn't ever have to use first gear. Quote Link to comment Share on other sites More sharing options...
duragg Posted January 3, 2014 Author Share Posted January 3, 2014 Some of this is just "the principle" of the battle.. I want to win. What I DIDN"T do on this last round was to roughen the synchro cone so the brass can bite better. I did that on 3&4 but frankly forgot on this last round. The cone gets real shiny and if I had broken that glaze it might have helped. I may do that someday in the future. No, 2nd isn't used much on the track. But I may want (need) to drag race the car some day and 2nd is helpful for that. And I just want to be able to report 100% success to my Hybridz bretheren. Quote Link to comment Share on other sites More sharing options...
inline6 Posted January 4, 2014 Share Posted January 4, 2014 If you are building a track only car, the first to second shift is generally only used when exiting the pits onto the track - if you're gearing is correct. I thought about that when I was posting. My car is also predominantly a track car, but I still drive it on the street every now and then. As with my other cars, I enjoy pulling to redline in first, shifting to second, then letting off. It's annoying when I can't enjoy that because of gear crunch. It won't be an issue at the track. Some of this is just "the principle" of the battle.. I want to win. Yeah, I am so like that. Quote Link to comment Share on other sites More sharing options...
weedburner Posted January 4, 2014 Share Posted January 4, 2014 I have thought about grinding some little directional slots in the face of the synchro rings to give any excess oil somewhere to go, but i went straight to dog rings before i got around to trying it. Quote Link to comment Share on other sites More sharing options...
grannyknot Posted January 21, 2014 Share Posted January 21, 2014 duragg, I'm rebuilding my 5spd at the moment and was told about this thread, just read it this morning, Fantastic. Thanks for taking it to the end and showing all the failures as well, that is where the learning is. I think someone at Drivetrain.com might be reading this thread, I just measured all of the key slots on my original, WORN 1983ZX syncro rings, .170". The same measurement on the new Drivetrain syncro rings is .155" . Now I don't have to file them! Quote Link to comment Share on other sites More sharing options...
Xnke Posted January 21, 2014 Share Posted January 21, 2014 You may still...or they may be unusable! You need to fit the rings to YOUR components...not every transmission will be the same. Quote Link to comment Share on other sites More sharing options...
duragg Posted January 21, 2014 Author Share Posted January 21, 2014 All good news above. Hope the results are positive. I had a really BAD weekend of transmission grinding last weekend racing 4 sessions at our first local event in Phoenix. All gears were crunching. One of the problems is my brand-new HD Act clutch is adjusted to the max and only releases the last 1/2" off the floor. I don't think it is getting enough release and is impeding good shifts. In addition the new race motor is very happy at even higher RPM and we are going faster and none of that seems to help. PLAN: I've ordered an adjustable clutch slave cylinder to get more release and can adjust the ball too I think (without removing trannY?) I may switch from MT90 to an even lighter fluid (1/2 MTF-SM + 1/2 ATF?) Quote Link to comment Share on other sites More sharing options...
duragg Posted January 21, 2014 Author Share Posted January 21, 2014 Oh, plus I had drilled my tranny "ears" to make a short shifter and I absolutely hated the feel of the short shifter. Quote Link to comment Share on other sites More sharing options...
Sam280Z Posted January 21, 2014 Share Posted January 21, 2014 Years ago ACT had a problem with hollow rivets stretching limiting disengagement. They subsequently went to solid rivets to fix the problem. I bought one about four years ago which never worked due to the belleville spring splitting in half. I had to spend an inordinate amount of time with their "customer service" to get it remedied. Ended up using a Spec clutch and haven't looked back. Quote Link to comment Share on other sites More sharing options...
Josh280z Posted January 26, 2014 Share Posted January 26, 2014 Why do you hate the short shifter? Quote Link to comment Share on other sites More sharing options...
duragg Posted January 26, 2014 Author Share Posted January 26, 2014 I hated it because it made the shift feel more particular. In "combat" (on a race-track), missing shifts costs time and more potential for damaging overspeed. Personally I never had any issue with the stock shift geometry and this just felt unnatural. Its not like you can actually shift faster in any meaningful sense in my experience. I'm going back to the stock throw for my preference. Others swear by it. Quote Link to comment Share on other sites More sharing options...
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