Jordan's '72 2 door KA project

[JordanTr]

Sadly I don't have amazing news for you guys.

The good: LSD still does solid posi burnouts

The bad:
First of all, the exhaust bumped into the driveshaft on any bumps which was no real surprise since clearance was minimal so I redid the middle section of the exhaust this afternoon and added a flex pipe. I wish this was the extent of the issues.

This was the third serious exhaust redo using a mix of 510 parts car and S13 exhaust so it really isn't pretty but it does its job. I added a heat shield so I don't cook the rear inner CV since they are pretty close. I'm getting good at welding miserably rusty muffler pipe lol.

The rear coilover mounts are just using the stock rubber which seems to be too low density or not clamped in enough (I'm at the end of the threads). We'll see what I can conjure up to fix that.

CV heat shield



Flex pipe



Rear end looks like Christmas say my friends



Long way from where I started... (Christmas 2012)



I still have an annoying vibration and the only thing left to change is the transmission output shaft... After all the shenanigans when I first built the car with the short driveshaft, it seems that the output shaft bearing on the trans is pooched. Swapping in spare trans tomorrow. Pops and I tried several (3) different yokes in the spare trans and there is zero slop. All the yokes we tested in the spare trans were used and they have pretty much infinitely less slop than my brand new yoke with the trans that's in my car. I got the trans on craigslist back in '09 so who really knows how bunged the output bearing was to start with. I can tell you one thing though, and that's that the trans output shaft bearing is bunged now!

Pic of the trans FSM showing how much leverage the short driveshaft forces would have on that poor bearing (right side).



Time for a drive with new exhaust and then a much needed wash. I'm off to the ole high school tomorrow to show my old shop teacher the 510. Last he saw was early 2012 just after it got front coils/ZX snowflakes. Lots has changed since then

[JordanTr]

Cleaned up the spare trans last night/very early this morning and installed it today. I was choked because I couldn't find my white speedo gear so the speedo is inaccurate due to the 3.7 rear end. Aside from that, the install went pretty well, I had pops help me get the trans back on which didn't take us much time at all.



Out with the old, in with the new



The good news is that the unknown trans has good synchros in all gears and a tight output shaft but the bad news is that the driveline vibration is still there and very bad at highway speed + and it has a resonance around 50 mph.

Tomorrow I'll be pulling the rear sub from the car and shimming the diff in the crossmember to get it perfectly parallel to the output shaft. I thought the misalignment I had would be OK with the CV but apparently not. If I get the alignment nailed, and the horrendous vibrations persist, I'll be taking the driveline to another shop to have it rebalanced because that would be the last thing to check.

Picked up some springs this evening so I can reassemble my rear coils with the 250# springs I want to run tomorrow as well.

One of these days we'll get it right....

6" to rocker flat section up front and 7" to flat rocker section in the rear.



Hehehe. All the brakestand components work!

[bertvorgon]

I found that if we are within 1 degree of angularity, I have not had a problem at high drive shaft speeds.

[JordanTr]

Spent all afternoon and evening under the car today... Pulled the whole rear end so I could clearance the crossmember to mess around with the diff shims. Initially, I had foolishly assumed that all would be well with the CV driveshaft so I stuffed the shims up top. Poor choice, and I payed for it today. Now it's all back together. After getting the diff shims below the diff and the car lifted up and sprung, pops and I popped a few different shims above the moustache bar to try to get the pinion and output shaft parallel. After adding 3/4" of spacers above the moustache bar, we were able to get the misalignment to an acceptable 0.7*. Tomorrow will be test drive time with the driveshaft alignment.

FWIW I did some messing around this eve with some other parts.

KA rev 1 driveshaft (shortened 510) weighs 11.5 lbs compared to the 18.75 lbs KA rev 2 driveshaft weighs. I wish I had asked for a thinner wall on my new driveshaft (not even sure if I would have had a choice).

Anyone think that the heavy driveshaft would be problematic provided it was balanced?

After some hacksawing....Z32TT driveshaft is 75.0mm OD with 2.7mm wall. Late Z31T driveshaft is 75.0mm OD with 1.6mm wall.

Redone work



Popped some set screws in my coilover sleeves to prevent the rattles and put in my new 250 lb/in springs.



After getting the companion flange off, the seal was somehow all bunged... all I did was pull off the companion flange. After getting it out, the metal spring clamp thing was squished totally flat in a couple places. New seal picked up at the last possible minute this evening and reinstalled.



Since I found the proper grease cup for my rear driveshaft joint, I could no longer install the driveshaft into the car complete due to the extra length of the grease shield. To remedy this, I pulled off the trans dust shield and mowed of 1/4" and then reinstalled. Pic below of how far into the trans you could get the driveshaft without a trans dust shield.





The last hoop in this project is proving to be a giant PITA to jump through. Hoping the car will drive good tomorrow. Off to go find an open gas station with brake fluid so I can bleed brakes first thing in the morning.

[bertvorgon]

Heavy wall should not be a problem, as long as really well balanced. I have been through the whole driveshaft B.S. and many times, even though it went to a couple of the local drive shaft shops, I still would have an issue.

I finally got Andy to make me a drive shaft, where he took TIME to install the yokes, as he welded, in the lathe...I now have a perfect drive shaft, with no balancing weights on it at all.

I do have a periodic issue, where the yoke opens up a bit due to my torque, and I will get a hair of play in the universal....we just squeeze it back together.

Nissan spec'ed universals did come with "shim kits" to really make sure the universal is center in the yokes, not sure if you can still get those, I know I have one left in my stock. Universal running slightly off center can cause a problem as you can well imagine. I will look today and see if I have a picture, but your drive shaft yokes are likely bigger then the 510 ones??!!. I wished I could up-size to the Chevy sized ones but my power train is really up tight in the tunnel so I have no room to swing the bigger one, at the front, with out opening up a small area in the tunnel.

I hate drive shaft/power train vibrations, as their harmonics can shake the whole car, or put annoying vibrations through EVERYTHING!

[Three B's Racing]

[quote="JordanTr"] The good news is that the unknown trans has good synchros in all gears and a tight output shaft but the bad news is that the driveline vibration is still there and very bad at highway speed + and it has a resonance around 50 mph.

Check out this site. Damn good driveline phasing info with pics.

http://www.hotrodhotline.com/md/html/dr ... monics.php

[bertvorgon]

That's a very good, simple explanation. I have my drive shaft angularity at .5 degrees and can zip my motor up to 8,000 RPM, so with a .864 over drive, it is spinning around under there pretty good!

[JordanTr]

Thanks for the ideas guys. Yes Keith, they are pretty beefy Spicer U-joints. Guy at the shop said his buddy with a v8 car was running 9s on them so they're seriously overkill. I had to use them to use the 3" tube for the rear joint though.

This was the most valuable piece of info:

Checking to see if you have got it correct:
If there is no vibration under normal operating conditions then the angles are correct.
If there is vibration under acceleration, you need to add more downward pinion angle preload. If the opposite occurs, the vibrations tends to decrease or disappear under acceleration, you need to reduce the downward angle preload.]

My vibes have always been under deceleration and unsurprisingly worst on throttle lift on a freeway pass. This at least makes sense now. When I built the car, the trans was angled too far down at the rear of the car which explains the symptoms I saw as explained above. The only saving grace of my trans angle is that the beefy driveshaft fits.

If it comes to it, I'll get the shaft high speed balanced to 0 at 6k. I sure hope my car never goes that fast with the 3.7 rear.

Anyone think this is a systemic problem since the front U joint doesn't have a second u joint on the rear to cancel vibes? Obviously it can/has been done since it comes stock like that on a GTR but...

Time to get out of bed and get in the shop!!

[JordanTr]

Redneck lesson 101: align the driveshaft.

Should have aligned the driveshaft 5 years ago and should have done it before the first time around this year.

She drives pretty dreamy now. Had her about as fast as she'd go and it's pretty smooth

Time to go drive around.

[S15DET]

Great!

[JordanTr]

This is the weekend plan. Stopping in to see Jeff on the way down.

[RONSLYCHUK]

Hey Jordan,congrats on getting your dime done. You will enjoy the drive down to Portland. If you have time check out Voodoo Doughnuts in downtown Portland. If you have not been to the Olympic Penninsula before I think that you will see some awesome sights. Check out Ruby Beach for sure. Cheers Ron.

[510tdi]

Since joining the Realm I 've enjoyed skimming through folks build threads and just caught up on yours last night. Super impressive. Not only because of the finished product but also the attention to detail and sheer tenacity to get it done. 5 years, right?.Congratolations! Have a great drive.
You ought to make a side trip out I-84 towards the Columbia River Gorge while you're here in the Portland. Great roads and views. You could even stop by our farm then give me a ride around the neighborhood in your dime. Just sayin'.

Drive skillfully,
Bryan

[two_68_510s]

Nice job Jordan, you are a maniac! Getting any waves and shouts as you drive around?

18 hour shakedown, eh?

I am sure you have rung that thing out in the last couple of weeks, have fun man, that looks like a dream drive to me!

What a gorgeous part of the planet.

[housew]

Redneck lesson 101: align the driveshaft.

Should have aligned the driveshaft 5 years ago and should have done it before the first time around this year.

She drives pretty dreamy now. Had her about as fast as she'd go and it's pretty smooth

Time to go drive around.

congrats on getting it sorted.

dumb question though: when you say "align the driveshaft" so you changed the angles of the rear diff or trans to get it "aligned" OR your driveshaft yokes were out of phase?

I have a similarly annoying vibe, usually worse on deceleration (but not with the clutch in) so im thinking I need to reduce the downward angle preload (ie raise the nose of my diff). I've dealt with this in jeep world with a CV at the front of the driveshaft and a u-joint at the rear, and the goal is to align the pinion angle with the shaft angle for the least vibes. I haven't started digging at all yet, but your thread gets the gears in my head turning.

enjoy your drive!