LS1/T56 into a 68 Camaro
12-24-2015, 01:01 PM
#161
Ok, so I installed the 3 degree shims and my new operating angles are Trans 5 deg down, driveshaft 1 1/2 degree down and rear 3 degree up. I have no idea why a 3 degree shim would change the rear angle 4 1/2 degrees but it is what it is. Now as the axle wraps up it should bring it closer to 5 degrees. So before I put the car down on its wheels, I figured I would run it up to 45-50 MPH to see if the vibration was gone. Guess what, vibration still there and just as bad as ever. I then the removed the tires one at a time to see if I could pinpoint the balance issue. The right tire seemed worse and when I temporarily bolted the left wheel on the right side it seemed to be just as bad so i decided to check runouts on the rear axle flange with the brake rotor removed. Side to side runout just outboard of the wheel circle I got .005" and up and down on the outside of the flange I also got .005". Next I called Currie enterprises and asked them what their manufacturing tolerance was and they told me .004" for both measurements and said my numbers sounded fine. The only thing I have left is the wheels, so I will send them out for balancing and runout check now after Christmas. I suppose I could also borrow a set of known good wheels and bolt them up so i may may throw out a query to my friends.
Lastly Merry Christmas everyone.
Lastly Merry Christmas everyone.
12-31-2015, 01:50 AM
#164
I think the operating angles should be around 1.5º just enough to keep the needle bearings rotating. Also they should be the same angle on each end to cancel one another out. Check these links out for more info:
http://www.hotrodhotline.com/md/html..._harmonics.php
http://www.roddingroundtable.com/tec...driveline.html
http://www.driveshaftshop.com/angle-calibration
http://www.hotrodhotline.com/md/html..._harmonics.php
http://www.roddingroundtable.com/tec...driveline.html
http://www.driveshaftshop.com/angle-calibration
12-31-2015, 07:11 AM
#165
Yes, 3 degrees is the operational design limit for U-joints. They need a minimum of half a degree for the needle bearings to work as designed also, so you need to be within that range to provide safe, reliable and vibration free operation. The maximum tolerable angle is also RPM dependent, which means the faster you spin them the less angle they can tolerate.
12-31-2015, 10:42 AM
#166
TECH Senior Member
iTrader: (7)
Tires rotate at a much slower speed (driveshaft RPM / R&P ratio), so the vibration frequency is much lower and driveline vibrations.
Andrew
01-05-2016, 11:31 AM
#167
I appreciate all the help you guys are giving me. I got a chance to road test on Sunday and the vibration is at least 90% gone. I am tempted to leave it alone at this point, but reading through all the links given to me and your suggestions have me thinking of shimming up the trans. If I can get the 5 degree down angle of the trans to 4 degrees down, it would probably increase my driveshaft down angle to about 2 degrees which would put everything within spec. If I knew the distance between my engine and trans mounts, I could figure out the shim needed to gain 1 degree. I will have to crawl under the car next time I am working on it to measure that.
02-23-2017, 11:57 AM
#168
Well I spent all last year enjoying the car since my last post. The only real modification I did was to replace the side and rear glass since my tint job had exposed all the imperfections in the original glass. I also took that opportunity to add sound deadener to the insides of the doors and rear quarters. That made the inside of the car quieter and the doors feel very solid when closing. Over this winter I tackled building and installing a new center console. I used 1/8" plywood and small 1/2" X 3/4" furring strips along with wood glue, aluminum brackets and brad nails to hold it all together. I then had a guy in my car club who is a great leather worker cover the whole thing in black vinyl. For the accessories, I used my 1st gen gauge package, 2nd gen shifter boot and shifter surround, 2nd gen console glove box, aftermarket cupholders and aftermarket 12V and USB ports. I am very satisfied with how it turned out.
02-23-2017, 02:54 PM
#171
I used the driveshaft that came with my Tremec TKO 5-speed conversion kit. This was back when I had the small block and TKO-600. I did have to change the trans input shaft since the TKO-600 and T56 have different diameters and spline counts. I thought I talked about that in the thread somewhere, but I may have glossed over it.
02-23-2017, 03:01 PM
#172
Check out post #64. That is where I talked about the driveshaft. Like 1964SS says, you really need to mock up your exact set up as everyone's will be a little different.
By the way 1964SS, you were one of the ones helping me with the console ideas, so I was wondering what you thought of my finished product.
By the way 1964SS, you were one of the ones helping me with the console ideas, so I was wondering what you thought of my finished product.
08-18-2017, 12:08 PM
#174
Not much to report since last time.
I added another fan relay to make sure one fan kicks on whenever the AC compressor kicks on. This helped the AC work better while the engine is warming up prior to the fans kicking on due to temperature. (I have a whole other thread on the Vintage Air to ECM communication issue).
I also changed my rear tires to a 275-40-17 M/T ET Street Drag radial which required a change of speedometer gear which I am still sorting out. I plan to go back to the drag strip soon to see how much better I can 60ft and ET.
Just this week, I removed my power steering hoses and replaced them with Russell Powerflex hose with AN fittings on the pressure side and dedicated Power steering hose on the return side. I couldn't stop a very slow weeping using the OEM hose that I had flared for AN plus the hose was digging into the alternator and I was afraid it would eventually fail. On the return side the generic hose I was using seemed to be weeping at the AN fitting on the rack so I was afraid the hose was incompatible with power steering fluid.
I added another fan relay to make sure one fan kicks on whenever the AC compressor kicks on. This helped the AC work better while the engine is warming up prior to the fans kicking on due to temperature. (I have a whole other thread on the Vintage Air to ECM communication issue).
I also changed my rear tires to a 275-40-17 M/T ET Street Drag radial which required a change of speedometer gear which I am still sorting out. I plan to go back to the drag strip soon to see how much better I can 60ft and ET.
Just this week, I removed my power steering hoses and replaced them with Russell Powerflex hose with AN fittings on the pressure side and dedicated Power steering hose on the return side. I couldn't stop a very slow weeping using the OEM hose that I had flared for AN plus the hose was digging into the alternator and I was afraid it would eventually fail. On the return side the generic hose I was using seemed to be weeping at the AN fitting on the rack so I was afraid the hose was incompatible with power steering fluid.
08-29-2017, 07:09 AM
#176
Well the 12 bolt rear finally decided it had enough and started howling on me really bad and vibrating. I took the car to a chassis guy and he found that the pinion bearing had lost all it's preload and was flopping around. I am going to take this opportunity to upgrade the differential to a stronger 4 series unit and upgrade to 4.11:1 gears. With the T56 I was only turning about 1400 RPM at 65 MPH, so I figure I can go a little steeper on the gear ratio. The guy I am using knows his stuff with setting up rear ends, but he swears my pinion angle on my rear should be like 6 degrees down vs the 3 degrees up that it is now. He wanted to cut off my spring perches and redo them. I told him let's get the rear sorted out and go from there, but there is no way I am going to do that.
08-29-2017, 07:25 AM
#177
TECH Senior Member
iTrader: (7)
Be mindful that going to 4.11 gears will raise your driveshaft speed at any given speed. With 4.33 gears in my Cougar the driveshaft is spinning at 4300rpm at 75mph!
Your driveline operating angles should definitely be less that 3 degree, preferably less.
Andrew
Your driveline operating angles should definitely be less that 3 degree, preferably less.
Andrew
12-27-2017, 09:16 AM
#179
Well, quite a bit has happened since the last post. I took the car to the Wildwood, NJ boardwalk car show and got a reckless driving ticket for doing a burnout. (Reduced to careless driving and 2 points which don't transfer to PA). Then I took the car Cecil County Dragway in Rising Sun, MD in early October. My first run was a 12.13 with a 1.8 60 ft at 116MPH. This was with a messed up staging procedure and no real burnout. Wanting an 11.xx I tried again with a better burnout and staged. Holding RPM at 3000 I dumped the clutch at the green and the revs shot to the redline and the car went no where. I looked under the car and the rear U-joint failed. Upon closer inspection, I realized the welds holding the spring perches to the rear axle tubes had failed and the rear rotated in the u bolts until the pinion yoke hit the floor and snapped the U-joint. Ouch
12-27-2017, 09:25 AM
#180
It is hard to see in this first pic, but look at the back of the rear and you can see how much it is rotated. The next picture you will see the failed weld and the angle shims I installed to fix the operating angle. Also note that these are not stock spring perches. I bought the car this way in 1985. THe car was an original 327 2 barrel, so this rear was swapped in sometime before I bought it. Next you will see the destroyed u-joint and then the damage on the floor where the pinion yoke hit it.