[Scarebird]

Quite a few things can crop up when you do a LS conversion you would not expect. My 79 TA had the Olds/Pontiac engine mount shells still on the subframe; I decided to reuse them after changing the rubber portion. The aftermarket mounts all use the Chevy style. I fabbed my own, lowering the engine with a 1/4" clearance on the 2014 Camaro oil pan. I fitted the LS with a TKO 600.

After some initial teething issues I noticed a vibration above 60 mph. After much checking I realized the drive line angles were off. The engine trans was 5.5° up at the front, the driveshaft was 1.2° up and the diff 1.0° up. Needless to say this posed an issue. I googled this issue and noted that a company made a drive shaft with a CV joint on the front end' they can take much more angular deflection without vibration. The cost was high. I have a well equipped metal shop so why not fab a dual CV unit?



I purchased a pair of BMW X5 / 5 series CV joints along with the weld in splines. I noted that the Ford F150 had the flat face needed to mount an aluminum adapter - and it had the same spline count and diameter as the GM 8.5". It would require filling up the holes with weld and drilling out new ones in a mill.

The Ford E350 van had a somewhat flat face, and the same output shaft need to fit the TKO, just required some machining too...

[Scarebird]

A piece a 5" round aluminum was cut to size then machined to center the CV joints and the pinion, same at the other end (this pic is a later pic showing some wear where the CV spline was moving fore and aft).



The spline ends were cleaned up, adapter pieces made and tack welded in a lathe, then fully welded on the bench. That assemble was sent out to be balanced. Other issues cropped up, such as the pinion seal was too big by 0.030": a few minutes in the lathe fixed that too.



Big Day comes as the CV's are greased and assembled then installed. Test ride showed a vibration under accerlation but steady stae travel was smoother.

Disappointed.

Disassembly shows that the CV balls are sliding linearly inside the outer cage - this should not happen but it is.

Failure.

In hindsight I should have just bought the damn CV unit from the vendor and bolted it up - the time wasted could have much better spent designing new brake apps, something I know a little about. I will most likely run a double Cardan unit in the front, they can take more of an offset without issue and handle more power. Some Cadillac's had Cardan units at both ends of the drive shaft - that is an option too.

[Squidward]

Much respect for giving it a go! I've been down the same road on lesser projects, where my DIY instinct cost me significant time for a minimal savings on material cost.

As Bruce Arians says, tho, "No risk it, no biscuit".

[Simple Man]

That's how you learn.

[camerjeff]

Thanks for posting this, I am currently swapping the stock 5-speed trans to a Tremec 6060 6-speed in my LS2 swapped 2006 Solstice. The shortened stock DS uses a CV style from joint to hook up to the stock AR5 output shaft. The 6060 uses a standard U-joint yoke. I havn’t decided what way to go with my driveshaft yet as the stock Solstice CV style worked very well with the stock trans.
But the stock at Syncro’s did not live with the LS 2’s torque

[BertMac]

I'm may not be reading your angles in your post right, I think you are saying that your tranny is to high at the rear tail shaft, but one thought is that you pull rearend (Leaf spring right?) and cut the leaf spring perchs off rear end, roll rearend to get your angles and re-weld... Probably the thing to do is lower the rear tranny mount..

Again, I might not be understanding your angles right, but it seems like I remember you need to be in the 3-5 degree range and front and rear angles should be close to each other but they dont have to be perfectly matched.

[Scarebird]

Bert, the engine/trans is tilted up 5.5° while the driveshaft is up 1.1° for a difference between the two of 4.4°. According to most literature 3° is max, hence the vibration. Lowering the mount would increase the engine/trans angle, making it worse.

[BertMac]

so you need to raise tranny rear mount? Hang on Im gonna draw something and post it

[BertMac]

which one is closeest or niether one...and dont make fun of my drawing...lol

[Scarebird]

This would be more accurate:



the trans cannot go any higher.

[BertMac]

the back of tranny has to go up...thats your issue... you will have to cut the floor pan..the motor to clear the tranny...I know its not what you want to hear but that will fix your problems
....and you draw better than me

[BertMac]

there should be 3 degrees at each point...raising back of tranny foxes both of these angles

[BertMac]

for example: if you could put a protractor on the bottom of the starter and raise the back of tranny till is was at 0 degrees.. then your rearend housing is at 1 degree you can string a line between the two (driveshaft)s and put the protactor on the string and read that degreesss.. if driveshaft was at 2 degrees then you would know that the front angle is 2 degrees and the rear is at 3 degress... make sense?

If past I would put a level on the intake and level that, get the degree reading and then start from there..
Of couse these should be taken with jackstands under rearend housng.
Hope I havent confused you more.

[BertMac]

I can also add that I put a TKO600 in my 72 Formula. thats the same body as yours and I had to modify the floorpans to clear and get the angles right....

[Scarebird]

Originally Posted by BertMac

I can also add that I put a TKO600 in my 72 Formula. thats the same body as yours and I had to modify the floorpans to clear and get the angles right....

Was this with a LS or Pontiac motor?

Lowering the LS engine would involve a new oil pan, and would mess up the scoop and exhaust. Another approach is to raise the tail shaft till it hits the floor pan, then remove the trans. While the car is on the lift, slowly lower the car and deform the floor pan with an iron post hole pic - this may gain up to an inch but may still not be enough... and cutting up the floor is not an option here.

Hence using the double Cardan joint. The 4 wheel drive community has been using these for years on lifted trucks - and simply rotating the axle to point to the trans.

[BertMac]

it was a Pontiac motor. I cant weigh in to much on the 4 wheel drive stuff.. If cutting the floor pan isn't a option then the CV might work for you.

[Scarebird]

Originally Posted by BertMac

it was a Pontiac motor. I cant weigh in to much on the 4 wheel drive stuff.. If cutting the floor pan isn't a option then the CV might work for you.

A few things have transpired since the last post. With the original shaft back in play the vibration is back too. I noted that only the front had the extreme angle, so I had a shop in Arizona fab up a shaft with the front having a double Cardan joint. $725 and a week later it arrived. I tried to slide it in, no go. The yoke was 0.012" too big (WTF...). When contacted they said I could sand it down as they did. Sure. I removed the yoke and lathed it to the proper size and installed it. A test run around the block realized it vibrated like a mf'er!
I sent it back for a refund - these guys simply do not know what they are doing...

Back to square one. I decided to get a CV shaft from a shop in Carolina. I sent multiple drawings of the dimensions and angles - they could not figure it out unless it was coached in their terms ("what way would water run down it"). ***head desk*** If they cannot read a simple drawing I decided I do not want these guys to build a shaft.

I figured the only way to rule this angle issue out this was to cut the damn floor and raise up the tail shaft over an inch, which I did. Floor pan cut and patched, exhaust cut and welded, scoop mount re-angled - ready to go!
I drove it home from the shop, even at 80 MPH nowhere near the vibration as before - but still some in evidence, so either the clutch or trans is not optimal here...

[72projectbird]

Isnt it fun placing newer parts in older cars? lol

Sounds like you're on your way to figuring it out. I have a slight vibration in my LS swapped car, but nothing as bad as you're fighting. Probably because my driveshaft has a golf ball sized dent in it near the rear U-joint. I think someone before me changed the joints in the shaft by using a sledge hammer.

[JSPONT]

Glad you got it better. I must say the guys at PST driveshaft are awesome, great customer service. Everything from carbon fiber to mild steel fast turn around. The one guy there, Ron I think ,was a Pontiac guy from CT. before he moved.

[PunchT37]

Boy, and they were talking about the headaches involved in putting a Pontiac 350 in a chevy truck.

http://forums.maxperformanceinc.com/...d.php?t=815874