Yeajimi

Hey guys, I'm in the midst of a 240sx LS1 swap. I've swung the engine and tranny into the car and I'm now ready to start thinking of mounts. I would love to do this right the first time, but many of you know thats not how these things are done. I was wondering if some of you vets could throw some pointers out there.

Anyways I was having some difficulties aligning the drivetrain into the car. The orig engine and rear end is 1" offset to the passenger side and I would like to keep that theme going. I know that for the sake of vibration control the trans and rear end must be within 3 degrees of one another.

My problem seems to stem when I correct one geometry problem, it creates another. Is there a specific order of things I should be doing in order to center the drivetrain in the car without disturbing the previous step?

G-Body

iTrader: (4)

Well I don`t know if your rear end pinion angle is adjustable, but I always start from the rear if its a car that I bought without an engine (if it had an engine you should measure off that before you start and use the reference points from there).

3 degrees up on the pinion is what you want to look for so with the car up on ramps at all 4 corners (or wooden/steel stands under the wheels and so that its level). Now I usually make a centerline on the car. Either by running a string down the center of the car or by a chalkline on the floor. (Use a plumb bob and go down from the control arm mounting points as those should be centered on the car). Now that your line is down for the center you can set the engine and trans in resting on the frame in the approx location (for weight) Re-check the pinion angle. Now center the engine and trans by using the plum bob off the center of the tailshaft and the center of the crank (In your case it sounds like you would put it 1" toward the pass side of center). After that is done check where your trans is, the back end of the trans should be down 3 degrees. You can either lift the front of the engine or drop the back of the trans to get the angle

sciff5

iTrader: (1)

No biggie if the rear end is offset to one side, its the same thing for the rx7s. You dont need to line up the driveline perfectly straight. As long as rear pinion is straight (this is a given assumption unless your cars been in a bad accident or something) and as long as you get the motor/trans in the car straight, which is should be anyway but you should check.

The 1" difference will be handled by the ujoints and you wont have vibration because the lateral angle of the driveshaft in relation to the tranny will be equal but opposite of the the lateral angle of the driveshaft to the rear end.


The other thing you have to worry about is vertical angle, again equal but opposite. I highly suggest this little tool

http://www.sears.com/shc/s/p_10153_12605_00948295000P


I used it when I did my driveline setup, and I also used it to do my own alignments.

Ideal setup would be around +3/-3 degrees vertical angle.. but I've seen people run as much as 5 degrees with little issue, in fact the rx7s stock pinion angle is about 5 degrees I dont know what it is in your setup, you just dont want the drive shaft to be too straight or you're ujoints will fail prematurely.

Pop N Wood

iTrader: (1)

The problem with angle finders is they only check the misalignment in the up down plane. A side to side twisit or offset is just as important as the up down one.

I found it much easier to do with laser pointers. Able to check the whole 2D pinion angles that way. My car offsets the engine 1 inch to the right also. laser pointers not only account for this offset, but make sure your engine centerline is truly parallel to the diff centerline.

here, hit a petco and make your own alignment tools.

http://forums.hybridz.org/showthread.php?t=109413

here is a good link on general driveline alignment info

http://www.4crawler.com/4x4/CheapTri...line-101.shtml

Yeajimi

Thanks guys this is exactly what I was looking for. PopNWood do you have any pics of your Datsun? Ive got a 79 280zx that I will be taking off the road shortly.

Pop N Wood

iTrader: (1)

Here is one engine shot I posted on the hybridz site. I have a few other build pics over there. I have a 240z. A 280ZX is a completely different animal. Doesn't seem to be as popular of a swap vehicle.