Thread: Angle of the Dangle
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10-31-2005 01:48 PM #1
Angle of the Dangle
I knew that would get your attention. Hey all you fabricators out there, I am working on my motor swap and this one is different than most I have done in the past as it is not just bolting one in in place of another. I will need to fabricate mounts, position a cross member etc. I have a good understanding of pinion angle and relationship to the crankshaft/driveline angle. Where I am not too sure is what to measure to set a base line. If I set the frame dead level, then put the motor 2-5 degrees tail shaft down from there, then make the pinion angle match that should get me right. My problem with that is, when it is down on it's wheels, my frame does not sit level. It has a slight downward rake towards the nose. Should I sit the car on it's wheels on the garage floor (it's pretty level) take a measurment, then jack it up to obtain that same attitude? Or should I jack it up to sit dead level, then work from there? I plan to take measurements with the existing motor in place for reference before I pull it out. I suspect it has a motor/pinion angle issue as it did have a driveline vibration at high speeds. I want the new set up nice and smooooth.
Thanks for your help, I am waiting with protractor in hand!
PatOf course, that's just my opinion, I could be wrong!
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10-31-2005 02:10 PM #2
Best to do it with the frame at ride height/attitude, though the engine/trans angle, relative to the diff will/should remain constant.Your Uncle Bob, Senior Geezer Curmudgeon
It's much easier to promise someone a "free" ride on the wagon than to urge them to pull it.
Luck occurs when preparation and opportunity converge.
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10-31-2005 02:18 PM #3
Well - you should get a lot of opinions on this subject.
I set the motor & pinion angles with the car at ride ht.,since it appears that you are not changing the suspension, but only the motor, it should be simple to measure this before you start.
I set the engine to get the carb level(usually 3 degrees down to the rear). I then set the pinion at the same angle (up at the front from horizontal).
DonDon Meyer, PhD-Mech Engr(48 GMC Trk/chopped/cab extended/caddy fins & a GM converted Rolls Royce Silver Shadow).
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11-13-2005 01:00 PM #4
Stu,
First of all, you have to set up your car for the ride height that you desire. In most cases this can be accomplished by the use of jack stands and steel shim blocks if this is going to be a one time thing. I like to use screw jacks that I set up on a frame table.
1. Position the frame on hard inmoveable surface (concrete garage floor will do fine). Position four adjustable jack stands, one on either side and one stand in front and one in rear. Raise or lower the stands until you obtain the stance or ride height that you want your car to have. You can use plywood circles cut out of 3/4" plywood to simulate the wheel sizes you want to use and bolt these to the front and rear suspension, or stand them in the wheel openings to get a better idea of appearance.
2. Once the general ride height is obtained, you now need to micro measure to level the height of the frame from side to side. Begin at the left side front and place a level across the frame to the same point on the right side. Place steel shims or wedges under the frame at the point where the jack stand touches, adding more until the frame will stay at that height. Do the same thing at the rear of the frame and carry the measurements across to the other side. This will now be your final ride height.
3. Your engine can be set in to its location. Please note that most intakes are cut with a 3 degree incline towards the front so that fuel passages in the carb willnot be uncovered upon acceleration causing a lean condition. Place a good dial type protractor on top of the intake manifold and make a 3 degree allowance for the intake and setup the engine side of the motor mounts. Plan your frame side of the motor mount to take in account steering shaft, brake and fuel lines, headers, etc. Don't forget to use gusset plates to add strength and rigidity to the mounts.
4. Mount trans up to engine. To double check for level of trans, place protractor on bottom of trans pan and it should read the same as intake ( + 3 deg. ). Place rubber mount in place and build down from there to trans cross member. Again, allow clearance for speedo and emergency brake cables.
5. Depending on rear suspension of the auto, coil spring, leaf spring, four link, follow the directions of manufacturer for installation. The end result being that the rear end position must retain the ride height of the frame. Leaf spring cars rely on the arc of the spring, the stiffness of the leaf to maintain ride height. Wedges in the spring perch are used to obtain a pinion angle of up to 5 degrees of downward angle iin high performance applications.
The transmission shaft and the pinion shaft should be parallel to each other. The drive shaft angle should be no more than 5 degrees angle or it will bind.
Any change in ride height will affect how a auto will perform and handle. A front end alignment should accompany any change.I didn't mean to hurt you Son, the slap in the back of the head was just to get your attention.
Nice, how did you get the curve in there?
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