COMET CENTRAL

Some of you fellas were wondering how close my alignment would be when I got it checked this morning, myself included. I used this "fastraxx" level style and a tape measure, with wheel dollies for turning plates. My goal was 0 to -0.5 camber, 2.5 caster, 1/16-1/8 toe. I fought it a little since my aprons and frame rails aren't perfectly square, but it drives out nice with just the tiniest hint of a pull to the left. So, to the local alignment shop.

So how did I do? Per laser alignment machine, toe was 1/16, camber -0.3LH and -0.4RH, caster was 2.4LH and 2.3RH. Ecstatic. Didn't change a thing. I guess my little alignment tool did fine! Ended up spending more time with the car up in the air with the fellow gearheads there just checking it out.

And yes, Pop, since they're on a beautiful straightaway on a 4 lane out in the county, I gave it that WOT blast it's needed.

Thanks for looking -

Dan

that's cool...you did good !! pop

Awesome Dan. I know I have to do the same thing and then have it checked out.
Tom

Ok, fellas. Hoping I can gain some assistance or insight here.

Drove the 65 yesterday quite a bit and noticed some vibration on acceleration - hard acceleration, that is. So, decided to doi some checking. And - we have an issue. It appears I crossed my eyes looking at my angle finder a while back, so the pic below explains it. I've always been told u- joints need less than 3 degrees ideally for life and vibration. Looking below shows my tail shaft with a net 0.5 degrees - no problem. Pinion, however, is a net 4.5 degrees - that's probably my vibration. Degrees are at ride height.

So here's the possible solutions-

(1) Lower the motor mounts. Problem is they're stock with no adjustment, and if I go any lower I'll have to fab a new lower tower brace.

(2) Increase pinion angle. Everything I've studied states a 4- link should be set around 1.5-2 degrees nose down. But, is that angle relative to the ground (i.e. to level) or relative to the driveshaft?

So that's why I'm cross-eyed right now pondering. Quickest solution would be to lengthen my upper bars from 1 degree nose down to 1 degree nose up. That should get me within 2.5 degrees max u- joint angle at the pinion.

Thoughts? Input?

Thanks in advance-

Dan

Of course you know I am no expert, but everything I studied on said the pinion should be the same as the engine/trans.

Like in my car the motor sits at approx 4 degrees tilted nose high so I made my pinion the same 4 degrees nose high, if I understand it correctly then the u-joint is properly aligned.

Anyway for what it is worth that is my understanding.

See Ya,
Mike

''front of the engine should be same as front of the pinion''. back of trans should same amount of degrees but opposite side of 0. so if your engine is 4° then the pinion should be 4° . some racers with leaf springs ,whose pinion raises up ,tries to climb the ring gear during hard launches allow a little for that .But your 4 link shouldn't have much movement so you shouldn't need to allow any.

This is how I did mine but at 4° (not my picture)



Of course my car has not drove yet so it may be whacky

See Ya,
Mike

Thanks for the input, fellas. I'm still studying on it, but I think I have a plan now.

Johnno, the statement about engine and pinion at the same angle matches what Mike posted, and that's the way I'm heading. I think, however, I need to match angles (but opposite) at each end of the driveshaft across the u-joint. That being said, if I lengthen my upper bars (or shorten ther lower) that should move the angles enough to get matching (opposite) angles at each u-joint. I'll make an adjustment and measure again. Fun fun!

Thanks, fellas.

Dsn

I have the exact same setup as Mike does including the 4 degrees. I have no vibration but, I haven't done any hard acceleration yet either. So I'm watching this post carefully.
Tom

Ok - think I've got it. I spent the better part of 5 hours yesterday fooling with this driveline angle, pulling my hair out, bumping my head, and just generally being frustrated.

Per Tremec during discussions last week and prior, the actual angles of each component aren't what matters; degrees of angle across each u- joint does. The goal per their gurus is 1*-3* across each u- joint, with opposing angles at each end. There's a few other measurements but those are the important ones.

So the saga. After studying on it a while, I felt the right thing to do was to go ahead and climb under the car, fight and cuss the bars out and move it the wrong way. After we got that out of our system, we started adjustments in earnest. In the end, to get in spec, I shimmed the trans at the yoke up 3/16", extended my upper bars 5/16", and shortened my lower bars 1/16". That gave me 2* across the yoke u- joint and 1.5* across the pinion u- joint. Actual degrees on an angle finder were 4, 2.5 and 1; and per ther experts, that's should be almost perfect. Keep in mind my initial angles were 1.5* across the yoke and 5.5* at the pinion, so as soon as the weather clears I'll give it a rip and see how we did. Going to try and get my driveshaft loop and armrests installed today during the coming monsoons.

On a side note, I prefer a regular old angle finder. I have a few new ones on order for a chassis I'm building, but used my old Lowe's specials for this fight - that is, until my 17 year old discovered all 3 I have on hand, on the same surface, measured different angles. So, make sure to check them against each other if using more than 1. And check out the tremec tool box app if you have a smart phone and are so inclined.

More later -

Dan

The alignment tool is worth it. It ain't rocket science, just a little math. For toe-in I use two pieces of light square aluminum tube. I don't remember its first purpose in life but it was scrap when I found it. I hacksawed a slot on one side of one of the tubes and both sides on the other. I strap the tubes to the wheels. I bought two cheap 10' tape measures. The tube with one slot gets the end of the tape and holds it in place. On the other side I pull the tapes through the ends of the tube with 2 slots in the ends and that is where I get my readings. I set it up with 1/16" toe-in.
The Falcon I started with 2.5 positive caster on the left and 3 on the right. I then drove it and fine tuned it until there wasn't any pull, left or right. I have adjustable strut rods. After the initial setup it pulled slightly to the right. At that point you have 2 choices, more positive on the right or less positive on the left, either will affect the pull. My camber ended up .5 and .7 negative. It's close enough and I haven't noticed any tire wear yet. It's too much of a pain in the the ass to shim that .7 down if I don't experience any tire wear. Hell, a buddy takes his late model Shelby to track days and street drives it with 3 degrees negative camber and no issues.

Lip ripper -

I can't remember what I gave for the little alignment tool but it was absolutely worth it. Only gripe I have is it can't attach to my wheels with the trim rings, and they're pretty much impossible to remove, so I swap to my old mock up wheels to align. They're the same height, so it works.

As for caster, I've debated taking a little out on the RH side, or adding on the LH to see if I can get that little pull left gone. After all, with the adjustable 63 style strut rods it's 10 minutes with an 1-1/16" wrench, just haven't done it yet.

Dan

Dan I have that gauge, or similar, I think it is just a different color. it didnt want to stay clamped to one of my wheels so I just tied it on thru the spokes. I realize you have solid wheels but maybe you could tie around the tire a couple of rounds of small rope. it doesnt take much, & would be easier than changing wheels. after you adjust even that slight amount,I'd check toe in again. always check it last. each movement affects the other readings slightly.

Lip Ripper wrote:Hell, a buddy takes his late model Shelby to track days and street drives it with 3 degrees negative camber and no issues.

Yes and he probably runs wider wheels and tires than us. I've read radial tires don't even notice 1.5 degrees of camber. I will probably run 1 degree negative static plus it gains 1 in bump travel. Toe is probably the most important measurement for tire wear.

Troubleshooting continues . . . . .

Finally took the 65 out to test the new adjustments. The vibration that appears to have originated from the driveshaft is gone, or barely noticeable, but now other issues seem to be arising. I do still have a slight vibe on acceleration, and a fairly steady one at 70-75 mph also.

For the acceleration vibe, plan is to pull the driveshaft and get balance checked, especially since there are no weights on it. I'm debating on motor and tranny mounts as well. Any recommendations on motor mounts - preferably something more rigid than the stock rubber? Trans mount ideas? Currently using a stock 68-69 Bronco mount - hey, it was the right height!

As for the high speed vibe. I'm thinking that could be a rotor or wheel; kind of curious if my trim rings could be throwing it off a bit.

Keep in mind these aren't ridiculous vibrations, but any one of us would notice. Any pointers are welcome -

Thanks for looking -

Dan