First, sorry for the novel, but please read on:

I am at a dead end trying to install my edelbrock no hop bars on my '69. Per the instructions, the car is supported by jackstands on the rear axle, and a floor jack under the pinion area to keep the pinion angle from changing. I got the OE upper driver's side control arm removed and the bushing on the axle removed.

Situation is now that the stock upper control arm is too long to bolt to the new mounting point on the no hop bar. The stock arm is 10 1/4" from center to center of bolt holes. Now I need an arm about 8 1/2" to work with the no hop bar. I figured I would have to get new uppers anyway, so I was not upset at that point.

So I called UMI and edelbrock and got them to tell me the shortest dimension their adjustable uppers would work on. Both of them say around 9 1/4" is the shortest. So I guess this is gonna be a typical dimension of all the aftermarket upper arms, and all will be too short for my setup.

This is all based on the assumption that I do not want to move the rear axle at this point, so I will preserve my pinion angle. Now, I COULD jack up the body from the rear bumper and try to increase the span from the frame to the rear axle to make one of these new arms work.

But this doesn't make sense as far as curing wheel hop goes, because I would be increasing the angle of the frame to the rear axle, that is, the lower control arms would be less parallel to the ground.

What am I missing here??? There are bound to be lots of guys that have installed the no hop bars and then adjustable uppers and made this work. I can get some pictures tonight if it will help. Thanks for any ideas-Dave.

Surely somebody has an opinion on this ???

can you post a picture of the arms on the axle? Do you have the stock or stock length lowers? I have the no hops on my 66 w/12bolt and the factory uppers.

I have a 71 SS and was considering buying the edelbrock bars you are having problems with. Sorry, I can't help you, but I am very interested in what others here suggest to ya. I might try calling a good suspension shop near you to see what they would suggest.

I took some pictures this morning to show the problem. Let's see if I remember how to insert a picture:
http://im1.shutterfly.com/media/47b8d603b3127ccec4b82ac49eff00000040O00IZN2TlwzcMQ e3nwQ/cC/f%3D0/ps%3D50/r%3D0/rx%3D480/ry%3D320/

http://im1.shutterfly.com/media/47b8d603b3127ccec4b992513f4a00000040O00IZN2TlwzcMQ e3nwQ/cC/f%3D0/ps%3D50/r%3D0/rx%3D480/ry%3D320/

You can see that stock uppers are about 2" too long. The 2 aftermarket arms I have specs for would be 1 inch shorter, but still 1 inch too long. So do I raise the body to make the gap long enough to use the no hop bars and change the pinion angle, or just blow off these no hop bars and put my adjustable uppers on directly to the pumpkin? Once again, thanks-David.

Dave, I put a set of these no hop bars on a car years ago and if memory serves me correct, I supported the frame, drop the rear end, removed the springs, then supported the axle. Remove upper control arm bolts attaching arms to rear end, move control arms up out of the way, install no hop bars on differential. tilt rear end back and reinstall control arm bolts, springs, etc. re-torque at ride height. As far as excessive pinion angle, never even gave it a thought and never had any trouble there after. Hope this helps, keep in mind this was at least 10 yrs. ago.
EDIT: Just noticed you said you were going to run adjustable uppers, check with the manufacturer of the bars about using no hops in conjunction with adj. uppers to make sure this will not in any way void your warranty.

Dave, here is another FWIW. My understanding is that you are effectively changing your instant center, by raising your upper control arms you are changing the imaginary point where the upper and lower control arms intersect, thus creating a new more favourable instant center. This is why the car lifts and plants the tires on acceleration, rather then squat. This is my limited understanding of this particular bolt on, maybe some one else will chime in and explain the science a little better than myself.

Dave,

Mine is a 67 - not sure of the 69 dimensions - but the same thing happened to me. No hops installed and I could not get the uppers to fit - too long. I bought the Edelbrock adjustable uppers and they fit. BUT I had to adjust the uppers to the smallest size - nut run all the way up. The pinion angle is fine now, just makes it to where it should be.

Dilemma now is - since I had to use adjustable uppers - why use the no hops at all. Should be able to get rid of hop by adjusting the pinion angle only?

Just a thought. I haven't done that yet.

Mike, from what I have read, wheel hop has more to do with instant center being out of whack than pinion angle. Although I've been told that aftermarket upper arms by themselves may reduce wheel hop just because they are beefier than the factory pieces and this stiffens the whole rear axle set up, and makes it harder for the right rear wheel to move independently of the other (to hop).

Dave,

Most threads on the site have focused on pinion angle. Whenever someone has wheel hop, the answer is 'lower the car to get the angle correct'. I would search on pinion angle and wheel hop (maybe you did already) and you will see what I mean. Some of the threads even have geometric diagrams explaining why the wrong angle makes the car hop.

I wanted my car up in back so I used the no hops.

Do you have the correct No-Hop bars for your axle/vehicle? There's the ones for '64--'72; and for '78 to '87 or so. What part number are you using?

The original upper control arms "should" work just fine. Connect the upper arms BEFORE drilling the webs in the axle. With the pinion supported at the original angle--or, better yet, deliberately tilted to the optimum angle--the No-Hops will tilt to where they need to be, then just drill the webs for the for the small bolts as needed.

At least--that's how I did it on my '68. I have the original Lakewood No-Hop units, not the Edelbrock copies.

http://www.chevelles.com/showroom/data/500/medium/No-Hop_bars_1.jpg

http://www.chevelles.com/showroom/data/500/medium/No-Hop_bars_2.jpg

Just use the South Side Lift Bars, i think Jegs has taken them over. One of our sponsors makes them also. Look how my car sits in my sig. No wheel hop at all. Those things you have never did look safe to me. Just my 2 cents.

Shurckey, thanks for the picture, made me think that I need to increase the distance by moving the axle UP, not down, to accomodate the upper control arm with no hops installed. This makes more sense anyway as it will lower the car's stance. I will just need to lower the front of the car as well. I should get the adjustable uppers in the mail this week and be able to start assembling everything. By the way, I don't see how there is any choice in where to drill the holes in the webbing for the no hops. Once they are bolted to the "ears" of the pumpkin,they pretty much only sit in one way on the webbing if you want to get 1/4" of engagement on the holes. I will report back on this once I'm done. Dave.

I need to increase the distance by moving the axle UP, not down, to accomodate the upper control arm with no hops installed. This makes more sense anyway as it will lower the car's stance. I will just need to lower the front of the car as well. I should get the adjustable uppers in the mail this week and be able to start assembling everything. By the way, I don't see how there is any choice in where to drill the holes in the webbing for the no hops. Once they are bolted to the "ears" of the pumpkin,they pretty much only sit in one way on the webbing if you want to get 1/4" of engagement on the holes. I will report back on this once I'm done. Dave.

I don't know why you're having trouble with the length of the upper control arm. Assuming you have the correct bars for your chassis, and there's no other out-and-out problems with the frame, engine/trans mounts, and the like--the pinion angle should be "built-in" to the No-Hop bars within a degree or two.

I'd really like to see what happens with that set-up when the axle is at normal ride-height (remove the springs and jack it up into position) and then measure the angle of the transmission output shaft; and the angle of the pinion shaft. Adjust the rear axle pinion angle as needed. I bet the original length arms would then be the correct length--or at least pretty close.

Overall, the No-Hop bars should NOT affect ride height. No need to raise or lower the ride height based on having the bars in place. True enough, ride height will affect pinion angle. Thus the reason to put the rear axle at normal ride height to check for proper angle.



Y'know, when I bolted these on, oh so many years ago--I considered drilling the webs and then installing a rod end on the web. I'd modify the No-Hops to remove the projections that go back to the webs, and just drill a hole through them for the rod end threads. Jam nut the rod end; and you've got adjustable pinion angle at the turn of a nut.

Damn.

I hope I'm not getting ambitious again. The thing is parked up in the air, I haven't taken it down since installing body mounts. Which is why you got photos--it's all nice 'n' convenient at the moment. Now'd be a great time to cut and hack and drill...

Shurkey, just curious, what was your pinion angle before and after installation.

Shurkey, just curious, what was your pinion angle before and after installation.
Sorry, it's been so long I've lost track. I'll have to re-measure to find out what it is now...

Sorry, it's been so long I've lost track. I'll have to re-measure to find out what it is now...
Thanks, this might help Dave out. I have only installed one set of no-hops but have been in other Chevelles which utilized them as well, the fastest one belonged to the high 10 sec. club, that said all of them sat at stock ride height, had so-so rubber bushings, stock boxed upper control arms and none of the owners checked pinion angle as I didn't and never had any problems outside of the slight wearing on the upper control arm bolt holes. I guess I just don't see the problem, bolt them on, lower the back of that killer '69 in your signature (to stock ride height) and go have fun. Many people have bolted these on with out any problems, try not to over analyze the situation till it becomes necessary. JMHO.

I also have the Lakewood No Hops and the stock upper and lower arms. No issue with installing. It looks like the edlebrocks top attachment is further forward. What does their tech line have to say?

When I was having my trouble with the no-hops I got the tech on the line. All he said was ' they should fit'.

Here is an example of how I knew I had a problem. I removed the rear case upper bushings, installed the no hops. Then loosely bolted the front bolts of the UCA's. When I went to connect the rear of the upper UCA's to the no hop bushing, I found myself twisting the rear end back (pinion up) to get to the bolt. Meant the length was a problem.

When I was trying to make that length I found the brake hose pulling tight at the brass junction. I had no more room to twist the rear case. Maybe lowering the car a bit might have helped but I just bought the adjustables and it was fine.....

Yeah I am probably thinking too much about it. I did notice in Shurkey's photos that the lakewood attachment point is forward of the original attachment point too. That is pretty much the same thing I got from the Edel. tech line though, just make it fit and if you have problems, buy some more edlebrock parts. Now I have to wait a few days for my UMI uppers to come in. Thanks everybody.

What is the center-to-center measurement of your LOWER control arms?

Are the frame brackets for the lower arms in good condition?

Shurkey, I did replace the lower arms last month and the aftermarket arms bolted right in w/o problem, I don't know the length.

BUT I was just looking at the Summit web site to see pictures of the Lakewood hop bars. I got to reading the Lakewood installation instructions and there is a major difference in the way their instructions vs. edelbrock's. Lakewood says to drop support the frame on jackstands and drop the rear axle all the way down to install the no hops. I am following the edelbrock instructions which very clearly say to leave the rear suspension loaded with the weight of the car. Now John's earlier post makes more sense, explaining how he dropped the axle removed the springs, etc.

Wonder why the major difference in installation approach between the two companies?

Can i ask why you want to use the old style bars and go through all that hassle....? All you have to is install the lower lift bars......http://cgi.ebay.com/ebaymotors/Chevelle-GTO-A-Body-Lift-Bars-Bar-Lower-Control-Arms_W0QQitemZ140259628610QQihZ004QQcategoryZ33583 QQssPageNameZWDVWQQrdZ1QQcmdZViewItem


http://www.umiperformance.com/images/4022a.jpg

Can i ask why you want to use the old style bars...
Stealth. Black and practically invisible.

...and go through all that hassle....?
Wasn't a hassle for me. I don't know why it's a hassle for the original poster.

Well I THINK I am done with this deal. Got everything put back together and took it for a shakedown run, about 10 miles at 40-50 mph on back roads. Nothing exploded or fell off. Did not get on it so I don't know about the wheel hop issue yet. This whole problem was based on crappy instructions from edelbrock. If you have a stock rear set up and install the edel. no hop bars and want to keep using your stock upper arms, you HAVE to drop the rear axle or raise the frame of the car, or this just aint gonna work. Their instructions say to support the car by the rear axle. The Lakewood instructions I found on the summit web site is what saved me. Oddly enough the hardest part of this whole deal, other than figuring out how to do it, was drilling the little holes in the webbing of the rear diff. case straight enough and set back enough to get a 5" bolt to go through. There was a lot of filing and reaming while laying on the floor.

Anyway the adjustable uppers needed to be shorter, so I adjusted them down 1/2 inch to 9 3/4" OC of the bolt holes, based on what others have written here and just figuring that stock length would have to point the pinion higher. On my short drive so far, I did not hear or feel any vibrations related to pinion angle, but did not really go any faster than 50 mph. I took a few pictures along the way and will post these if it might help anybody.

Why would I go through all this? It all started with some free parts. One thing led to another and now I've almost completely rebuilt the rear suspension. Just need new shocks. Thanks to everybody who posted-Dave.