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Just assembled my new POL upper tubular arms with the original shafts and new poly bushings. After a quick mock up on the car, I immediately noticed something was off. I took a photo of both sides for comparison. The left side arm ball joint flange sits almost level while the right side, as you can see in the photo, is quite a way off level. Not sure which is arm is correct but I assume the level one or left side is correct.
My logical assumption is either the frame mount bolts are are off angle or the arm fabrication angles are off. To investigate, I measured from the mounting bolts on both sides to a couple locations on the frame cross member and side rails and all the numbers are identical on both sides. To get the right side arm angle to match the left angle, I have to raise the front mounting point on the right side arm shaft up approximately 3/8".
With the info I have, my assumption is that the arm angles are off. BTW I've owned the car since 1989 and I did a frame off resto 10 years ago and encountered nothing to suggest the frame is damaged or out of factory specs in any way.
I’m inside with a head cold today, brain not fully engaged. Let me know if I can help further.
Eddy
Thanks Eddy. Sorry to here that you're under the weather. My brain these days it seems is never fully engaged
Been waiting for these arms seemingly forever and now this. Ugh .. I guess I'll have to call Brandon tomorrow and see if he can send me another arm to compare. Any suggestions?
My logical assumption is either the frame mount bolts are are off angle or the arm fabrication angles are off. To investigate, I measured from the mounting bolts on both sides to a couple locations on the frame cross member and side rails and all the numbers are identical on both sides. To get the right side arm angle to match the left angle, I have to raise the front mounting point on the right side arm shaft up approximately 3/8".
The only other thing that I can think of at the moment would be:
1) bent cross shaft - you would have noticed that much damage visually and when installing the bushings. So probably not.
2) bent the control arm installing second bushing cup by compressing the shaft together. If you used a press, did you support the arm with a piece of angle iron or section of pipe cut to length? I doubt it but that’s all I can come up with besides frame, or part itself.
Eddy
Mark, what is the relation dimensionally of the control arm to the inner fender? It’s hard to tell with the scale on the control arm. Is it different on the side with the extreme angle?
The only other thing that I can think of at the moment would be:
1) bent cross shaft - you would have noticed that much damage visually and when installing the bushings. So probably not.
2) bent the control arm installing second bushing cup by compressing the shaft together. If you used a press, did you support the arm with a piece of angle iron or section of pipe cut to length? I doubt it but that’s all I can come up with besides frame, or part itself.
Eddy
Eddy ... great minds think alike! I eliminated those two issues. No shaft visuals or issues installing bushings. I pressed in the bushing sleeves with support at the tube eye alone ... no torque or compression on either tube, individually or together.
I'll check on your other question regarding the inner well.
Pauldana your opinion is appreciated as always.
Me, as a thread starter, just wanted to raise the awareness that the parts are interchangable and that we, corvette owners, don't have to pay "corvette tax" on our parts.
Sure, some parts as you said are heavier and don't neccessarily bring all the bonuses to the table but still they bring something to our cars.
In case of these arms they bring some more camber and some more stiffness and that is about it!
But I do appreciate a lot when someone raises a question when we do things as this makes everybody else think a bit in different direction.
BTW that cai of yours is bad ***!
Pauldana your opinion is appreciated as always.
Me, as a thread starter, just wanted to raise the awareness that the parts are interchangable and that we, corvette owners, don't have to pay "corvette tax" on our parts.
Sure, some parts as you said are heavier and don't neccessarily bring all the bonuses to the table but still they bring something to our cars.
In case of these arms they bring some more camber and some more stiffness and that is about it!
But I do appreciate a lot when someone raises a question when we do things as this makes everybody else think a bit in different direction.
BTW that cai of yours is bad ***!
I do think you did some amazing work.. and I was on the edge of my seat with this thread...
And again... THANK YOU for doing this for us... as we would have not known any of this without you... and yes, this is how innovation is done... great work..
I WISH they would have been lighter... if so, I would have copied EVERYTHING you did...
But for me, and my sons... We are very performance driven,,, and so the added weight in the suspension unfortunately killed it for me:-(....
my hat is off to you for your forward thinking and bucket load of work... FYI, you can get all the Caster and Camber and MORE from those upper control arms I posted...
Thank you for your open and friendly response... and as far are the CAI's.. we have made over 500 of the now... :-)
pd
Thank you!
Oh believe me pauldana that I have looked at those arms of yours but me as a military guy that lives in Europe I just can't afford them.
I must calculate shipping and customs to the price and that a lot of times kills all the fun for me.
Me and my friend just made some body mount reinforcements with help from forum members. Saved me some $$$!
They came out nice! So we also do some manufacturing!
So, has anyone used the aluminum units from Speed Direct? Frankly, the CAST aluminum part scares me. If they were forged or billet, I would try them. I have seen a stock one wrecked, and they will rip off the frame before giving way.
Maybe the C4 pieces could be made to fit. I don't even know if they are forged.
So, has anyone used the aluminum units from Speed Direct? Frankly, the CAST aluminum part scares me. If they were forged or billet, I would try them. I have seen a stock one wrecked, and they will rip off the frame before giving way.
Maybe the C4 pieces could be made to fit. I don't even know if they are forged.
That was already tried and while it can be made to work the cost will be more than buying tubular arms from Van steel which made them as close to the C4 arms as they could.
The C4 frame is totaly different and arms also.
I am nearing completion of my front end rebuild using Performance Online upper and lower controls arms and wanted to report back with you all. Thank you Primoz for creating this informative thread.
My personal objective in using a tubular upper control arm was to gain additional caster. I also chose to replace the lower control arm with a tubular unit, a decision which was not necessary, and a penalty of additional weight was incurred which I understand clearly. In my case, most of that weight is offset by having installed Wilwood front calipers, which nets a savings of 6 lbs per side. Unfortunately, I did not weigh the upper control arms before installation but did weigh the lower arms. The factory arm, minus the shaft, weighed 11.6 lbs and the POL arm, minus the shaft, weighed 13.4 lbs.
I chose the POL control arms primarily for two reasons. 1) Price 2) Use of factory shafts (read- no machining).
I am well pleased at this point with the POL upper and lower arms. I will report back to this thread with the alignment specs once the rear suspension work is completed and the alignment has been done.
Eddy
Last edited by 74_stingray; 02-04-2019 at 01:42 PM.
Reason: Spelling
That looks nice. One observation, it looks like you are using the moog problem solver upper shafts and it looks to be installed with the offset the wrong direction. You may have too much negative camber because of it.
01-20-2019, 02:08 PM
Weird! Is the long side of the arms on both arms to the front of the car?
