Frame measurement tolerances - is 1mm realistic

[Taymar]

I've got the measurement diagrams and have dropped my car off at a body shop to be measured up.

They mentioned that +/- 1mm tolerance might be tough to achieve. From what I understand, some domestic cars have a 5mm tolerance.

Does this sound about right? I've had some work done there before (non-structural) and it was top notch.

They're going to call me with the findings of the measurements and we're going to go from there, I just wanted to try and get some feedback here on whether any shop is likely to hit the 1mm tolerance.

[FB73tii]

From what I've been told by frame shops when I looked into straightening a frame is that if the frame is already close, often messing with it will make it worse than before. Expecting 1mm tolerance (I assume you are talking about the cross measurement from front subframe bolts to rear subframe mounts) in a 40 year old car is just not realistic. I would be very happy with 5mm. Mine was off more than that, but since it is a track-only car I left it alone. With proper alignment it drives fine. I will be interested to hear what others have to say. I wonder if a 2012 BMW M6 would be spot-on after 40 years of driving... ?

Fred '73tii & '69GT3

[TobyB]

I'm with Fred- if it's within a few mm, consider it 'as new'.

t

[Taymar]

Would this apply to all the measurements, or just the diagonals? I know the front shock tower centers are off by more than a few mm (too narrow). I spoke to Ray Korman on the phone about this one and he said it's not uncommon for this to happen.

I gave the body shop the measurement diagram, and hopefully they're going to measure as many of the dimensions as they can from it.

[FB73tii]

I am curious what your concern is here. Was the car in a bad accident? Are you concerned with body panel alignment? Did you just buy it and want to see if it is straight? Are you having alignment problems? Is this going to be a super-duper concourse car? Did you weld the back half of one '02 to the front half of another '02?

If there is not a problem then I would suggest leaving it alone. If there is a specific problem/issue, then let us know what it is. Perhaps someone on the FAQ has gone through it before. Best of luck!

Fred

[Taymar]

I am curious what your concern is here. Was the car in a bad accident? Are you concerned with body panel alignment? Did you just buy it and want to see if it is straight? Are you having alignment problems? Is this going to be a super-duper concourse car? Did you weld the back half of one '02 to the front half of another '02?

Very valid questions - In fact, most of the above apply to some extent.

Yes, it was in a front-end accident at some point in its life.

Yes, the body panel alignment could be better (the front end panels align with each other, but are skewed to one side slightly when compared to the frame rails and wheels).

Yes, I did just buy it recently, and I do want to see if it's straight before investing too much time, effort, & money into fixing the numerous mechanical and cosmetic issues.

It doesn't handle very well at all, no doubt worn out steering and suspension is largely to blame here. But, before I commit to the cost of a suspension overhaul, I want to see if there's anything more serious that needs addressing.

I don't have delusions of it ending up as a concourse-winning car, but I do want to end up with something that's finished to a high standard, yes. Panel fit is important.

As far as I can tell, it's not two 02's welded together! (I hope...)

The car is pretty solid and has no significant rust issues (nothing structural anyway). Really, what I'm hoping to get out of this is the peace of mind that nothing's bent enough to adversely affect handling once it's 'finished'

[LS1CMR]

Being a collision specialist for Mercedes Benz, as long as all the measurements are +/-3mm you will be just fine, 5mm it too high and 1mm would be hard to achieve, i repair cars using the cellete bench which has dedicated fixtures which puts them within +/-3mm or better.

[Taymar]

Being a collision specialist for Mercedes Benz, as long as all the measurements are +/-3mm you will be just fine, 5mm it too high and 1mm would be hard to achieve, i repair cars using the cellete bench which has dedicated fixtures which puts them within +/-3mm or better.

If you wouldn't mind me asking you a couple of questions, please could you send me an email at taymar02@gmail.com?

thank you very much.