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General Forum : Anyone ever notice how lopsided e21's are?

- BMW E21 Community
   - General Forum
      - Anyone ever notice how lopsided e21's are?
Bill in MN   Posted Tuesday, Nov 21st 10:28pm [Edit] [Quote] [IMS] [View car]
Member
Post nr. 43

Minnesota USA
1988 735, 1986 535 turbo, 1981 Baur 323i
We're trying to wrap up panel fitment before primer goes down next week. I'm pretty anal about panel fitment, especially when a car's been completely apart and I wasn't real happy with the way the pass. side beltline was looking. All of the panels matched up, door gaps are as close to perfect as you'll get, hood fit is good but I'll be damned if the beltline looks right. I can't explain it but it's not the same as the drivers side in comparison. Doors and front fenders are new and the rear of the car is completely free of any fender benders.

I've taken the car to a frame shop to ensure everything's within at least 1/16 from spec. It's perfectly leveled up on its dolly and after a half day of accurate measuring using laser levels and some good measuring tapes we've come to the conclusion that the pass. side is between 1/4 and 1/3 off from the drivers side depending on where the measurement is made.

This drove me nuts when I redid the e28,only to find out from others that they too had discovered the car to be quite a ways off from symmetrical.

Has anyone else found this to be the case with their e21? It's amazing how far things have come with the use of robots and computers!

M42powered   Posted Tuesday, Nov 21st 11:15pm [Edit] [Quote] [IMS] [View car]
Staff
Post nr. 684
   
Arizona, USA
1981 BMW 320i
Some people call it "character".

BruceH   Posted Tuesday, Nov 21st 11:23pm [Edit] [Quote] [IMS] [View car]
Member
Post nr. 1042
   
Atlanta, GA USA
81 323 Baur, 85 745
Bavarian craftsmenship?

phillbriggs   Posted Wednesday, Nov 22nd 1:12am [Edit] [Quote] [IMS] [View car]
Member
Post nr. 230
   
Suffolk - United kingdom
BMW E21 320/6A CABRIO, PRE 09/1979 FACELIFT, ONLY 1 OF ITS KIND
by belt line do you mean the side trim or the swaiss line, sorry but people in different countries call some parts different names. is the line highier or lower

Bill in MN   Posted Wednesday, Nov 22nd 4:15am [Edit] [Quote] [IMS] [View car]
Member
Post nr. 44

Minnesota USA
1988 735, 1986 535 turbo, 1981 Baur 323i
I suppose the swaise line would be the euquivilant.

The line simply doesn't flow as smoothly as the drivers side. There isn't as much of a gentle downward curve to the line from the front of the rear quarter, through the door and into the front fender when viewed from the rear at tail light height.

The gaps get all messed up if I move the panels around to make the beltline flow better. I'm being really picky and nobody would probably notice it besides me. My wife and daughter can't see it so it's not all that bad.

The reality is that the car being assymetrical has nothing to do with panel fitment in the long run. Any time you take a 25 year old car apart it never goes back together quite the same. The fact it's been cut up to do the Baur conversion probably doesn't help the matter any.

However, here's some examples of what we found.

The opening for the pass. door is 1/4 wider (front to back) than the drivers (left) side.

From the gutter to the top of the rocker is 1/3" deeper on the drivers side than the passenger.


The front pass. fender is just shy of 1/4" wider between the arch and the rear of the fender....you know, the area that always rusts out.

None of this really means much but it is interesting to learn. I've got a whole new respect for auto body guys that know their stuff!

bmw_m_320i   Posted Wednesday, Nov 22nd 4:54am [Edit] [Quote] [IMS] [View car]
Member
Post nr. 731
   
Helena, Montana
none right now :(
I bet alot of it has to do with the car flexing over time, the strut towers flex alot, and I'm sure there not exactly where they were when manufactureed originally, and I've noticed that when you put an older bmw like an E21, or E28 on a lift that the doors dont always open as smoothly, or sometimes they wont open at all without lifting up on the door a bit because they catch on the door striker.

melloh   Posted Wednesday, Nov 22nd 5:40am [Edit] [Quote] [IMS] [View car]
Member
Post nr. 450
   
California, USA (San Jose)
1980 320is, 1991 318is
Ditto that - if I lift up one corner, the door on that side will not open at all (unless I lift the other corner on same side). This does not happen w/ the e30. This has therefore gotten me in the practice of rolling all windows down when I work on the car (in case I need to turn ignition or whatever) and to keep it on stilts for as little as possible.

wharthog   Posted Friday, Dec 1st 9:17am [Edit] [Quote] [IMS] [View car]
Member
Post nr. 96
   
SF Bay,California, USA
1982 323i, , R1150RT
don't forget that one of the properties that defines metals is that they're malleable. You apply force to any piece of metal for 20-30 years it isn't going to be straight anymore.

wharthog   Posted Friday, Dec 1st 9:18am [Edit] [Quote] [IMS] [View car]
Member
Post nr. 97
   
SF Bay,California, USA
1982 323i, , R1150RT
I'd be curious to see the same measurements done on a new car...

MayanArch   Posted Friday, Dec 1st 3:02pm [Edit] [Quote] [IMS] [View car]
Member
Post nr. 1209
   
Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978
I would say that a lot of it has to do with the way they arrived at the molds for the stamps. Remember that in the old days a lot of these cars are carved out of full scale clay models by the designers.

BMW and most other car manufacturers make incremental improvements to parts from year to year. It is very noticeable on the M20 engine of how they incrementally increased displacement and flow over the same basic shape. A lot of mistakes get carried on and tolerated as they design over previous versions.

Yes, I agree with the observation that no car is perfectly stiff. It is designed to flex. The steel flexes for 20 years and sooner or later it starts staying in its flexed form.

A brand new car would not have these problems. They are designed in computer simulations where the meausurements are typed and the computer renders the molds with complete accuracy. They are also designed to flex, but also with a lot less play.

Last, the cars are NOT symetrical.......and therefore DO NOT flex symetrically. There is a driver, engine, steering....that all but insure that weight wont be distributed in a symetrical way. The result of 20 years of that asymetrical load has consequences.





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