LWB suspension pan dimensions

[Grilleguy]

Hello All,
I'm in the process is replacing my rusted out suspension pan on my '71 911T. I am wanting to machine my version of a tram gauge so I can make sure it is square to the car. Attached are a few pictures from the service manual that I've found online and used to get the needed dimensions.

scan0001.pdf
scan0003.pdf
scan0004.pdf
scan0005.pdf

The 656mm dimension is the very front torsion bar mount hole, not one of the 2 that are closer together.






I used Solidworks to convert from metric to SAE (I'm a non metric kinda guy)
The last picture is a measuring bar that I plan to machine holes at the various locations and install a 1/2" aluminum rod turned on a lathe to a point to go into the bolt holes in the chassis/pan. I will be keeping the measuring bar level when fitting the pan. The 1/2" rods will be adjustable to achieve this.

I think I've dotted my i's and crossed my t's as best possible. Am I correct in my planning this?
I don't have a Celette table, but the car is sitting on a 4 post lift that is within a 1/16" over 20' determined by using a self leveling laser level. The car is on a set of metal adjustable "horses" and the car is leveled using corners of the fenders for side to side and the bottom edge of the rocker for front to back. I can get pictures if anyone wants to see how I did this.

Feedback appreciated,
Dan

[71gold]

Dan
Well first suggestion is get used to Metric for sure……
All parts, bolt size, length etc are metric.
You could use the frame of suspension to check hole alignment especially if 2 mounting points
To back side of fuel tank are original in place.

I had used a bought tram ….it was close but must be right on with bolt thru frame & into new mounts

[bob joyce]

i am retired operating engineer ... all that i did was layout and conduct operations.
i spent most of my career using tenth of a foot, as did the operators i worked with.
when the federal mandate came down to do all work in metric there was resistance and in some cases refusal.
ultimately once using the metric it was appreciated.
i am writing this as a warning because when the metric jobs were amended or detailed the engineer would think in tenth of a foot and print that number on a metric plan.
so an error of x 3.28.
since you will be referencing metric drawings as you build it would be wise to stay with metric.
Just a suggestion ....
it would be wise to take all of the elevations in the plans that are now referenced to datum zero and present you with elevations higher and lower that datum zero.
create a new datum ether above or below the car so that you are not working with both positive and negative elevations.
Also a heads up ....check your laser .....turn it i80 degrees and find its error.... it will be i/2 of what ever you observe.
new laser are often not accurate.... check and send back to maker until you get a good one. brands do not mater
you do not want any error in you set up... it leaves your work in a compromised position before you even start

[Grilleguy]

Hello Bob,
Thanks for your input. I appreciate it.
I'm probably more hesitant to switch to metric because of my milling machines. I'm self employed and do a bunch of obsolete/one off parts that I reverse engineer and then machine. So while I know my HAAS mill can be changed from SAE to metric and back, I just choose to stay SAE (for now)

Because I am a machinist, I did check from multiple locations and multiple times the accuracy of my lift and the car. Kinda OCD/anal about that kind of thing.

Dan

[bob joyce]

another heads up .... there are a lot of errors in the Porsche work shop manuals.... also be on the alert for their labeling and dimensioning. look closely... and use all of the shop drawings, comparatively to confirm. restoration design has the drawings on their website and you can zoom in to see better ...