911 SC to 911 Carrera (compared to 964) body weld differences ? Upgrades to perform ?

[Blackbyrd]

Driving my 83 911SC up and down driveways can sometimes make a symphony of body creaking noises. I automatically in vision the front tub twisting like a windy bridge, since that's where the source of the noise comes from. As well as the Transmission tunnel and up to the Rear inner quarter panels.
(yes, I have no stereo and can hear this.

Hope my car isn't bent.

I didn't notice this as much when driving my 88 Carrera, but it had a roll bar + strut tower brace.

The 964 didn't do it at all.

Are there any specific areas to target when welding up a SC ?

hopefully with out having to repaint the car or do extensive mechanical work to get to the welds.....could turn into a "while I'm there project"

I can only Imagine what it's like when it's being driven hard.
I'm working on better suspension and braking so I'd figure it's time to do some possible bracing.


I've been meaning to add a Roll bar with cross tube to the chassis since I'm not even running seats in the back.

Currently the SC has a Rennline strut tower brace for the front
(aka 12/24 pack holder)



Ideas would be cool or past photo projects
I've read up on Seam welding and understand the process but never really saw a super detailed document of all the exact points.

I've searched for Factory spec sheets to do "cup" / "RS" welding but haven't found any such bulletin.

[Mothy]

One source of tortional creaks that had me stumped turned out to be the seal between the fuel tank and the body.

There is a foam strip between them but when this perishes and the tank starts to rub metal on metal with the chassis, the tank clamps allow some small movement which generated squeaks - but only when rolling into driveways.

Tim

[jmitro]

seam welding......basically you stitch weld all the seams in the chassis where different body panels are held together with spot welds. It makes the chassis more rigid. Here's an example from my BMW racecar project. This is on the front frame rail:






Seam welding a car that has not been acid dipped can be very frustrating because the seam sealer in between the seams bubbles up and contaminates the weld, no matter how thorough you are with wire wheel cleaning.

[RWebb]

the squeaks you envision may be cold flow of the suspension bushings

[Blackbyrd]

I think I do hear this gas tank rubbing seal with the addition of other creaking.
Thanks for the tip I think I'm going to try that first.

Ahhh Acid dip! I took a welding class years back and that was definitely one of the top subject
a clean pallet to weld on.... is there maybe spray on "leave it over night" type solutions

I don't want to take the car apart to do an acid dip (good idea though)

Fun times ahead

[jmitro]

I agree, I would definitely not acid dip the car based on what your describing. there is a spray on solution at Eastwood to remove undercoating. However, it was useless against the stuff on my BMW.

IMHO I would not even worry about it, except maybe to take it to a body shop for a good examination and make sure there aren't any broken or cracked body panels/suspension joints. That would be the most concerning cause of you creaking.

[Blackbyrd]

I think I'm going to take your advice for the Body shop,

I have a friend with a body shop who could look at it for me.


Since I might have missed something a trained technician will notice.
Maybe I'll upload a youtube video of the sound lol

Thanks of the help. I'll try to look for the stuff your talking about, Since I won't have my piece of mind at high speeds till those corners are nice and welded.

.....