Chassis / Body mounting & ground connection

[crypto]

My Sprint has a galvanized replacement chassis. Is it normal that these chassis needed drilling of holes and threads for the body mountings after the body was lowered ?

The previous car owner complained about electrical problems and while I'm preparing the car for new paint, I removed the dash and interior and found the body mounting screws behind dash were just plugged into the body bobbins, but the chassis has no holes to tighten the screws !?

body mounting screw behind dash

[Famous Frank]

Good question. Although I can't answer your question because I've never owned a new frame much less has one galvanized, having the body secure and providing good grounds is paramount! Years ago I owned a 65 Elan with numerous body mounts bobbins stripped. You could not torque the bolts, the just spun and spun. The previous owner had tried to insert bolts with the improper thread which then stripped out the bobbins. Instead of trying to replace the bobbins, I inserted helicoils where possible and then used new bolts and lock nuts in the other locations. Good luck and keep us posted (great pic by the way)!

Frank

[Geoffers71]

I've just put my body back on it's new chassis and the chassis needs to be drilled and tapped behind the dash as you have pointed out. This is the main earth for all the dash electrics, so if it's not good you will get electrical problems. Also needing drilling and tapping are the two turret fixings in the engine compartment and the rear turret fixings through the rear bulkhead behind the seats. The remaining body fixings are fitted through threaded bobbins ie 2 in the bottom of the boot, 2 near the steering rack and 4 (2 either side) through the floor at the side of the central tunnel.

[Mick6186]

Sounds like the whoever fitted the replacement chassis drilled & tapped the turret mountings with the body on to reduce the work necessary in marking & removing the body to drill. It is not really possible to drill & tap the mountings behind the dash with the dash in position, so looks like this was left for yourself to sort out!! Body off ??

[Lyn7]

Hi guys, I have a galvanised chassis that I fitted myself a long time ago. I drilled the chassis mountings just behind the dash with everything in place!! I used a very short drill bit and a flexy cable drive chuck from an electric hand drill. It worked very well with an able helper operating the drill and me at the sharp end. I seem to remember using smaller drill bits and working up to size. Necessity is the mother of invention.
Good luck Lyn...

[TroonSprint]

I have recently fitted the body of my Sprint on to a new Spyder chassis. I lowered the shell on and made sure it was right down and central. Then I marked through the body bobbins. Then I lifted the body off and drilled and tapped the six points mentioned. I also had to drill the remaining ten points where the UNC bolts go up through the chassis flanges into the threaded body bobbins. Once back together again everything lined up properly. I can't imagine how you could tap the points you show with the body in place, but I suppose it might just be possible with the dash out.

Mike

[snowyelan]

90 degree drill should do it, I've done similar close quarter tapping before. Dash will have to come out though. To be safe and ensure a decent result I'd suggest drilling only and using a tap wrench. You can mark the centre of the hole by using a drill bit the same size as the bobbin and drilling down a mm or so then switching to the tap drill size. Have a look down the chassis tunnel as there's a fuel line somewhere under there which you don't want to drill and tap as well....

[crypto]

Thank you all for your replies

because everything is apart there is plenty of space for drilling and to tap a threading
unfortunately I had no drill for 3/8" extra fine threading, so I used metric M10 (I swear these are the only 2 in metric size I did )

watch out for the fuel line on the right hand side !

Thanks and a Happy New Year !
Peter