chassis shortening (telescopic)

[Marlin]

This can be an easy and forgiving way to shorten a chassis
No butt welding ,No gaps to fill
Plenty of adjustment for fit
This is just the general idea, you may want to improve upon it
for your own application

67 pan

clean and ready

a portaband is handy to start straight cuts
also it keeps you from cutting to deep into the tunnel
and avoiding the tubes,you can't cut all the way around with it
use a cutting wheel for the rest of the cutting

Scribe a line on each side of the tunnel.This will help you level the tunnel.
I have highlighted my scribes with a sharpie for you to see

I cut out 13 1/4 " thus leaving 1" to fit inside the back section
Its better to fit front inside rear because it flairs out to the rear

section out

while you are inside the tunnel brace your clutch tube here
I started about 2" behind the e-brake bracket to avoid this area

drill out your e brake tube hole with a 5/8 or larger bit
so the tubes can fit back through the hole

notch corners out

bend with a pair of adjustable wrenches at dotted line

I used two come alongs to pull it together
Here is where its really an advantage to have plenty of adjustment to work with.Pull it tight and pull left or right to get square using the X measurements from your reference points

all lined up

even if your cuts are not straight it doesn't matter
What matters is that you are square with your measurements
I pulled together at exactly the 14 1/4 mark

tack weld at corners
Use self tapping screws to pull the two areas together for welding
turn up the mig and weld it up,remove screws and fill holes
no gaps,less of burning through trying to butt weld

I hope this can be a help.It's fairly easy. Just take your time and take
plenty of measurements.Measure and remeasure
I'm not posting this to knock any other method in any way.
Just to share the method I use.

completed weld



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[BL3Manx]

The gauge of the steel in the tunnel is more than thick enough to be MIG welded without burning through. I really suggest you take it to a pro and have it welded. The tunnel is all the strength of the tunnel. Screws just won't do.

[rlmartinez]

If I read the post correctly the screws were used only to pull the tunnel metal together in preperation for welding.
A completed photo of the pan shortening would be great!
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54 Bug
56 convertible

[BL3Manx]

Okay, I think you're right, I didn't catch the last part. I guess it'll be a kind of combination rosette welds and also welded along the seam 360 degrees around the tunnel, sounds good.

FWIW, where I see a lot of cracks in tunnels is in those heater lever slots on each sde of the parking brake handle. I really recommend you weld those closed.

[Marlin]

I should have added a photo of the completed welded up, sorry guys
This is my first time posting any work that I have done.
Seeing the finish is part of it for sure

thanks rlmartinez

Thanks BL3Manx for the tip of welding up the heater cable slots
I will do that
You are right about the gauge being thick enough for sure to weld without
burning and falling through
This is just a combination of having plenty of material to weld and plenty of adjustment to get things lined up

[Skulptorchaz]

Nice job!! I own a welding shop and am very proficient at welding and fabrication but the method you shown is just plain simple and smart. The weld at the cut along with plug welding the screw holes makes that a VERY strong area.
Again, very nice job and thanx for helping others out!

[911GT2]

I would recommend a layered cut.

That way the bottom half lines up better and it's stronger.

[Skulptorchaz]

Good call 911GT2. By far better since the stress is not in a straight line top to bottom but not as easy for home DIY'ers. You could also "fish plate" it for more strength.
My guess is that there are enough "straight cut" pans out there to be a proven method.
I tend to overkill when I build. My pan was already cut and welded but I still stitched a 1/4" x 2" strip along both sides of the bottom of the tunnel. Plus, the outside of my pan is 1" x 1" x 1/8" sg. tube with 1/4" plate over the top drilled and taped for the body.

[Dr OnHolliday]

Havent done this yet, but I was considering using the removed portion and welding it over the joint area, after butt welding the 2 halves. That said, your approach looks fine.
_________________
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[bugvert]

Nice work!! Looks plenty strong.

[Marlin]

Skulptorchaz
Thanks for the kind reply

911GT2
I like your recommendation. I have seen that type of layout for the cut posted
on here. It does line up better at the bottom.
I have others to shorten for future projects.
I might try this one and fit it inside itself in a telescopic manner next.
Thanks

bugvert
thanks for the kind reply

[BL3Manx]

DBG, I like your method, particularly the way the "telescope" gives a range of a adjustment to get the front and rear sections aligned but still keeps the two halves in contact, where it can be easily tacked once its right.

You demonstrated your method after the floorpans had been removed which does make it a less complicated job. However, if the pans are in good shape, removing them would add unnecessary work and cost.

If you use your method and also keep the pans, I'd maybe suggest combining a technique I usually use. I lay the body on the chassis where it fits perfectly in front, then make a mark on the two outer channels where the body ends in back. I then cut the channels at a point 1 1/2" forward of the mark. I also cut away all of the channel behind the cut, back to a point even with the front of the sloping rear bulkhead channel. I also remove all the recessed floor under and behind the seats.

I bring the front and rear halves together and keep removing metal from the tunnel faces until the outer channels just touch the front edge of the sloping rear bulkhead. With your method the tunnel neatly telescopes. At that point I know the chassis is the exact correct length for the body and the only adjustments I make from that point are to ensure its straight. After its welded I fill the hole where the wells were removed with a flat floor section. A flat floor makes it easier to mount aftermarket seat rails. I usually remove the stock seat rails unless someone wants to use the stock seats.

[Marlin]

BL3Manx
I appreciate all of your input.This is the whole concept that I wanted for readers contemplating taking on shortening a chassis themselves.
To show that its not that difficult to do,while at the same time sharing ideas
and know how from skilled builders such as yourself to do a quality job.
Here in the Southeast now a days most all donor chassis have pans that are shot.I even have some napoleons hat repair on this one to do.
Pan replacement is pretty much a must do any way.
I am about to start work on the pans next
Thanks again