Coupe into Speedster Conversion

[MMW]

Just a little info here, the standard gas for stainless mig is a tri-mix consisting of 90% helium, 7.5% argon & 2.5% CO2. This keeps the corrosion resistance up & welds with less spatter than a 75/25 mix. of argon & CO2. Of course many stainless welds have been done with the 75/25 mix without anyone ever knowing.

[Jack Staggs]

Justin, I never noticed all those spot welds on those little brackets before. I counted about 40 from the ones in your pictures!!! I can't imagine any reason why it would need so many. Nice work BTW

[JTR70]

Thanks for the Stainless info Per and Mic. I assumed there were Stainless specific products for MIG out there but in my world this material is normally so far off my radar that I never bothered to look.
I'm only comfortable welding this tube up with what I have now because I had good results welding up a cracked SS license frame from Harley a while back. Thanks you guys!

I agree Jack, it was certainly overkill with the spot-welds on that center bracket. They didn't want that one coming loose, Counted 40 huh? seemed like a hundred. Thanks again! Justin
8/18/14

Tunnel brackets complete.
Finished up the third and final bracket this afternoon.

Same process as with the two before; a couple of templates then onto steel. Like the other two the sides are asymetrical
with the left creating a cradle for the throttle rod.

Fortunately there was enough of the original to make a direct copy from. Throttle cable guide highlighted by the punch.

Initial mockup with all the basic parts minus the heater cable tubes.

Also decided to wise to begin test fitting a throttle rod for clearance and alignment.

Lots of fine tweaking and careful adjustment as it goes but its basically there.

I can actually begin tacking it together tomorrow. As it goes I'll also be triple checking for throttle rod clearance and anything else I can think of. If you give it a chance to go wrong it usually will and I would certainly be up "Shits-creek" if I waited until it was all welded and buttoned up with the tunnel on only find out then that throttle or some other system was blocked or misaligned.
More tomorrow, Thanks for looking! Justin

[tperazzo]

Really clean Justin. Looks like you're building an airplane the way those shiny cable tubes lay in there!

[Carrera_The_Kid]

Rally cool Justin. Thanks for sharing. It is amazing how many little things you pick up reading these excellent restoration threads

[John Pierce]

Very nice Justin.

When welding SS make sure you have a lot of ventilation as hexavalent chromium is formed during the heating, which is toxic and carcinogenic.

[merbesfield]

Justin, are those brakets affixed to the floor or the tunnel? I am wondering what to expect when I start to remove my floors. Will I only have to deal with the spots welds along the perimiters or will those brackets also be affixed somehow to the floors vs the tunnel? In the 911's that I have done that was not the case, but this is my first 356. Thanks for the help.

[JTR70]

Thanks a lot Tom and Joris!

John I kept that advice in the back of my head as I tacked the tubes together today, Thank you!


Mark, of the three brackets only the center one is directly welded to the floor pan. The other two float and are attached to the tunnel walls. As Jack and I were discussing earlier its attached to the floor with some 40+ spot-welds. Being the only floor mounted bracket maybe that was their rational for all the overkill Jack...

New center bracket which will be welded to the floor and the sides of the tunnel.


8/19/14
Tunnel conduit fabrication completed.

Began by tacking the parking brake runners first working from the center outward.

Once these tubes were set I set screwed the center bracket into final position and then started adding the heater control tubes in. All the conduits complete here. BTW the standard welding wire just loved the SS and flowed better onto the tubes than the new brackets.

The original conduits from my coupester laid directly over the top to check for accuracy. close enough for Gov't work..

and the forward comparison

original and new

one more..

Definitely a long road to rebuild this tunnel and its plumbing but am very relieved that its almost behind me.



Several loose ends, prep and some double checking to do before this goes on for good but I should be mounting the conduits by tomorrow.
Thanks for looking! Justin

[merbesfield]

I'm glad I asked. Yes I saw that post about the 40 spots but did not catch it relation. So I guess I will have to cut that from the back side and then punch holes in the new pan for new spots. Are there any throttle bushings that should be replaced like a 911 while I have easy access? We got the pans out last night, but that's the easy part. Now we have the get access to the underside of the tunnel. We have decided to build a quick octagon style hoop so we can roll the tub for easier access. Way to old to do. Looking up, even if it were on the lift.

[JTR70]

Yes, that the way I'll be attaching that center bracket to the floor. The plug weld holes will be in the floor pan; far easer to dress and clean-up from the outside versus down in the bracket. There is no bushings or anything like that, pretty much what you've seen so far is about all that there is down in there(very rudimentary compared to a 911) save for removables like the wiring, power cable, brake and gas hardline and the shifter rod which floats freely in there without a guide collar or bushing. I couldn't imagine chassis repair work on these cars without the ability to roll one over while I worked on it even if I was in my 20's so its not a matter of age as much as it is pure practicality. Building a contraption giving you the ability to roll it over will be time well invested!

8/20/14

Tying up loose ends


Spent today welding up the assembly in the same spots the factory did.

Also time spent running the assembly sequence in my head to ensure I don't lock myself out. For instance the end of the clutch tube (red) gets welded directly to the wall of the tunnel but the conduits will have to be installed on the floor first. So I'll have to cut a plug weld window in the correct spot to attach it after the tunnel is installed.

Also have elevate the brackets in the correct post and install weld holes for those before the tunnel goes on and weld after its installed.

More loose ends are a small tube sheath for the heater conduits as they exit the bulkhead. Lots of little details and things easily overlooked to screw myself with so I am taking extra time and care before I weld these units in. Thanks for stopping by! Justin

[Jack Staggs]

I would highly suggest pushing the cables with the ends attached through the welded tubes, to be sure that no weld slumped through even slightly that would prevent the cables from being r+ rd. Some of the fits are very close tolerances. BTW, isn't there a tube that the wiring loom and battery cable run through in the tunnel?

[roy mawbey]

First time I have ever seen all that presented in photos. I remember taking off the front tunnel cover and the back cover and trying to prepare it for paint as well as changing the backup light switch. The middle part of the tunnel I never cold see or reach.

Jacks question is sensible but from the photos I took 6 years ago I believe the wiring loom is just under some clips in the tunnel. You can see the loom ( I think) running alongside the tunnel in one view and in the back up switch view the wiring to that which comes of the main loom??? ( Of course I could be wrong in my assumptions regarding the loom fixing)

I took a long time preparing all that in the tunnel and the back area under the rear cover but can I cannot find a finished photo. I do know with the view of surface rust you can see another 10 years in the rain on our roads and my original 55 year old floors would be no more.

This plumbing job you have done is really nice Justin. Tell me if the normal guy replacing the floors does not attend to these tubes and brackets how does he manage that?





Roy

[JTR70]

Thanks Jack, It was good suggestion and a wise precaution to take considering how buried and permanent these tubes are once its all said and done.

Went ahead this afternoon and poked an E-brake cable through all three tubes.(tested the clutch tube as well) Relieved to report that there wasn't a hint of an obstruction from the weld molt breaching the tube walls

Here is the wiring and power cable conduit or partial sleeve that they both share. The seat track reinforcement plate comprises the other half of the tube against the upper corner of the tunnel then as Roy said it turns to a couple of metal tangs up by the gear shifter. The left side has a matching conduit and is as far as I know Unused. Maybe the tach cable might pass through there??

Thanks a lot Roy! I think this tube replacement is sort of the exception and not the rule. I was really surprised to find that they had rotted so badly. Worse case scenario would have been to have just left them alone and let them puke grease worms inside the tunnel a side benefit of which would be a little more rust inhibitor down in there. Your tunnel looks like its never been disturbed since it left the factory. If that was mine I'd keep that tunnel bathed in penetrating oil or some other petroleum product to keep that rust from getting any worse. Thanks again for the help you guys!

8/21/14
Tying up the last of the loose ends.

There was a lot of little things that had to be done but before the session was out I had them complete. At least the ones I know about right now. Below are a few of them:


Plug weld holes for the center bracket. Not quite 40 spot-welds Jack but more than enough plug welds to hold it down.

establishing the plug weld holes for all three brackets on the tunnel wall.

Installing the reliefs in the mount flange profile for the lateral embossment where the pan halves meet so the tunnel can sit flush.

By sessions end I had the conduits and floor ready. Its mounted in for the last time here.

Ready to lay down the plug-welds tomorrow. Now that the stage is finally set this should really begin to move together quickly. (I hope)
Thanks for looking! Justin

[big jock]

I love this thread.Great work and thanks for it.

[JTR70]

Thank you Duncan! I appreciate you taking the time to read through all of this. Thanks once again Justin

8/22/14
New conduits finally in for good.

Before welding that center floor mounted bracket I set the original threaded ends and welded up the top sides of them first, Once set I shoved the conduits/bungs back through the wall so I could get a bead on the bottom side. This again was one of those assembly sequences I went over in my head.

With those tips welded and set the bracket was welded up next.

Decided to finish the outside first before installing the tunnel. ready to run a bead around the bung and the Bulk-head wall flange as originally done. The sheath for the heater conduit was also next. ready to install here.

left side welded up as originally. It was really tough getting the weld on the upper section; A very tight spot.

Cap and jamb nut reinstalled.

Ran out of time today but will wrap up this other side tomorrow.
Thanks for looking! Justin