Replacing 240Z floors Part1

[Z Kid]

Nah fair call, 99% of the time I am being dodgy, and dodgy would be a kind way to describe the way I do most stuff, but I figured with the Z it deserves to be done at least semi well (to the best of my ability). Yeah its nice to actually do something on the car after letting it sit for so long, not sure if I can still call it a car in its current state but what the hey. It was you getting close to finishing your project that got me all keen again.

Chris

[Zthing]

Awesome information. I will be experiencing that wonderous event in the near future, so any info I find on the subject is golden. At this point, I am still trying to find the best place to purchase the replacement floor panels. So far Canada is the source I hear most. Wish there was some place within the USA closer to the east coast. Anyway..... thanks for the post with pics!!

[ncz]

Hey Zthing, if you are close to Charlotte, bring it over and we will cut yours first!! I've got the cut off wheel, the welder and fridge in the garage, bring the metal!

[Zthing]

NCZ.....I am about 2 hrs away from you.....would'a been great. Keep me posted if you do your floors soon. Will be a little bit before I get to mine. May need to pick your brain. By the way....I am in Moore County.

[Z Kid]

So its been a while, and I have bitten the bullet and bought another bag of tech screws, knowing the ones jumbo took will never be returned, well not at least until after I buy another box. Now the floorpan is fitted roughly into shape, tech screw it everywhere, till the point it wont/cant move around. There would be nothing worse than a half welded floorpan thats now not sitting on the floor like it should be.

Below are some pictures of what a tech screw is (not sure if thats what they are called in the states) and a couple showing just how well attached the floorpan is with screws. Dont worry about the shedload of holes after you remove them, they can be filled with weld and form kind of a mig spotweld.

[Z Kid]

Once that is all in place, its now time to trim down the transmission tunnel side, which is in theory the only edge of the new pan which should need trimming. Tech screw the edge of the floorpan and the transmission tunnel together (as can be seen in the last photo above) then take a small drill/fine grinding disc and cut through both layers so that you can fit your jigsaw blade in and cut down the lenght of the floorpan. As an alternative you can use an angle grinder with a superfine blade, but angle grinders create sparks, remove fingers and the end result has far more sharp edges than the jigsaw with metal blade cut. As you cut along make sure you are cutting throught both layers and havent moved soo far offline that you are only cutting one layer leaving a big gap to deal with later. Remove the techscrews as you come to them, if using a grinder you could probably just cut through them, but the jigsaw didnt like this.

[Z Kid]

Well now the floorpan is stuck firmly in place, and the correct size so its time for welding. I am using what borders on a "toy" mig welder, but I do beleive at the very least you must have a gas mig, not a gasless, as the material is very thin.

I have found .6mm welding wire to be the best/only wire I could get to work any thinner and the weld sits ontop and thicker and you blow holes everywhere. My floorpans were also made from a zinc coated material, and for safety/spattering reduction it pays to grind this off in the area where you intend to weld, just the mm either side of the weld. The gas is also toxic.

Initially the best thing to do is just move round tacking the floorpan in all places and several times along the trans tunnel joint, ie every 3-4cms. So you now know for sure its all where you want it to be.

Once it comes time to weld the long joint along the gearbox tunnel it needs to be done in lots of tiny bursts of welding with plenty of time to cool down inbetween otherwise you will end up with a slightly wavy finish as the metals cool at different rates etc. So weld a bit, go to the other end weld a bit more, then go tack somewhere else, remove a few tech screws have a drink of beer then repeat. Do this till its all done along the lenght of the joint and everywhere else is welded to your satisfaction.

Once this is done grind down the welds till they are fairly neat and tidy, of course your welding could come out neat and tidy and you wont need to grind at all, but due to the nature of lots of small welds joining etc its not going to look perfect until you grind it back a bit.

[Z Kid]

So once the floorpan is welded in its now time to add the underfloor frame rail, my pans didnt come with one so I went to the local engineering shop and for 20bucks had him bend up two bits in the right profile, slightly longer, thicker and zinc coated.

These were techscrewed into place and welded in fairly straight, now would be the time that I recommend a few less beers during the above welding process, one of mine is about 2mm out, stuff all in the scheme of things, but still frustrating.

As you can see on the second side I still need to close off the end/bend it down then weld it.

[Z Kid]

So now the floorpans are just about in, reinstall the back seat mount if you took/tore it out and fill up any remaining tech screw holes with mig. The next thing to do would be to cover welds with a waterproof primer, or in my case continue the fun of welding.

[Z Kid]

As can be seen by the last photo, I still have a shedload of welding to go before I can be considered to be "done". Now I just need to stop getting sidetracked by all those other projects such as the moulds for ZG flares seen below (a friend needed a set for his racecar and actually thought he would be able to borrow my flares to pass scrutineering, I think not, so I took a mould and knocked up a set).

Happy floor pan replacing

Chris

[Cuong Nguyen]

good write up Chris! it should be helpful for all those that are thinking of fixing their rusted floors but havent bodywork before.

all those pictures as well as the writing make it very easy to follow the steps.

as a side note, are the front and rear ZG flares both from the one mould?

Cuong

[Z Kid]

Cuong, there is an individual mould for each flare, ie 4 moulds, everyone is different. At the moment I have got to the stage where I am really happy with the quality of the front moulds and one of the rears, but the other rear I want to improve/redo.

Chris