Project Theseus

[zedfoot]

Amazing progress. How many hours of work between posts?

[Noll]

Amazing progress. How many hours of work between posts?

Thanks! Most recent post was probably 6-7h of work (1:30pm today till 7-8ish), and the one before that was a similar amount of time on Thursday. I kinda just get into the zone once I start working and time flies by.

I find that anything longer then that in one stretch and I start getting tired and making mistakes. Could probably have got the quarter fully welded today, but decided to leave it till monday to best decide how to deal with the taillight surround fitment stuff.


Side note, looks like I'll also need to shim the hatch a little towards the roof, as on both sides it extends past the body by about 2-4mm (worse on the side I just welded on, but I'll aim to improve that before finishing all the welds). Should be easy enough, just can't really do it until the other quarter is on as the hatch is a known quantity to make sure I get the gaps right.

[grannyknot]

Noll, looking really good, at this rate you will be expected drive it to Zfest next year.

[Noll]

Noll, looking really good, at this rate you will be expected drive it to Zfest next year.

Thanks! That's the goal, will be driving it next summer or bust. Did a little googling, seems zfest is typically end of june?

Side note, who does everyone use for insurance? Hagerty won't touch me as I'm under 25, and seems like a similar story elsewhere. Just want an agreed-value policy without much in the way of mileage restrictions, even if I end up with a standard (non-classic) car insurance policy. It also doesn't help that I was dumb and got the mother of all speeding tickets a couple years back, but that will be off my record next august. Might need to put the Z on facility insurance for the month or two it's roadworthy before that, then change over to a more reasonably priced policy after that's done with.

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it's still odd to think that I've transformed this entire area from a gaping rusty hole back into a complete car. A little uglier than I'd like, but its the underside of the car so no biggie. I'm going to need to strip off some of the paint to seam-seal the quarter, now that it's butting up against everything. After some undercoating it should all be pretty hidden.




Finished welding everything:






And ground down:






Door on and adjusted so it closes. Gap is still pretty tight by the quarter, but it doesn't hit. Not going to do any more tweaking until I get my replacement doors on, as they probably will fit slightly differently anyway.






Now just the dogleg and floor, and all the metalwork on this side of the car is done!

[Noll]

Started on the seatbelt-mount area today.

Began by figuring out what I was cutting off the replacement section:





Cut the swaybar mount off the mangled remains of the old one, and cleaned up. Won't weld on until I have everything back in the car so I can mock it up with the swaybar to ensure I don't mess up location.




All cut, cleaned, and mocked up. I still need to do some trimming to make sure everything slides fully in to place, and re-make the right-hand side from where it was hacked up when the person who sent it to me cut it out of their car.




I left as much of the old brace in place as possible, so as to be able to weld as far from the control-arm mount as possible for simplicity's sake. Will plug-weld the panel back on top afterwards.



My plan is to weld everything i can from the top, then get the floor/underfloor rail/seat mounts in, and go from there. In the future I'll drop the rear subframe to clean everything up and swap the rear diff (so long as I can source a 4.11 LSD), and will do the bits that need to be welded from the underside then.

[grannyknot]

Why a 4:11? 4:11 will give you a fast launch from a stand still but will be loud and lousy gas mileage at highway speeds.

[Noll]

Why a 4:11? 4:11 will give you a fast launch from a stand still but will be loud and lousy gas mileage at highway speeds.

From the calculations I did, with the 5spd I'm also putting in it should allow for acceleration as you mentioned, while also having 5th gear highway rpm not be TOO terrible.

I'll mostly be on 80kph roads with this thing anyway, with some 417 driving on the way to work.

Do you think a 3.9 would be better though? I haven't bought anything yet, just considering options at this stage.

Seems like a 4.11 from a Subaru xt turbo wagon should drop right in (bolt-style flanges too), and have a decent lsd.

I'm sure I can find a similar 3.9 or 3.7 setup, just trying to avoid sending 800 on a STI diff and then a few hundred more on the flange adapters.

[Dr.Diesel]

Noll, I have to agree with Grannyknot. I don't think your going to like the 4.11 when your driving on the 417. I put 3.90's in my 240Z when I put in a 5 speed transmission & am very happy with that combination. I am pleased with the acceleration & the rpm when on the highway like the 401. The 3.90 rear end gears with the close ratio 5 speed transmission woke the car up significantly over the stock diff gears with the 4 speed. What I do feel a need for is more horsepower & torque from my engine.

[Noll]

Noll, I have to agree with Grannyknot. I don't think your going to like the 4.11 when your driving on the 417. I put 3.90's in my 240Z when I put in a 5 speed transmission & am very happy with that combination. I am pleased with the acceleration & the rpm when on the highway like the 401. The 3.90 rear end gears with the close ratio 5 speed transmission woke the car up significantly over the stock diff gears with the 4 speed. What I do feel a need for is more horsepower & torque from my engine.

Good to know! My knowledge in regards to the diff ratios is all theoretical, so hearing from others who have done it is much appreciated! 3.9 it is then. What diff setup are you using?


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did a little datsun work this evening.

This rubber pad mount and the frame horn in the surrounding area was pretty sorry-looking and had pinholes, so I decided to repair it.

The starting point:





Made the replacement mount. I'm sure it'll flex a little more than the double-stepped one, but shouldn't matter much. I may weld a little bit in the center to reduce flex.




And the point I got to when I ran out of welding gas. Top/side of the main patch done, and bottom tacked in (it wraps around all 3 sides there).




Before I welded it up I had a look inside; other than the usual surface rust, there doesn't seem much unexpected. Some metal flakes sitting by another area I need to patch, but I'll be cutting that out (then welding back in) at a later date for the repair there. Will also be using an internal frame coating on the whole cavity.

[Dr.Diesel]

Noll, to answer your question, I am using a R200 long nose diff with 3.90 gears I acquired out of a 1981 280Zx. In addition, I installed the Ron Tyler style diff mount that converts the front diff mount from the bottom to the top of the diff. Im not sure if you are aware, but this means that during acceleration, the upper mount is compressed as opposed to the lower mount as it comes from the factory which is pulled apart under acceleration which requires the factory strap over the diff to contain it from pulling apart.
All this is connected to an aluminum driveshaft with bigger universals to take the torque from an intended future engine upgrade. The down side of the R200 diff is it is significantly heavier than the factory installed R180 diff. Hopefully this will give you some food for thought regarding the direction you are going with your project.

[Casey_z]

I also have the 3.90 ratio with a 78 280z 5 speed
Lots of get up and go and 70 mph is about 2800 RPM

[Noll]

Thanks for all the info guys! I'll have to look into that alternate diff mount, might want to diy something. I'm going to see if I can find a R160 1:3.90 ; according to the 510 guys they're good till about 200hp so should be fine for me and save some weight and cost.

Now debating if it's worth the hassle of trying to acquire a LSD in that ratio, or if an open diff will be fine for street use with stock power - any thoughts as to how noticeable it'd be?

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Finished welding and grinding the front frame horn patch, and seam sealed and painted it. Not the prettiest, but some undercoating will smooth things out once it gets to that point.







Made a new patch for the rear inner wheel arch where it meets the seatbelt mount area - I had done this before, but it was with my old welder (bad penetration) and there was another section I couldn't patch until I removed the rear seatbelt area anyway. Decided to cut it all out and start from scratch.





Welded it in, and also got the fitment finalized on the rear subframe stuff and welded it in too!





I'll need to put the floor skin back on the areas I cut out to gain welding access for the structural members, as well as make some bits for it to meet with the inner wheel arch, as the person who cut this out of their parts-car cut it there by mistake. Now the frame is in the correct location, patching the skin is the easy part.





Stuck the floorpan in to check fitment, there's some stuff I'll need to cut before I can tack it in and start patching the trans tunnel.






I also need to figure out where to weld the seat mounts in; does anyone have a measurement to, say, the firewall from the front mount holes I can use for a reference? I may very well move them back a little as I have pretty long legs, but it would be good to have a starting point.

Side note, I also realized that 240z and 260z seatbelts are different; the bucket that the retractor spool goes in that I just welded on is off a 240z, and my 260z assembly is too wide to fit - looks like they changed to wider belts in the later cars. Anyone want to trade for some 240z assemblies?


Also stripped the rubber off the front bumper and polished it up. Looking pretty clean now imo, I'll probably leave the holes (or possibly use carriage bolts to fill) as they're pretty small.





Oh yeah, and I finally ordered some wheels! 15x8 + 0 RKRs. I'm undecided as to if bronze or gunmetal will be better for the blue car colour I'm aiming for, but they were they only set I could find in Canada (no customs fees, free shipping, and the price was actually pretty excellent), so I went with them. Can always paint later if I want.

Found a used set of 225/50/15 snow tires for cheap that I'll be picking up to use for rollers and fitment/suspension testing; can probably sell them for what I paid when I'm done with them.

[Noll]

Big milestone today, got the floor in! Lots of transmission-tunnel patches to do still, but pan and frame rail are both welded on for good. Also need to decide how best to do the front curve to the firewall, but shouldn't be too bad.




Welded in one of the multiple patches for the seatbelt area. Will clean it up when it's all welded in.







Floor is pretty solid, I'd say:





And underside. Will clean up the surface rust and get it all painted when I get the car lifted up to do some other stuff.



This also seems like a good time to decide on getting rear frame connectors from bad-dog, but from their pics it looks like it might interfere with my current swaybar. Definitely getting their jack plates, seems like a worthwhile mod.

[Dr.Diesel]

I ran into the same issue with the rear sway bar that wraps under the nose of the differential after installing the Bad-Dog frame connectors. A modification to the rear sway bar mounts to the body corrected that issue. Not difficult for you with your skills.You could also change the rear sway bar to the type that wraps around the rear of the diff & that will also solve your problem which is a more expensive direction. However, you should be aware that if you go that route, you will also have clearance issues if you decide to install C/V shafts because the ends of the stabilizer bar will interfere with them. If you stick with the original shafts from the diff to the stub shafts, there is no concern.

[Noll]

I ran into the same issue with the rear sway bar that wraps under the nose of the differential after installing the Bad-Dog frame connectors. A modification to the rear sway bar mounts to the body corrected that issue. Not difficult for you with your skills.You could also change the rear sway bar to the type that wraps around the rear of the diff & that will also solve your problem which is a more expensive direction. However, you should be aware that if you go that route, you will also have clearance issues if you decide to install C/V shafts because the ends of the stabilizer bar will interfere with them. If you stick with the original shafts from the diff to the stub shafts, there is no concern.

Thanks for the info! I'm thinking I'll stick with the stock swaybar setup (or at least mount style) for now, so if I do go with the subframe connectors I'll want to do the modification as you mentioned.

I'm thinking some square tube steel to space the mounts and bar down a bit for clearance may be the way to go? Changing the angle a bit shouldn't matter unless I was going to make it like + or - 45 degrees or something silly.

Going off this thread it looks like I'd only need to move the mount down about 12-15mm. Ii suppose I could also cut the connectors to change the angle so the rear-most bit instead intersects with the front of the T rail leaving clearance for the swaybar, but that seems a bit counter-intuitive to spend 150usd on something that then needs extensive modification.

https://forums.hybridz.org/topic/54722-bad-dog-rails-installed/

How did you do it on your car?