My '72 240z project -- Rotisserie Restomod

[jkelly]

Hey guys,

 

I recently bought a 240z and it ended up having more rust than I originally thought, thus begins my new winter project.

 

Pulling her home with my 1987 2WD Toyota Pickup. That was a long haul between northeast of Sacramento and Southern California. The truck performed well though!

 

 

 

The car sat for a while and the engine internals have rusted.  The overview plan is to pull the engine, fix the front half of the car's rust problems, swap the SUs from the L24 to my rebuilt L28, install the engine, and drive it while fixing other things (interior).

 

 

 

Some hood damage. Hopefully I can bump these out.

 

 

Starting to inspect for rust on the passenger side frame rail/firewall interface. It's definitely in need of some work.

 

 

 

Inside engine bay rail.

 

 

Engine removal

 

 

In preparation for cutting into frame rails I dropped the front suspension to remove as much stressed from the rails as possible.

 

 

 

Stand I welded up to support car from the transmission mounts.

 

 

I've made a little more progress -- started making patch panel templates and cutting metal from the battery tray area.  It looks like I'm going to be replacing a lot of metal around the battery tray area -- frame rail, battery tray inner fender, a piece of the firewall, and passenger side floor pan.  Hopefully driver side isn't this bad.

 

 

Edited November 6, 2017 by jkelly

[jkelly]

Made some patch panels for the battery tray area today.

 

First made a template from poster board and traced it onto hardwood to make a hammerform.

 

 

 

Clamped the sheet metal cutout between the two hammerforms and hammered the edges over.

 

 

 

I made this one using a Hardbor Freight shrinker.

 

 

A rough fit of both.

 

[Leon]

Nice metalwork!

[jkelly]

Thanks, Leon! I picked up David Gardiner's Bodywork Restoration Tutorial DVD a while back and have been watching it off and on.  It's a really good DVD.

 

Yesterday I decided to brace up the engine bay a little more before cutting into the frame rail.

 

I drilled the spot welds on the forward main frame rail and removed the entire section from the firewall to the tension rod bracket.

 

 

Here's a picture of the inside of that section. Lots of heavy pitting.

 

 

I'm going to replace this section and the rest of the under floorpan frame rail with 16ga metal.

 

I noticed that most guys replace both floor pans at once, but my driver side floor pan is in decent shape. I'm guessing there was a nasty weather stripping failure on the passenger side.  Do you guys know if you can buy only the p-side ZF floor pan?

 

Also, if you guys have any suggestions on how or if I should brace the forward frame better, please let me know! I'm planning on cutting away that portion of the engine bay frame rail that connects to the fire wall in picture 2. Perhaps a couple braces from the firewall to my current braces would help even more.

Edited October 19, 2015 by jkelly

[jkelly]

It's been a little slow as I got a piece of hot metal in my eye while cutting sheet metal for the frame rails. Had to go to the ER and then to an optometrist to have it removed with a needle and a drill. Pretty gnarly. Still healing.

I finished up my hard line condenser and filter system for my compressor. ~30' of 1/2" Type L copper pipe with a drain valve at the bottom of each leg. Using a Devilbiss QC3 for water sensitive tools and a $35 Pneumatic Plus filter/regulator for other tools. First time sweating pipe and no leaks! Since I'm in a rental house I wanted to make it fairly portable, so I attached it to a piece of plywood and set it on two jack stands behind my compressor. Waiting on a 3/8" air hose whip to arrive to run from compressor to the condenser. I also don't bother with an automatic drain valve and just be sure to manually drain my compressor tank every time I use it.

 

 

I disassembled the front suspension in preparation for sand blasting. I ordered a new Energy Suspension master urethane bushing kit to replace all the bushings. I may end up swapping the front sway bar over from my '78 280z to the 240. I believe it's a couple millimeters larger in diameter.  I'm also planning on using either rubber bushings, drilling the urethane bushings, or using a ball/joint style compression rod bushing in order to avoid the issue of snapping compression rods.

 

I also ordered new Moog lower ball joints and tie rod ends.

In addition to urethane bushings, I ordered all new Timken inner and outer wheel bearings and races.

 

This came in handy when looking for wheel bearings.
http://www.showmetheparts.com/timken/

 

 

I'll be honest, I've found most of my replacement suspension parts at the best price on Amazon. And usually with Prime shipping.

I've also started repairing the fiberglass headlight bucket that cracked and had missing chunks.

 

 

 

 

With sheet metal repair on this car, my goal has been to eliminate any unnecessary lap welds by using butt welds and improve rust prevention when possible while keeping an original look. The passenger front frame rails to compression rod brackets were pretty rusty so I decide to cut it all out and fabricate something that seals better.  It will be two pieces. 1.A piece that fits around the compression rod bracket and should eliminate most of the water access. 2. A piece that connects to the under floor pan frame rail. All 16 gauge.

 

 

 

 

 

 

[jkelly]

Fabricated the rest of the passenger side forward frame rail.

 

Test fit:

 

 

 

Next step is to cut away the rusty portions of engine bay frame rail that connects to the fire wall, fabricate that piece, then cut away part of the firewall that's rusted and fabricate that panel. Then I start welding in all of the replacements.

[V-Fib]

Most impressive metalwork, don't know if you have prior experience or not but impressive nonetheless.

[RebekahsZ]

These are only my humble suggestions based on 35 years of owning old cars. A lot of what you are calling rust I would call patina. All the repairs you do will rust on the inside of the concealed panels just like the part you cut out. From what I've seen in your photos, the only rust worth cutting out has been in your battery tray/fender. That rocker panel looks great-sure wouldn't replace that or cut it out looking for internal rust. If any of the lap welds don't have rust now, I wouldn't fool with them either, you are just likely to start a problem where a problem doesn't exist. When it comes to sandblasting, consider the fact that sand will strip rust, paint, and any factory primer and rust proofing/tinning/metal prep. My car was chemical stripped then ground to the bare metal by a prior owner, and now any little scratch in the paint turns instantly orange with rust. I wish I still had some of that factory prep left. So, I would limit my sandblasting to areas that really need it and I would not do the whole car even though all the car shows on TV do that. You are doing a great job on your fab work. Looks great! I've got my eye on another chassis that is in dry storage. The only part I plan to strip is the panels that the prior owner sanded to the metal before he got cancer. They have surface rust. The rest of the car I will lightly sand for paint adhesion, then paint right over it in the color of my choice. No way I can metal prep as well as the factory.

Edited November 15, 2015 by RebekahsZ

[RebekahsZ]

In years of hard abuse the only welds that had broken are the welds in the tranny tunnel. They are at the edge of the panels and the metal has torn away from the infrequent, globby factory welds. I think later cars have a lot more spot welds in these areas. The broken welds are at the junction of the tunnel and the firewall, along the tranny area where there is a joint for a floor lap weld and in the diff area of the tunnel. No broken welds in the engine bay or cowl area or strut towers. That tranny tunnel must carry a lot of tension. All Zs seem to crack in the A pillar and B pillar of the roof. Some guys say that's just from filler contraction, but I think the car flexes there as well.

[jkelly]

Thanks for the feedback and compliments guys! I don't have any prior experience. I just watched a bunch of videos on metal work then dived in head first!

 

Thanks a bunch for the advice RebekahsZ.  Some of the big questions I've always had: When do you cut metal out? When is the pitting too bad and it has to be cut out? A lot of the lap welds on my 240 do have rust in them. It's only surface rust, but how long will it take to spread and get to a point where it will need to be fixed, if I ignore it now?

 

I see you live in Florence. I grew up and lived just down the road in Corinth MS. Just recently moved from there to Southern California.

Edited November 15, 2015 by jkelly

[RebekahsZ]

Luck dog, living in CA with surf and desert-preserved cars! I'm probably here for life since my wife hates moving and I just built my dream shop (not finished and still need more space). I guess if there's paint bubbling on the lap joints they need to come out. I have only one such place on the joint below the rear bumper where the fender and rear valance come together. It's the rust you can't see between the two panels that you need to be concerned with but if the paint is a little thin where the lap joint creates a corner, I'd just scuff that off. Send a pic of some of the spots you are worried about. The Kroger in Corinth always has the best gas prices in the area! I think there's an old song that says "When you get tired of California, I'll still be here." Or something to that effect.

Edited November 15, 2015 by RebekahsZ

[rturbo 930]

In years of hard abuse the only welds that had broken are the welds in the tranny tunnel. They are at the edge of the panels and the metal has torn away from the infrequent, globby factory welds. I think later cars have a lot more spot welds in these areas. The broken welds are at the junction of the tunnel and the firewall, along the tranny area where there is a joint for a floor lap weld and in the diff area of the tunnel. No broken welds in the engine bay or cowl area or strut towers. That tranny tunnel must carry a lot of tension. All Zs seem to crack in the A pillar and B pillar of the roof. Some guys say that's just from filler contraction, but I think the car flexes there as well.

The car does flex at the pillars. The cracks you see are because the steel chassis flexes, but the lead filler in the joints does not, and the result is a crack.

 

As for the broken welds on the trans tunnel, IIRC, JohnC has said that the chassis flexes a lot at the front and rear bulkheads, which is at the firewall, and the area more or less where the welds failed on your car. The solution is a triangulated strut brace up front, and a roll bar in the rear.

 

 

My take on when to cut rust out, vs just treating it - if it is pitted enough that the metal no longer has it's structural integrity, cut it out. surface rust that you can just wire brush off, and minor pitting, I would probably leave alone. If you're still unsure, post a good pic of the area(s) you're concerned about and I can give you an opinion.

[rturbo 930]

I should've read the thread first. Here's my opinion on two areas you posted.

 

 

 

Starting to inspect for rust on the passenger side frame rail/firewall interface. It's definitely in need of some work.

 

IMG_20151002_222406.jpg

IMG_20151013_192001.jpg

 

The surface rust on the rocker there looks fine IMO. Also, I'm curious about that thing in front of the car that looks like it's made out of copper tubing - what is that?

 

 

Here's a picture of the inside of that section. Lots of heavy pitting.

 

IMG_20151018_160002.jpg

That needs replacement.

 

Looks like you're a pretty good fabricator though, so bending up a new piece shouldn't be a problem.

 

Edit: Not sure why the pics showed up as links but I don't know how to fix it, so they'll stay that way.

Edited November 16, 2015 by rturbo 930

[jkelly]

Thanks for the replies guys.

 

The copper tubing is a condenser I made for my compressor. It's about 30' of tubing and has three drain legs before coming to a DeVilbiss QC3 and another filter/regulator. There are some more pics of it in post #5.

 

Here are some more pictures of areas of concern. Most of them being lap joints where rust is creeping underneath.

 

Rocker panel again. You can see the rust inside that cavity.

 

 

 

Lap joint of the upper inner fender where it meets the front bulkhead area.

 

 

Inside the radiator support looking outboard.

 

 

More radiator support

 

 

Where the radiator support meets the inner fender.

 

 

I can grind away a lot of the rust because it isn't that bad. But what do I do about the stuff I can't get to (lap joints, cavities, etc.)? Just treat it?

Edited November 16, 2015 by jkelly

[jkelly]

Rear dog leg to rocker

 

[RebekahsZ]

Hmmm-I dunno. Maybe the other guys can weigh in. Perhaps this car was more coastal than desert. I think I would blast or grind those spots to a limited extent and see what's left before I cut that surface stuff out.

[rturbo 930]

Okay, in order:

 

1 and 2) Probably fine. You're going to find surface rust in a lot of the cavities. IMO it's generally nothing to worry about.

3) Looks like surface rust, maybe a little pitting. Not enough to worry about. Wire wheel + treat appropriately - something like POR 15.

4) Looks like some rust scale on the right of the pic. I'd knock it down a bit with a wire brush (hand held) or maybe some sand paper or something. Whatever you can get in there. Then treat with POR-15 or product of choice.

5) 99% chance it's no big deal. Wire wheel it and see what you got.

6) Looks like surface rust/mild pitting, not rotten. Wire wheel and POR-15.

7) Doglegs are one of the most common rust spots, especially that seam. My guess is that your dogleg is rotting from the inside out. If you want to investigate without cutting the whole thing out, consider drilling a hole on the backside of the dogleg, in the wheel well, fairly close to the fender lip. If you can get a borescope or something you should be able to see what shape it's in. Or just cut the damn thing off and weld a new one on. It's not necessarily a hard spot to fix, depending how you do it (cut it out within the body lines).

 

Anyway, that's my take on it, for whatever it's worth.

[V-Fib]

rturbo covered most of it - I'll chime in and give you my opinion.

 

You're never going to get 100% of the rust. Splitting the seams and lap welds to eliminate the rust is excessive. Wire wheel the surface scale if the portion has no pinholes or frank rust-out treat it with a product of choice (I use phosphoric acid) then epoxy prime it and seam seal it so it cannot get any moisture or air trapped in it and continue the chemical reaction.

 

The inside of panels that have mild surface rust that you will not reach I would spray with cavity wax which is a petroleum based product, it will saturate/penetrate the metal and repel moisture vital for the oxidation. Only spray this after you have finished welding near the area - otherwise you will have weld contamination. If you Google it 3M makes a nice products called Rust Fighter. Eastwood also makes a rust encapsulator product for spraying inside cavities and frame rails.

 

The patches you weld in will also flash rust from the inside unless coated it. I use a weldable zinc or copper rich weld through primer. Regular paint will burn and smoulder contaminating your welds.

 

My tirade.

Edited November 16, 2015 by V-Fib

[jkelly]

Great advice guys. Thanks for taking the time to reply.  Glad to hear the lap joints can be dealt with without drilling 100 spot welds and removing panels.

 

I picked up some U-pol #2 weld thru primer a while back.  Probably going to pick up some of the 3M Rust Fighter and a wand too.

[jkelly]

I got some 3M Rust Fighter with a wand attachment for the frame rails.  Also ordered some 3M 08360 Ultrapro seam sealer; supposed to be good stuff.

 

I made a little progress on the rust battle over the holiday. I cut out the portion of engine frame rail to firewall and removed the rust from the firewall and welded in patch panels. Being a beginner to welding, the  butt welds were pretty hard and I had a lot of blow through starting out. I started using a copper backing plate, which helped, but still pretty difficult.

 

Hopefully my welds hold up, considering this seems to be a higher stress region that others. Comments or suggestions?

 

 

 

 

EDIT: I did end up fully welding the patch panel gaps.

Edited November 30, 2015 by jkelly