The 14 Car Performance Therapy Project Rushforths, Baers, Yokohamas, and more

[NOT A TA]

Originally Posted by gofastwclass

I was on a super tight budget and kept the attitude that anything that came up and wasn't part of the original project (while I'm here upgrades, other people's ideas, etc.) would not even be entertained until the next phase. The next phase was only to be thought about after the car was back on the road.


I love the tutorials on how your updating everything, I do the same thing. This helps people understand normal people like us can build cool cars at home if they can't afford a big name shop.

The current project is the "next phase" for me. It's most of the things I said "next time the car's apart".

I build cars for others so I might not be quite as "normal" as my thread might appear because I usually keep other peoples projects, parts, etc. out of pics. I think the only car I've done for a member here was a 69 Camaro a couple years ago. While his car went from shell to complete in a year or so my car is still apart, like a plumber with a dripping faucet ahahaha.

I had a customer ship down a car almost just like mine a couple weeks ago. It was here for a complete suspension swap, steering replacement, body mounts, frame connectors etc. He wanted me to drive it for a couple hundred miles before shipping it back and was nice enough to give me permission to do some aero testing with it. As you'll see later in the thread my car's getting quite a bit of aero work so testing with his car gave me a good baseline since it's the same ride height, tires, etc. but with the stock body.

Everyone likes pics so here's a couple of those cars then I'll get back to bringing my thread up to date.

[NOT A TA]

NOTE: The work done in the post below was done quite a while ago and things have changed since that time. The car is now sponsored by PTFB so the stock arms etc. will all be replaced later in the thread. Also doing this prompted me to start a company that makes sub frame repair/upgrade pieces as well as some other things. So now I sell kits to do things like the LCA reinforcement.
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The lower control arm mounting points holes in the 1st and 2nd gen frames are often worn or damaged. The design really isn't very good IMO. Forces from cornering, bumping parking blocks, hitting potholes, etc. is transferred to the frame through the LCA bolts to the edges of the holes in the sheet metal the frame is stamped out of. Thats not much surface area and making it worse the bolts are shouldered on one side but the other side of each bolt just has the tips of the threads hitting the frame. Since the bolts are hardened steel they deform the holes in the softer metal of the frame ovalizing them. I see it a lot on 2nd gens and since the 1st gens did the same thing I'm surprised the engineers at GM didn't come up with something better for 2nd gens.

Now some of us put stiffer springs, tubular control arms, solid bushings, wider modern sticky tires, and big fat sway bars on the car and then take the car out for spirited driving, auto-X, and even road track use. The force on the thin sheet metal bolt holes in the frame far exceeds what the engineers had in mind. Heck, radial tires weren't even standard on most American cars yet when the suspension was originally designed.

If the LCA mounting holes are ovalized (or you want to reinforce them) a piece of thick steel with a hole drilled in it or a thick washer(s) can be welded to the frame. Welding something to the frame should also reduce flexing theoretically allowing our cool new suspension & tires to perform their best. When possible, I like to use a long piece of all thread rod with nuts through the frame to line up the holes of the washers or metal being welded and hold them tight to the frame to tack weld in place. Then remove the rod and fully weld. If a rod won't slide through all 4 holes on one side because of crossmember interference I'll bolt the control arm in place with the pieces to be welded, tack in place, remove arm and then fully weld.

On the frame I'm currently preparing (81 subframe into a 70) I wanted to strengthen the frame, reduce flex, and reduce wear as much as possible within my budget. To complicate things I want to use my old control arms with the 1/2" bolts in a frame made for the larger diameter metric bolts.

Here's the 2 different bolts I'm aware of, Metric 81 on the left and 1/2" on the right. In the next pic note the shoulder where the frame sits on one side while the other side is on the bolt threads. Really GM? Couldn't think of a better way after seeing it didn't work well for the 1st gens?






So here's my plan for the current project where the LCA attaches. This will reduce the holes to 1/2", stiffen the area, and hopefully prevent ovalizing.

1. 1/2" ID 2 1/2" OD body washers 1/8" thick to stiffen the frame. Some are cut and bent to fit and welded into place.

2. 1/2" grade 8 bolts with a shank section about 3 3/8". The long shank section will keep the threaded part from transferring the shear forces to the edge of the frame sheet metal. New tapered thread locknuts will be used for final assembly, regular nuts for mock up etc. are seen in the pics below. Keep in mind kids those factory tapered thread locknuts are considered single use fasteners and should be replaced if removed.

3. 1/2" grade 8 washers welded to each other and welded to the big washers will take the forces that originally went to the edge of the frame sheet metal. This will spread out the force because the combined thickness of the washers is greater than the frame sheet metal. Also, because of the longer shank section both sides will have full contact rather than one side putting the force on the thread tips. With the large washers and 3 of the grade 8's on each side the nuts won't bottom on the shank when tightened. Grade 8 washers are being used because they are made to closer tolerances than cheap washers and fit the bolt shank tighter. I'm aware they'll lose their heat treating when welded.

Since I'm switching from the metric size frame holes to the smaller 1/2" holes there's a slight movement before everything is welded. I'll pull the LCA So any slight change in position will give me a little extra positive castor. I'll do some more weld grinding and polishing before sandblasting so the frame is pretty for body color paint. Next post is upper control arm/shock mount modification.

[NOT A TA]

[NOT A TA]

Upper control arm/shock brackets got trimmed where the bracket hangs over the outside of the frame rail then bent to the rail and welded across between the factory welds. The increased stiffness ar added strength advantage is probably debatable but in theory it should be a bit more durable, removes a little weight, and looks cleaner (although you can't see it under stock upper arms).



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[NOT A TA]

The donor 80 bird had taken a punch in the nose at some point in time that had stretched the slotted bumper bracket holes in the sub frame. I put a hydraulic cylinder in the frame and massaged the metal back into place with a BFH. In the first pic you can see the piston in the frame for support behind the hole on the right thats been straightened quite a bit already. Without the support inside the frame the area around the stretched area would cave in if I just started smacking it in with a hammer, it would work, but the bumper brackets might be harder to adjust later.








With the frame ready for mock up and the unibody (except splash pan) in the final coat of PPG K38 primer it was time to get the body off the rotisserie and onto some wood cribs. Then I spun the body around to roll the subframe into place, took some measurements, and then set it straight with the body before snugging up the body mount bolts. Next I started hanging suspension parts so I'll have enough weight on the front to get the rear suspension, axle, and wheels installed so that I can use wheel cribs and go-jacks under it. The rotisserie lifts cars much better than lowering them so it's easier for me to just use my jack cribs to get it off. I made some special cribs to fit on top of the go jacks so that I can use the wheel cribs on the go jacks which roll soooo nice. With the car being as stiff as it is because of the cage I've found it's more stable to have the car on 3 stacks when it's not fully loaded with weight especially if I'm going to roll it around. Once it's where I want I take out the go jacks and put it on 4 stacks of cribs.







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[NOT A TA]

After test fitting the subframe to make sure the body mounts lined up properly I cut down the body mounts for the rear of the subframe to make up for the metal I added boxing the frame where the rear body mounts are. The thickness of the metal boxing the frame isn't really thick but this will keep the subframe from tipping up and raising the radiator support.





Once the cut down body mounts were in place I laid out the chassis/suspension components and started mocking up all the components. The plan is to assemble most of the suspension and front end sheetmetal. Then once everything is in place the doors and front end sheetmetal can be aligned and blocked sanded before final primer. Then everything will be taken apart so the subframe and most of the components can be painted. First time it's been back on 4 wheels in a few years!











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[Flash68]

Great thread. Thanks for sharing everything.

[gofastwclass]

Originally Posted by NOT A TA

The current project is the "next phase" for me. It's most of the things I said "next time the car's apart".

I build cars for others so I might not be quite as "normal" as my thread might appear because I usually keep other peoples projects, parts, etc. out of pics. I think the only car I've done for a member here was a 69 Camaro a couple years ago. While his car went from shell to complete in a year or so my car is still apart, like a plumber with a dripping faucet ahahaha.

I fully understand and I got that impression by something you said earlier. But you're still not a "big shop" if you know what I mean. You're a guy typically working alone, just like me.

I build / update stuff for people from time to time but it isn't a job or business. I'm selective about projects I take on due to space and time limitations. All my work is done in my small detached workshop by me alone.

It's still awesome that you're sharing this how and why stuff. I also share what I know and do, but too many people won't share. The hobby will die if no one shares knowledge. This forum is actually really good about sharing stuff.

I would share my current build, but it isn't the type of car that would really fit in on this forum. It's not a road course / auto cross car, I just want it to handle well if I were to enter an event but it's really a street car with some cool stuff on a 1960's body.

[NOT A TA]

Thanks Flash!

gofastwithclass, Thanks also and you should start a thread about your car. At least post a couple pics and description so folks can see what you've got if they look up your previous posts. I'm curious, whatcha got?

On with updating!!!

[NOT A TA]

While cleaning and prepping the rear swaybar for install I remembered I wanted to post about reuse of locking fasteners.

Lock washers, nylock nuts, tapered thread nuts, and other locking fasteners work best the first time they're used and in many cases are considered single use fasteners. I see far too many instances where people building/rebuilding cars remove and reinstall these types of fasteners over and over to the point the fastener has no locking effect before the car ever hits the road. Then when the car starts being used various things start loosening up.

For a rebuild like this one I lay out all the parts. Then I take one of each locking fastener and tag it as to where it goes and how many I need, go to Fastenal, hardware store, Home Depot or wherever and buy all new fasteners. When I get them, I bag and tag them to be used during final install. It's cheap insurance that I won't be sidelined in the middle of an event or stranded roadside. I don't replace all the hardware, only the locking pieces.

In the last pic you can see there's two nylock nuts on the bottom of the shock absorber. I run two different rear ends, one for drags and one for high speed. I'd swapped the rear a couple times and removed the shocks for clearance (reusing the nylock nut) and then during a track session at Road Atlanta I heard a clunking in the rear. So I got off track and pitted only to discover the nylock nut had backed off. Simple fix once I found another nut and just double nutted it, however it cost me most of a track session so probably a couple hundred bucks in track time when all the expenses of a track day are considered. Been double nutted since but getting new nylock nuts for the bottoms of the shocks now.

When I installed the Hotchkis suspension the first time (long ago) I reused the tapered thread nuts that hold the upper control arms to the frame mounts. Took the car to a shop for alignment then took the car on vacation from CT to FL. When I got to FL I heard a clunk in the front end entering a parking lot. Not only had a nut backed off but the alignment shims were gone! Yay! Got to pay for another alignment. So, learn from my mistakes and don't reuse locking fasteners.







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