Introducing: Project 1/2-TRAK

[dolf]

How are you going to run a 275 front tire on a stock sub?

[Neil B]

That's a really neat project and a great story behind it. Be careful with the black/satin paint on the hood and front end. With my track cars, I've always had to use wax to get the rubber streaks (from race tires) off the front end and from behind the tires.

[Damn True]

Originally Posted by dolf

How are you going to run a 275 front tire on a stock sub?

Yes, I will be using the stock subframe.

You see, I firmly believe in letting other people do my R&D for me. The simple reason for this is that I really cannot afford to experiment. So for the most part, I am using what I know to work.

Thankfully, one of our own, Carl Cassanova has already sussed out the details of running a 275 on the front of a '68.

You can find all the required information on his excellent website:
http://www.geocities.com/casanoc/

The only differences in my setup will be the use of an ATS spindle and wheels/brakes. I will be duplicating his wheel dimensions and also will be using the Speed Tech upper and lower control arm. More about those later though. I don't want to get ahead of my next update.

[Damn True]

Originally Posted by Neil B

That's a really neat project and a great story behind it. Be careful with the black/satin paint on the hood and front end. With my track cars, I've always had to use wax to get the rubber streaks (from race tires) off the front end and from behind the tires.

Thanks for the input. I hadn't really considered that aspect of the finish. With the "flattened" blacks that are on the market are you able to get a little wax on them w/o staining? I mean they are a catalyzed single stage right? Less glossy than a normal clear coat but not porous. Am I off base?

[Damn True]

So....not a lot happened in September. It was a busy month at work because I was only AT work for about 2 weeks out of the four. My wife and I spent a week in Hawaii, and another week fishing and camping in the Sierra's. She treated me pretty good for my birthday. All things considered I'd have preferred Camaro stuff to going to Hawaii. Having lived there for seven years it feels more like going home than going on a vacation. But it was nice to get out of the office. The fishing trip though was awesome. The planks are 2"x12" for reference.



So as I said a few posts back, I got the sheet metal stripped from the car pretty easily. No broken or stripped hardware and no rust to speak of. As you can see though, the subframe is really grungy.



Not bad considering the age of the car. Really stoked about the lack of rust. This really was a "grandma car" and as such it was never really driven hard so I'm not even finding evidence of severe wear or any kind of stress cracks.



So I stripped all the suspension off and yanked the subframe in preparation for sandblasting and then finish welding.

Here's what we started with



A little quick work with a wire wheel allowed me to inspect the potential trouble spots for cracks before sandblasting and allows me to explain what I'm up to here. You see how the subframe is only partially welded? Well each unwelded bit is a flex point and the beginning of each weld is a stress riser.

[Damn True]

So what we are going to do is link all of the factory welds and tie the whole thing together.

I thought this was going to be easy, but nooooo. It seems that a 40 year old lap joint is nigh impossible to clean. I sandblasted it. I wire brushed it. I sprayed solvent in there and blew it around with a blow-gun. I heated the joint with a torch to burn off contaminants but my welds were just looking like rubbish. This thread catalogs me figuring out the problem with the help of Jake and Matt...

http://www.pro-touring.com/forum/showthread.php?t=46863

So with the problem solved the welds came out pretty well. You can see the factory lap weld above my weld in this picture. It looks like they were stick welding these things and doing so very quickly.



Now remember, these are flux-core welds on a dirty, 40 year old lap joint. My torch technique is as you can see "rusty" to say the least. But, the welds are super solid and fully penetrated.

[Damn True]

In addition I also finish welded the seams inside the LCA pocket and the entire K-member. Overkill? Maybe. But it couldn't hurt.



You can see the string of itty-bitty spot welds that were originally used to join the upper and lower halves of the K-member here. Running the bead along both sides really made the assembly into a very solid unit.



I had to roll the subframe over a few times while doing all this work the difference in the stiffness of the assembly was very noticeable. Early in the process I could feel the thing wobble around a bit if I grabbed it by one corner and shook. I mean it felt like grabbing one corner of a sheet of 3/4 plywood. Strong, yet with some springiness to it. With everything welded up it is completely rigid. More like a sheet of 1-1/8 subfloor.

Yeah, my welds still kinda suck and the flux-core wire is messy, but they got better through the process and functionally the welds are good.

Next step.......

Installing the ATS coilover conversion system.......

[awr68]

Nice progress! Boy, that takes me back a year!!

Cant wait to see the next round of pics!!

[Damn True]

I'm really glad I'm doing this work myself it's so much damn fun!

[awr68]

I really enjoy the design/planning stages...but it's also fun to get the hands dirty!! As long as things are going well that is!! I'll let ya know what the driving stage is like and if I like that too next year!!