Thanks, Jazzy! I'm not a machinist, just a hobbyist/dilettante. The first metal chips I ever made on my machines were documented on this thread some pages back. Still learning as I go.
In the pic above, you see the rectangular tube of quarter inch walled 6061-T6. That's going to serve a couple of purposes in this project when cut down to size. For one, it's forming the mounting bracket for one end of the future titanium trailing arm. I could have used a 16mm steel bolt, but that would have been too easy. So I made a 16mm titanium pin, held in place with a circlip. Spacers center the rod end in the bracket. I'm going to bolt this bracket to a beam that will cross the chassis in place of the old t-arm.
I've been spending an inordinate amount of time machining the titanium bar (duh! that goes without saying) for the trailing arm. Got one side finished and threaded. I have to pause before proceeding with the other side, because I'm not exactly sure how long to make this bar.
I need to fit that beam which will be replacing the trunnion arm in order to get an accurate measurement. Alternatively, I thought about mounting the trailing arm directly to the underside's sheet metal, but haven't had a good look under the car to see how that would work.
Got this in the mail today. Who's that nutty guy lurking back there behind the Porsches?
Clawing my way up past the Triumphs, trying to get a whiff of the Porsche tailpipes. If the sliding block buys me a couple of seconds per lap, I might just catch them. Especially if I was running the right tires. Look at my them, they're only 185 profile. I need me some 205s.
There's been a new development in my efforts to build a sliding block. So that project will be on hold. In the meantime, I lightened up the alternator tensioner/turnbuckle thing. Swiss-cheesed it real good.
I resumed work on replacing the steel-braided oil lines, but then quickly remembered what a pain it is. I documented that struggle in this thread a few years and many pages ago. So I stopped after one small section. It's a project that needs to be taken in bites. So what else to do on a Seattle rainy day?...
As I alluded to, the sliding block project is on temporary hold until I get some new parts and take accurate measurements of where things should go. Nonetheless, I returned my attention to the trailing arm to finish threading the other side despite not knowing how long it should be. It's what happens when the Seattle rain keeps me indoors (in a tiny work shed) trapped with my own impatience/impulsiveness.
I figured the threads needed to be started regardless of the length, and I could just extend the threads along the body and cut it down to size if this arm turns out to be too long. I made the arm as long as my lathe would allow, so if it needs to be longer, I'm SOL without some extra-creative bracketry. The picture below shows the beginnings of thread-cutting on the Ti bar. It takes many, many light passes to eventually cut a deep enough groove that a hand-die can finish.
I've said it before, and I'll say it again; thank goodness for carbide cutting bits. Watching the shavings peel off the work piece is really satisfying. Check out that grocery bag full of Ti shavings. I have two more bags like that. I'm not sure why I'm keeping them. I love Ti. Maybe I'll use them as packing in the world's most awesome muffler.
I wanted a rod end that would fit over the stock mounting pin located on the differential. It's an odd size, so I got the next biggest rod end and fabricated a sleeve fit over the pin and eliminate play. But that larger size (25mm) means that its threads need to be m25 as well. Which the Ti trailing rod arm isn't. So I made a threaded insert to reduce the rod end's hole. Really digging this whole threading-on-a-lathe operation.
Thanks, fellas! I'm just a hobbyist taking matters into his own hands, for better or worse.
Not much to report, even though I've spent hours over the last few days taking advantage of unusually dry (but cold!) weather here in the Pacific Northwest to work on the car in the driveway. I brought it home this offseason instead of leaving it in its trailer at the offsite storage facility (to my dog Baldor's dismay).
Spent a fair bit of time under the car taking measurements of where things need to go for the sliding block. Lots of staring, poking, and pondering. I've concluded that the exhaust system needs to be rerouted, and the fuel pump relocated before I mess with things further. I'll probably do a GTA-style side dump exhaust since the sliding block and it's reinforcing struts will block the usual exhaust route.
I also took a few more bites out of the oil system upgrade project. It's made up of a new homemade remote adapter, Setrab cooler, fresh lines, and Aeroquip fittings. Like I said, this was a pain. Glad it's done. Haven't tested it yet; for all I know, I might have introduced worse oil seepage than before. But for now, I'm going to imagine lower oil temps and a drier engine bay.
Robert is absolutely correct about the excessive noise of a side dump GTA exhaust. Which is why I am retaining my magna flow muffler. That means cutting the collector pipe shorter and moving the muffler forward.
But first, I wanted to weld up those holes in the manifold pipes near the head. My engine builder drilled and tapped those to insert temperature probes for when he tuned the engine on a test stand and dyno. I'm not sure what benefit individual cylinder exhaust temperatures would give, since I don't plan to tune each cylinder individually with its own carburetor jets.
Anyway, he plugged those holes with brass screws and then secondarily fastened them with hose clamps. That's been annoying me for the last five years, so I'm glad to be able to finally address it, since I was planning on sending out the reconfigured exhaust for a fresh ceramic coating. A few quick spot welds and some light grinding with sanding, and the problem is done.
The old collector pipe was seized with rust onto the end of the header. I destroyed the collector while removing it. Having to remake it, I used the opportunity to use thinner (lighter!) gauge pipe, and reinforce it where needed.
This being my first detailed look at the exhaust system, I was surprised and a little disappointed to see how heavy a gauge of pipe was used for the original setup. I felt like it was unnecessary on a car this small, especially one that's going racing. At the time it was built, I wasn't very involved in the build process of the car beyond writing checks to the pros (a lot has changed since then). If I knew then what I know now, I would've specified things a bit differently. At any rate, I'm glad to now have the opportunity and ability to do it my way.
The rust colored stuff there is weld-through primer. That Magnaflow muffler is a straight through design, effective and quiet enough, but kind of heavy. I may need to address that someday in the future. Maybe fab up my own muffler and get a chance to use all of those titanium shavings I've been saving.
With the old exhaust system, my car was relatively quiet. Maybe too quiet. shortening up the system by half might make it a little louder, but to guarantee that I get the volume I need, I decided to fabricate and install a megaphone.
The old exhaust system had several bends to get it up and around the rear axle. Don't need those anymore, so I was able to repurpose a section of bend to point the exhaust out the side. Retaining the muffler will keep the volume from being painful, but I still need to share with the world the beautiful music of an Alfa Nord race engine at full song.
Got the pieces back from ceramic coating. It was just the header, collector, and megaphone that were treated. They get sandblasted, then coated inside and out. I sprayed the muffler with Rustoleum High Heat spray paint. Perfect match!
This is how it lays out. Tomorrow I'll see if I can get a YouTube video of the noise , I mean, music it makes. I don't know yet myself, it was getting kind of late when I finished buttoning it up. So I haven't run it. It will need a few heat cycles to help the ceramic coating cure.
Been looking for some time for a new shift boot for my 1983 Spider Veloce . . . . yes, there are many black boots but trying to find the original color that also matches the dash (non black dash) Its kind of a light taupe color. Anyone? I guess I could buy a boot and have an upholster stitch one...
I recently bought a 74 spider which someone replaced the original rubber mat set with carpet. I want to replace that with the original rubber mats. Does anybody have any experience with the mat sets from Classic Alfa, Centerline or others that they'd recommend (or tell me to avoid)?