Transmission Failure

It was bound to happen eventually, but the law of averages finally caught up with me. At the last event, something went very very wrong with the transmission. Not enough to disable the car, but it came in from a run and was stuck in 2nd gear. We were able to reef on the shifter until it popped out and into the neutral position, and got it loosend up to where 3rd and 4th were usable (but really really hard to find at speed). 5th and Reverse were completely locked out.

Upon inspection at home, I expected that there was an exploded shifter bushing inside the turret that was fouling things up, but the one in there is delrin, and shouldn’t degrade and get brittle like the stockers. There was no evidence of debris in the turret, so the transmission had to come out to get the good spare in.

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While I was under there, I realized that there were a couple of brackets protruding into the tunnel that interfere with the transmission going out / in from the bottom, so I did some Prepared things to them and…let’s just say they’re not a problem anymore.

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Pro-tip: there’s a bunch of different bolt lengths and sizes holding the transmission to the block and starter. Organization is important.

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While pulling the transmission, I found a coolant weep from the cap on the back of the head that always fails. I guess it was pretty close to failure when it got bumped by a wrench or socket disconnecting the transmission from the block, so I replaced that while I had everything apart. It’s much easier with the transmission out of the way.

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Now’s where stuff got decidedly un-fun: I’d forgotten, because it’s been an age since anything like this has gone wrong with the car (just before 2013 Solo Nationals, IIRC) that the mating between the Competition Clutch and the transmission input shaft has always been a massive pain. Honestly , it’s nearly a press fit. It’s obviously not, because it works, but ever single time I’ve had to work on it, it was a matter of getting the transmission close enough to start a couple of bolts 180 degrees off from each other in the bell housing and then slowly tighten them to pull the transmission into the clutch. Obviously, that’s not what you WANT to do, but I’m going to keep telling myself it was careful so it’s fine.

I have other friends running the same twin-disk clutch without these issues, so I’m pretty sure mine’s just on the tighter side of the tolerance.

The point of all this is that after one and a half hours under the car, we weren’t able to make any progress in getting the transmission in. We just could never get quite the right angles in 3 dimensions while working on our backs. After being thoroughly exhausted by that, we decided to pull the motor.

….to install a transmission. I know. But it was going to be easier to work on everything out of the car vs under. In about 45 minutes we had the transmission out. We then spent the next hour once again fighting to get it on until it seated JUST far enough to get the aforementioned pair of bolts started and pulled the trans in.

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We stopped for the night after getting them mated and picked back up Saturday morning. From there, it was 2 hours from turning the first wrench to do up the rest of the bellhousing and starter bolts, until firing the engine.  Another 30 minutes and the exhaust, intake, prop shaft, trans fluid, shifter, coolant bled, etc.  were done and I ran the car through a warm-up cycle to make sure everything was working as designed. With the exception of that damn clutch, I LOVE LOVE LOVE how easy this car is to work on.

Less than 3 hours from engine and trans being out of the car to wheels on the ground and race-ready. That *may* be a personal best.

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That afternoon, I took a couple hours to dig into the transmission and a) see how they go together (and realize I’m not cut out for working on them), and b) see what actually broke.
What I found was the counter-shaft (the one offset from the input and output shafts) was *TWISTED* so that the wheels that should move fore and aft on those splines couldn’t, jamming it in gear, and locking us out of the 5th / reverse gate all together.

Click to zoom in, it’s impressive just how bent that shaft is.

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I’m only making 130 whp, but I guess 10 years of clutch-dump launches finally caught up to us. Given that consistent abuse, I’m pretty impressed it held up as long as it did. Because it wasn’t a gear wheel, or a shift fork or syncro, something relatively straight-forward to replace, the transmission has been relegated to the scrap bin. Before I tossed it out, however, it was recommended to me that an actual input shaft makes a FAR more accurate clutch alignment tool than the plastic ones every clutch kit ever comes with, so I cut the last foot or so of the input shaft off to keep as a useful tool, so I guess the transmission failure wasn’t a *complete* loss.

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Shop Project – Small Lathe Rebuild Part 2

With the rest of the supplies to clean it in hand, it’s time to get back to it.

I really want to show the Before and After in the same shot. 0000 Steel Wool and WD40 (and some elbow grease) did the business on that crud.

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The spindle face got a similar treatment, though it took much less effort. Load up a piece of steel wool with WD40, then turn the motor on and it basically cleans itself.

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With the big cleanup done, it’s on to the ol’ “install is reverse of removal.” First the carriage goes on…

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Followed by the apron and lead screw.

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Then the cross-slide, compound and spindle go back on. She cleaned up fairly well if I say so myself!

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The shear pin for the lead screw was pretty well boogered on removal. Thankfully, I had this handy-dandy lathe with which to make myself a new one:

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After getting it back together, the cross-slide feed was still really sticky. I thought maybe the feed screw was bent (because it’s super skinny). I took it all apart and everything measured fairly straight, so I dove a little deeper and found that the graduated ring was binding up against the screw’s housing at the same spot on every rotation. If I took the ring off, the handle turned perfectly smooth.

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I could make it loose enough to work but then it wouldn’t hold its position, or I could make it tight enough to hold its position and it would be impossible to turn through that rough spot. You can sort of see where it’s interfering here, on that dark ring. I broke out the emery cloth and a fresh can of elbow grease and spent a few minutes knocking it back just enough that it turns nice and freely now.

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Next, the tail-stock’s alignment was an unknown quantity, so I wanted to take the time to center it up correctly with the bore of the chuck. Usually you’d use a couple of tapered centers for that, but, well, I don’t have any of those yet. I turned a center from a piece of scrap steel rod, and then used a centering bit in the tail-stock (which also comes to a point) and used those 2 points to get it trammed in. It’s probably not *perfect*, but it’s well within good-enough range.

Before:

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After:

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Next week, the quick change tool post arrives. I’ll need to make a spacer for that, get the tools aligned, and get some feet made for this thing. After that I’ll…probably… have motivation to clean it’s spot in the shop, and then, at long last, put this thing to work.

Split Lip Bumper Repair

My front bumper has had a split in it for ages, that’s been progressively getting worse. Honestly, it’s impressive that it’s lasted as long as it has, through nearly 10 years of dedicated autocross use.

I found a piece of *cough* scrap sheet metal to make a patch to strengthen the area:

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I figured 10 rivets would be a nice, round number. It obviously doesn’t need that under static conditions, but when you hit a cone at 50 mph, more is probably better.

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After a couple minutes on the drill press, then belt sander to debur, I positioned it on the bumper to transfer the holes through.

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Final positioning before riveting it in place.

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And the rivets in. Job done. And just picking up the bumper I can feel that it’s far stronger now, with a lot less flex overall.

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