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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Ballast Part 2

Since first making the ballast for the racecar, it has gotten bigger wheels and tires, all the aero bits added, the electric power steering column (and the heavier, faster ratio PS rack), and a few Hill Climb safety bits and bobs. With nearly an empty tank, it rolled across the scales about 59 lbs overweight.

1983 lbs, where my class minimum is 1924.

I was able to drop 1 of the two 5/8″ lead plates, and also cut about 1/4 off the other one.

I got down to 1932 (8 lbs over minimum).

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I’m generally not comfortable with that tight of a margin, but I never run with that little fuel, so there’s a bit more wiggle room than it would seem.

 

Shop Project – Small Lathe Rebuild Part 3

Merry Lathemas!!!

UPS finally delivered: The quick change tool post with tool holders, boring bars, carbide insert tooling (up until now I had 1 single high-speed steel tool that the lathe came with), centering bits, and a dial indicator (and a few other odds and ends). This’ll be a HUGE step to making this machine productive. The only problem is that my tool-post wasn’t designed to take this kit, so I’ve had to make an adapter that threads over it to make it work. I’m not done with that yet, but I’m SUPER stoked to have some proper tooling for it.

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I next took some time to get the quick change tool post set up. This is going to make life SO much easier. As with most bolt on stuff, this kit was made for similar lathes, but not this exact lathe, so it wasn’t exactly a bolt on affair. It came with an M8 internal thread – 9/16 external thread adapter, because the newer versions of this lathe all came with M8 tool posts from the factory. Well, mine came with an M10 tool post. Fortunately, I have this handy-dandy lathe! So I chucked it up and drilled out the M8 internals to 11/32 (which is the standard drill size equivalent of an M10 tap-drill size), and then drilled a much shallower bore to compensate for the M10 post’s longer unthreaded shank. After that, I tapped it as deep as I could go with my M10x1.5 tap. Unfortunately, that tap wasn’t long enough to thread the full shank, but it was long enough for PLENTY of thread engagement, so I simply cut the top 8mm off of the stock tool post (yeah, taking a hacksaw to my tools? Not my favorite.), smoothed out the top of the post with a flap disk, and then ran the die back up the threads to clean them up.

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All that done, and she fits like a glove!

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And since I just cannot and will not leave well enough alone, I had to set up a few of the tools, get them aligned and make a few chips. The insert tooling is going to working with this machine A LOT easier.

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The quick-change tool post set came with a boring bar holder for a 3/4″ boring bar. The tool set that came with it came with…. 1/2″ round-shank boring bars. The last part is important because I can’t just throw them into one of the normal tool holders as it would be held in by 2 set screws against a round surface. That sketch-factor is outside of my comfort zone.

I’ve got a bespoke holder on its way, but that will then tie up one of the normal tool holders. That’s fine, I guess, but I’d like to use the boring bar holder I’ve got.

I says to myself “self… you know a guy with a lathe. He’s near and dear to you. I bet he’d make you a sleeve to fit the 1/2 boring bars into a 3/4″ bore!”

So I turned down a piece of 3/4″ stock to just under 3/4″ OD, then drilled it out to 1/2″ ID, and broke all the edges and parted it off:

It’s a decent fit, plenty good to do the job:

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The way these tighten down is that the sleeve would have a slit cut along its length, and a hex screw pulls this thingamabobber (technical term) up and clamps everything together. The concern is that the sleeve has a 1/8″ wall thickness, no matter how tight I make it, it probably won’t deflect the sleeve enough to adequately hold the boring bar, which brings me back to my original problem of sub-optimal sketch factor.

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After consulting with some much more experienced fabricators, the recommendation came to essentially make a collet out of it (something like this). So I got to work and cut 8 opposing slits on the bandsaw. The slits aren’t perfect (…they were cut by hand on the bandsaw), but it gets plenty of bite on the shank of the tool now.

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I took advantage of having my brother in town this week for Christmas to do a bit more work on this. We cleaned up the shop a bit and re-organized the messy tools area to make room for the newcomer.

We also made a couple of risers with machine leveling feet to go under the feet on the lathe. With the feet and risers, it’s about 3″ taller. And with it being already top heavy, I made the feet a few inches wider than the machine’s feet to give it a wider footprint.

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We used the engine hoist to pick up each side to measure for the feet, and managed to find a good balance point to move it across to the other side of the garage. To get it turned to be along the wall, we just used a 2×8 under the lathe bed and muscled it into position.

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And finally, I made a couple of parts for the race car! A pair of steering-rack stops to keep the 10″ wheels and tires from ramming into rubbed the front sway bar at full lock. It’s *usually* just a concern in paddock and grid, but: with the power steering and the faster rack, I really want to make sure we’re not smashing hard parts together.

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I got a nice, snug fit on the rack. It’s not really STRICTLY necessary, but I do like knowing it won’t be moving around much:

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As with any good project, there’s plenty left that I want to do to / for it, but this was a huge chunk of work to make this into a useful tool. I’m really stoked to get a bunch more trigger time on the machine.

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.

Shop Project – Small Lathe Rebuild Part 1

I know, I know. It’s not a Miata build, but it is Miata adjacent. I’ve already got some parts I’m looking to turned on it for my car. And it’s an interesting process, so I figured some of y’all might be interested.

I’ve been shopping for a small lathe for the shop for some time now, but kinda had a deal fall in my lap for a used, neglected, Emco 8×20 lathe. A buddy had bought it at a “used tool” auction at his work many years ago, then had a kid (and inherited his grandfather’s lathe that also needs work), so this one was just collecting dust.

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Only a moderate sketch factor with the rigging, but I stopped a couple times in the first few miles to cinch the straps down as it settled in place (and secure the rear door that had swung open), and it was fine the rest of the way back home.

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And just for fun, I turned Baby’s First Chip just to say I had before the teardown started. Because boy did it need to be gone through.

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With a little help from a couple friends, we got it down to my workshop. If you’ve ever seen where my shop is, you know how sketchy THAT was. I backed the trailer down the hill, then used the winch to slowly slide it off the trailer and into the workshop, with someone on each side to steer.

One of the first things I noticed (and was pretty worried by) was the runout on the chuck. Hopefully the entire headstock won’t need to be rebuilt, because I found the most likely culprit: a bunch of swarf built up between the back of the chuck and the lathe’s face plate. Hopefully tidying this up will improve that situation, or else I’m going to have to figure out what’s crooked in the system. The nice thing is that the lathe can be used to true itself up if need be.

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Next up was the sticky lever in the quick-change gear box for the power feed for the compound. Apparently they’ve been using grease in this thing instead of machine oil. This…will become a running theme. I let it soak in simple green then oiled it while the machine ran for a few minutes and that freed the lever up to move freely side to side. The lead screw will need to be taken off and THOROUGHLY cleaned, however, as it is caked in fine chips. This too will become a running theme.

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My next biggest problem is both the free play and stiction in the cross slide. The free play can be tuned out by adjusting the gibs and the tension on the nut that the adjustment screw rides in, but a lot of the stiction is from old, crusty grease. So, the entire compound / cross slide / top slide and apron are going to come apart to be thoroughly cleaned up. I’m not going for “car show” levels of cleanliness, but I want it to run well even if it’s not the most beautiful belle at the ball. Once again, a ton of crud under the tool post. I actually couldn’t find the witness mark for setting the tool post angle because it was caked in dirt and oil. It should turn much more freely now.

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Got the cross slide wheel & screw out. Again, CAKED on grease everywhere I turn (unintentional lathe joke!). To be clear, this isn’t grease as you think of it, just heavily applied. This is stuff that’s been on there for 20 years, dried up and left a thick coating of dry crap that has to be scraped off by a fine pick in many instances.

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And finally, the compound comes off the ways. This is the bottom of the compound, where it would slide on the lathe bed. As you can see, some surface rust (not anywhere it actually touches the lathe ways, thankfully), and a lot of old oil & dust and grit that will need to be cleaned off.

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With the compound, apron and lead screw off, she’s now pretty stark naked.

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Up next was to work on the apron (ie: the gearset that uses the lead screw to run the power feed for the compound, and rides under the compound). This is what greeted me when I took it off. Take a moment to click the picture and zoom in on just how bad it is. The amount of crud caked in the threading half-nuts, the caked on grease (more…). After I’d run it for a while, the handle for the power feed was jammed on and couldn’t be disengaged because of what ended up being a chunk of dried grease getting caught in its working. It was bad.

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A bath in the parts washer made almost no difference in the grease on the gear train there. I ended up to have to disassemble the power feed engagement lever and gear assembly and then go through the entire gear train and the lead screw, tooth by tooth, thread by thread, with a pick to actually get the hardened gunk out of the system.

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The compound angle was really tough to set earlier. This is what I found between the angle dial that’s pressed onto that arbor, and the tool post.

20171205_133947  It was a ton of work, but MAN everything turns smoothly now. It’s such a huge difference. I put the barest whiff of white lithium grease on it per the factory service recommendations, and then it’s maintained afterwards with 140W gear oil. 20171206_115325

She still needs work, but we’re getting close. I’ve got the final cleaning supplies (specifically, some 0000 steel wool to clean the ways and gibs) coming in the next day or 2, and a handful of replacement parts and upgrades that should be coming next week.

Electric Power Steering Conversion – Part 4

HAHAHAHAHAHAAAAA!
Man, it’s so good. The adjustments are pretty darn sensitive. We spent the first 6 or so runs dialing out a little bit at a time until we got to the point where the previous spot was better and dialed it back up that notch.
Video won’t show much, but being able to make fine adjustments was a nice change of pace… it went from having to be muscled around the course to finally being able to have soft hands on the wheel.

All in all: if your class allows it, or if you’ve got a street car without PS, this is a great bit of kit 😀

Video:

Electric Power Steering Conversion – Part 3

Continued from Part 2.

Deech came over to help out with the wiring (which is to say: do the wiring) so that it would actually be done properly.

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I decided that as much as possible would go into the switch panel box, just to keep everything out of the weather. The controller was secured to the box, then wired to switched power & ground through the switch box panel. We connected to the rheostat, and we were able to use a pair of unused wires for the clutch pedal switch that were already wired into the switch box (but not used) to carry the power and CANBUS signal to the ECU on the steering column.  We tapped into those wires near the column and spliced the connector on.

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Before tidying up the wiring completely, we went ahead and did a systems test to make sure everything worked. Much to my surprise (because I worked on it…) it worked properly the first time.

“Like a kid at Christmas” is a pretty accurate descriptor. The fact that the steering turns easily without the lever-arm of the steering wheel attached was astonishing. What else can you say other than it just works, as advertised. I ended up needing to turn it down to about 1/3 power on the rheostat just so that there would be some heft in the steering system, even with the tiny steering wheel.

A proper test is coming up at this weekend’s autocross, where we’ll spend some time tuning it in to where it’s happy on course, and happy-enough everywhere else.

Continued in Part 4