The War of Eternal Mikuvan Improvement: Operation DEAD CAT BOUNCE; SHOCKS AND AWE

Saturday, December 21st, 2013 @ 6:43 | mikuvan

Ongoing van facility upgrades have been continuing since September. Basically, every time I go to Rock Auto to spec out one part:

I needed ONE thing…

This ends up happening. But everything is so cheap ;  _  ;

So I need to find an excuse to use them! Improvements have focused on non-engine work, since I still don’t believe in internal combustion. . This isn’t to say that the engine and transmission have been purposefully neglected, but I’m just not going to add a turbo kit any time soon. Believe me, I did want to “just add a turbo” with no other changes and see how long the engine would last, but apparently you don’t “just add a turbo” – everything else has to accommodate it or it would be a waste, so there goes that.

Mechanical work has been at the forefront – upgrading all sorts of other infrastructure first, such as the suspension, doing bodywork repairs, and maintaining that which would prevent spontaneous grenading of any component. And in continuance of forced and hackneyed tradition, I’ve given all of these major ops a cheesy bad pun name. Don’t worry, I spend only a few seconds thinking up each one, at most.

Operation: Dead Cat Bounce

Ever since I got it running, one characteristic of Mikuvan has been “That Weird Rattle”. It only occurs under high loads at low to moderate RPMs, such as pulling onto the highways or going up a hill without dropping a gear. It was a very hollow metallic rattle, not like something was interfering mechanically, but was always worrisome since it indicated that something could be interfering mechanically all of a sudden. I had a number of theories revolving around the transmission and loose bolts in the crankcase, but careful interviewing of passengers focused the sound to the middle of the right hand side, coming from directly under.

Well, there’s very few things going on in that area – pretty much only the exhaust system. And a rattle under high engine loads probably indicates something loose or jiggling with it.

A tap with a rubber deadblow mallet confirmed that something small and jiggly was indeed trapped in the front of the catalytic converter (or “the cat”). Since I automatically assume that every component on this thing is near, at, or past its end-of-life, I figured that the catalytic element was completely destroyed and has slowly become a pile of ceramic pebbles. But it never sounded like that many pebbles, so maybe a little chunk just fell off or something!

Either way, time to shake them out. Except everything on the exhaust path – and I mean everything – was rusted solid. Half the time, I couldn’t tell what was bolt and what was nut, and the rear cat hanger had become this sort of malformed rust icicle that I think had fasteners on it at one point, but which were now amorphous lumps protruding from a bracket likely salvaged off the Titanic.

Out comes the cutting wheel. I’m going to have to do some fabrication to get the system back together anyway, so I had no remorse in removing these by force.

As I learned after cutting this apart, it was in fact a nut.

After removing the rear spring mounted hanger (why the hell is this specific area on springs when the whole thing is on flexible rubber hangers?), off comes the cat. First, the gasket is utterly disintegrated, and there are erosion channels in both it and the mating flange. So I’ve definitely been having an exhaust leak issue along with it.

This is one more layer of refab I’ll need to take care of. Haven’t I learned by now that any time I touch something, I’ll eventually have to re-mine the iron ore from scratch and derive its engineering from first principles?

Well, the catalytic element is clean. Very clean, in fact – I would have expected even a little graying or blackening, but this thing was still stark white. No missing chunks or holes, so what is going on? Let’s turn it upside down and shake it:

I literally laughed out loud, in real life, in the garage, at like 2 in the morning.

Yep, that’s the shield off an oxygen sensor. The O2 sensor is located at the exhaust manifold, so it probably fell off and has been jiggling in the cat for who knows how long. I haven’t seen any Idiot Lights being thrown, so I can only presume the O2 sensor itself is still working, maybe just a little naked.

What to do now? I had taken the exhaust system apart in the garage with no way to jam it back together. I’m out a gasket, two studs, and need an evening’s work in resurfacing the mating areas. I’d need to buy some exhaust gasket material or sealant beforehand.

Solution: Leave the cat off, and drive with straight pipes.

If it weren’t so very illegal, I’d post a video. It actually didn’t sound bad. For the tiniest sliver of a split second, I wanted a ricer exhaust.

After stopping by Advance Auto Parts (all customers wondered what the hell just pulled in) to gather new exhaust studs and high temperature sealant, it was back to MITERS for the surgery. I first cut the studs off nearly flush with the mating surface, and cleaned off the old gasket with a wire wheel on an angle grinder and then some hand-scraping. Then I slowly drilled through both using incrementally larger drill bits to keep the hole centered and the drill controllable.

Usually, for fixtured parts, I just blast with only 1 intermediate step, or even straight to the final hole size, but I was counting on using a small drill bit to start the hole in the dead center of the stud remnant. But this was not a traditionally fixtured part – it was hanging by its folded sheet metal flange in an extremely beat-up vise in MITERS, on a table that has non-lockable 12″ caster wheels. MITERS has different definitions of fixturing.

New studs installed with a healthy dose of antiseize grease.

I wasn’t able to locate any high temperature gasket sheets, so I resorted to mainlining the sealant and used it in between the two mating faces as an in-place gasket. Then I went totally overboard around the outside. So far, this seems to be holding up, even though it is way up there in terms of bad hack fixes and might not last long.

And that was it for That Weird Rattle.

In one of the “well, it was on clearance” orders, I did pick up a new O2 sensor because (again) I figured the current one was at the end of its life. For $10, I got a Bosch OEM-replacement sensor. It has a way cooler shield:

Back in the confines of the garage at 3 in the morning (when all the middle managers and white collar types who live in this condo complex aren’t awake to nag me for ‘servicing’) I pulled the O2 sensor from the exhaust manifold and replaced it with the new unit. The old one seems to be indeed intact, but missing its shield. Gee, I wonder where it could have went.

I discovered upon removing the exhaust manifold heat shield that some asshat had attempted to weld this thing at some point, and either failed miserably or didn’t know that welding cast iron is a very difficult to get correct kind of thing. You don’t just wave a “splatter stick” at it like this weld. There’s a barely visible hairline crack running parallel to the weld bead, about 2 inches long.

Welp. That’s going to have to wait. It doesn’t seem to be causing any problems, and is covered completely by the heat shield anyway.

New O2 sensor in, with the heatshield removed. This operation required me to resort to vise grips, because the only wrench I had that was big enough  to fit over the hex shank was too big to maneuver into the region. I’m sure there is a special bent wrench that is in the list of special service tools just for this.

Another small, random part has been replaced. One at a time! In the future, the Ship of Theseus Paradox will be known as the Charles’ Van Conundrum.

Shocks and Awe

One of my favorite van activities, occurring at about 50% of all stoplights, has been this sort of thing:

I’m not as pro as him – I can’t maintain it at-speed, only rolling very slowly or at a full stop. With a load of 6 people, the amplitude can get pretty ridiculous.

Overall, what I mean is, the shock absorbers are toast. As much as I love doing “The Thing” (one of many things we call The Thing around here), I’d also like to avoid riding like a battleship – even like a Space Battleship would be okay, but not a normal one – or dying in a rollover.

This time, I explicitly went hunting for “cheap but good” shocks. Through recommendations and haunting the sales of Rock Auto, again, I ended up with these KYB units.

I went for the “Improved Handling” category because I figured “Original Ride Quality” meant “slightly less battleship-like, such as perhaps a trash barge” and that wasn’t appealing. The smaller boxes are sway bar connecting links. While doing the suspension inspection, I noticed the rubber bushings on the “original” ones were pancaked and cracking – the suspension has been getting more and more creaky in colder weather. So this was a “Oooh, it’s on sale!” item which I actually did need.

A few days after, the operation commences on my loading dock of choice. I attacked the rears first because they were much easier to get to and did not involve removing wheels. The rear left was super easy to get to.

The rear right required some Technical Contortion.

The worst thing about it was the upper anchor bolt. I had one click of ratchet movement for this whole thing, and I had to wrap myself around the rear axle to get to that. After the initial tension breaking, I actually used a second wrench driving the T-handle of my awesome right angle handle-drive ratchet thingie to fully remove the nut.

I should be getting brownie points from Harbor Freight, since I think I’ve personally sold 10 of those to people. On the other hand, I’m not sure I want to eat a Harbor Freight brownie.

A removed rear shock absorber unit. This thing was covered entirely in black undercoat grease, and was also very, very dead. Like, dead to the point of needing only around 10-15 pounds of force to push around. I heard air gurgling inside whenever I changed directions. On an automotive force scale, this was probably almost nonexistent.

I wiped off the grease to find a Mitsubishi OEM part number, as well as KYB logo. I’m going to guess these are literally “original equipment”.

Staying true to the brand (which I didn’t know anything about just days before).

And the rears are done. The fronts had to wait for a day when I could roll into the garage to use the lift.

And up we go.

Note that between the rear shock replacement and now, I suffered a rear right tire failure, so the narrow wheel is a “donut” type spare I purchased for all of $25 a while back when I had to dispose of the very rusted-out full-size spare. A full complement of winter tires is on order.

With the front wheels removed, the s way bar links were extremely easy to get to. Here’s the new front right side installed. The old rubber bushings were hardened donuts, and the whole thing was actually loose, having lost tension long ago most likely.

Not pictured here, but while I had the bar loose, I also took apart and inspected their frame-mount bushings (They look basically like that). These weren’t in bad shape, so I cleaned, greased, and reused them.

I dumped some penetrating oil onto the shock absorber anchors and let them marinate a bit while doing the sway bar links.

I cleaned the old mating areas with isopropyl alcohol and some very fine sandpaper to loosen the debris. Underneath all the underbody spray, I can tell more parts of this used to be white.

There’s nothing very exciting about the shock installation, since like the rears, there were exactly 2 bolts involved. I had trouble with removing the lower anchoring bolts, which had nuts that were more rusted on their threads. Not wanting to shove everything right off the lift by using a bigger wrench, I just whipped out the impact driver again for those two bolts.

All in an evening’s work, and hopefully now nothing will creak either. I have yet to get a chance to road test for robust anti-ship suspension behavior, since there were some other things I wanted to take care of as long as I had the opportunity to stand completely under it.

little things

There’s some things I do that aren’t so epic and thorough as to warrant a poorly thought out name, but in the interest of completeness, I recorded them anyway.

I bought a can of underbody coating spray a while back, meaning to treat some not-yet-problem-spots to prevent them from becoming such later. Up on the lift, I could get at them much easier.

One of them is this front …. brackety thing that holds the steering rack and lower half of the A-arms. It was fairly rusty, with much of its previous undercoat treatment having flaked off, but not bad rust – just superficial. I knocked off much of it with a wirewheel, then manually with a handheld wire brush – whatever flaked off on its own was removed and then the whole area cleaned and resprayed.

Another not-yet-problem spot was this corner of the rear right wheelwell, which was showing the same signs of cracked undercoat with superficial rust. Luckily, this isn’t a hole yet. The same procedure was followed here.  With my rear hatch repair going off pretty well, I’m plotting ways to tackle the sides that DO have holes.

But before that, back to the interior!

What good is christening my rolling Craigslist wreckage MIKUVAN if I can’t blast Hatsune Miku from it obnoxiously? Well, I can, but not very well. The sound system is what could be called “stereotypically 80s” – cheap paper cones, tiny drivers, hollow panels and dashboards making for all midrange and nothing else.

I wasn’t out to completely re-engineer the system or add 12″ subs, but I did score a nice deal on some Pioneer TS-D1002R speaker sets for $25 a pair recently. Nobody really uses 4″ speakers any more, so I was pleasantly surprised when I was haunting eBay that there were many low and closeout/clearance type sales going on. The Pioneers seemed to be the ones with the least hype. I figured anything made in this century (literally… this century.) would be an improvement.

I began with an overall inspection of the stock sound. The left speaker is really easy – a little panel pops off and it can be replaced without hassle.

There is a very pitiful but honorable attempt at a subwoofer installed in the center underneath the dashboard. It’s a little plastic, stuffed box that is smaller than most computer speaker subs.

It was also empty. Like, no driver in it at all empty. I can’t imagine Mitsubishi leaving in literally everything but the driver if someone decided to forego the upgraded sound package or something, so I assume it was taken out some time over the past 24 years.

I didn’t have a voltmeter or oscilloscope at the time, so I couldn’t verify if the internal amplifier was alive. Given that it might have been driving a speaker with infinite! impedance, it’s probably fine.

Comparing new with old… The stock driver is a 7 watt unit. I think the PC speaker inside my old desktop from 1998 was larger.

Left: Super easy!

I only had to splice the two (20 gauge, such power!) wires – my little nano-iron is seen on the bottom right. I used up the rest of the exhaust silicone glue on it, by the way, since someone dropped it years ago and cracked the handle near the base of the heater. The element was jiggling inside (sounds familiar…), but that’s no more.

Center: also easy. At this point, I verified that the system was working, but very weak. It could very well be “broken”, or the amplifier IC half-dead.

This is left to a future investigation or replacement by a Ragebridge pulling a class-D at 100kHz.

The right side: You must be shitting me.

Nope, I didn’t get a nice little hatch out of Mitsubishi this time. The right speaker bracket is second to last on the list of things to do in order to remove the dashboard. After scouting the Internet, specifically the Delica forum (this thread), I found how sneaky people would do it.

The operation involved maneuvering an 8mm socket (the right speaker is mounted with 2 nuts on studs, not 2 screws) into the removed glovebox and around the corner. In many ways, it reminded me of flying a guided missile into a secret switch panel in Descent II’s level 13 to obtain the Omega Cannon.

I was a huge Descent player back in the day – don’t worry about it.

Unfortunately, the instructions pertained to a Japanese or Euro spec L300. Clearly there’s something else going on in the US spec Van, because there was a Bracket of Irritation in the way and I could not reach the mounting nuts without removing it first. This was a half hour operation on its own as I figured out the exact right combo of strangely angled sockets and extension bars to get all of the hardware.

It was also really rusty (surface only, fortunately), so it left this disgusting smear behind. Most of it came off with petrochemical distillate scrubbing.

Said Bracket of Irritation.

See where the Bracket of Irritation goes? Almost immediately behind it is the necessary mounting screw. Anyways, this is a post-installation shot – after the BoI was removed, I could remove the speaker, splice the cables, and reinstall.

With this mod complete in one night, I’d say the results were worth it. It’s not a sonic drag racer – I’d rank it somewhere near “Mid-2000s economy car”. The giant hollow dashboard doesn’t really help the case, but with appropriate EQ diddling, I get tremendously improved low-end response (read: discernable).

I may revisit the subyiffer (does not qualify as subwoofer) issue later, but I am still satisfied with the two stereo channels alone.

Stay tuned for the latest battlefield reports!



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    6 Responses to “The War of Eternal Mikuvan Improvement: Operation DEAD CAT BOUNCE; SHOCKS AND AWE”

    1. Andrew H. Says:

      You’re right! Oxygen sensor socket:
      offset with a lil’ slot in it so you can slide it over the wire.

      also, “brackety thing that holds the steering rack and lower half of the A-arms” is the front suspension crossmember :P


    2. FrankTheCat Says:

      I just started to do suspension work on my car. I’m infinitely jealous of all the GODDAMN SPACE YOU HAVE TO WORK WITH. To replace the steering rod bushings on my ’97 Saab 900, I have to work in a 5″ wide gap between the engine and the firewall. Removing the rear shocks requires crawling into the hatch and shoving your hands in the tiny space between the top of the shock towers and the rear speaker pods. Sigh.

    3. the chuxxor Says:


      And yeah, truck-like levels of space. It’s clearly for batteries.

    4. Ned Says:

      Did… did you use silicone sealant on the exhaust system ahead of the cat?

    5. the chuxxor Says:

      I used a possibly silicone-containing substance marketed as exhaust sealant. I’m fairly sure it’s for plugging small cracks and leaks, not for gasket duty, but…

      I also have no downstream O2 sensor, nor OBD ° 3 °

    6. Jeremy Bloyd-Peshkin Says:

      When in doubt, red RTV for sealing exhausts will work. You just don’t want any arrant bits inside the pipes and ending up in the cat.
      I did recently (read: yesterday) discover that most “DoItBest” hardware stores have sheets of high-temp gasket material in the plumbing section. Some testing is in order to see if it will hold up to exhaust, but preliminary blowtorching looks promising.