Operation: Bad Timing and Mikuvan Adventures

Monday, May 20th, 2013 @ 5:25 | mikuvan

I think my new life mission is to collect the 3 legendary birds derpy Japanese 80s vans. Here’s an interesting review of the 3 competing Japanese marques in the November 1987 issue of Popular Science! As an enthusiast of things which go quicker than they need to, I’m glad to see the Mitsubishi Van win the most sporty award. All of these models were discontinued by 1990, and I think the Nissan in particular is the rarest since there was an active mass recall for them. Definitely next on my list…

Anyways, as previously announced, Operation: BAD TIMING went down Saturday, and I am proud to say that it was a resounding success; the sound you hear is a hilariously lawn-mower-sounding 4 cylinder Mitsubishi 4G64 powering a vehicle which resembles a normal American minivan, just with the nose belt-sanded off and a few corners hit with a deburring tool.

Here’s the story of what all came together on a bright, sunny Saturday afternoon in (a basement in) Cambridge.

The scene of the crime. A few days before, I went to the neighborhood Harbor Freight and invested a very low 3-digit sum in a 3-ton hydraulic jack and 3-ton jackstands (among other handy accessories). As someone who has used HF equipment for years, I’m fully aware of the need to de-rate everything Harbor Freight tries to sell you by 50+% in order to use it safely. Especially on a matter which would probably reduce me non-consensually a few inches in thickness if the equipment fails. The van weighs 2910lb (1.5 tons, basically) empty, so 3-ton everything it is. Jackstands were placed according to The Official Derpy Van Strategy Guide – there’s a convenient round frame rail on the underside that fit the stand cradles exactly, almost like they anticipated people doing this or something.

The jackstands enabled free access to the underside of the vehicle in order to release several engine cover/timing belt cover bolts, and to release the lower transmission cooler and radiator coolant feed lines.

To get to the timing belt, the radiator and all accessory belts and pulleys needed to come off. This stage was basically done by Official Strategy Guide and some finger-feeling. The service manual doesn’t show some steps, figuring you know this stuff already.

For instance, the only step in radiator removal was “RADIATOR”, not “Remove these 2 bolts, this hose, and this other hose but from the underside of the car, and drain the transmission first so you can also get these two other hoses. Oh, by the way, the radiator shroud doesn’t clear the main cooling fan, but it will if you yank hard enough so you don’t have to take these 4 other bolts out.”

Yeah. That’s how you do it. “RADIATOR”. We decided that yanking was the best way.

After the radiator was wrestled out, I started attacking the fan and fan clutch. This right angle T-handle drive ratchet came in handy immensely for many of these tasks – among others being a makeshift impact wrench and hammer.

Leverage was used to break the fan bolts hold, then the T-handle used to quickly extract the bolt. There was no space to actually put the electric impact wrench I bought in there.

One of the fan nuts needed some Vise Grip Assist to untighten. It didn’t make it back onto the fan hub afterwards. Surely 3 bolts out of 4 is enough…

About midway into the disassembly process, and all the accessory belts have been removed.  The next stage was to remove the crankshaft accessory pulley, which was another 4-bolts torqued way too tight. I actually had to have Adam counter-torque me through the camshaft pulley (holding a socket wrench locked the other direction from my torquing) and rock my own wrench back and forth to break it loose!

After the accessory pulley came off, a few bolts later and the timing belt cover could be removed.

…and this what fell out as soon as we did that. A ball bearing.

Not a good sign.

As the cover was removed further, several more ball bearings fell out. This was not looking good.

A shot of the front of the engine with timing belt components exposed.  The lower left, short timing belt is the balance shaft belt, to be replaced along with the main timing belt. Its tensioner was actually pretty intact. The main timing belt, however, was a different story.

The tensioner is a “offset cam roller” kind of thing mounted on a swinging, lockable mechanism. The mechanism, a single steel stamping, was just fine. But where the hell is my tensioner?

Oh, there is is! At least, that’s the inner race. The actual tensioner roller itself was freely jiggling around inside the timing belt case. It seems that the bearing disintegrated long ago, scattering balls everywhere inside and causing instantaneous and likely fatal timing loss for the engine.

I purchased a full timing belt components kit, so it came with the 2 tension roller assemblies and belts. This is the new balancer belt assembly.

Bear in mind I was not the person taking the pictures, or you’d likely have gotten a picture of the main tensioner roller with every ball bearing recovered and piled on top of it. Others are not so OCD about photos as me, so for now, enjoy this picture of the lettering on the timing belt.

And this photo of nothing in particular. You can kind of see the new (green shielded) tension roller for the main timing belt installed. Much carb cleaner was used to make sure the mating surfaces and pulley faces were clean, then the new timing belt was installed. We didn’t go to extraordinary steps to clean everything, nor was the water pump replaced.

We had thought that “line up the timing marks” was going to be an arduous process of HERE, HOLD MY EVERYTHING WHILE I PLUG IT IN, but rather found that all the engine parts just sort of rolled into place. The cam shaft has 4 big springy detents from valve actuation, one of which was just the correct timing. The balancer shaft naturally rotated from gravity to the right timing.

It’s almost like it was designed this way or something.

After the timing belts were installed, we plugged the (newly replaced) distributor and rotor in, connected the spark plug cables, and tried a test run. This was the make-or-break here – if something was terribly amiss, it would show itself upon cranking. If the engine still didn’t start, I was prepared to keep removing things on the spot.

The video is of the second test run. On the first, we were all taken by surprise as to how quickly and smoothly it started up. I was honestly expecting explosions or jets of flame or something.

The engine idled smoothly and revved up smoothly. I blipped the throttle to about 2500 RPM briefly before we remembered that it had no cooling whatesoever and decided to end the test. Success for now.

After the test run, everything is getting reinstalled and refilled.

Your pretend-mechanic hoodrats of the day are Adam, Dane, and yours truly.

Buttoning up everything and rerouting all the cables. The passenger engine everything compartment hasn’t been this together since I got the thing.

Finally, after about 5 hours of work, Mikuvan is back together again. We finished at around 7PM Saturday, still early enough for the sun to be out!

Naturally, a high-stakes all-hands test drive was in order.

The total mileage of the first ever test run was about three or so. Not very much, but enough for me to observe that everything was in good working order (up to 3rd gear), that nothing was overheating or making weird noises, or that for some reason it really wanted to turn left. Hell, I’ve ridden in friends’ cars which were consistently less reliable.

The evening resulted in one discovery: the source of the coolant leak. First, a major leak from a misplaced hose clamp on the radiator from our servicing. But second, a persistent but lower flow leak which left me puzzled as to why I was leaving a bread crumb trail of coolant droplets everywhere. It turns out that someone in the van’s 23 year history had sheared a bolt on the thermometer to radiator hose connection, so the gasket was completely uncompressed and leaking.

Well, I sure fixed that.

mission 1

The conclusion of the test drive was the N52 parking lot:

That evening, I topped off the brake fluid and also refilled the gas (with 93 octane premium for sheer kicks) and cleaned off some of the bird shit stains and tree droppings.

Sunday has been filled with gratuitous driving (to places I would normally scooter to or even walk and stuff… amazing, right? It’s the weekend, I can park anywhere!) to double check and recheck reliability in starting and fluid leakage. At this point, I haven’t stalled out once, nor had any more issues with dripping fluids with the exception of some small oil dots that appear after a long period of parking. This tells me that there’s probably a very small but consistent oil leak somewhere. I’d like to get this thing on a lift, still, to fully clean the engine and transmission so I can watch oil leaks form.

Other things I have noticed include a pretty rumbly ride, which could indicate bad bearings. At 151,000+ miles, it’s about time for them to let go. However, during the time on jackstands, I did not notice any wobble or looseness in the front at all. It could just be a natural noise from sitting right over the front suspension.

I have yet to take Mikuvan on any highway cruising to obtain true steady state operation; this is on deck for this coming week. At this point, it only has a pile of minor issues to redress:

  • The body panel rust holes on the underside, and the bumper
  • The swivelly chairs can’t lock in place – the mechanism is obviously broken on both of them.
  • The broken coolant gasket bolt can be resolved by buying a new thermometer unit
  • The idle is still erratic, though I have yet to stall out. It varies between over 1000 RPM and what appears to be 450 or less (expected: 750rpm). The idle air control servo is known to get sticky over time.
  • The front blower is broken! I don’t mind not having air conditioning, but some moving air would be nice. The blower assembly does not seem to be accessible short of an entire-dash teardown, however. I may get desperate enough to do so.
  • Rims
  • Subs

This week, my intention is to maybe take it to a detailing shop to clean the rest of the superficial imperfections out (stuff I can’t attack with a towel and kitchen counter cleaner) and to actually register it. I’m already having immense amounts of fun trolling drivers of more conventional modern cars with its Zeerust-future look and 27 foot turn circle. My ultimate fear is not that I have to learn to handle its peculiarities, but that I’ll forget that everyone else has wheels in front of them. I don’t have front wheels, just middle ones.

 

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    2 Responses to “Operation: Bad Timing and Mikuvan Adventures”

    1. Alexander Says:

      It’s… Beautiful… FSM, I haven’t been so happy to hear an old engine crank over since my dad bought the Triumph from a barn…

      Congratulations Charles. You earned it!

    2. FrankTheCat Says:

      Probably needs wheel balancing and an alignment to end the pulling/rough ride. Depending on the shop, they might refuse to do an alignment if all of the suspension bushings are sufficiently disintegrated.

      And the Toyota Previa should be easier to find than the Nissan torchvan.