By on September 1, 2017


timing chain

Tamar writes:

Hi Sajeev,

Hailing from Myanmar, I have a first-gen Toyota Mark X. Forbidden in the U.S., and of interest to many JDM enthusiasts, I happen to think it’s just a stretched Lexus IS 250 (but not quite a GS). It’s got the 2.5-liter 4GR-FSE engine, and I’ve had this cold start rattle for a few seconds every morning, and sometimes during the day as well. The issue’s well known and attributed to the cam gears in the VVTI system. Mine is a 2005 model with more than 100,000 miles on it, so I wouldn’t want to spend a substantial amount of money if it’s not necessary.

So, if there are makeshift fixes that’ll hold it up until I let it go in a year or so, I’d like to know. If it is a real issue that threatens engine failure, I’ll get it fixed. What would you do?

Another problem: I think the Mark X is well made and mostly a nice car, but I have gripes with its (surprise!) steering feel. So I swapped out the steering rack bushes with aluminum ones (pretty hardcore, huh?). The on-center feel improved a whole lot, and I now have this hands-on-asphalt feel in a Toyota midsize sedan. The problem is, once I start to turn the steering wheel (this being electric steering), it’s floaty and I still can’t feel how far I’ve turned the wheels! I never thought a car with so much feedback on center would have problems with feel while off-center. For better steering feedback for the EPS system, I’m thinking of pulling the fuse for the electric steering. I looked for the answer on the interwebs but couldn’t find any — would running the electric power steering system without power assist harm the innards of the system or not? I find a lot of people encouraging it as an enthusiast’s option, but no mention of possible harm to the steering system or not.

What say you?

Sajeev answers:

How cool is it to get a Piston Slap query from Myanmar? Very cool, as recent events encourage me to get another stamp on my passport.

To your first query, cold start rattles are annoyances at this point on the depreciation curve. The forum posts you mentioned mirror the “problem” I have with my ’95 Lincoln Mark VIII. Just last week I noted how Houston’s triple digit weather (i.e. hot oil) effectively silenced my rattling timing chain guides upon cold start. Sure, there are chain guide upgrades to Ford’s Modular V8, but considering these motors are good for well over 250,000 miles before losing significant amounts of power…why bother?

Run synthetic oil and let the motor rattle when cold. It’s not gonna change anything for a long, long time. If the motor’s new to the synthetic stuff, it might leak in a few spots (oil filter adapter gasket), but hopefully it’s no worse than when I made the switch on my Mark VIII. That’s a small price to pay for the extra protection.

Your second question?  Go ahead and pull the fuse (or disconnect the wiring harness) to the assist motor. If common sense and GM recalls are any indication, these systems are designed to operate even when the motors fail to provide assist. But your tiller will definitely hate you tugging against that poor leather wrapping with every labored yank on the wheel.

Unlike my power steering-free Ford Sierra, the Mark X is a heavy vehicle with an engine above the turning wheels. Since the tires are significantly larger (and the tiller smaller) than old-school rides with no power assist, just a single maneuver into a tight parking spot shall make you regret this decision.

I wouldn’t even do the aluminum bushings — I hate unnecessary NVH — but since you did, I reckon you’ve done all you can to improve the Mark’s vague electric steering. Perhaps one day there will be a superior motor upgrade for all systems!

[Image: Vasyl S]

Send your queries to [email protected]. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.

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12 Comments on “Piston Slap: There Once Was a Mark X in Myanmar…...”

  • avatar

    I put polyurethane steering rack bushings in my 4Runner to replace loose and worn OE rubber ones and it made a world of difference in on-center slop, but once mid-turn and the rack is loaded up against whatever bushing is there, I don’t think there is much of a difference in control/feel/slop any more.

  • avatar

    another thing is that non-power and power steering gears have different ratios. It’s going to be a lot harder to turn the wheel at low speeds in a car with a power steering setup lacking assist.

  • avatar

    You most likely know it as Myanmar, but it will always be Burma to me.

  • avatar

    The startup noise is a common thing on high-mileage GR engines. My wife’s ’08 Sienna (3.5l 2GR-FE) has had the cold start noise for some time. It had 83,000 miles on it when we bought it six years ago, and I switched it to synthetic oil as soon as we got it. It’s now at 165k, and makes the noise sometimes on cold start, more often than it used to. It also has some piston slap when cold, but that’s only noticeable on cold weather. No oil leaks, even after switching to synthetic.

  • avatar
    30-mile fetch

    Longitudinal small block V6, RWD, and JDM all sound very tempting when put together but that Mark X has to be one of the more anonymous looking pieces of Forbidden Fruit.

    I don’t imagine the loss of power assist for parking maneuvers is going to be worth the gain in road feel at speed. Is the chassis on this car engaging enough to make this tradeoff worth it?

  • avatar

    Synthetic oil is overrated. Unless it’s used to meet necessary specifications for extreme situations that “conventional” oils cannot, it’s basically just a marketing tool.

  • avatar

    Is it possible to install a shutoff switch for the e-power steering motor? Then you could switch it on for low speed maneouvres.

    But seriously, if you have to go to such great lengths to modify a car to meet your wants/needs, then why not just get one that does.

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