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Crankshaft Pulley Removal 2012/10/06

Posted by Michael in my IS300.
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There is a long thread at my.is about timing belt and water pump service for IS300s, with a lot of people encountering difficulty removing the crankshaft pulley bolt…


I changed my timing belt  yesterday and hacked up a custom tool to hold the crankshaft pulley in place while the bolt was loosened.  In addition to using this tool, I left the vehicle in 5th gear with the parking break pulled.  Once I started pulling on the breaker bar the bolt was loose within about 2 minutes.  See pictures below…

Key dimensions of the crankshaft pulley…

My custom tool, made from scraps of aluminum and the remainder of a satellite dish mount.  On the bolts you can see aluminum spacers I used because the bolts I had were too long.  The bolts only need to be long enough to extend 30mm past the front face of the pulley.  Note that if your bolts are much longer they will interfere with the timing belt cover that’s behind the crankshaft pulley.

Here the tool is installed on the crankshaft pulley and supported by a jack-stand (to oppose the torque from the breaker bar).

While pulling on my 3′ breaker bar the front of the car lifted a few inches.  After rocking on it a few times it cracked loose.

Lastly, a regular harmonic balancer puller made removal of the pulley from the crankshaft straightforward.


Raptor V and Intercooler Installation 2011/01/01

Posted by Michael in my IS300.
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There was a lot of iterative fitting, measuring and fabricating, but I’ve finally got the Raptor V mounting brackets and the intercooler piping done. Pictures tell this story best…

The Raptor mounts to a generic plate supplied by 928 Motorsports. I custom-built two pieces to attach to the side of the 2JZ engine via two existing bosses; one pre-tapped for an M10, and the other pre-drilled for an M10. Also visible in some photos is the 3″ hole drilled through the body sheet-metal and lined with rubber hose for the intercooler piping.

A third custom piece attaches the Raptor mount plate to the alternator bolt. These components are all sized to align the pulley for the serpentine belt.

The inter-cooler is mounted to the crash-bar with M8 bolts and steel right-angle brackets.

The plastic liner for the front-left wheel-well gets a big hole for the inter-cooler piping pass-thru.

With the plastic belly-panel removed. looking from the middle of the car at the hole in the plastic liner.

Now with the inter-cooler plumbing installed…

I fabricated an aluminum heat-shield to fit between the intake filter and the exhaust manifold. Also visible is the aluminum air manifold (with copper and brass fittings). The manifold collects exhausts from the PCV, cooling air for the Raptor, and the Bosch bypass valve, and redirects it back into the compressor intake.

Engine Bay Organization 2011/01/01

Posted by Michael in my IS300.
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Fitting a supercharger into the IS300 engine required a little more work and effort that I originally bargained for. The stock location for the ABS block is right in the path of where the compressor stage should sit, so it needs to move. And unfortunately the most convenient alternate location for the ABS block is where the battery sits. So, I set about moving the battery to the trunk.

It seems as though some Engineers at Toyota at one time thought the battery was going to be in the trunk from the factory; in the right side of the trunk there are two threaded studs welded into the body sheet metal, a tab with a thru-hole suitable for a grounding strap, and a drain hole with rubber plug ideal for a battery vent. I purchased an MT-47 from Interstate Batteries; a liquid lead-acid battery with a sealed top and vent tube. Note that vent tubes are a *must* for trunk-mount batteries to prevent explosive gases from collecting in the enclosed space. The MT-47 fits nicely into the recessed well in the right of the trunk. I fabricated a mounting plate out of aluminum bar stock that attaches to the existing threaded studs and mounts two eye-bolts so that the battery can be secured with a Nylon strap. The battery vent runs down and out through the drain hole (lined with a rubber grommet) in the bottom of the trunk.

For the wiring, I ran #2 AWG from the battery to the engine bay (running it beneath the rear seat, along the passenger-side door sills, and then through an existing rubber grommet in the firewall, about 15′ is needed). A 175 AMP slow-blow fuse is connected within 12″ of the battery +ive terminal. A #4 AWG connects the battery -ive to the sheet metal tab in the trunk (cleaned with a wire brush to ensure good electrical contact), and a second #4 AWG runs up to the stock battery -ive connection point in the engine bay (following the same bath as the #2 wire). Note that the stock starter is a 1400W motor (117A @ 12VDC). I originally had run a #4 AWG for the battery +ive from the trunk but the voltage drop was too significant and resulted in what sounded like a dying battery every time I started the car. (Refer to for further information on current ratings for conductors and a voltage drop calculator).

Next I set about relocating the ABS block. This turned out to be easier than expected as each of the brake lines leading to the ABS block only needed to be bent to the new location (they didn’t need to be shortened and re-flared). Care was taken to ensure that new bends in the brake line were in the virgin material to avoid fatigue cracks. All bends were made with the smallest brake-line bending tool I could find ($10 at Princess Auto). I also took the opportunity to flush the brake fluid, install braided SS brake lines, and refill with ATE Dot4.

Tube Bender used for ABS relocation

The images below show the results of the battery relocation…

and the ABS block relocation…

Clutch Dampener 2010/03/09

Posted by Michael in my IS300.
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In the stock clutch hydraulic line, there is a Clutch Dampener Device (CDD).  This device acts as a flow restrictor when releasing the clutch pedal (engaging the clutch) but offers unrestricted flow when pressing the clutch pedal.

The design intent of this is presumably to soften the engagement of the clutch and contribute to some sort of Lexus luxury.  It is not effective for someone who prefers to feel more connected to the mechanics of the car.  Eliminating the effect is simple; disassemble the CDD and remove the flow restrictor components.  Below is a picture of the CDD disassembled.

The CDD is located on the driver side near the firewall.  Just follow the clutch hydraulic line from the reservoir.

The Rear Sub-frame and DIY Alignment 2010/03/09

Posted by Michael in my IS300.
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The rear sub-frame of the IS300 seems one of the weak points in the vehicle design. It is stamped from fairly thin and soft steel and is apparently easily susceptible to damage. Excessive inner tire wear is a common complaint noted by IS300 owners, both front and rear. I had experience with excessive wear at the rear wheels.

Performing an inspection revealed that the toe control arm attach points on the rear-subframe were deformed. Toe is adjusted using a cam washer which is normally trapped by a formed lip. The pictures show the damage to this lip…

Similar deformation was evident at the lower control arm attach point for both left and right sides which contributed to maladjustment in the camber. This picture shows a normal lower control arm. Again, adjustment is by a cam washer trapped by a rolled lip. Circled in yellow (picture below) is the lip that was deformed on both my lower control arms.

The cause of this damage is unclear; I had a shop perform an alignment on the vehicle once and they seemed to struggle… it took them almost 3 hours. By that time I’m sure they were as anxious to finish as I was. In frustration they may have torqued down the suspension bolts and crushed the sub-frame lips. Or perhaps this damage occurred during normal wear-and-tear while driving.

I fixed both problems myself.

For the rear-toe I installed turnbuckle toe-control arms similar to these…

The attachment at the sub-frame has a ridged detail that bites into the mating surface. Torquing this down to about 80 ft-lbs locks it in place. Toe is then adjusted by rotating the body of the link and securing the lock nuts when the correct amount of toe is attained.

For the lower control arm damage I used a wooden board and blunt force to hammer the tab back into shape until the suspension cam washer was again held securely in place.

The next challenge was to check and adjust the alignment.

The front suspension didn’t seem to exhibit any signs of damage similar to the rear (that might have come from the alignment shop or otherwise), and the alignment report showed alignment numbers exactly where I wanted them: ~-1deg camber, < 1/32″ total toe-in. Thus I was able to use the front wheels as reference to align the rears. Here is the procedure I developed and followed…

  1. Find a flat level surface to work on (luckily, my garage floor meets this requirement).
  2. Find a flat board large enough to cover the face of the wheel/tire.  It should contact the highest edge of the wheel/tire all the way around (compromises can be made if you don’t have a suitably sized board).
  3. Toe: Place the board against the face of the wheel and mark the outside edge at the front and rear of the board.  This is half of the toe measurement.  Repeat on the other side of the vehicle and measure the distance between the front marks and the rear marks.  The difference between these measurements is an expression of toe.  Convert it to an angle or extrapolate to the edge of the tire tread to obtain actual toe.
  4. Camber: With the board still flat against the wheel/tire, measure the vertical angle of the board relative to the level surface you’re working on.  I used a combination square and trigonometry to calculate the angle.  This is a measure of camber angle.  Note that you might need to account for tire bulge at the bottom due to vehicle weight and tire inflation.
  5. Thrust Angle: Make sure the steering angle of the front wheels is at zero.  Run a string from the centre of the front wheel through the centre of the rear wheel.  I tied the string to one of the spokes on the front wheel.  Ensure the string is in contact with the front wheel.  Hold the string tight and against the edge of the rear wheel.  The angle of the wheel relative to the string is a measure of the thrust angle.  Note that one-side alone is not the thrust angle.  You must consider both sides, and also toe to assess the thrust angle (consider the front wheels might have a different width than the rear wheels).
  6. With all measurements taken calculate the current condition and the adjustments necessary.  The next step requires elevating the vehicle, adjusting the suspension, and repeating the measurements above.  This is an iterative process.  Set the camber first, and the toe and thrust angle second.  With the turnbuckle toe-control arms I have, correcting toe/thrust angle can be made exact by using the thread pitch to calculate number of turns required to correct for the measured toe angle.

Swift Sport Springs 2010/03/09

Posted by Michael in my IS300.
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I’ve read claims that stiffer springs installed in a vehicle can reduce the life of the shock strut. Argument being that a stiffer spring increases the rate of work that the shock strut is required to do.

In researching and preparing to install a set of Swift Springs I decided to analyze the problem. These springs are advertised as having a 25% stiffer spring rate than the stock IS300 springs.

An automotive suspension is easily approximated as a spring-mass-damper system. The motion equation for which is…
mx” + cx’ + kx = F(t)

m = mass
c = damping rate
k = spring force
t = time
x = displacement
x’ = first derivative (velocity)
x” = second derivative (acceleration)

For the analysis I made the following approximations/assumptions…
mass is = 1/4 vehicle curb weight = 340 kg
spring force k is constant = 43 N / mm (245 lbs/in) (front wheel)
damping rate c is constant
damping rate c for the IS300 is estimated at about 0.3 of critical damping which = 2300 Ns/m **

** Milliken (Race Car Vehicle Dynamics) apparently recommends 0.15 – 0.45 of critical for damping rates on road vehicles. I took a guess that the IS300 would be somewhere around 0.35. As this analysis is comparative the exact value will not be critical to the results.

My analysis is for a road disturbance = 0.10m to the front wheel, and an initial vertical velocity of the suspension = 0 (these initial conditions are used to solve for constants in the solution).

The motion equation (mx” + cx’ + kx = F(t)) is a second order linear differential. The general solution for an underdamped case is: x(t) = exp(-pt)(A cos(wt) + B sin(wt) [1]. A thorough explanation is best left to a calculus textbook.

Solving for 2 scenarios…

1. Sport Design IS300 with stock springs
2. Sport Design IS300 with Swift springs (25% stiffer)

For each scenario I solved for suspension travel, suspension velocity, and suspension work vs. time. A brief discussion on each follows:

The Suspension Travel graph shows that all three suspension setups oscillate for approximately the same duration. The oscillation frequency is higher with stiffer springs (expected).

The Suspension Velocity has higher velocity peaks for the suspension with stiffer springs only.

This is the interesting graph. The “Work” for a shock is the amount of energy it dissipates. After 1s the suspension with Stock springs dissipates 365 J of energy for the 10cm input. The Swift spring suspension dissipates 419 J of energy: 14.7% more.
IS300 Suspension Work

The analysis suggests that installing 25% stiffer springs results in the shock strut performing 15% more work. All other things being equal, a shock might be considered to have a usable life proportional to the total work done. Thus 25% stiffer springs can be interpreted to result in an approximately 15% shorter life.

[1] Differential Equations and Boundary Value Problems 2nd Edition, Edwards, Penney.