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Mitsubishi 3000 GT Restoration Project (With Videos)

Hardlymoving writes about do-it-yourself automobile maintenance on various makes and models.

1992 Mitsubishi 3000 GT SL

1992 Mitsubishi 3000 GT SL

For years, a friend of mine was bugging me to get involved in a car restoration project. I warned him of the cost, time and frustration involved in doing something of this magnitude. Most projects like this get started and never get finished, because of frustration, lack of funds, lack of available parts, lack of time, and so on.

I set some sensible and realistic guidelines he could follow to make a project like this both enjoyable and affordable.

What Makes a Car Restoration Project Worthwhile?

  • The acquired car has to be affordable (less than $1,500).
  • The interior and exterior have to be in reasonably good shape (good paint, little rust, few broken parts).
  • The car's history should have no major accidents.
  • All the off-the-shelf parts needed must be available from local or on-line parts retailers; that is, no custom aftermarket parts (for example, cold air intake, adjustable coil springs, quick shift kits, etc).
  • You have to be willing to walk away and discard the car if costs get out of hand.
  • You have to believe the resale value of the car will at least cover the cost of the purchased parts.

Our 1992 Mitsubishi 3000 GT

By chance, I recalled that another friend of mine had had a '92 Mitsubishi 3000 GT sitting in his driveway for around ten years. I called and asked him if the car was still in his driveway. He said,sd "Yeah, do you want it? I was ready to have it towed to a salvage yard." He hadn't started it in over three years and had given up on charging the battery. We negotiated a price of $700 and paid around another $700 to have it towed 1,200 miles from New Jersey to Memphis, Tennessee.

The Mitsubishi 3000 GT We Chose for Restoration

In the era that this car was made, it competed with the Mazda RX7, Nissan 300ZX, Toyota Supra, and Subura SVX.

  • 1992 Mitsubishi 3000 GT SL 2+2 hatchback sports coupe
  • Current odometer reading: 160,000 miles
  • MSRP when new: approximately $26,000
  • Engine: 3.0L DOHC V6, 222 hp, port fuel injection (6G72 engine designation)
  • Transmission: FWD, 5-speed manual
  • Brakes: 4-wheel disc with ABS. Front: dual piston. Rear: single piston
  • Suspension: 4-wheel independent McPherson strut with electronic control
  • Interior: Leather seats and steering wheel, LCD HVAC Display, Cruise Control

Our To-Do List for Renovation

Factoring in the age and mileage on the car, we decided to remove, replace or rebuild as many parts as possible of those that would normally succumb to failure. Here's our to-do list of engine bay parts to be cleaned, rebuilt or replaced:

Rebuild or Cleaning:

  • Alternator
  • Fuel injectors
  • Throttle body
  • CV axles

Replacement:

  • Radiator with upper and lower hoses
  • Timing belt
  • Camshaft seals
  • Crankshaft seals
  • Timing belt idler pulley
  • Timing belt tensioner pulley
  • Timing belt tensioner
  • Water pump
  • Thermostat
  • Accessory belts (for A/C compressor, power steering, and alternator)
  • Clutch master cylinder
  • Clutch slave cylinder
  • Brake master cylinder
  • Spark plugs (Denso Iridium Long Life)
  • Oxygen sensor
  • Ignition wires
  • Valve cover gaskets
  • A/C condenser
  • A/C accumulator

Suspension, Brakes and Drive Train:

  • Front and rear brake suspension struts
  • Front lower ball joint
  • Front and rear stabilizer bar links
  • Front stabilizer bar bushings
  • Front and rear brake rotors
  • Front and rear brake pads
  • Transmission output shaft seals

Conversions:

  • R12 A/C compressor (replace mineral-based oil with ester oil)
  • A/C high and low pressure quick-connect conversion adapters

Episode 1: Getting the Car to Start

After we got the car delivered, the first priority was to get the car started. We installed a fresh battery, the engine cranked over several times, and then ... nothing. No start. See the video below to see what we did.

I disconnected the fuel line from the fuel rail, then cranked the engine over. No fuel. Okay, we had a fuel problem. I pulled out the fuel pump regulator and pump assembly from the fuel tank and saw that the pump's filter screen had basically dissolved, melted away. Also, the fuel had turned a murky brown, and I figured we should pump it out. We cleaned out the fuel tank (drained it and wiped it down dry with towels), blew compressed air through the fuel line from the tank to the fuel filter connection point, replaced the fuel pump, the fuel pump filter screen, and the fuel filter, and added fresh gas. After cranking the car over a few times . . . voila! The engine started!

Episode 2: Removing Parts From the Engine Compartment

We started the 3000GT tuning process by focusing on replacing engine components that typically get worn. If there's anything that could ruin an engine in quick order (especially on this car), it would be a broken timing belt or a seized water pump. In the process of getting to the timing belt and water pump, we used this opportunity to remove other parts that would be difficult as well as time-consuming to get to if we were performing a stand-alone specific repair. In the video below, Episode 2, we removed the radiator, alternator, AC compressor, condenser, accumulator, accessory belts, brake master cylinder, brake booster, clutch master cylinder, the timing belt covers, timing belt, camshaft sprockets, and water pump.

Parts Removal Photos

3000 GT Radiator Assembly

3000 GT Radiator Assembly

3000 GT New Clutch Master Cylinder Installation

3000 GT New Clutch Master Cylinder Installation

Episode 3: Installing the Timing Belt, Water Pump, Camshaft, and Crankshaft Seals

In Episode 2, we removed the old timing belt and water pump along with other major components. In Episode 3 we started the reassembly of new parts beginning with the timing belt and water pump.

This V6 engine has quad camshafts; that is, two camshafts per engine bank. Aside from a universal sprocket holding tool, no specialty tools were needed to keep the camshaft sprockets in place while installing the new timing belt. 12-mm-long bolts were used as temporary utility bolts to hold the sprockets in place. We were fortunate that on this particular engine, Mitsubishi engineers had provided 12 mm bolt holes behind the camshaft sprockets, apparently to ease belt installation.

The timing belt tensioning procedure is a rather unique two-step process: Install the belt tensioner and tensioner bracket, applying specific tension on the new timing belt before tightening the bracket, and then release the tensioner shaft spring. You'll have to watch the video to see what I mean.

New Water Pump and Timing Belt for the 3000 GT

New 3000 GT water pump

New 3000 GT water pump

New 3000 GT water pump attached to pump housing

New 3000 GT water pump attached to pump housing

New 3000 GT DOHC timing belt

New 3000 GT DOHC timing belt

Episode 4: Installing Engine Compartment Parts

Episode 4 continues after the completion of the timing belt replacement. We buttoned things up by installing the lower timing belt cover, mounting the A/C compressor with new A/C ester oil, installing a rebuilt alternator and installing new accessory belts. Other components we installed include the brake booster, new brake master cylinder, clutch master cylinder, clutch slave cylinder, A/C condenser, A/C accumulator, A/C hoses with R134a quick connects, thermostat, radiator and radiator hoses. The old subframe cross member brace was rusted, so we picked up a replacement at a salvage yard. Along with the subframe brace, we replaced the old front motor mount. With everything attached and installed, we evacuated the A/C system and recharged it with R134a refrigerant, and added new coolant.

Refinishing a replacement engine subframe bracket

Refinishing a replacement engine subframe bracket

New 3000 GT Clutch Master Cylinder with new pipe and compression fittings

New 3000 GT Clutch Master Cylinder with new pipe and compression fittings

Episode 5: Replacing Valve Cover Gaskets, Fuel Injectors, Spark Plugs, and Ignition Wires

In this episode, we removed the intake plenum to pull the valve covers off to replace the gaskets. This gave us the opportunity to clean up and refinish the covers. After we re-installed the covers, we replaced the fuel injectors, spark plugs, and ignition wires. We had the injectors remanufactured, replaced the Bosch Platinum spark plugs with Denso Iridium Twin Tips, and replaced the ignition wires with Denso brand.

3000 GT valve cover removed for clean-up

3000 GT valve cover removed for clean-up

Refinished 3000 GT valve cover

Refinished 3000 GT valve cover

3000 GT valve cover gasket installation

3000 GT valve cover gasket installation

Episode 6: Replacing the Exhaust Downpipe

In this episode, we replaced the exhaust downpipe . . . the source of all the loud noise emanating from the engine. Upon examining the pipe, we clearly saw major leaks coming from the downpipe's flex joints. After shopping around, we picked up an aftermarket stainless steel replacement pipe advertised by various vendors on Ebay. But we noticed the new downpipe did not have a bung hole to mount the O2 oxygen sensor and the flange holes to mount on the exhaust manifold were too small. Not a big problem. Using a step drill bit, we enlarged the flange holes and had a bung welded on at a local muffler shop. After the new downpipe was installed, the engine sounded much nicer, but more importantly, quieter.

3000 GT broken downpipe flex pipe

3000 GT broken downpipe flex pipe

3000 GT oxygen sensor replacement

3000 GT oxygen sensor replacement

New 3000 GT downpipe and 02 sensor

New 3000 GT downpipe and 02 sensor

Episode 7: Rear Suspension and Brakes

In this episode, we rebuilt the rusty rear brake calipers (new piston seals and caliper pin dust boots), and replaced the brake pads, rotors, brake lines, suspension struts, and suspension stabilizer bar bushings. The 3000 GT SL model for this year came with electronically controlled strut dampeners. We replaced them with conventional struts made by a Japanese OE (original equipment) manufacturer called KYB. They're found on many Japanese domestic and import cars, and their ride quality as well as durability is very high.

3000 GT old rear suspension strut

3000 GT old rear suspension strut

3000 GT new rear strut installation

3000 GT new rear strut installation

3000 GT rear caliper pin dust boot installation

3000 GT rear caliper pin dust boot installation

Episode 8: Front Suspension, Brakes, Ball Joint and CV Axles

In this episode, we rebuilt and refinished the front dual caliper brakes and replaced the rotors and brake pads. We used Raybestos corrosion-resistant coated rotors, which prevent ugly rust buildup, and their EHT (Enhanced Hybrid Technology) brake pads. One of the lower control arms' ball joint had a broken dust boot and was visibly worn out. We pressed it out and pressed in a new replacement. Two brake lines constituted each front wheel corner and they were replaced with new lines. Although the CV axle boots were not split, we chose to replace the boots and the output shaft seals. As on the rear end, we replaced the suspension struts with KYB's along with new stabilizer bar links and bar bushings.

Mitsubishi 3000GT Dual Caliper Front Brake Assembly

Mitsubishi 3000GT Dual Caliper Front Brake Assembly

Mitsubishi 3000GT Replacement Front Brake Pads

Mitsubishi 3000GT Replacement Front Brake Pads

Mitsubishi 3000GT Lower Control Arm

Mitsubishi 3000GT Lower Control Arm

Further Episodes Coming of the 3000 GT Restoration Project

Watch for these videos we hope to create and post.

  • Replacing the radio with a double-DIN head unit with Bluetooth and USB interface
  • Interior cleaning and seat repair
  • Repainting the car?

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2020 hardlymoving

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