GDII's 1990 G-Limited

[GDII]

What's 'wrong' with the tool in the first photo?

11mm bolts don't exist on Japanese cars! The exhaust heat shield has 3 12mm bolts that get hot and rust down to a smaller size. The top 2 were a perfect 11mm and the bottom one was still a 12mm. Would you believe I managed to get these off with stripping or snapping a bolt? I was surprised I did! I'll be buying new bolts for this even though 1 was no longer holding the heat shield down. I'll repair it and figure out the best way to coat the shield. I'm not sure what the OEM coat these in? It doesn't appear to be zinc, maybe nickel plated? If you know, keen to learn!

04 11mm bolt head.jpg (61.09 KiB) Viewed 331 times

01 Heat Sheild Rear Bolt.jpg (82.63 KiB) Viewed 331 times

02 Heat Sheild Front Bolt.jpg (53.03 KiB) Viewed 331 times

03 Heat Sheild Turbo Bolt.jpg (45.19 KiB) Viewed 331 times

05 heat sheild removed top.jpg (56.52 KiB) Viewed 331 times

06 Heat sheild removed bottom.jpg (58.89 KiB) Viewed 331 times

07 Heat Sheild Removed from Turbo.jpg (75.6 KiB) Viewed 331 times

[GDII]

Exposing the CT15b turbo. This turbo is quite unique in that the manifold and turbine housing are cast as one piece instead of a bolts flange arrangement.

01 Turbo Front.jpg (75.6 KiB) Viewed 330 times

02 Turbo Downpipe Side.jpg (71.92 KiB) Viewed 330 times

03 Turbo Compressor Side.jpg (75.04 KiB) Viewed 330 times

04 Turbo Front.jpg (64.55 KiB) Viewed 330 times

05 Turbo Oil Drain.jpg (61.25 KiB) Viewed 330 times

06 Downpipe Top Heat Sheild.jpg (53.6 KiB) Viewed 330 times

[*84vvt]

Heat Shield will be the same as exhaust tubing / mufflers will be coated in aluminum.

[GDII]

Heat Shield will be the same as exhaust tubing / mufflers will be coated in aluminum.

Really? I did see some tubing that was sold as aluminium coated that I was going to use for something but thought better of it. Seems to last rather well for the conditions it is subjected to.

[GDII]

A 22mm spanner to get the O2 or oxygen sensor off. I think I put a 23mm spanner on the end of this one to give me more leverage but probably didn't need it. Came off very easily. This is a narrow band sensor so can't use of for tuning. It's a 4 wires so has a heating component to it even though it's right behind the turbo making it hot. It looks quite new so I'll reuse it for now. Easy to replace if I find it's an issue.

07 O2 sensor.jpg (82.44 KiB) Viewed 315 times

08 O2 sensor.jpg (115.49 KiB) Viewed 315 times

09 O2 sensor.jpg (68.28 KiB) Viewed 315 times

[GDII]

1. The coolant feed and return nuts are a bit rusty for my liking. More bits to replace.

10 Coolant feed and return.jpg (85.56 KiB) Viewed 315 times

2. Same for the nut holding the CHRA (Centre Housing Rotating Assembly). Sadly it has no part number as it's part of the turbo so I'll need to find something suitable. My OCD says I must use the OEM nut.

11 CHRA clamp.jpg (37.74 KiB) Viewed 315 times

12 CHRA.jpg (44.31 KiB) Viewed 315 times

[GDII]

Soaking the exhaust manifold studs in CRC556. I was quite afraid of damaging the head with the stud on cylinder 1 but the nut came off perfectly fine. However the stud on cylinder 1 is not the OEM stud. It's really short without the star pattern on the rest. I'll check the part numbers but I don't believe it's right. I'll be replacing all of these anyway.

18 Soaking Exhuast studs in CRC.jpg (100.08 KiB) Viewed 305 times

19 Soaking Exhuast studs in CRC.jpg (66.43 KiB) Viewed 305 times

20 Exhaust Manifold Leak.jpg (66.34 KiB) Viewed 305 times

[GDII]

To get the downpipe off the turbine housing you need to remove the top heat shield around the oxygen sensor. Held on by 3 bolts, again no issues getting these off although a little stiff to unwind.

15 Downpipe Upper Heatsheild Lower Bolt.jpg (92.09 KiB) Viewed 305 times

Hmmm, that's not meant to be loose! One of the nuts was fully wound out and the heat shield was holding it on the end of the stud. No leaks from the flange though.

16 That's not meant to be loose.jpg (105.84 KiB) Viewed 305 times

17 Exposed Downpipe Nuts.jpg (124.69 KiB) Viewed 305 times

Removing the downpipe. As previously mentioned one nut had already wound its way off. That left 5 done up tight. 3 nuts came loose from the studs, 1 nut started to remove the stud very briefly then came off, the other took the stud with it.

21 Downpipe to turbo nuts.jpg (93.71 KiB) Viewed 305 times

22 Downpipe to turbo nuts off.jpg (88.52 KiB) Viewed 305 times

The downpipe has 2 brackets holding it to the block. 1 has 2 studs on the downpipe and 2 bolts on the block, the other has 1 stud and 1 bolt. These came of fine even with all the rust on them.

Once the downpipe is off there is 1 more bracket holding the turbo to the block. 1 stud and 2 bolts there. This thing isn't going anywhere!


Then you need to remove the 3 large brackets off the sides.

13 Downpipe Bracket 1.jpg (92.54 KiB) Viewed 305 times

13 Downpipe Bracket 1 2.jpg (101.41 KiB) Viewed 305 times

13 Downpipe Bracket 1 3.jpg (96.11 KiB) Viewed 305 times

14 Downpipe Bracket 2.jpg (83.4 KiB) Viewed 305 times

14 Downpipe Bracket 2 2.jpg (92.21 KiB) Viewed 305 times

14 Downpipe Bracket 2 3.jpg (64.51 KiB) Viewed 305 times

23 Lower Turbo bracket.jpg (121.54 KiB) Viewed 305 times

[GDII]

Down pipe off. Turbo turbine looks good, waste gate is ok too. However the back of the catalytic converter has collapsed and melted! I'll have to do something about this. Either get an aftermarket downpipe or gut this thing and weld a 3 bolt flange to base to fit the MR2 exhaust b pipe.

24 Turbo Turbine end.jpg (102.45 KiB) Viewed 301 times

27 Downpipe behind turbine.jpg (109.14 KiB) Viewed 301 times

25 Melted Cat.jpg (47.05 KiB) Viewed 301 times

26 Melted Cat.jpg (84.38 KiB) Viewed 301 times

[Benckj]

Looks like a load of work on the ol’ girl. I’m sure you will get it sorted and be ready for another 300k.

[GDII]

The last few things to take off the turbo before you can remove it from the head and block.

Coolant feed and return hoses. You can see the straight hose has been replaced before as it's not smooth like the return hose below it. The hose clamps are not OEM spring clamps, rather worm drive. I've seen this hose bulge and blow out on other GEN4s.

33 Turbo coolant feed and return hoses.jpg (105.34 KiB) Viewed 298 times

Vacuum reference line for the top of the wastegate to the boost controller. I was sure this hose was soft rubber. I went to pull it off and it just cracked!

28 Waste Gate Boost controller hose.jpg (72.1 KiB) Viewed 298 times

29 Waste Gate hose broken.jpg (76.44 KiB) Viewed 298 times

30 Waste gate hose broken.jpg (92.16 KiB) Viewed 298 times

Last but not least is the oil drain to the upper sump.

31 Turbo Oil Drain.jpg (105.67 KiB) Viewed 298 times

32 Turbo Oil Drain.jpg (95.6 KiB) Viewed 298 times

[GDII]

Looks like a load of work on the ol’ girl. I’m sure you will get it sorted and be ready for another 300k.

Yeah a fair amount of work but it's just replacing seals and gaskets and a few other bits I want but don't need to replace. This is my forever car so I'm doing almost everything to make it stay running for a long time. Ok, I won't be removing the head, doing piston rings and crank bearings but almost everything else will be done. If I open the engine I have to deck the head and block, buy forged rods and pistons, hone the bores and get new bearings. That's well outside my current budget and the way I see it, this engine is in good condition despite being dirty. If it got this far now, it will keep going. My current engine has 420,000km on it so 307,000km is just broken in compared. These GEN4 engines are far better built than the GEN2.

My goal is to get a turbo engine, not make stupid power. The way I see it, my current 100whp is tiny vs the 265whp these engines can easily put out in an MR2 with next to no mods. That's 165% extra power, plenty to keep me happy in a small car like this. The engines are very responsive for road use, no need for silly top end power you can't use.

[GDII]

With the turbo off you can see one of the GEN4 3SGTEs traits. A leaking exhaust manifold gasket. It's not actually the gasket being the problem but the manifold itself. It seems to have a missing fixing point in the casting so it doesn't hold well to the head and as time when on it warped. Toyota eventually found the problem and fixed it but with only 3 months of production left, you'd be hard strapped to find a GEN4 with the updated manifold as per the last image. The GEN5 then went on to use this exact same updated manifold.

So to fix it I'll have to flatten the manifold flange and somehow come up with a good way to clamp the edge of the manifold using an extra stud of which the head has a threaded hole for already.

More exhaust gasses going into the turbo, the better!

34 Turbo off.jpg (111.85 KiB) Viewed 296 times

35 Exhaust Manifold Gasket.jpg (90.01 KiB) Viewed 296 times

36 Exhaust Manifold Gasket Leak.jpg (93.81 KiB) Viewed 296 times

37 Exhaust Manifold Gasket Leak.jpg (89.39 KiB) Viewed 296 times

38 Exhaust Manifold Gasket Leak.jpg (126.82 KiB) Viewed 296 times

Screenshot_20200902-070949.png (270.4 KiB) Viewed 296 times

[GDII]

The exhaust ports are surprisingly clean. Not like my 232,000km GEN2 3SGE that had so much carbon caked onto the ports and valves it must have shrunk the size by 2-3mm. For 307,000km I'm happy with this engine. Thanks to a mate for finding this car for me. It's pretty much bone stock except for replacement wear parts here and there. It appears to have had a good life even though it's rather dirty on the outside.

39 Cylinder 1 Exhaust Port.jpg (78.63 KiB) Viewed 299 times

40 Cylinder 4 Exhaust port.jpg (86.74 KiB) Viewed 299 times

41 Cylinder 2 Exhaust Port.jpg (54.64 KiB) Viewed 299 times

[Swampy]

What's the damage on the seal and gasket kit for this engine? I'm doing the same for my ej20g but it is Uber expensive (632 nzd from Amayama) then I've got to get multi layered steel Headgaskets separately.

I think that you'll get plenty of life out of this engine once it's done, it might pay to check that the head and block aren't too damaged by any past overheating etc and that the bottom end is okay. Also maybe consider testing the intercooler piping and intake system for any leaks with a cheap DIY smoke machine. It'll drive nicer off boost if there aren't any splits in the Hoses etc.