Interviews with Chief Engineer Tetsuya Tada

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justbake

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Could you reliably run a 7M daily? Or should I 1JZ it? I've heard they'e fine as-is.
See what I am saying about them getting all the hate? Blow a headgasket at 100k and people question if the 7m will be reliable when thats a one-and-done fix. For everyday driving, the motor is not any less reliable than a JZ after you double check everything is up to date, which you will have to do with a JDM-Junkyard JZ as well

Like I mentioned earlier, between my uncle and I, we have around 650k total miles between 3 cars - all 7Ms. Don't listen the local guy car meet guy who bought a neglected mk3 and blew the hg shortly after modding it when he knew all along it was going to happen if it has never been replaced.

Edit: I would like to be clear, the hg has been well known for many years to have issues from the factory. If someone mods one of these cars and blows the hg shortly after, it is their fault for being negligent and not the motor's fault.
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MA617M

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^this 100%
I've got a 7M, 1JZ and 2JZ across three supras.
The key difference is the age of the 7M ans headgasket woes mean they require work, virtually none left are 'set and forget ' like a JZ.

My 7M has been running for over ten years of daily driving and track days, but I had to spend more earlier on to get Jz reliability.

The 7M is a cool engine. Sounds different to a JZ and has a boatload of smooth torque.

I'm about to throw ITBs on it too.

My 2JZ with GTX35 is fantastic too.
 

MA617M

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7Ms are piles of garbage that should be relegated to the dump where the vast majority of Japanese owners dropped theirs in the 90s.


sidenote: motors that are opposed to themselves (see: boxer) were never a great idea; self hate is a big contributor to engine suicide. this message has been brought to you by the society for preventing Subaru ownership.
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A70TTR

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I wrote a more in depth comment on why they're meh, but it's such a dead horse that I deleted it. Basically, the issue isn't just the head gasket and improper stud tq values; Toyota used weak aluminum that was prone to annealing, as well as engineering a head bolt seating area thinner than it should have been. So what happens in many cases is that even after a metal HG and properly tq'd headstuds, the head will still lift due to cracking or stretching of the aluminum.

Those that wanted truly bulletproof results bought new heads from Toyota, had them x-ray'd for microfissures/cracks and hardness tested before settling for one.

That said, for daily driving and lower power levels, it's fine and I'd even own one for that.

(7M and JZ like reliability should never be in the same sentence unless you're someone like Duane Stevens.)
 

SupraFiend

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JZ like reliability, not a chance. Toyota abandoned the M motor for a reason. A 2jz for all practical intents and purposes is the same motor. They burned it to the ground and started over due to all of the LEGACY issues. People seem to forget a 7m is stroked 5m which is a stroked 4m which is a stroked 3m... etc etc. The HG issue on the 7m gets all of the bad press because it goes the most (again, legacy, they reused the same HG style they had been using for decades), but it suffers from other issues like rod bearing failures because they didn't widen the rod mains on the crank (again, stroked motor of a stroked motor... etc). And then there's the stuff A70 mentioned, the weaker piston design (cracked landings are common), the stupid oil cooler design that can rob peak pressure and only cools the oil that exceeds the max oil pressure, the inadequate PCV intake, erosion in the combustion cylinder issues, bores that too close together, etc etc. The 7m was a pretty decent motor at the time, but they stretched and tweaked that architecture longer then they should have, the JZs fixed all of that motors (many) problems.
 

Bryster

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sidenote: motors that are opposed to themselves (see: boxer) were never a great idea; self hate is a big contributor to engine suicide. this message has been brought to you by the society for preventing Subaru ownership.
Meanwhile i was thinking of buying a WRX hatchback
 

SupraStew85

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The general consensus with the supra owners that I know is a properly built and maintained 7m can be tough.
Although not quite the same I have pushed a 34 year old 5m to absolute living hell for 5 years and 40,000 miles and it has never ever let me down... and I'm not talking like oh wow he took his car to 6000rpm. I mean constant redline pulls/revlimiter/general shenanigans. Theres only so many ways you can make 160hp fun lol.
 

MA617M

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I wrote a more in depth comment on why they're meh, but it's such a dead horse that I deleted it. Basically, the issue isn't just the head gasket and improper stud tq values; Toyota used weak aluminum that was prone to annealing, as well as engineering a head bolt seating area thinner than it should have been. So what happens in many cases is that even after a metal HG and properly tq'd headstuds, the head will still lift due to cracking or stretching of the aluminum.

Those that wanted truly bulletproof results bought new heads from Toyota, had them x-ray'd for microfissures/cracks and hardness tested before settling for one.

That said, for daily driving and lower power levels, it's fine and I'd even own one for that.

(7M and JZ like reliability should never be in the same sentence unless you're someone like Duane Stevens.)
100% this. There's more to a bulletproof 7M than a new gasket. I had my head hardness tested, crack tested and spectro'd prior to use.

The JZ is far superior to the 7M. The 7M can be great, but factor in a lot of money first. I did three gaskets before doing the extremes.

Happy to answer PM's to keep on topic. The only reason to go 7M these days is nostalgia, so unless you want a 7M (and are prepared to spend lots on the engine) go JZ.

My 7M superiority posts are purely tongue in cheek :p I like it because it's old and suits my old car, but screw building another one.
 
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Prius_F_Sport

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Okay, then. I'll try to find one with a JZ. Thanks for all your advice.
Back on topic, has the person who was going to talk to Tada done it yet?

And on the inside right now I'm just like "Lmao I singlehandedly derailed 15 posts and defined a meme for this forum with one ask".
 

justbake

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Okay, then. I'll try to find one with a JZ. Thanks for all your advice.
Back on topic, has the person who was going to talk to Tada done it yet?

And on the inside right now I'm just like "Lmao I singlehandedly derailed 15 posts and defined a meme for this forum with one ask".
Dont take their comments out of context, youre not building a 600hp 7m
 

Prius_F_Sport

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Are you entirely sure?
Just kidding. I might do that 1.5JZ thing for the fun of it.
 

justbake

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Are you entirely sure?
Just kidding. I might do that 1.5JZ thing for the fun of it.
1.5jz only makes sense if you have a blown 1jz, and want to replace and upgrade the bottom end without changing your entire setup. You could probably piece together a craigslist 1jz head and 2jzge bottom for cheap but will most likely be more expensive piecing the rest together and with more complications than just buying a 2jzgte from the start.
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