You know about 1JZ, you know about the 2JZ, but do you know about the Toyota turbocharged inline-6 engine which came before both of them? That engine is the 7M-GTE and while doesn’t get nearly as much attention on the internet compared to the JZ series of engines, it’s a cool engine with a lot of potential and it laid the groundwork for the JZ series.
Toyota introduced the M engine family all the way back in 1965. It went over many changes over the years, but the most well-known version is the 7M-GTE. Every engine in the Toyota M series family is a straight-6 engine with overhead cams, although many of the earlier engines were single-overhead-cam, and they all use a cast-iron block with a cast-aluminum cylinder head. By today’s standards, those features aren’t particularly special but back then the M series family was relatively advanced.
The breakdown of the engine code is as follows:
7 – 7 generation engine
M – Engine family
G – Performance wide-angle DOHC
T – Turbocharged
E – Multi-Point Electronic Fuel Injection
Because the 7M-GTE is part of the M-Series family, it uses a cast-iron block with a cast-aluminum cylinder head. Because this was designed as a performance application, Toyota used a dual-overhead-cam head to maximize airflow and power potential. What makes the GTE version of the engine interesting, is the fast that it’s turbocharged with a CT26 turbo that outputs around 6psi of boost. This is completely different than the 7M-GE with is naturally aspirated. If you’re familiar with Toyota’s typical naming scheme, this shouldn’t come as much of a surprise.
The 7M-GTE featured electronic fuel injection, which was just making its way into cars in the USA. We expect this feature on any car today, but back in the day, this was a relatively new technology and really helped put the 7M-GTE above the pack. Naturally, with a cast-iron cylinder the 7M-GTE is a heavy engine, but that’s to be expected with that material.
In terms of internal specifications, we’re looking at a 83mm bore, 91mm stroke, 8.4 to 1 compression ratio, and four-valves per cylinder. This is all pretty much standard stuff, with the exception of bore and stroke. The 7M-GTE is under-square with a longer stroke compared to bore, which is great for producing lots of midrange and low-end power.
- Production Run: 1986 – 1992
- Cylinder Block Material: Cast Iron
- Cylinder Head Material: Cast Aluminum
- Weight: 463 lbs
- Valvetrain: Dual Over Head Cams – Four Valve per Cylinder
- Stroke: 91mm
- Bore: 83mm
- Compression Ratio: 8.4:1
- Horsepower: 232 horsepower @ 5,600 RPM
- Torque: 240 lb-ft @ 4,000 RPM
Unlike other Toyota engines such as the 2AZ, 2GR, or 1MZ, the 7M-GTE wasn’t used in a bunch of different vehicles. The M family was used in many vehicles overall, but the 7M was only used in a couple of vehicles. This engine was a performance-based engine and Toyota doesn’t make nearly as many performance vehicles as it makes economy vehicles.1986 – 1992: Toyota Supra MK3 (7M-GE)
- 1989 – 1992: Toyota Cressida MK2 (7M-GE)
- 1989 – 1992: Toyota Chaser MK4 (7M-GE)
- 1987 – 1991: Toyota Crown (7M-GE)
- 1986 – 1992: Toyota Supra MK3 (7M-GTE)
- 1986 – 1991: Toyota Soarer (7M-GTE)
As you can see from the list on the screen, the 7M-GTE was really only used in two vehicles. Once again this is because the 7M-GTE was a performance engine and Toyota doesn’t make that many performance cars at the time. Plus the 7M-GTE was pretty quickly replaced by the 1JZ.
Quite a few Toyota engines of the past have been known for excessive oil consumption. This problem typically occurs from worn down piston rings, and it’s common on the 2AZ-FE and other Toyota engines. Luckily, the 7M-GTE doesn’t have an oil consumption issue, or atleast it’s not nearly as bad as other Toyota engines of the time.
The big issue with the 7M-GTE is with the head. During assembly, Toyota failed to torque the head bolt as tight as they should have been. Once this issue was discovered, they changed their assembly process and raised the torque spec for the head bolts.
Because of this issue, a massive amount of 7M-GTEs experience a blown head gasket at some point. If the engine is old, it can experience many blown head gaskets throughout its lifetime. The simplest way to fix this issue is to simply re-torque the head bolts to the proper spec, but sometimes the problem is worse than that.
Another common issue with the 7M-GTE is rod knock. Unfortunately, Toyota didn’t build the 7M-GTE to extremely high standards like they did with the 1JZ and 2JZ, which ultimately means it’s not as strong or as reliable as those later engines. That’s not say that it’s an unreliable engine though, because you have to remember it’s still a toyota engine and it’s still capable of outlasting most other engines. Basically, the 7M-GTE was one of the least reluable Toyota engines produced in the 80s and 90s.
7M-GTE vs 1JZ-GTE
If you’ve heard of how legendary the 1JZ and 2JZ are, you may be thinking the 7M-GTE is just as awesome, but unfortunately it’s not. Don’t get me wrong, the 7M-GTE is a strong engine with lots of potential, but compared to a 1JZ-GTE it simply isn’t as strong or reliable, which is why many MK3 Supra owners swap to the 1JZ-GTE engine.
Even better than both of those engines is the 2JZ, but that’s a discussion for a different time. Compared to other engines of the time, the 7M-GTE was insanely tough, but Toyota managed to out-do themselves with the JZ engines. That doesn’t make the 7M-GTE bad, it just makes the JZ engines better and that’s not a bad thing. Thanks the 7M-GTE laying the groundwork for the JZ series, those engines ended up being better thanks to the develop and experience Toyota gained from the 7M-GTE.
Of course, it’s hard to argue that the 7M-GTE is in any way superior to the JZ series of engine family. And while it’s true, if you have a vehicle which powered by a 7M-GTE, the difference in superiority from the 7M to JZ might not be big enough to make it worth swapping engines.
Part of this is because swapping to a JZ engine is becoming increasingly expensive as quality JZ engines become harder to find and more popular for swapping. The 1J and 2J have a very strong cult following, and if you want to get your hands on one, you’ll probably have to fight with the JDM fanboys that are willing to pay the insane price, just so they can sit at a meet and talk about how great the JZ is.
On the other hand, the affordable 7M-GTE can be found laying around in your local junkyard for a fraction of the price of a JZ while still giving you 80% of the power potential of a JZ. This makes the 7M-GTE potentially better when it comes to potential power output per dollar spent.
The JZ and 7M aren’t the only options either, don’t forget there are other awesome Toyota performance engines such as the 1UZ, 3UZ, 1MZ, 2GR, and more.
Moving on to the block, the 7M-GTE block is very strong just like the 1JZ, but the bottom end can only hold around 400-500rwhp. This a rough number and there are plenty who exceeded this power figure, but it’s generally accepted as the safest upper limit for the engine.
This amount of power is plenty for a streetcar, but if you’re building a drag car or time attack car, you may need more power. Luckily there are quite a few aftermarket rods and pistons to choose from when it comes time to push past that aforementioned power limit.
The factory CT26 turbocharger can’t really make more than 14psi because of its small size, so many people upgrade to a T3/T4 turbocharger or something like a Garrett GTX3076r which is a good balance between power and throttle response.
If you want your modified 7M-GTE to last than decking the head and block surface is highly recommended. This will get rid of any warping that has occurred from the previously mentioned head problem. Combined with some nice ARP head studs you won’t ever have to worry about the cylinder head issue ever again. Of course, big power will require an aftermarket bottom end. If you’re happy with staying under 500whp(ish), then the stock bottom end should do just fine.