Early 7M-GTE (1986.5 to around 1989-1990):
Pros:
6M crankshaft - spins up quickly
Easiest to find
91mm stroke - makes more torque at a given rpm
Cons:
Head gasket issues - a metal head gasket + ARP studs solves this problem and makes the gasket stronger than a stock JZ (JZ does not come with ARP studs from the factory)
6M crankshaft - is known to be 'harsher' due to not being fully counterweighted from the factory
Generally high mileage
Late 7M-GTE (late 1989+)
Pros:
Beefier block than the early 7M
7M Crankshaft - fully counterweighted
Stronger bottom end (very similar to the JZ)
91mm stroke = more torque at a given rpm range
Cons:
Head gasket issues - a metal head gasket + ARP studs solves this problem and makes the gasket stronger than a stock JZ (JZ does not come with ARP studs from the factory)
7M crankshaft - Heavier than the 6M, so the engine does not spin up as fast
JDM 1JZ-GTE
Pros:
Extremely good looking engine
Factory metal gaskets
Short stroke (71mm) allows for extremely high rpm range
Head flows better than the 7M, stock for stock
Cons:
Cost (half cut + any missing parts + wiring harness)
Parts availability (This is not as bad as many make it out, but 1JZ parts are not as easy to find in Alachua, FL as 7M parts)
71mm stroke means less torque at a given rpm
2JZ-GTE
Pros:
86mm stroke means more torque than a 1JZ, but less than a 7M
Factory metal gaskets
Head flows better than the 7M, stock for stock
Parts availability - I CAN find parts in Alachua, FL for the 2JZ
Cons:
Cost
86mm stroke means less torque at a given rpm
Cost Analysis
7M-GTE
Generally 150k+ miles
Very worn out
Often found with a blown head gasket
Stock Rebuild
Pistons/Rings: $120
Machine work: $237 ($75 deck the head/block, and $90 bore/hone for pistons $72 to recon rods)
Rods/Mains/Thrust bearings: $125
ARP Head Studs: $140
Cometic MHG: $140
Valve Seals: $50
Valve Springs CCA-975-12 x 2: $70
Considering you doing your own labor rebuilding your own engine, you can have a stock, zero mile 7M for under $900. The stock-style cast pistons will handle 350rwhp reliably, and the new metal head gasket + arp studs, reconditioned rods, and CCA springs will let you have a nice, solid motor for your Supra.
Performance Rebuild
Pistons/Rings: $400 (Probe Forged pistons from Driftmotion)
Rods: $450 (Eagle Rods)
Lower End Machine work: $1500 (This is what I paid, for absolutely top notch work. No piece of metal was left untouched)
Upper End Machine work: $1000 (Valve job + mild porting)
Rods/Mains/Thrust bearings: $125
ARP Head Studs: $130
HKS Stopper MHG: $320
Valve Seals: $50
Valve Springs CCA-975-12 x 2: $70
Figure about $5000 for a complete, forged, bad ass 7M-GTE. This motor will handle more power than you should have on the street. Fully forged internals, completely zero balanced rotating assembly, no problems to extended rpm ranges. I would consider this motor to be BETTER than a 2JZ, in all ways. Same head flow, forged vs hypereutectic pistons, better forged rods, completely balanced rotating assembly, etc
Certainly, you can fall anywhere in between. And if you want to get REALLY crazy, you can sink another $5000 into the engine with ease.
Also, I recommend you do the above with a Late model 7M (with 7M crankshaft. Lighten the crank if you want to spin like a 1JZ with the torque of the 7M
)
1JZ-GTE Swap from Halfcut
Generally 30-60k miles on the halfcut
Shipping can be a pain in the rear
Getting the Halfcut generally insures you are getting everything you need to swap to a 1JZ-GTE in your USDM MKIII Supra.
Turbos often die
Straight swap
$2800 + s/h from Driftmotion
$350 - Exhaust
$0 - Intercooler + piping is often in the clip
Figure on spending around $3500-$3800 for the swap. You buy the clip in one large purchase, but then you need to extend the harness, and do basic maintenance. When you are done, you have a 30-60k mile motor.
And pray your stock twin turbos don't go - you'd be looking at an additional $700-$1000 to take care of that problem
You also have stock hypereutectic pistons, with a metal head gasket. You are pretty much where the stock 7M rebuild will leave you, except the 7M doesn't look anywhere near as good, and the 7M would also have NO miles on it. The 1JZ will have however many miles of unknown care on it that the clip comes with. New motor that you know inside and out, vs unknown condition 1JZ?
Not to mention the extra $2000 I'm putting into the 7M at this point. Draw your own conclusions - that is my thought on the 1JZ vs 7M debate, and all I care to say on it.
2JZ-GTE Swap
2JZ gets lots of attention
Often with 60k+ miles
$2300 for the engine from Driftmotion
I *think* the $2300 gets you the harness/ecu as well - have to ask Aaron about that
$350 - If you are automatic, you need a new transmission (tranny often comes in the 1JZ clips) - or at least, if you are 5 speed, a new JZ bellhousing.
$650 - Intercooler and piping
$350 - Exhaust
After misc hoses, belts, A/C setup, etc - you'll be looking at $4000-$5000 to get the 2JZ-GTE into your USDM MKIII Supra. Compared to the Forged 7M, you'll be lacking the forged internals, and zero miles of the new 7M. For what? 5 mm less stroke, and 4mm more bore? Big deal, I say. The new forged 7M will handle just as much power as the stock 2JZ does, and then some.
DISCLAIMER: No, I did not consider things such as NA-T swaps, or running the 2J on the stock 7M electronics, and you'll see I left headroom in the pricing to consider miscellaneous items that will be needed as you go along.
The fact of the matter is, the JZ motor will die if neglected. We've got rod knocking JZ motors out there, and we've got rod knocking 7Ms out there.
Nothing replaces good maintenance on an engine.
Those are all of my thoughts on the 1JZ vs 7M vs 2JZ debate. For the money, I believe the best value is a built 7M on the street. For a race-only application, with unlimited money, I'd go 2JZ. Go price forged 2JZ pistons/rods vs 7M forged pistons/rods. A lot of the guys with MKIVs have the money to throw at the engines, and the companies make a killer profit off of them.
The MKIII guys aren't willing to throw cubic dollars at their cars (for the most part - looking at you, Duane, Ian, Nate, etc
) so we have to get companies to build us things in quantity, or find businesses that are willing to work on less of a profit margin for us.
That is damned hard to do. So far, we've gotten Probe involved with forged pistons. We've got Energy Suspension with poly bushings. Andy (ARZ Performance) with his KILLER 4 piston big brake kit.
Overall, we work at our cars as a community. Few of us are willing to single handily pay for R&D on parts - but as a community, we can sometimes get things done (as evidenced by the pistons + bushings so far)
