Engine Overview
Engine Overview - Quick Access:
This engine design has been praised & damned. Praised for its inherent design, & power potential; damned, for blowing head gaskets. The solution is only a metal head gasket away, & a standard Toyota rebuild is plenty robust to deal with the rest. With all due respect to various setbacks my particular engine has suffered [basicly, NOT it's fault], it just dyno'd at ~362RWHP & ~420RWTq [July, 2001]. With nearly 150K total miles on the block, crank & rods, I stand in awe at this engine's durability; even if they were reconditioned as of ~50K miles ago. And since my power goals don't exceed 500rwhp, I don't even need to think about forged pistons & ARP cylinder head studs.
Other than an obviously robust bottom-end, each cylinder breathes sweetly via its 4-valves, while the mild dual overhead cams make sure all of the 24 dual-sprung valves dance in step. The engine management system is not notable in this day in age, as it was the 1st incarnation of ODB [On Board Diagnostics], but considering it included a fully distributorless [DIS] ignition system, and peak-hold fuel injectors in a semi-batch fire configuration... the design was far ahead of its time, back in mid-1986. Take note that many current-day vehicles are just beginning to utilize DIS, & most still use the less-precise saturated type fuel injectors, despite being fully sequential.
With all due respect to engine renovation, one must remember that this cylinder head & block are seasoned, ~15 year veterans of almost 150,000 daily driven miles. Mobil One 10W-30 synthetic has been sole engine oil, since break-in procedures with 10W-30 dyno oil were completed. Engine facts alone seem insignificant, when considering the transmission & differential, amongst other things, are original equipment; serving daily duty, withstanding the frequent romp through the gears. They remain happy on a diet of Redline gear oils.
~56K Miles total on custom rebuilt 7MGTE by Koji Haraguchi, Japanese Performance Car Specialist @ Hiro's Auto Repair in Costa Mesa, CA.
At ~40K Miles on stock Toyota 0.5mm oversize piston set #1, & HKS
1mm stopper-type metal head gasket, ringlands #2 & #5 broke on the dyno from a malfunctioning fuel pressure
regulator.
Stock Toyota 0.5mm oversize piston set #2, & HKS 3mm bead-type metal head gasket are currently at
~16K miles. ~2990cc displacement; ~8.0 : 1 compression ratio. These figures calculated using
Performance Trends' Compression Ratio
Calculator Version 1.2.
As of the initial rebuild
All new stock:
Pistons, rings, valves, rod bearings, oil pump, head bolts, hoses, & seals.
Non-stock:
HKS 1mm Stopper metal head gasket [MHG]
Machine work:
3-angle valve job, both cylinder head & block machined mirror-smooth, & all reciprocating assemblies balanced.
As of the 2ndary rebuild
All new stock:
Pistons, rings, & MHG.
HKS 3mm Bead metal head gasket [MHG]
Machine work:
Cylinder head & block surface honed for MHG.
Note:
The cylinder head was replaced subsequent to the rebuild, having been cracked during a re-torque @ ~7K miles
after piston set #2. The replacement cylinder head was sourced from a 100K mile '89. The previous 3mm MHG
was reused, as were the stock head bolts.
This is the HKS 3mm bead-type metal head gasket.
The only non-stock part used in building the motor.
