Since 7AG engine's seem to be a hot topic on here at the moment,
Thought I'd share my engine build and experiences with the Toyota Nation.
I had been running a 1600cc 4AGE Silvertop 20V turbo motor in my car,
and was running at just under 300HP, but was on the search for more power.
So I built a 7AGTE with a Blacktop 20v head, and a GT3076R turbo.
The car is strictly a race car, so the build would be a little different to a street car build.
I took a 7A block and crank, and bought a set of ARGO aftermarket conrods,
and a brand new set of 4AGZE 0.5mm o/s pistons and rings.
I know the pistons are for a 16V, but they work on a 20V fine as long as you get the cam timing correct.
I used a Blacktop 20V head with standard cams, valves, springs etc etc.
Bolted it together with a standard 20V head gasket, not a TRD item as I didn't feel like they had enough thickness in them.
Cambelt used is a standard smallport 16V 4age Belt, which fits fine as long as you run the Blacktop 20V oil pump with the hydraulic tensioner.
Made a custom made inlet and exhaust manifold and run it using a stand-alone aftermarket ECU.
It has been running now for a season and a 1/2, have had a few drama's along the way,
some really weird one's which I will show later,
and made the awesome figure of 325kw or 440hp at the wheels on 20psi of boost.
Here are some pictures of the engine and the car.
The car it is in is a 1980 KE70 Corolla DX
The engine was all built, assembled and fitted to the car, and went to the dyno tuners to get tuned for the first time.
As it was only a few weeks before the first event of the season I didn't want to push it right to the limit,
so left them with instructions to only tune up to 18psi or 380hp max.
Had just finished the tuning and on the last run it lost all drive to the rear.
Thought it had buggered the clutch, as it was the same clutch that had been built for the 1600 motor, but when we stopped the motor and tried to re-start it found it wouldn't turn the motor over, just spun the flywheel.
and here was the reason why,
They were brand new flywheel bolts and had been torqued up.
So I had extra dowels fitted and installed ARP bolts along with a new flywheel.
So the theroy's on the 7AFE and 4AFE being weak due to the 6 instead of 8 bolts on the flywheel maybe tru.
But I thought we had fixed it by adding extra dowels,
but first race this season, after it had done a few events and had a retune to now run 325kw/440hp atw, there was another flywheel problem.
This one was a bit different though,
The flywheel was a std toyota unmodified flywheel, so this is still a bit of a mystery,
but I like using the excuse of too much power, lol.
Apart from breaking a gearbox (w57) in practise, and having to replace it before qualifying,
there were no problems, and I got some really good results.
For those that are interested here is one of the incar video's from last weekends racing.
So the theroy's on the 7AFE and 4AFE being weak due to the 6 instead of 8 bolts on the flywheel maybe tru.
Dude, honestly, at over 400hp at the wheels, you've more than quadrupled what Toyota was putting out. I wouldn't say that makes those parts "weak". You're going so far beyond the design goals of Toyota's engineers that you're bound to break something.
Nice job. There are plenty of guys on MR2OC who'd like to know more about this build.
Dude, honestly, at over 400hp at the wheels, you've more than quadrupled what Toyota was putting out. I wouldn't say that makes those parts "weak". You're going so far beyond the design goals of Toyota's engineers that you're bound to break something.
Nice job. There are plenty of guys on MR2OC who'd like to know more about this build.
Yeah, maybe not weak then, but the 6 bolt "FE' engine cranks are "not as good" as the 8 bolt 4AGE stuff.
But it's pretty good for toyota stuff considering the rods are the only non Toyota parts in the whole motor, (excluding the externals like turbo's and manifolds etc).
I've broken all the 8 flywhell bolts on my 4ag smallport before, it doesn't mean anything, it just means that "A" you over torqued the bolts or "B" you miss shift too much or "C" these things happens. The crank for the 7a is not weak, anyone who says that its weak has never had any experience with them before, also its not the crank nor the rods that are the weak point of the 7a, it's the rod bolts that tends to break under stress.
I've broken all the 8 flywhell bolts on my 4ag smallport before, it doesn't mean anything, it just means that "A" you over torqued the bolts or "B" you miss shift too much or "C" these things happens. The crank for the 7a is not weak, anyone who says that its weak has never had any experience with them before, also its not the crank nor the rods that are the weak point of the 7a, it's the rod bolts that tends to break under stress.
we are well past the point of braking rod bolts, and rods.
Running ARGO aftermarket rods and arp stuff,
including ARP flywheel bolts.
Getting to the point of breaking flywheels now,
thats on standard unmodified toyota flywheels,
but thats at about 500hp.
Next problem we encountered is gearboxes,
using W55, W57 versions etc, and due to the power levels now,
have broken two gearboxes in two events, both under full load on the track.
Well with 500hp and bigger wheels and tyres for more grip,
it's at the stage where W series gearbox's are just not lasting the distance.
When run hard at full power they seem to last less than one race weekend,
so after needing 3 boxes in 3 weekends I have been searching for something more to hold the power, without have it feel like a truck gearbox, or costing 3 x the value of the car.
I have come up with an aftermarket gearset for the W series box that should fix all the problems, and have the advantage of being a really close ratio box.
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