First Entry!
Well, I have done some preliminary measurements and other investigation into the building of the 7A-C and the swap process, and I have decided it's a "go".
As requested, I will document EVERY detail, for any/all who are interested.
A brief foreward: my primary driver is an 84 Tercel 6 speed 4 wheel drive SR5 Wagon, US spec.
The current engine is a 3A-S with ALL emissions stuff removed, all extra vacuum plumbing, EAC, EGR, cat etc all removed, and stock carb replaced with a Weber.
The car has given me approx. 140,000 trouble free miles, averaging about 30 MPG, with RADICALLY improved power over the stock setup.
IF everything was still working fine, I would not be DOING the swap... but, everything is not fine.
The car now has just a few miles less than 250K on the clock, and it has been driven by a chinese girl the last 5 months... I loaned it to her (she sold her other car) and she "learned" how to drive a car with a manual transmission using my car.
I will not detail her "trials", and I will not get upset. She is a good friend, and the car's current condition is a PERFECTLY good reason for me to do the swap.
The car was recently broken into for the stereo, and the thief TOTALLY mangled the dash... so, one of my parts cars will be donating it's dash, and I will have the local Toyota dealership do that swap (insurance is covering the repairs).
Before doing all of this work, I have test driven several of the available current 4 wheel drive wagons, and I have been pretty disappointed by the offerings.
None of them are very competent off road, with the exception of the Mercedes Benz E500 4 Matic Wagon... and for THAT much money, I could buy THREE houses in Corpus Christi, Texas.
The Subaru offerings are very well appointed, but also spendy, and not very good off road (the sales dudes did NOT like that I took their cars into the dirt... hahahahaha). I drove both the Forester and the Outback. I wasn't impressed with them, in the dirt.
The Audi and VW wagons were VERY hot, and DID handle VERY well off road, but... look at those interiors. I couldn't bring myself to splatter mud all over them... I have dogs, and my dogs get dirty on road trips, too. I definitely liked the german cars, but... too spendy, too fancy, and too "pretty".
The newer (but not "brand new") Corolla AllTrac Wagon has a nicer interior, but the car seems way heavier, and again, not as competent, off road. These were made in the 90's.
What irony! The dog-simple, cheapest suspension componentry Toyota offered in 4 wheel drive seems to have the best articulation and manners, in the dirt. I prefer the way the Tercel handles rocks and ruts over the Subaru and the Corolla.
So. I am dedicated to spending some time and money on my ugly little wagon.
Engines: As previously discussed, I ruled out the 4AG-E swap. I have driven my friend's car in Phoenix, and it was too peaky and the engine is just too heavy. The horsepower and torque were very good, but the torque was WAY up in the rev range, which did not suit the wagon. I have owned Mister 2's and Corolla GTS cars before, so, I was kind of expecting this. Too bad... I *love* that motor. But, it is not a good mating with the Wagon's transmission and character.
I also ruled out ALL of the other 4A engines... either, not enough power gains to warrant the hassles, or TOO much power (like the 20 valve 4AG-E or the supercharged 4AG-ZE) or they weight too much, etc.
This left me with the 7AF-E... however, there were some "issues" with THAT, as well... the twin cam motor is cross flowing, so none of the intake/exhaust componentry will be in the right place... ignition, fuel injection, sensors, etc... too complicated of a swap, for the return investment (in my opinion). The donor engine will be from a 95-97 JDM car, 7AF-E.
So, I have settled on a "C" series head (from one of my 3A-C equipped cars) on a 7AF-E block... in essence, a 7A-C motor.
My intake and exhaust stuff will all work, no changes to ignition or sensors will br requisite, and most everything CAN be "bolted in".
The oil galleys and valvetrain all line up, no clearancing issues, between the 7AF-E block and the 3A-C head. I cannot testify to this with OTHER A series blocks and OTHER C series heads.
I have already measured my Weber air cleaner assembly, and it will DEFINITELY be banging into the hood once mounted to the 7A-C. The 7A block is considerably taller than the 3A block, so the added altitude would actually make my air cleaner several inches TALLER than the hood. This will neccessitate cutting the hood, and putting in a cowl type induction/scoop setup. I will be documenting this, as well. I know you will want photos of me cutting holes in my hood
The pulleys: The only pulley I know for a FACT that I will be keeping is the cam pulley... I will check on the clearances/alignment/sizes/mounting of the crank pulley, alternator pulley, water pump pulley, power steering and idler pullies. I will definitely document WHICH ones (from which motors) I use, and where, and why.
The head from one of my 3A-C motors will be going to the machinist and getting bead blasted on the outside, hot tanked, then getting a 3 angle valve job, bigger intake valves fitted (along with new valve seats), new springs, a new cam, and the deck shaved (to square the head as well as to increase compression). Intake and exhaust ports are NOT going to be messed with, with the possible exception of deburring/smoothing.
The exhaust manifold will get sandblasted, and then ceramic coated by a local shop in Auburn that specializes in this. This will increase power for the FOLLOWING reasons: a) it will lower underhood temps, which means a colder intake tract, and colder air and colder fuel mean more power, due to increased charge density (you can discount the whacko thread somewhere else on this forum regarding PURPOSELY heating the fuel... that is voodoo, and will cause a LOSS of power), B) the exhaust gasses will REMAIN hot in the manifold, which increases gas velocity and scavenging in the exhaust system, and c) the ceramic coated exhaust manifold will be less inclined to parasitically transfer heat BACK to the exhaust ports, which will decrease the incidence of ping and knock.
The larger valved, high compression 7A-C should net approx 90-95 horsepower, and about 120 ft. lbs of torque without any emissions gear or a cat... once I get the cam timing dialed in correctly. I am aiming for smooth, tractable low end power, for nice off road treks.
We will see! I will dyno the results.
The Weber carb will be getting a fuel pressure regulator (set at 3 lbs) per the manufacturer's instructions, and I will use my wide band O2 sensor and the stock oxy sensor bung location to tune air/fuel and ignition timing.
As I said, I will document and photograph the entire affair.
- Teddy
