Engine Swap options

[ARCHINSTL]

Boy - ALL of you guys know how to make a feller feel dense and out of your league!
Wow!
Tom M.

[takza]

I'm not the only one to think cooling the head first makes sense-

I think they do it that way because the alum heads are more sensitive to temp changes. cracking issues?

[Petros]

It is actually more efficient to cool the less hot parts first (the block) and the hotter parts last (around the combustion chamber), this is true with all heat exchangers, you get more heat out of the engine that way with the same amount of coolant flow. I would also suspect having an aluminum head kept at a more uniform temp would be best for long term durability of the head gasket. Aluminum thermally expands way more than cast iron with temp rise, that is why the head gasket is coated with graphite, to allow differential movement at the surface between the head and the block. Keeping the head at a uniform temperature helps this, and it is likely better for efficiency and emissions as well.

I see no reason to risk making changes in the direction of the coolant flow since the cooling system it works well the way it was designed from the factory. It only adds to an already complex problem when you are swapping in an engine that was not designed for this car.

what you quote there says the intake part of the head is cooled first, then the block, then the head? I do not see how this is possible, unless he is taking about cooling the intake manifold first, and then into the block, then the head. Large temp gradients in the head will cause the head to warp and/or crack, and then gasket failure (I have seen it racing engines). It would take a special water jacket in the head which would be right next to the super hot water jacket in the other part of the head. I do not see how it can be done, unless he is taking about a special coolant passageway in the intake manifold. I will have to take a close look at a 7AFE next time I am in the wrecking yard.

Also, I wonder if the 7AFE intake manifold will bolt on to the 4AFE head, the heads look very similar, and it puts the throttle body in a different location. Also the intake plenum looks easier to modify than the 4afe manifold since it is a two piece assembly.

[SynthDesign]

I went thru all of these options and figured the 4age was the best bet.
I have an 85 w/ a 4ac and it doesn't feel as powerful as a 3ac w a properly tuned Weber set up.
So far the 4age swap is becoming a bit of a thinker but I still beleive it is possible.
As for power, yes it peaks at higher rpm's versus 7afe or 5afe but it still offers about twice the hp versus the stock motor. The true question is how much HP and Torque can the trani and front Diff handle?

BTW, In cold condition driving, an EFI system has been more reliable for myself. 22R hard learned lessons

[Typrus]

To reiterate.

100HP
100ft/lb of torque.

More=BOOM on driveline shock.

[gatemaster]

More=BOOM on driveline shock

I wouldn't shock(hard shifts) the driveline with a 3ac let alone a 4age. So obviously soft shifting and no trying to climb the side of a mountain or pulling. I think more power can be used safely with care. The tranny is the real downside to this car, too bad they didn't make it stronger. I would look for something else but my car is in such excellant shape inside and out. I have built various engines for 40 years and I have to say that I don't think the 3ac is a real reliable engine. There are many design flaws even for a basic 4 cyl. I have studied engine design all my life. The 4age is a reliable engine that is built to run for a long time. I believe in overkill on engine design. Good point about the EFI in cold weather. Unfortunatly the 4 & 7afe's have that dizzy problem. Unless there is a low cost solution to the fly wheel problem the best setup i think is the 4 or 7 afe with a 4age head. Based on Petros finding about the heigth problem of the 7afe I would say the 4afe with 4age head looks like the easiest setup. I haven't done one yet so that is just what I think so far based on what information I have.

[AlbertaBeef]

To reiterate.

100HP
100ft/lb of torque.

More=BOOM on driveline shock.

Here's a question: Would Cryo-Treatment of the components improve the strength to the point where a 4AGE would be a viable option?? My personal opinion is that the 4AGE is the most reliable of all the Toyota A-series engines, and it's also one of the easiest to find parts for ...

Personally... I'll likely do a 4A-C swap in the future... but a 4AGE would be nice... if something could be done to the transmission/drivetrain to handle it...

[SynthDesign]

I don't think cryo-finishing would help with Trani failure issues.
So far the only problems I've had with the drivelines failing was an issue with a bad carrier bearing and another with mixed diff. ratios.
Trani wise, I've grenaded two ft diffs and snapped a shift fork and some sheared synchros over the past few years.
Really I'm pretty impressed with what the tranis can handle. I'm sure if you push anything hard enough it will break, but I still think they are way better designed than what Honda offered in the wagovan 4wd.

It is what it is and Toyota never used a similar trani platform on anything else.

[Petros]

The trans problem seems to me cause by worn out trannys, not necessarily over powering them. The car I drive now is on it's third trans, all of the others worn out, not broke. I suspect if you have a good trans, and keep good synthetic (slippery) oil in it, the extra power should not be a problem if you avoid drive-line shock and "speed shifting". The CV joints and drive shaft u-joints would likely have shortened life too, but these can still be replaced with new parts (unlike the trans).

I like the rear wheel drive version of the 4AGE engine for this car, I but I have not found one yet (I may have to buy a wrecked MR2, the most common car they came in). If I do find one at a good price I am hoping I can get cams that bring the peak power and torque down to a lower RPM, I might also consider putting in a Corolla 4afe fuel injection system on it to help economy and low end power.

And modern EFI systems are always superior to carbs any where, anytime, especially in cold climes. Both the 4age and 4afe use excellent EFI systems, and both are reliable, but I suspect the 4AFE system has better economy and low end power.

BTW, I ran across a "hobby" website for an amateur racer and engine tuner (in New Zealand I think) who builds up 4AGE racers. He has a tweaked 4AGE engine in his Corolla GT-S he figures he is getting 185 hp out of, but still claims 42 mpg for daily driving (with a light throttle foot). I suspect one of these in a Tercel would even be better since it should be a lighter car.

The search continues...

[terceldude]

I wanted to try the 4A-ELU.

[Ron B.]

All of this conjecture regarding swapping this engine or that engine is giving me dyspepsia! Will someone please step forward with genuine experience regarding a swap. Please? I need to know which engine actually works. At 63 years of age I don't know if I will have enough time left to perform a swap!

Cheers!

Ron B. in Lake George, NY

[Teddy]

Petros,

I have done virtually every (or nearly every) tenable swap in the 4WD Tercel in the past few years.

Fuel injection conversions basically come down to:

1. Factory setups (including harness) from donor car (Corolla or Geo Prizm)
2. Custom hybrid (from salvage yard cars)
3. Spendy aftermarket setups, which make no sense on our cars (Autronic, Motronic, Motec, SDS, Electromotive, etc.)
4. Inexpensive open source solutions, like MegaSquirt... plus varied salvage yard parts. Expect to do a lot of hacking.

The 7A-FE swap (with most of the factory harness and ECU) is tough to beat (torque comes in a lot earlier than the 4AG-E, and the motor is not as high strung).

Send me an email at: ted@accutransinc.net if you want to discuss further.

[Don Jorgensen]

This swap is easy and you get 300+ horsepower, 6 speeds, fulltime 4wd...just 2 smalls bolts.

Ultimate Tercel.JPG

[AlbertaBeef]

Personally, I want to just put a 4a-c into mine when the engine I have wears out... but it got rebuilt just before I bought it, and runs beautifully... no need for a swap at the moment...

But someday...

[Typrus]

Hideous hatch... Why they killed the sedan I'll never know.... That thing looked wicked... Maybe I'll warm up to it though...

ANYWAY!!!!!

Big issues I see with our tranny...

The big counter gear that transfers power from the input to the main shaft has bearing that like to fail. A little lube starvation and its the first to pop from what I've seen. Maybe better bearings? Maybe an actual oil feed system?

Our front diff is TEEEEEEENY... As is our back one. No concrete size measures on the front, but it can't be much bigger than the rears 6.2". It'll grenade with much power adding. Heck, the one guy who dropped in a stock late 70's 350 into a Terc blew the rear diff by the end of his driveway. And stock late 70's 350's do not have much power.

If we could find a way to put a 7"+ diff up front and out back, then we'd find the next weak point in short order.


I do believe cryo-treating would help. Get the whole thing rebuilt (new bearings, seals, etc and if you can afford it, gears and shafts cut from stronger, modern steel alloys) and have the entire thing cryo'd.

Heck, modern steel alloys are on average, what? 25% stronger than 20 years ago? If you could get new shafts and gears cut, maybe beefier bearings in some places, internal strength could go up quite a bit. Then we'd find the limit of the case holding everything together. lol.

tercel4wdrules and I have been exchanging ideas for some time. We both think the terc would do great with around 200hp available on tap. Small, high revving engine perhaps with variable valve timing and/or lift? Maybe a small turbocharged powerplant? Maybe a diesel?
The idea being you have the power to get going quickly, and the ability to back off and let efficiency kick in.


I have been driving the 85 for the last week due to snow making my bald-tired Camry unsafe (money shortages stink) and it WILL NOT move until warmed up a bit. Combo of the 3-speed slushbox and needing a new carb. Then drove the Camry.. Turn key, VROOM... Off you go. Sweet.


Again...

F series heads have great torque and economy characteristics. Not overly high revving though.

I think a diesel would really suit these cars well. Really sweet torque for offroading, and awesome cruising economy.

If we could get better diffs in, maybe with a fairly better appliable carrier, we could get a Torsen up front with maybe a 2.89:1 ratio for the diesel economy. Or maybe 4.73:1 for the offroading crowd and high revvers.