To swap or not to swap? Ice racing Tercel

[Petros]

I just noticed you want to swap a 4age head on to a 3ac engine. The 4ac and 3ac heads are almost the same, the 4age head is totally different and I am not sure are compatible. The only savings on attempting a head swap is not having to make the flywheel work, and all the other issues you would still have, plus the trouble of trying to make the 16-valve head work on the 3ac short block, I do not think I would attempt that. It might bolt up, but you have cooling jacket issues, clearance issues, timing belt issues, front cover issues, as well as making the EFI set-up work, and still have to make custom header.

[Petros]

-I know I need to use the 3a flywheel and have it re-drilled for the 8 bolt crank

find someone who specializes in welding cast iron, they will know how to heat it up and weld the old holes properly. Than it has to get machined smooth, lightened, and drilled for the 8 bolt crank. Have the new flywheel rebalanced. I got the flywheels for Synth and my projects down to about 14 lbs. Anything under 16 lbs is good, the stock flywheel for the 3a is 19 lbs, the stock flywheel for the 4age is 16 lbs.

-What about the starter? If I use the stock 4ag one does it line right up with the flywheel?

with the new flywheel the Tercel bell housing will bolt to the back of the 4age engine, and you will use the Tercel starter (since it meshes into the altered Tercel flywheel), same with the clutch cable, stock Tercel. You will also be using the Tercel clutch, you will have to get a heavy duty clutch SPEC makes one, and so does CAP clutch manufacturing.

-Are there any sensor to flywheel issues?

None, any sensors on the 4age are in the front pulley.

-Which alternator do I use? I am not using PS if that matters?

You can use either alternator, you may have to fab or alter the mount however (we have not gotten that far). PS pump is the same unit either way.

-I know I need to use the oilpan off the 3a but are there any fit issues or does it bolt right on.

bell housing and front engine mounts bolt right up. It will clear radiator and elsewhere, but you will need about an inch more hood clearance over the throttle body. So you either have to alter the hood with a bump or scoop, or lower the front engine mounts.

-I know the exhaust downpipe needs creativity to clear the steering.

Not a big deal if you do not have power steering, you can have a production 4age header (for a '83-86 corolla GTS) altered to fit. cheaper than having custom header made, unless you can make one for yourself.

-Can I keep the stock clutch cable etc?

It will be stock Tercel since you are keeping the Tercel trans

-Is there anything else that isn't listed here that is anything but a straight bolt in?

All the hard points bolt up good, you will have to rig a throttle cable mount, and the wiring for the EFI. And either install an accessory EFI fuel pump, or swap tanks with the in-tank fuel pump from an EFI corolla or Celica. It can be done with a bit of messing around with the mounts and filler necks.

-Will the stock 4ag or 3a coolant hoses work with the 3a radiator?

If you have the 4age engine from a Corolla GTS, it is a straight forward install, you can use the stock tercel radiator, or get the larger one from a same year corolla which uses very similar mounts. I have not check with mine in my garage, but at worst you can swap over the 3a water pump and coolant lines, inlet, outlet, etc. to the 4age.

BTW, if you do not have the RWD version of the 4age (from the '83-86 Corolla GTS) you will need to get the intake manifold from this engine. The transverse installation for the 4age is far more common, but the cooling system and intake manifold are not compatible with the Tercel engine installation, it can be made to work, but there is a lot more fit and clearance issues, and more parts to fab to get it all working. Not a big deal but it will not be as clean an installation.

Also, there are twin side draft carb and intake manifold set-ups available for the 4age, it will take some of the swap issues away since you would not have to install an ECM and EFI fuel system. But they are pretty costly unless you can get one used somewhere. They put out a lot of power and were sold for racing, not street use. Personally I would rather stick with the EFI set-up, it is better as a daily driver and will cost less to adapt to the Tercel.

[dlb]

petros, what are the differences between the 3A and 4A heads? would a 3A head need to be modified to properly work on a 4A block? i think it's called a block, anyway. hopefully you understand my caveman speak.

[Petros]

I have not inspected them closely, but I think are almost identical, and should be interchangeable. They use the same size intake and exhaust valves, so everything else should be pretty much the same.

[shanehutton]

I figured I would give you guys an update on the ice racing Tercel. We are 1/2 way through the season and I am doing quite well. I made some improvments to the car and it is quite competitive despite it's modest power.
I Removed whatever weight was still in the car after last year. No dash, no soundproofing, skinned hood and hatch, lexan windows, single race seat etc, relocated battery to rear passenger side footwell, 32/36 Weber, cut about 1 inch off spring (losing all the weight had her riding a bit too high). Also went for a historic TRD livery and ended up having to reverse mount a WRX hoodscoop to give the carb some clearance.

Next year it is either leave it as is and get an MR2 for the RWD class and race both or I am doing a 20v swap and pushing this car as far as it will go.

Anyone know how I could source an LSD for the rear?

[ARCHINSTL]

The kitty GROWLS !

Tom M.

[dlb]

that's unreal! and i don't believe there's every been such an action shot of tercel, either--they could have used that in the old 'ideal for taking the family skiing' ads.

[Petros]

Great pictures, please post more! And here I have been thinking there is no class of racing the Tercel4wd would ever be competitive in because it is so underpowered. Perhaps with ice there is only so much power you can use, so traction is more important that total power. What other cars are in your class? What are the class rules for modifications? You could try going to 4ac with the weber and cam, that should give you a bit more power and it is an easy swap (unlike the 4age).

For an LSD the best bet is to try and locate a rear axle assembly from a rwd Corolla GTS. There are three different brands of LSD that fit in the GTS rear axle, and they were a factory option. All the mounting points are the same so it should bolt right up. You will have to find a 4.1:1 rear ring and pinon set for the larger diff in the GTS rear axle to match the front. Since this is a track car only you can also just weld up the spider gears for "poor man's" limited slip dif.

List member Synth was going to look into getting an old Mazda RX7 rear diff to fit in the Tercel diff. The Tercel rear axle is the same one from the earlier rwd corollas (not the GTS, which is heavier and uses a larger diff). I have never heard of an LSD available for the lighter/smaller corolla/Tercel4wd rear axle.

[shanehutton]

Just bought a 4age and I am picking it up tomorrow night. Looks like the tercel is getting a wee bit more power for next year. Petros - I will probably be on here bugging you in the summer when I actually get around to doing the swap. Here are a couple more photos. It looks like I am going to take the rubber to ice championship and end up top 5 in the AWD studded class. Even in the rubber to ice races the tercel has been clocked at 60MPH with the 3A. I can't wait for the 4age.

Sitting on the pole position


Duelling with a Mazda 323 GTX


Chasing down a corolla alltrack and a 20v Audi quattro.

[Petros]

Those are some hot pictures, great to see a Tercel competitive in a class of racing!

Going all the way to a 4age? this is a big investment, did you get the ECM and all the wiring, or are you going to convert to carbs? Someone makes a duel side draft carb kit (with manifold) for the 4age, it is pretty pricey but I see them show up on E-bay regularly used. Do the class rules allow for this drastic of an engine change?

Using all wrecking yard parts that I can (including using a Celica GTS pump-in-tank fuel tank), and doing all my own work as I can, my own 4age conversion (plus a basic rebuild) will cost about $1500, not counting buying a performance clutch. So that is what you are likely in for unless you can make your own header, flywheel, do your own machining on the engine. BTW, do not waste any money on performance cam shafts, they are very costly and put all the power way up in the 7000-8000 rpm range. Instead get some adjustable cam sprockets, by adjusting the intake and exhaust cam separately you can lower the peak power rpm and get more power and torque in the lower rpm range. I would think that is better for this type of racing. That is my long term plan for my 4age conversion, it should also improve my hwy fuel economy as well. looking for more power AND 40 mpg.

[shanehutton]

Engines are wide open in the rules. You can swap, turbo etc. It usually isn't a big issue cause with limited traction power isn't that big of a deal. My car, however, is so underpowered that I can actually use the help. Anything over 100-150 is plenty though and you wouldn't see very big improvements even if you added another 100hp.

Fuel will be via fuel cell and external fuel pump.
Just got a megasquirt that will handle the ECU duties.

The swap will be done this fall as I have lots of work to do on the road race car in the meantime. I will keep everyone here posted once I get started.

[shanehutton]

So, the time has come and the motor is being swapped. I ended up with a 4a-ge and a 4a-fc and it came down to the wire but I opted for the 4a-fc and will run my Weber 32/36 on it. The engine is in and I only have a couple of things left to do.
-Fabricate exhaust manifold
-Finish wiring
-run coolant lines

I need help with the last two.

Does anyone have the stock Tercel wiring diagrams? I need to locate the wires for the coolant temp gauge as I forgot to label them when I pulled the 3a. I have two possible conectors so even a photo of the location and conection would be helpful.

I also need a coolant diagram for a 4a-f engine as it has a ton of coolant paths I want to delete (i.e. the ones running through the intake manifold) but I am not 100% sure how it flows and don't want to mess up the flow through the engine.

Does anyone know a good source for really cheap front fenders? Are they common to all the Tercel models?

HELP.

In the meantime, here is some bonus.

Empty engine bay


Video of some of the firewall modifications we did.
http://s635.photobucket.com/albums/uu79 ... G_0850.mp4

[shanehutton]

I can also report that the car is about 1900lbs with the 3ac and some gas in the tank.

[Petros]

the wire diagram is in the FSM link I think (at the top of the page). The temp gage is run by the sender at the front of the head, not on the outlet.

All of the second gen Tercel models have interchangeable front fenders, some have a larger lip on the wagons, but the all interchange.

You will not harm anything by blocking off both ends of the coolant supply and return for the manifold, nor the heater either. they typically tap coolant from a high pressure area (after the pump) and than return to a low pressure area (at the lower rad return hose area). Blocking it off only means it will circulate more through the engine block.

looks like fun, let us know the results.

[shanehutton]

The odd part is on the intake manifold it looks like the coolant actually flows through the intake into (or out of) the head. If it was a simple inlet and outlet I wouldn't be concerned. I really need to see an accurate diagram for this motor.

Any idea what color (and shape) the stock tercel connectors are for the coolant temp and the oil pressure switch?

Manifold is almost done thanks to my friend letting me do it as his work (and welding half of it.)

Just need to make an outlet. Save the comments about flow cause I don't care much about losing a couple of HP.