Rebuilding

[tercel4wdrules]

The Prizm came with two engine options depending on the trim model. It either has the 4A-FE or the more desirable 7A-FE (less common). Usually you can tell by looking at the under hood emissions sticker and it will tell you which engine it has. If that fails, you can always use a VIN decoder.

[WarWagon]

Thanks mate

[WarWagon]

Few more q's

7ac with a 4ac head using the 3ac intake and carb? Will it be enough fuel and air to get 10.5-1

Do clinometers go out of whack? Can it be recalibrated?
What would a nice led light bar take for energy? A mild sound system, bright lights, maybe a winch, what alternator would work. A yellow top optima battery is on my list as well.
What is distributerless ignition on the 4ac head. What would ignition timing and tuning take them?
Petros! How would you build a 7ac for 6,000-10,000ft? I want the motor because it can be tuned for a tad bit more top end but I think it would still be torquey with the enlarged valves I thought you talked about somewhere over the rainbow. And the added front end weight would stick a lil bit better on the ice here in the winter. Rear end is mostly solid but in a roundabout the front likes to say no no no @10mph.
Last one. How often do sunroof s break? Fixable?

Thanks terc gurus!

[dlb]

Do clinometers go out of whack? Can it be recalibrated?

yes and yes: viewtopic.php?f=7&t=9908&p=73281

How often do sunroof s break? Fixable?

i find they don't leak that often. yes, leaks can definitely be fixed. i think leaks are usually due to the drains being plugged, the seal being old and stiff, and the sun roof being out of alignment so that it doesn't seat tightly against the seal. the first two possibilities are pretty easy to deal with, the other would be more work.

[Petros]

7ac with a 4ac head using the 3ac intake and carb? Will it be enough fuel and air to get 10.5-1

that combo should give you about 10.7:1 compression ratio. You will gain displacement, but the small carb and eight small intake and exhaust valves will limit total power output. Should have lots of torque at the low end. you will have to find a timing belt the correct length, and the block is taller and there may be a few issues trying to get it all to fit in the Tercel. It can be done, but there will be a few minor items to work out.

What is distributerless ignition on the 4ac head. What would ignition timing and tuning take them?

the 4ac head can use the same distributor as the 3ac, no reason to go to distributorless unless you want it. Easiest would be to buy the costly kits to convert it, but you can assemble the parts from newer production cars and rig it up yourself. Not sure there would be any noticable benefit since the stock system is already a very reliable eltronic system, you get a slightly more precsion spark by eleimnating the distributor shaft and gears, you would have to rig up a crank fired sensor to run it.

Petros! How would you build a 7ac for 6,000-10,000ft? I want the motor because it can be tuned for a tad bit more top end but I think it would still be torquey with the enlarged valves I thought you talked about somewhere over the rainbow.

I never desired a 7ac for any car I have, there are a number of unknown problems that might manifest after you get it all together, so I would not want to experment that much with that kind of a frankenstien block and head combo. I would rather go 4afe and eliminate the carb. If you stay with the 3ac carb you will be limited by how little air that will breath, might do better if you put a weber on it and than fiddle with the jets until you get the airfuel ratio matched to that altitude. I would keep the the stock head and EFI for the 7afe, put in a mega squirt to control the mixture and tune it for high altitude. There would be a new exhaust system to fab, and wiring to rig up for the EFI, plus the fuel system to convert, but you would end up with a better, more modern engine with both more low end and high end.

And the added front end weight would stick a lil bit better on the ice here in the winter. Rear end is mostly solid but in a roundabout the front likes to say no no no @10mph.

more weight in the front will give you much more understeer, you would have to find some stiffer springs up front to take the weight. And than you would have to balance the front to rear by adjusting the front and rear anti-sway bars (you may have to fabricate an adjustable rear bar). Or you can try and hunt down the smaller rear bars that come in the rwd corolla and ceilca and trial and error to see if any of them would bring you back to neutral steering. You can also attempt to balance the over/under steer with stiffer rear springs as well, but it will also be trial and error, and you could end up with too stiff a suspension all the way around.

Last one. How often do sunroof s break? Fixable?

They are fairly reliable but they do fail occupationally. Not just leak (which are easier to repair) but also the internal mechanical parts can fail and break. I have taken them apart and fixed them. The drive is riveted together and you have to drill out the rivets to get to the internal parts. than locate replacement parts (or make them if possible), and but it all back in. I used pop rivets to assemble the drive mechanism after I managed to fix it.

[WarWagon]

Petros was one of your 3a's without a weber close to 85hp?

Who wants the cruise control off this thing? Linkage was severed right at the carb for your information.. Somebody else not me. What kind of metal can i use to weld on new tool/jack box onto the rear left of my terc? Anybody hit a deer @45mph on the front left? Gonna send er in to a collision repair shop to true everything up. Who has a 4ac for me to buy? Im in Colorado.

If all fails and i say F it! Anyone got a 1969 Chevy k20 with an eaton ho52 rear end and a dana 44 up front?

[irowiki]

So can the cc be fixed?

[WarWagon]

It is the same kind of wire that a bicycle has for brakes, you imagining it? It has been cut, ill take of the air box and take a picture later.

[irowiki]

Ah, so it was cut and the other end is gone?

[teranfirbt]

Factory alternator is good for 65 amps at running RPM (I think > 2000). I had it running a decent sound system (300 watts of amps) and an extra pair of driving lights and it held up ok. It would drop voltage at idle if the headlights were on.
A reasonably easy swap is a GM CS series. The CS130 (95-100 amps) is more than enough generally, but the CS144 (140 amps) will fit in the same space as the 130 and is generally more reliable. I installed a CS130 when I did my 5AFE swap and it only drops voltage when everything is on at idle, and even then it still doesn't drop to battery voltage.
Distributorless ignition isn't tooooo bad, but you pretty much need to buy a Megasquirt to do it. Factory Tercel plug wires will work with a mid 90's Hyundai Accent coil pack, which is what I used for the 5AFE. Ford EDIS coil packs with early 90's Escort plug wires also work, which is what I was running when I had CBR600 throttles on my old 3AC.

The hardest part of a 7AC will be the timing belt since the block is taller.

[WarWagon]

Dodge colt, I forget What gen. Awesome sound advice man!!! How's the 5afe goin?

megasquirt 4ac tuned ill have a good 100hp ya think. All I want it reliability and I'm going to do all the work myself so I learn in the process.

[yellowsnow4free]

7AC

WarWagon, if you go this route, please document your build and what issues you run into.

I'm very interested in building a 7AC myself, and there is a serious lack of info on it. When I have time this week I can post some links I've compiled on the subject; there aren't many.

In some ways I'm with Petros; building a "frankenstein" motor can result in unforeseen problems. However, enough guys have built 7AG engines and beat the living you-know-what out of them, and haven't ran into any major issues AFAIK.

If you need more info, there's a lot you can pull from 7AG builds and apply it to a 7AC.

Good luck!

[WarWagon]

Either a 4ac, 4afe carbed, or 7ac..... if i can get a 4a from the folks on tercel4wd then im going that route.

[Petros]

A properly built 4ac with a weber and Delta street grind cam will get you most of the way there and it is an easy bolt up installation, no experimenting or custom parts required. Even keeping the 3ac carb like I am gives decent power, that is what I am running now. I estimate 85 to 90 hp, and good cold weather start and driviablity, 30 mpg hwy driving. Adding the weber and a custom exhaust (I am running the stock exhaust sytem) will get you a few more hp as well. though there will be some experimenting with rejetting the webber to get it optimized, but that is not difficult.

If you want more power I would go fuel injection, more reliable, low maintenance compared to a carb and both improved power and fuel economy. I think it would be a wasted effort to put 8 tiny intake valves from the 4ac/4ac on a 7a short block, not enough breathing. The 7age is quite a differnt story, the 4age head is one of the best breathing heads toyota made at the time and others have shown it can be done, the stoc 7afe head is already stimilar design too, you can not say that about the 3a head vs. the 7afe head.

Converting to EFI is a lot of tinkering, but you get a more modern system, better performance and economy, and you have a lot more options for aftermarket performance parts. The 5afe conversion is a nice set up too, though as you can see in Teranfirbit's thread on the topic, there is a lot of custom parts and tinkering required to make it all work. Or you can get almost triple the hp, AND improve the fuel economy by going the Larry McGrath route and shoe-horn in a 174 hp 20-valve 4AGEZ, big job but I think larry is happy with the results.

[yellowsnow4free]

I think it would be a wasted effort to put 8 tiny intake valves from the 4ac/4ac on a 7a short block, not enough breathing.

A few people have mentioned this, and it does make sense. However, I haven't heard of anyone running a 7AC (granted, there aren't many) who had any problems running a stock 4AC head on the 7AFE short block. Having said that, would a worked 4AC head provide enough breathing for a 7AC build?

Petros, I've never asked or found this info, but on your 3AC / 4AC powered vehicles, did you need to do any head work on them? I know about your notches to help with detonation, but I have no idea if you did any porting / polishing.

From the info I've gathered, there isn't a lot of custom work that needs to be done on a 7AC. One of the biggest ones is using the 4AC timing covers. I believe the top one will bolt up, but the bottom one requires the 4AC (or 4AGE) oil pump, because it has the proper tensioner location. I think you need to use the 7AFE tensioner spring though.

And there's of course the water line mod:

http://www.86garage.com/forums/viewtopi ... 180#p63887

There's also the 2-piece 7AFE oil pan, which doesn't line up with the T50 bellhousing:

http://www.86garage.com/forums/viewtopi ... 180#p63867

But you can get around it buy using a 4AFE / 20v 4AGE oil pan:

http://www.86garage.com/forums/viewtopi ... 180#p63862