Engine swap ?

JARED · Post by **JARED** » Fri Nov 12, 2004 3:04 pm

I read a post about installing the bottom end of a 7A-FE into a 4A-GE car. Is there any possibility of doing the same thing with the tercel. I don't kow much about the head differences.
I also saw a 5A-c motor listed on ebay. Does such a thing exist?
Thanks for any information you may have on either subject.

GTSSportCoupe · Post by **GTSSportCoupe** » Fri Nov 12, 2004 5:21 pm

I've thought about doing this too. As you might know, in the world of 4age's, 7age's are built to create a 'stroked' 4age. It increases the displacement from 1.6l to 1.8l and creates a good deal more torque in addition to good top end power. I've seen this done mostly with the AE86 Corolla GTS. If you are interested on exactly how to build a 7age, you would be best off doing a search on http://www.club4ag.com . (no one here has done a 7age to the best of my knowledge). However, if you are considering building a 7ac (using the bottom end of a 7afe, and the head of a 3/4ac, I believe you will be trying something new. I've sort of toyed with this idea as an easy way to increase the displacement of my tercel to 1.8l for more torque. Installing a full 7age into the tercel would probably provide it with more power than it could handle. A properly tuned 7ac could work out ok though. I would use a 4ac head on the 7afe bottom end. I believe that a 3ac head is the same as a 4ac, but am not totally sure. I am sure that a 4ac head would fit on a 7afe bottom end though. The only problem with this setup is the poor flow of the 4ac head. You would need to port it out a bit and maybe install a bigger cam. You also probably have to upgrade the carb to a larger one. I think this could work out fairly well, but you would have to be handy with building hybrid engines, and definitely be a fairly capable mechanic.

I've never heard of a 5ac, although I know there is such thing as a 5af and a 5afe. The 5af is carbed and DOHC; maybe this is the engine you saw on ebay. It would be an improvement over a 3ac, but would be difficult to install as it is probably from a fwd and has the intake/exhaust on opposite sides of the engine as opposed to the single side on the 3ac.

Gasoline Fumes · Post by **Gasoline Fumes** » Fri Nov 12, 2004 10:33 pm

I really want to see someone build a 7ac. If somebody sends me all the parts, I'll do it!

Would the cam, porting and carb upgrades really be necessary? You should still see a nice increase in low-end torque with a stock head/manifold/carb setup. Of course, more airflow is always better.

Guest · Post by **Guest** » Fri Nov 12, 2004 11:07 pm

Are 7A-fe's hard to get a hold of? If I can find one cheap I would be willing to do the swap. I think the bottom end on my girlfriends 3a-c is shot and I don't want to do a rebuild. No oil in the system is not good for any motor! If the oil light comes on just before crunchy noises and a lot of bucking I am assuming this is a good indication that a bearing spun on at least one rod. Yeah maybe her parents will send some money and I can play cars on my christmass break. I'll let you know what I end up doing. Thank you for your imput. I must not be completly nuts.
jared

Gasoline Fumes · Post by **Gasoline Fumes** » Sat Nov 13, 2004 12:37 am

Guest wrote: Are 7A-fe's hard to get a hold of? If I can find one cheap I would be willing to do the swap.

I don't think they're too rare. I think they were used in some 90s Corollas and Celicas.

Guest · Post by **Guest** » Sat Nov 13, 2004 11:29 am

I haven't seen a 7a-fe in a rwd car. Will the engine mounts and excessories transfer from the 3a or will this just be too hard of a swap? I really want to do some off roading but I will need more torque. Getting stranded is not my idea of fun. If I could find a 4af head or a 5af head I would trow that in later. From what I understand is they are the f style dohc head with a carb on it. I don't want to convert to fuel injected.

Gasoline Fumes · Post by **Gasoline Fumes** » Sat Nov 13, 2004 9:24 pm

I didn't think of that. The RWD mounting points might be on the block, I've never taken a close look at a 7A block. I'll try to remember to look when I'm at the junkyard.

JARED · Post by **JARED** » Tue Nov 16, 2004 11:15 pm

I have another idea. What about a bottom end rebuild kit from a celica that had th3 7afe? That would replace the crank and the rods. Basicaly a stroker kit using oem parts from another engine. Would this work? Has anyone looked into it? Checker doesn't cary this kit but I will check other places soon. They made it sound like such a thing did exist.
They said a bottom end kit should cost about 400-500 dollars. That is in the range of affordability.
JARED

GTSSportCoupe · Post by **GTSSportCoupe** » Wed Nov 17, 2004 7:11 am

JARED wrote: I have another idea. What about a bottom end rebuild kit from a celica that had th3 7afe? That would replace the crank and the rods. Basicaly a stroker kit using oem parts from another engine. Would this work? Has anyone looked into it? Checker doesn't cary this kit but I will check other places soon. They made it sound like such a thing did exist.
They said a bottom end kit should cost about 400-500 dollars. That is in the range of affordability.
JARED

This won't work for sure. There is not enough room inside the block of the 3A or 4A blocks (any of them). HKS used to make a stroker kit for the 4AGE, and I believe it was a lesser stroke even than the 7AFE has, and one of the things that had to be done was machine out parts of the inside of the crank-case so there was room for the larger crank.

Usually rebuild kits don't come with a new crank and rods anyhow....just new bearings, seals, gaskets, bolts, etc.

FH Bible · Post by **FH Bible** » Mon Nov 22, 2004 12:45 pm

Ok now I can tell that the head should be able to swap onto a 7a-fe. Who could tell me if the proper mounting places are in that block to put it into our car. I really want to do this and I am gathering info now for a major engine overhaul through december and possibly january. If I can come up with enough information to go for this swap, then I promise that I will write up a HOW TO with all the info for someone else to follow. Maybe later if the first engine project works out I may do a 4a-f or 5a-f carby head HOW TO this summer. I am finishing college this semester and finally I should have the time to do some projects. I have connections with a good welding shop and the owner wants to get into car fabrication so I may also have the lift strut spacers made this winter. Let me know if any of you are interested. I could probably have them made real cheap.

GTSSportCoupe · Post by **GTSSportCoupe** » Mon Nov 22, 2004 1:23 pm

FH Bible wrote: Ok now I can tell that the head should be able to swap onto a 7a-fe. Who could tell me if the proper mounting places are in that block to put it into our car. I really want to do this and I am gathering info now for a major engine overhaul through december and possibly january. If I can come up with enough information to go for this swap, then I promise that I will write up a HOW TO with all the info for someone else to follow. Maybe later if the first engine project works out I may do a 4a-f or 5a-f carby head HOW TO this summer. I am finishing college this semester and finally I should have the time to do some projects. I have connections with a good welding shop and the owner wants to get into car fabrication so I may also have the lift strut spacers made this winter. Let me know if any of you are interested. I could probably have them made real cheap.

That would be awesome if you did the 7AC project! Would be great if you could have parts fabricated to sell to people on here too!!

I believe that when AE86 guys swap the 7A bottom into the AE86, the 4A engine mounts bolt just fine to it. So I would assume that the 3A engine mounts will also bolt to it.

If you use the 3AC/4AC rwd head/intake/exhaust, everything should hook up as before (fuel/wiring/coolant).

Issues you'll have to sort out include: which flywheel/clutch setup will fit and work, which water pump to use (I think a 4AC one will fit and work...if the 3AC one is the same, it'll probably work too), and the main thing is what timing belt to use. Guys who build the 7AGE use a timing belt off of a Porshe 924. The 3AC head is only SOHC though, so you will need a different length timing belt. It will need to be longer than the 3AC one though (as the 7A block is taller). Also, make sure that the height of the 7A block doesnt make the 7AC result too high so that it hits the hood of your car. One last thing too....you might want to swap the pistons in the 7A bottom end. The cut outs on the 7AFE pistons are for a narrow angle DOHC 4 valves per cylinder setup. You now have a SOHC 2 valves per cylinder setup. You might be able to make the pistons from a 4AC work in the 7A bottom end. But you will need to confirm the piston pin size is the same between the two engines. They'll either be 18mm or 20mm. You could probably use the 7AFE pistons, but you might experience piston to valve clearance issues. And if your timing belt ever goes, you will definitely not have a non-interference engine - the pistons will probably smack into the valves and destroy your engine.

This stuff is never as easy as it sounds, so don't expect to get it working in a weekend.

Keep us posted though.

Gasoline Fumes · Post by **Gasoline Fumes** » Tue Nov 23, 2004 12:00 am

GTSSportCoupe wrote: and the main thing is what timing belt to use. Guys who build the 7AGE use a timing belt off of a Porshe 924. The 3AC head is only SOHC though, so you will need a different length timing belt. It will need to be longer than the 3AC one though (as the 7A block is taller).

Does the 7AFE have the same/similar head as the 4AFE? If it's like the 4AFE head with the single cam pulley and a set of gears driving the other cam, maybe the 7AFE belt would work.

GTSSportCoupe · Post by **GTSSportCoupe** » Tue Nov 23, 2004 7:35 am

Gasoline Fumes wrote:
GTSSportCoupe wrote: and the main thing is what timing belt to use. Guys who build the 7AGE use a timing belt off of a Porshe 924. The 3AC head is only SOHC though, so you will need a different length timing belt. It will need to be longer than the 3AC one though (as the 7A block is taller).
Does the 7AFE have the same/similar head as the 4AFE? If it's like the 4AFE head with the single cam pulley and a set of gears driving the other cam, maybe the 7AFE belt would work.

Ahhhh....VERY good point. I had forgotten about that. I think you might be right. There is a possibility that it will work. Although I think the DOHC heads are taller, so the timing belt might still be a bit long. Definitely worth a try though. Maybe the tensioner will adjust enough to take up the extra slack?

20vtercel · Post by **20vtercel** » Tue Nov 23, 2004 9:50 am

GTSSportCoupe wrote: Maybe the tensioner will adjust enough to take up the extra slack?

better hope it has the same amount of teeth or timing will be out REAL fast!!! slack is one thing but the teeth have to be the same.

FH Bible · Post by **FH Bible** » Tue Nov 23, 2004 12:03 pm

Well I will just have to see how cheap I can get a 7afe and then tear it apart and see what I find. The tercel is dead right now and I am not the kind of person that will spend hours of time and tons of money hopping to get back where I started. So in order for me to be interested in resureecting this car I will need a challenge or goal that is better than the car was before I started. If you know what I mean. I will start working on this in 2 weeks. Until then research time.