4afe Head Conversions

[LOROLA]

Hi all

 

don't know if this has been asked before and sorry if it has. I am wondering would it be to difficult to change 4AFE heads from a newer motor to an older one. As i have read some forums and sites that there is a difference in the ports etc... and was wondering if i could be able to bolt on the heads from a 94-96 4AFE motor into a 90-94 4AFE block.

 

Thanks before hand for any help.

[towe001]

Personally i can't see any problems with the swap at all.

[Sam_Q]

If it is the earlier series of engine then the intake side of the engine would be tottaly different. The earlier head has a nasty port design and it would be highly unrecomended to downgrade to it when the later heads are faily easy to come by. Just curious why would you want to do it?

[Hiro Protagonist]

If it is the earlier series of engine then the intake side of the engine would be tottaly different. The earlier head has a nasty port design and it would be highly unrecomended to downgrade to it when the later heads are faily easy to come by. Just curious why would you want to do it?

 

Doesn't he want to do it the other way around? Late head onto early block, thus improving it?

 

As Sam said though, the intake is completely different. Early heads have the injectors firing into the head itself, whereas the late models (same head as the 7AFE too, mind you) have the injectors in the intake manifold. Plus, the late head does away with the cold start injector, and I think the t/b is different too (can't adjust idle speed on late model heads)

[Sam_Q]

oops I misread it, now I can have a proper answer.

 

The combustion chambers are a different shape between the two engines and I believe that going to the later head would cause it to the lower the compression a bit but if this is the case then fitting a 7a gasket should help that.

 

the whole intake and probably the ecu with its wiring harness would need to be changed also, however these are probably available dirt cheap.

 

I believe the exhuast side is the same

[LOROLA]

If it is the earlier series of engine then the intake side of the engine would be totally different. The earlier head has a nasty port design and it would be highly unrecommended to downgrade to it when the later heads are fairly easy to come by. Just curious why would you want to do it?

 

 

hey SAM

 

well one of the reasons being that i read somewhere you can muck around with the newer 4afe head, and that even if i did some internal work to the motor block or head wise, i could get away with not even having to get a blue slip. I know i could go for the 4age or 4agze but then i have to get to many things to pass the car and this car isn't really worth all the hassle. i just wanted something little bit extra on the torque or little on the power providing the different newer heads will give little extra. Its just my mind thinking to much and wanting to muck around alot.

 

thanks for the help SAM

[Sam_Q]

yes from what I hear from the south africans there is quite a bit you can do to these engines to make them perform suprisingly well. I am thinking that going off what Hiro said that maybe theres an option to take all the sensors/wires/injectors off your current head and then put it on the new head with its manifold. With the cold start injector weld a new boss in the intake manifold to hold it. This is definately not my area but I think it might be posible to get the original ecu to accept this different head.

 

Do you know what I mean?

 

Hey I need to go to the wrecker soon anyway because I think my diff center is just about to have a small contained explosion any time now so while I am there I can compare injector plugs/placement/interchangablility or all sensors. Ah its a pity your not in Vic

 

What did you have in mind for mods anyhow? I can tell you whats been reported to me on what works, you can dismiss cams for one.

[Hiro Protagonist]

yes from what I hear from the south africans there is quite a bit you can do to these engines to make them perform suprisingly well. I am thinking that going off what Hiro said that maybe theres an option to take all the sensors/wires/injectors off your current head and then put it on the new head with its manifold. With the cold start injector weld a new boss in the intake manifold to hold it. This is definately not my area but I think it might be posible to get the original ecu to accept this different head.

 

Do you know what I mean?

 

Hey I need to go to the wrecker soon anyway because I think my diff center is just about to have a small contained explosion any time now so while I am there I can compare injector plugs/placement/interchangablility or all sensors. Ah its a pity your not in Vic

 

What did you have in mind for mods anyhow? I can tell you whats been reported to me on what works, you can dismiss cams for one.

 

Why not swap the ECU over at the same time? Doubt there'd be too much difference in wiring.

 

But there is definitely potential in the FE heads, you just have to spend money on them. Couple of my mates (from Twincam) have had modified 7AFEs putting out around 80kw at the wheels (they only made 85 stock at the flywheel, and normally get mid 60s at the wheels)

[Sam_Q]

I would doubt that the wiring loom would plug into the the newer ecu let alone be the same, however I think it wouldnt be that hard to transplant both the ecu and full harness, probably be cheap as. I wonder if theres a real difference between the later model 7afe ecu and the later 4afe ecu. I would think the loom would be the same.

 

I tottaly agree with you on the potential, I did plan on ditching my blacktop head for a 7afe head after-all. So what mods did your friends do? I think that figure would be misleading though as even with 80kw I am sure they would be killing many 4age engines because of the killer torque.

[Hiro Protagonist]

I would doubt that the wiring loom would plug into the the newer ecu let alone be the same, however I think it wouldnt be that hard to transplant both the ecu and full harness, probably be cheap as. I wonder if theres a real difference between the later model 7afe ecu and the later 4afe ecu. I would think the loom would be the same.

 

I tottaly agree with you on the potential, I did plan on ditching my blacktop head for a 7afe head after-all. So what mods did your friends do? I think that figure would be misleading though as even with 80kw I am sure they would be killing many 4age engines because of the killer torque.

 

I've got the Gregorys for the AE101/102, which has both the 4AFE and 7AFE, and ECU pin-outs seem basically identical between the two (apart from the odd difference like knock sensor, which the 7A has but the 4A doesn't, not enough so they don't show different diagrams for the two ECUs)

[Sam_Q]

yes thats because they are both the later models, I was comparing the later model 4/7a head to the earlier model 4a head. Late model 7A looms + ecu + heads should be very easy to come by. I think thats the better options as my vernia tells me it has an unusually large amount of valve lift 8.6mm!!

[LOROLA]

yes from what I hear from the south Africans there is quite a bit you can do to these engines to make them perform surprisingly well. I am thinking that going off what Hiro said that maybe theres an option to take all the sensors/wires/injectors off your current head and then put it on the new head with its manifold. With the cold start injector weld a new boss in the intake manifold to hold it. This is definitely not my area but I think it might be possible to get the original ecu to accept this different head.

 

Do you know what I mean?

 

Hey I need to go to the wrecker soon anyway because I think my diff center is just about to have a small contained explosion any time now so while I am there I can compare injector plugs/placement/interchangeability or all sensors. Ah its a pity your not in Vic

 

What did you have in mind for mods anyhow? I can tell you whats been reported to me on what works, you can dismiss cams for one.

 

 

Hey SAM

 

sorry for the late reply shift work killing me here. thanks for your help and advice and hiro also. what i have in mind is a few minor mods but not so sure if they will work together besides the newer 4afe or 7afe head on older block.

1. Would the 4agze injectors fit on the newer 4afe or 7afe.

2. extractors not the full hog but a level up on the standard manifold and probably half inch extra exhaust wider on the standard.

3. Gearbox wise i was wondering what would be and easy 5speed auto or best 4speed auto that wouldn't need to much mocking around with the standard.

4. front and rear sway bars for better control.

thats some of the mods making my mind just wonder crazy, coz like i said earlier i don't wanna do something to major that i would need a major blue slip just something simple that would pass through.

 

Appreciate the help and advice to you SAM and hiro and all that input.

[Sam_Q]

don't worry about appologies I know know what a lack of time is like.

 

1. not sure but the standard injectors should flow enough

 

2. in theory it should work on either engine but I havent heard the results from anyone doing it

 

3. no idea, I would think that any gearbox made for a 4a engine would work?

 

4. this is a highly debated topic and it varies car to car, I sujest upgrading your srings and shocks beforehand but thats just my personal opinion.

[Hiro Protagonist]

Extractors will help a little bit (stock FE manifold is a cast-iron lump of crap, apart from the AE112 7A manifold which is better), but the big exhaust restriction is in the engine pipe where it goes over the crossmember. Stock it flattens out to an oval shape and gives a big reduction in flow and power. Replacing the full exhaust will obviously give good results (I gained somewhere between 5 and 10kw with extractors, 2" to cat, 2.25" through hotdog to Lukey Ultraflow), although thats on a 7A so you should probably just stick with 2" all the way for the 4A

 

As for the gearbox, sticking with a manual is the best bet (do you have manual or auto at the moment?). 4-speed autos behind 4AFEs are slower than a wet weekend, and there hasn't been a 5-speed auto Corolla gearbox, ever.