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starni_boy
13th April 2008, 12:27 PM
Hey everyone,

As you may know, I am currently building a 7AGE 20v fomy ke70, and decided to write this up as I have seen the question pop up a few times.

http://www.ae86drivingclub.com.au/dcimages/4/8/4/3/154841.jpg

Now, first off, for those who don't know what a 7AGE is, it is a 1.8L engine (7AFE) out of a few models of Corolla which were all of FWD Origin. These were such cars as the AE102X, AE102R etc. People then change the head of the engine with a 4AGE head for a number of reasons, hence making the "7AGE" hybrid engine. The 7A block is 10mm taller than a 4age block, giving it the extra stroke of a 1.8L.

To get the engine bolted to the crossmember, I used standard 4AC (RWD) steel engine brackets which bolted straight onto the block. Make sure that these are bolted into the correct holes, because if they are bolted too far forward, the RHS mount will bolt up 2 out of the 3 holes, and the LHS mount will only bolt in 2 of the 4 holes.

http://img258.imageshack.us/img258/5236/img1640li0.jpg
^^What happens when the RHS mount it too far forward. If the bracket is moved back into the rear "triangle", it will bolt up all sweet.


The LHS mount has to share holes with the rear alternator bracket, so use the pulley bracket bolts on the rear two holes, and use the alternator bracket bolts on the front two holes. This works perfectly. As Shown, if mounted too far forward, only 2 of the 4 holes line up. You can see the rear bracket for the alternator, which you share the holes with the engine bracket

http://img337.imageshack.us/img337/3624/img1641ym5.jpg

Get your AE86/AE71 engine crosmember, with 4AC/4AGE rubber mounts and bolt the crossmember on. It should all line up.

I have no Alternator at the moment to mount up with the LHS bracket to check clearances, but I will update that accordingly.

http://www.ae86drivingclub.com.au/dcimages/4/8/4/3/154980.jpg

As for the RWD cooling assembly*, you can do it like this:
Get a 4ac waterpump and take the rear housing off, and do the sa with the 7A pump. Keep the 7A front housing, and keep the 4ac rear housing, as these will be bolted together. This is done because the rear housing of the pump is already a RWD version, and the front housing keeps alignment with all the pulleys, because the front housing is a tad longer than the 4ac. You will have to make up a custom rear water line for the rear housing of the pump. I have forgotten a lot of what I have read on this section, but please read Sam_Q's RWD water guide at the bottom of the page. Thats pretty much all you need to do in that guide, but the alternator is on the other side of the engine, Which means not as many water hose modifications on the water pump.

I got an AE71 (RWD 4AC) Alternator in the mail yesterday, and have trial fitted it to the engine. As I don't have the original Alternator brackets here for the alternator I'm using, it means I have to buy yet MORE things. The alternator goes on the same side as the 4age motor, which is the drivers side (Right hand side). I need to get the 20v or 16v pulley and mount from somewhere.


Now, If your doing the 20v head on the 7a bottom end like me, read on..

The 20v head will bolt on straight up. But some modifications are needed to other parts to make it all work. Again, Sam_Q's RWD water guide is used with the 20v head (See link at the bottom of the page). But the 20v head can be made to work in a different, not as neat way. It will require bashing of your firewall with a hammer to make some room.

The 20v head has a water outlet at the back of the head, which causes dramas with your firewall, which needs to be bashed out so the housing can fit. Modifiers then make up a water line and run it underneath the exhaust manifold to the radiator. Like I said, It makes it look ugly as you can see by the picture below. I don't really know all about how to do it, but thats the idea pretty much right there.

http://www.ae86drivingclub.com.au/dcimages/4/8/4/3/168060.jpg (http://imageshack.us)
^ The waterline goes underneath the extractors. Doesnt look as neat.

The dipstick on the 7A has a 90 degree bracket for bolting to the head, But of course there is no ho on the 20v head there for it. So the bracket needs to be hammered flat (180 degrees) so it can bolt into a hole in the front of the 20v head. Then get a bolt from the RHS bracket (If you hace a spare one like I did. 12mm i think) It will go straight into the hole in the front of the head. The dipstick hole is only just out, so you will need to drill another hole in the brcket to allow it to bolt on.

http://www.ae86drivingclub.com.au/dcimages/4/8/4/3/154970.jpg

Thats all for now as is all i can remember. I will Put more pics up tonight or something.

***PLEASE NOTE**
The 20v head I am using is a silvertop, I don't know if its the same as blacktop so some info might not work.

federal
13th April 2008, 12:33 PM
good work champ, but can you please add it to the FAQ

www.ae86drivingclub.com.au/faq (http://www.ae86drivingclub.com.au/faq)

cheers

slydar
13th April 2008, 12:44 PM
so.. you have the 7a bottom end, with the sump on, attached to the cross member using the stock engine brackets? i was always led to believe (on good authority) that the sump fouls the x member? and either the engine brackets or x member needs modding.

would be good if you could clarify.

SEXY 16
13th April 2008, 12:47 PM
what rods are you using lad and how much machine work have you done to your crank ???
interesting read!

starni_boy
13th April 2008, 12:53 PM
<div class='quotetop'>QUOTE (slydar @ Apr 13 2008, 12:44 PM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=517219)</div>
so.. you have the 7a bottom end, with the sump on, attached to the cross member using the stock engine brackets? i was always led to believe (on good authority) that the sump fouls the x member? and either the engine brackets or x member needs modding.

would be good if you could clarify.[/b]

Yes I have the 7A btom end on the crossmember with the sump and everything. No, I am not using standard engine brackets, I am using standard 4AC brackets which bolt straight on

<div class='quotetop'>QUOTE (SEXY 16 @ Apr 13 2008, 12:47 PM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=517222)</div>
what rods are you using lad and how much machine work have you done to your crank ???
interesting read![/b]

Hi mate.
I havent got any rods as of yet, I was going to run the standard engine for a little while, until I could afford to fully build the engine. I am having doubts that it will last very long though.

Was planning on tying out a 4agze crank and seeing if it will fit. I will be doing a bit of experimenting.

SEXY 16
13th April 2008, 12:56 PM
why not try to machine a 7a crank into a 4a block

i fitted a 2.4 lancer crank into my evo engine well i didnt fit it wilky did lol

anythings possible

little tip

don't waste your money building 1 with standard rods it wont last

might as well pee your money up against a wall

federal
13th April 2008, 02:13 PM
are you planning to go turdybro or stay na?

starni_boy
13th April 2008, 02:37 PM
N/A most likely.

Well for now anyway. Maybe further down the track when in need of more power.

70XIN
13th April 2008, 02:44 PM
i am currently doing the same conversion, but with a 16V head :)

i will write up my findings once i am finished



good write-up so far man!!

Felix
13th April 2008, 03:00 PM
I just took some photo's of my 7age /w 16V head

engine mounts and waterlines

will post them up shortly

starni_boy
13th April 2008, 08:07 PM
added some pics..

more to add tomorrow sometime.

slydar
13th April 2008, 10:40 PM
yeah thats what i meant, standard rwd brackets.

how close is the sump to the x member?

starni_boy
14th April 2008, 01:51 PM
There is a bit of room there. The same as a 4age I would guess. Will get a pic for you now.

slydar
14th April 2008, 02:00 PM
i am just thinking once you have the engine supported by the mounts, it will sag, and foul, as this is what people have found in the past, though it would be nice if it didnt.

starni_boy
14th April 2008, 02:19 PM
http://www.ae86drivingclub.com.au/dcimages/4/8/4/3/168179.jpg (http://imageshack.us)
^^There should be enough room height wise, maybe it might be too wide and hit the back of the sump. But it should clear hieght wise it has about 40-50mm clearance there.

http://www.ae86drivingclub.com.au/dcimages/4/8/4/3/168180.jpg (http://imageshack.us)
^^This pic was taken on a slight angle, so the X-member actually sits in between the deep part of the sump and the bolts. It has about 20mm clearance there on the closest lower edge.

Going to update my members ride thread now.. Rust FTL.

Did you want any other pics Slydar? I have a few here but can get some if need be.

slydar
14th April 2008, 07:31 PM
nah don't need more photos. just seems odd that it doesnt hit, as that is one of the problems you hear of always.

mostly just mentioning for your sake and others who are reading.

the washers under the engine mount nuts atleast do seem pretty high, are sure the stud coming out of the mount is bottomed out in the x member?

dr1ft-pig
14th April 2008, 07:52 PM
it can't go any lower as the 2 claw looking thing come up over the top of the mount on x member

Felix
14th April 2008, 11:25 PM
Here is my clearance front & rear

Engine mounts

and water situation - custom radiator = win

no drama's at all

Note: this is with a 16V head

DAMO46
15th April 2008, 02:57 AM
How hard would this engine rev to?
is it only 5500rpm?
and also, is it a hassle to cut into the firwall?

riojin
15th April 2008, 08:17 AM
stock internals its safe to rev to 7500. if you flog anything hard enough itll break. if you want peace of mind buy aftermarket rods. its suggested you do to start with but it depends on how often youll be flogging it

machg
18th April 2008, 11:03 PM
A standard 7afe bottom end will last as long as you keep to a sensible rev limit (I stick to 6000 in my 7AGE, has never looked like failing)

shelldrake
11th June 2008, 12:22 AM
Any more info on this build?

Does anyone know the piston to valve clearance of using a 20v head with standard cams? If one was to build a bullet proof 7a bottom end, would you use forged 7a pistons? Or forged 20v pistons?

Are the pins and pin heights the same?

Has anyone worked out comp ratios with those combinations?

Thinking about the possibilties...

rileymoore05
11th June 2008, 12:51 AM
never had clearance issues with my sump too cross member either.
i did figure out copression ratios but with the 16v head.
can't rember what they were though, will see if i can't dig up my old info.
i know that the stock 7a pistions bring the compression down too around 8.5:1 from memory, just right for turbocharging.
but be warned, they are not very strong.
rods are weak due too the factr they are fitted with rod bolts, rather than studs and nuts, and where the thread is cut into the rods, there is a thin bit with a sharp edge.
having said that, ive never actually heard of them breaking.
i did alot of measureing and found it would be very difficult too fit a 7a crank and rods into the 4a block.
and even if you could, con rod angle becomes unacceptable , whcih further loads already weak conrods.
the crank is a pretty sturdy unit though, but not nearly as good as a 4age one.
if i were too go this path again, id save up my dollars and buy some better rods, and do some serious crank work too enable it too rev like a 4age safley.

starni_boy
11th June 2008, 09:07 AM
Unortunately nothing has really been happening with the engine, I have been concentrating on bodywork and suspension. I need to get a differen alternator, and 20v alternator brackets. I havent really been looking around, but I don't think they will come cheaply.

I was planning on using 20v pistons, low compression ones though.

shelldrake
11th June 2008, 10:05 AM
<div class='quotetop'>QUOTE (starni_boy @ Jun 11 2008, 08:07 AM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=544335)</div>
Unortunately nothing has really been happening with the engine, I have been concentrating on bodywork and suspension. I need to get a differen alternator, and 20v alternator brackets. I havent really been looking around, but I don't think they will come cheaply.

I was planning on using 20v pistons, low compression ones though.[/b]

Mmmmk... If I was to go this path, I would be aiming for 11:1-11.5:1, But I'm not sure if this is achievable with stock silvertop pistons. If anyone has the figures to save me the trouble, it would be great....

Crank work = $$$

starni_boy
11th June 2008, 06:10 PM
I am aiming for stock 20v silvertop compression, maybe 0.5 above that. Stock compression is 10:1 for a silvertop, so might go up to 10.5:1 CR.

Looking at the ACL 8.5:1 forgies, which should give me a decent ratio. If not, I will skim the head and put a TRD HG on.

slydar
13th June 2008, 08:40 AM
i have the bracket you want.

also, are you building the engine NA? if so the extra compression should be welcomed. 7a/4a's are a short rod ratio engine, they are very knock resistant.

shelldrake
13th June 2008, 04:20 PM
<div class='quotetop'>QUOTE (slydar @ Jun 13 2008, 07:40 AM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=545431)</div>
i have the bracket you want.

also, are you building the engine NA? if so the extra compression should be welcomed. 7a/4a's are a short rod ratio engine, they are very knock resistant.[/b]

So does anyone know approx comp ratios for building one with stock 20v pistons (bt or st), (standard or trd head gasket)??

slydar
13th June 2008, 08:31 PM
well the cr increases a little bit with the extra displacement. stock st are 10.5 and bt is 11. there was some discussion on it in the ae86 only section. i think it was about half a point extra. basically a bonus the way i see it.

rthy
14th June 2008, 12:20 AM
7a block with a silvertop head and pistons: 11.5:1
7a block with a blacktop head and pistons: 12.1:1

7a block with a blacktop head and silver pistons: 10.9:1 (have to double check my calculations on this one though)

I planning on doing an article next that has a big chart for various combinations of engine parts with the reseulting theoretical compression ratio.

rthy
14th June 2008, 12:26 AM
linky:

http://www.ae86drivingclub.com.au/faq/inde...pression_ratios (http://www.ae86drivingclub.com.au/faq/index.php/Main_Page#Calculating_compression_ratios)


I don't mind if anyone asks me more questions about this though as I don't expect anyone to understand my explinations shown on that link.

shelldrake
14th June 2008, 01:56 AM
<div class='quotetop'>QUOTE (Sam_Q @ Jun 13 2008, 11:20 PM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=545807)</div>
7a block with a silvertop head and pistons: 11.5:1
7a block with a blacktop head and pistons: 12.1:1

7a block with a blacktop head and silver pistons: 10.9:1 (have to double check my calculations on this one though)

I planning on doing an article next that has a big chart for various combinations of engine parts with the reseulting theoretical compression ratio.[/b]

What gasket thickness was used for these calculations?

rthy
14th June 2008, 10:17 AM
the stock thickness for the head being used. Which I am lead to beleive is 1.2mm for all of the G heads

wide s13
3rd July 2008, 08:01 PM
just wondering how the 7age motors are holding up?
especially the 16valve heads
reason being my 4age 16valve let go and I need a motor and 4afe's i can get cheap as appossed to 4age's.
cheers

riojin
3rd July 2008, 11:39 PM
i was wondering,

say i take a blacktop 20v and a late model 7afe and build a 20v 7age. with the remaining parts (the 20v block, crank, rods; the fe head, pistons) could i build a strong 4afe and if so could i use the 7afe computer?

I'm think bout this because my new daily has a 4afc in it with 200XXXm on it (still going strong) which will eventually die and need a new motor or rebuild. if i had those leftover parts laying around why not put them to good use

rthy
4th July 2008, 12:20 AM
you could build a very strong fe engine however I don't know how it would go with the different type of con-rod design, the 20v rods would be floating and the fe pistons wouldn't be. However the 7afe pistos would have too low a compression anyway and using 4age pistons might be a good bet.

Another option is to just sell off all the 20v bits which I would think woudl be very easy and then just buy a 4afe engine for like $5, well not quite but they can be had pretty cheap.

Gunner
4th July 2008, 12:25 AM
<div class='quotetop'>QUOTE (riojin @ Jul 3 2008, 10:39 PM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=556337)</div>
i was wondering,

say i take a blacktop 20v and a late model 7afe and build a 20v 7age. with the remaining parts (the 20v block, crank, rods; the fe head, pistons) could i build a strong 4afe and if so could i use the 7afe computer?

I'm think bout this because my new daily has a 4afc in it with 200XXXm on it (still going strong) which will eventually die and need a new motor or rebuild. if i had those leftover parts laying around why not put them to good use[/b]


thats a good idea, id be in for that one, and just so you know i ran my 4afc dry on oil at 280xxxkm topped it up and its goin fine so don't expect it to die anytime soon, ive pumped so much nitro methan into it for my mate to har the pingin, in the car next to me, and it didnt die lol, thyre awesome.

But your little hybrid is an awesome idea, it should work, it is a 4a aftr all, be really effecient too.