7afe's.. tell me everything you know.

[Dimitri]

very strongly consdering a 7age for my latest AE86 project.

have thought about these are fair bit before, but to be honest i really only know the basics.

from what i know, if you want a 16v 7age, you use a porsche 924 timing belt.

for 7a 20 you use camira.

the rods are said to be shit and they probably are. but people who actually run these motors dont seem to get much trouble from them.

ive heard the later ones might be missing or not have tapped some of the desired bolt holes in the block for rwd mounting/alternator brackets.

ill be building it as 16v, so obviously i want to use the small port pistons. will they fit? what i mean is theyre 20mm wrist pin (floating). is that the right size/style for a stock 7af rod.

any other tid bits of information people would like to add to this thread are most welcome.

[Hokey]

http://www.toymods.net/forums/showth...highlight=7AGE
see if you can get a hold of him for a chat. i'd imagine he would have some very useful iformation.

[EldarO]

provided they're balanced properly, i dont think the rods are much of a problem.

personally, i think they just have less margin for error before eating shit and dying....

Eldar.O.

[Tats]

I half-heartedly looked into building a 16V 7AGE and found a lot of conflicting information. Most people said that the rods were weak and shouldn't see more than 6.5k rpm or so, but the pistons are fine. Some seemed to think that the 7A pistons were crap but the rods are strong, but that doesn't matter because you have to use the 4AGE pistons anyway. I think they were mostly referring to boost applications.

There's a tech article on Club4AG if you haven't seen it already, but the link seems to be dead...
http://www.club4ag.com/faq%20and%20t...20and%207A.htm

[mullett]

CVAP has a complete 7A-FE, if it helps, and he's a great guy to deal with. I was looking at the 7A, but funding fell through. Apart from that, I've heard that the crank is pretty average, and the rods are also kinda half-arsed. Maybe if you nitride the crank and rods, they'll be OK for an NA application, depending on how hard you rev it, or for a light-boosted one. Anyone know what the stock rev limit is for a 7A? What is your overall goal in the way of HP, driveability, torque etc?

RM.

[Tats]

Anyone know what the stock rev limit is for a 7A?

6,500rpm IIRC. Redline is about 6,200rpm.

[mullett]

Yeah, so revving it to a GE-like 7500RPM would hurt unless you did some serious balancing and lightening. Well...I guess it would.

RM.

Disclaimer: All I know about these engines is hear-say and the conclusions I've drawn from limited data...

[Dimitri]

i actually know a guy whos had both 16v and also now has a 20v 7age in a ke55 improved production race car.

hes a mechanic, older bloke. reallynice guy but he is hard to get specifics out of. not cos hes not forthcoming, just that like alot of people who have been around cars for a long time hes not that interested in the details, he just gets it done. he does rev the 7a20 to 9000 rpm under race conditions and hasnt had a failure yet. he admits it has no right to be, but thus far has proven reliable.

as for goals. i have driven simlar cars in weight and chracteristic to my 86 before, which were 1.8 litres, and even though ive had 2 big ports, 2 black tops and a small port, there is that slight punch they are lacking that i think will be very dificult to find without increasing the capacity. i love 4ages, but i think id just like to try the 7ag, could really be something in it.

that ontop of if you can get good CR without changing pistons, then it seems like a really cost effective way to build a rewarding NA motor. having the extra torque/capacity and not needing to rev as high means some expensive things are less neccesary. like light weight flywheels for example. with the lower rev limit i think you might make some decent power on some pretty small cams, increasing driveability and the life of the motor/valve train is an added bonus.

also there would be no need to go to a super short diff ratio, or for a close ratio gearset. again making the whole build cheaper. you might also not need to be so brutal in your driving style (for drift) which could help the life of your driveline too.

it just seems to make alot of sense, the only down side is it puts you over 1600cc but not close enough to 2L to be competitive in any form of racing that has those class's. realistically for me though, thats not an issue.

[mullett]

Yeah, for sure. If it's been done, and he can rev it to 9k...you're lauging. If you redline it at say, 8, hold the thing together with a bunch of ARP bolts, it should be awesome. Get onto CVAP, he had a 7A, 20V head and all the other stuff needed.

RM.

[Hen]

I seem to remeber discussions of this on the old forums and a rallying bloke named Johnny sounded like he had built a 7A or two and had put a lot of research into it. Maybe try looking him up.

Hen

[johnny]

I seem to remeber discussions of this on the old forums and a rallying bloke named Johnny sounded like he had built a 7A or two and had put a lot of research into it. Maybe try looking him up.

Hen

Hen, you should know I would find this thread. Ring CB Performance, have around $7K ready, and they'll produce a 20V 1900cc engine that rev's to 'only' 8500rpm and makes 170-180hp all day. They won't release any spec. except that mentioned.... but on the topic at hand, we have had problems with the stanadard rod's letting go above 7500 rpm, mind you guys this was an FE and not a GE..... the problem was mostly due to the thread being taped into the rod themselves. In the states I have heard a few guy machining them up to use a similar system as the 4AGE's (bolt passes through the whole cap and rod), we just change the rods for A/M and the problem was solved. other specs on this engine was 12.5:1 comp JE forged pistons, camtech cams setup for torque, not power, spec unknown but we think 256 deg with high lift, 1ggze injectors, diet of elf ato rally fuel (102 ron) GZE coils, autronic (list goes on!), best power it made was 110hp, 250Nm, this was backed by a AE101/111 six spd box, lighten flywheel.blah, blah, blah....It now runs a
20V to comply with the F16 rules now used for rallying. The 7AGE we did have die due to some mis-treatment by the guy who had it on lone in his car. Using standard stuff, revved only to 7500, it made the best of 100hp (74 kw), we change the cams, but being a boof head and not waiting for a good tune, he drove it, it leaned out, and now it is sitting on a pallet til I get a few projects out of the way (thank god one is nearly done!) Now the plan is to use the good stuff from the Grp A 7AFE and the 7AGE. Bill Sherwood would say use the FE head, I disagree due to lack of parts and expense, though he has some very valid points about the FE head...
The GE basically was straight forward, use the GE head, Pistons and merge these with the 7A bottom. The FE pistons will drop the comp from a standard FE's 9.5:1 to around 7.5:1, which is no good , even for turboing! ever drive a Turbo car with this kind of static comp? Lag city baby!!, We did use the 16V head for two reasons, firstly it was cheap ie freebie! secondly the mixed results people were getting using the 20V, which now I can say should be laid to rest cause CB also build and help me with 7AFE, 7AGE and the new 20V's we're running and alot research, testing and development have going into all, include the monster that IP under 2L are seeing here in NSW. Serach the old forums as I have covered the process several times... and this next time I will make sure I take pic's all the way not just when I remember to bring the camera!!

[Dimitri]

johny. thanks for the reply. 7500 rpm should be fine. there is not way i am taking 7k and handing it to anyone. i am all about the cheapest solution for a satisfactory result. not pouring thousands into something to try to achieve perfection.

which 4age pistons did you use? there are two types ofcourse you know, but which ones did you use. early 18mm press fit gudgeon or later floating 20mm?

[johnny]

johny. thanks for the reply. 7500 rpm should be fine. there is not way i am taking 7k and handing it to anyone. i am all about the cheapest solution for a satisfactory result. not pouring thousands into something to try to achieve perfection.

which 4age pistons did you use? there are two types ofcourse you know, but which ones did you use. early 18mm press fit gudgeon or later floating 20mm?

I've used both and both seem to work well. The 7AFE rod are also a press fit, which can be bored out. also keep in mind that late model 4AGE N/A have a raised crown which increases comp.

[NVD05X]

also couldnt hurt to have the rods shot peened...

[3sgte]

A few scans for you: