How good is a 7AG?

[Ben Wilson]

I'm planning a nice NA 4AG, and got thinking about the idea of going to a 7AG instead.

I know the bottom end isn't as strong as a 4AG, but if I was to keep it under about 7-7500RPM, I assume it would hold together OK?

Is the 6 bolt flywheel really an issue?

[RO11LR]

Whats a 7AG ?

[RONA]

Whats a 7AG ?

7afe bottom end with a 4age head and a few other things to make it work

[ViPeR_NiPPleX]

how hard can you rev a 7afe normally?

[Ben Wilson]

I just found http://www.toymods.net/forums/showthread.php?t=6751this thread with a lot more info.

It looks like 7-7500 should work.

[Hiro]

how hard can you rev a 7afe normally?

Factory redline is 6250rpm, cutout somewhere around it, but by that time everything is over and done with, no point revving it out to 7500. Of course, with a G head it gets there a lot faster, so then it's something to worry about


ARGO do a set of conrods that give the bottom end some strength, only thing is this just means the crank will be the next thing to go. Then again, I know of a guy in NZ with a 20V 7AGTE putting out over 300kw, so products must be available.

[river]

Hi,

Factory redline is 62500rpm.

Crikey... that is fast!!!!!

seeyuzz
river

[Hen]

Also if you want a serious 7A, Bill Sherwood (and some others I think) will tell you to stick with the late model F head. Apparently it has a really good design, with potential beyond a G head, but needs more work to get there. There was a good thread on it on the old forums, titled "4A, F vs G heads" or something similar.

Another option to consider if it's an all-out engine.

Hen

[Hiro]

Hi,



Crikey... that is fast!!!!!

seeyuzz
river

The RA25 will rev that high too you know, just need to use that right foot a little more......

[Ben Wilson]

Also if you want a serious 7A, Bill Sherwood (and some others I think) will tell you to stick with the late model F head. Apparently it has a really good design, with potential beyond a G head, but needs more work to get there. There was a good thread on it on the old forums, titled "4A, F vs G heads" or something similar.

Another option to consider if it's an all-out engine.

Hen

I have thought about it, but I'm thinking about a BDA style motor for an Escort. As the 4AG was basically a copy of the BDA, I'm hoping to keep the feel original....

[jezza323]

maybe talk to these ppl http://www.roadandtrack.net.au/ as they sell an off the shelf 7ag package for race use (i just cant find the page on the website at the moment), if they are feeling nice they might let u in on some of the things they do?

EDIT : Found the link to the engine info http://toyota-mr2.mine.nu/mr2/topic.asp?TOPIC_ID=4405

[Darren]

There's a starlet killing everything in the NSW under 2l improved production championship at the moment. Doing lap times that would put it at the front of the over 2l field.

It's running a 7a bottom end with a 20v head and is making big power at big revs.

I can put you in touch with the guy that builds the engines, but only if you have the budget and are serious about doing it. I doubt very much he would share any info, it would be a case of drop off an engine, head and cash then pick it up a couple of weeks later.

Darren.

[Ben Wilson]

Thanks, but that's definitely not my style.

I'd rather pay for my own mistakes than someone elses. At least that way I learn something...

[Hiro]

One of my mates on Twincam has warmed up the 7AFE without going to a G head, apparently it makes quite a big difference and doesn't break the bank

I'm also thinking of going a warm 7A for the '55 when I turn it into a hill-climb car, no idea as to whether it'll be an FE, GE or 20V, but it'd definitely be something different (every man and his dog does 4A conversions these days, and I want it to stand out)

[RONA]

http://www.toymods.net/forums/showth...highlight=7age

maybe try and get in contact with that guy, just like you want to do he has done it himself.