7agte build diary, my progress so far Options

[nik]

Feb 25 2005

recieved
intake manifold w/ throttle body (small port)
stock cams gears (small port)
oem FPR
fuel rail (big port)

(( from Bee aka kwanza ))

big port head from a 4agze ebay

Feb 28 2005

i drop the head off at F-Tuning (local shop) to get the head pressure checked if good the head will get fully tuned new valve spring P&P etc.

sent money off to a MR2 member for a
AE101 LEVIN MAP/DLI 4AGZE 1992+ MAP/DLI engine wiring harness

also bought 440 cc 7mgte injectors
4ag AEM adjustable cam gears
talking to frotou about a custom manifold

Need to talk to the shop about what cams to use i'm thinking 256 intake 243 exhaust

March 1 2005

things a need to do
track down DLI coils and distributor
track down a 92+ levin Map ecu ( any help on this one will be a big help)

This post has been edited by nik: Mar 11, 2005 - 12:39 PM

[FallenHero]

I am using your thread nik.

So what is the biggest bore you guys have heard of on a 7afe. I've seen 82mm, but I wonder if you could take on to 83, or 84mm... in the grand scheme of things, that isn't much of a difference, but i wanted you guys' input.

[nik]

I am using your thread nik.

So what is the biggest bore you guys have heard of on a 7afe.  I've seen 82mm, but I wonder if you could take on to 83, or 84mm... in the grand scheme of things, that isn't much of a difference, but i wanted you guys' input.
[right][snapback]282387[/snapback][/right]

yeah edo's 82mm is as big of a bore that i've heard of. I read a post over on club4ag about bore size + rev limit and some other stuff

but anyways they were saying to take advantage of the bigger bore you would need higher rev i'll have to find the link it had some good info

here it is

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montj
Club4AG - Freshman


USA
11 Posts Posted - 04/29/2005 : 00:40:38
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ive seen 1mm-.5mm oversized pistons available.

is it for getting your cylinders bored to match the pistons? for a better seal


wolfman
Club4AG - Freshman



15 Posts Posted - 04/29/2005 : 02:38:42
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could be a lot of reasons. I'm in no way an expert, so someone else may correct me (or just a difference in oppinion). If you are trying to bump up power. Don't know if .5 mm will make that much a difference. If you're rebuilding and your cylinders are warped. Maybee like you said to get a better piston seal, which you're probably running bigger pistons in search of more power. hope this helped a little bit.


oldeskewltoy
Club4AG - The 24/7 Club


USA
4558 Posts Posted - 04/29/2005 : 06:14:52
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there can be two reasons for an overbore, 1) the cylinders are damaged and need to be overbored to acquire a clean honeable surface, 2) you are looking for more power and a overbore will increase displacement


Red
Club4AG - Lifetime Enthusiast



1365 Posts Posted - 04/29/2005 : 08:36:10
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And sometimes a third reason, if the cylinders are simply worn from old age. Maybe that counts as "damage"?

Original Owner, 85GTS 3-door 5speed. Will swap even for a Ford GT40 or GT44, or a Cadillac-Gage V100. (Which is nothing like a Cadillac.)

oldeskewltoy
Club4AG - The 24/7 Club


USA
4558 Posts Posted - 04/29/2005 : 14:29:34
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quote:
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And sometimes a third reason, if the cylinders are simply worn from old age. Maybe that counts as "damage"?





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Thats why I was as vague as I was... damage to cylinder walls encompasses wear, or damage....


DWLowe13
Club4AG - Addict


USA
297 Posts Posted - 04/29/2005 : 16:54:55
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Most of the time when I rebuild an engine, I overboar to get rid of imperfections in the cylinder wall.

In small blocks like the 4AGE, .5mm and 1mm is a very big differance. You do not want much more. Due to the thining of your cylinder walls. If you go over to much the walls become weak.

I do know of one shop on the east coast, Wayne and Earl Edge of Edge Bros Machine Shop in Jacksonville NC, that will over boar engines by 2mm-3mm. But they also install sleeves into the cylinder walls that reinforce the block.

Overboaring is a way to increase HP. But the risk is you make your block that much weaker and easier to crack under stress...

" If You Fail To Plan
You Plan To FAil "
DWLowe13

DWLowe13
Club4AG - Addict


USA
297 Posts Posted - 04/29/2005 : 17:01:16
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Here is some more info about Boring and sleeves, from the circle track world..

Seeking The Right Bore Jenckes found a possible advantage of using sleeves: They come with bigger bores. "Today, people find that particular bore and stroke combinations are very effective," he adds. "Typically, people are running bigger bores and they find that, no matter what the application, a bigger bore may be helpful. I'd certainly say that's the trend in Nextel Cup. Obviously, if you want to make a block last a long time, you can't go to the big bore size immediately. You'll get one rebuild, and then it's junk and you've just spent all this time building this nice block. A sleeve can allow you to go to your optimal bore size. When you have problems, just replace the sleeves.





Boring for cam bearings is a precision step in which modern engine builders rely on high-cost machinery. When building an engine, there's plenty of emphasis on the operator as well as the machine.

"Some teams in Nextel Cup use sleeves, and some don't. In Nextel Cup, the well is deep money wise, but it's not endless. Consider that you can use a smaller number of pistons and crankshafts, and that means less money tied up in crank and piston inventory. Some teams might approach it from that standpoint."

Power From Bore Center Bigger bores have proven to have better results in most cases. "A larger centerline is preferable because it allows you to have a bigger bore," says Jenckes. "A Ford block has an inherent handicap compared to a Chevrolet or the current Dodge because of the smaller centerline. Having more metal there, other than a weight handicap, means it's more stable and it can allow you to run a bigger bore.

"Most racing has some kind of displacement rule. As long as there's not a bore size rule, you're probably better off running a bigger bore, shorter stroke if engine speed is not limited. If you are limited in engine speed for some reason, say an rpm limit, then always going with a bigger bore may not be the way to go, depending on how low the speed is. At higher shaft speeds, bigger bore engines help the cylinder heads work better. In Nextel Cup, 4.185-inch is the biggest bore size you can have. Even if you have 5 inches between bore centers, it doesn't help you other than the fact you've got more metal there to be stable. Then you have to worry about the weight. The trend has been to bigger bore cylinders. GM is working on a new, next generation Nextel Cup engine with a bigger bore center.


" If You Fail To Plan
You Plan To FAil "
DWLowe13

montj
Club4AG - Freshman


USA
11 Posts Posted - 04/30/2005 : 01:48:17
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nice. Clears that up for me, thanks.


DWLowe13
Club4AG - Addict


USA
297 Posts Posted - 05/02/2005 : 15:43:39
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No Problem..

" If You Fail To Plan
You Plan To FAil "
DWLowe13

othick
Club4AG - Addict


USA
680 Posts Posted - 05/04/2005 : 01:56:23
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1mm overbore in a 4ag = approx 40cc's more displacement. A 1627cc 4ag will make about 2.5% more hp/tq than a standard 1587cc 4ag. Closed deck iron blocks can usually handle this no problem. The later 7rib 4ag's are bored out 2mm quite frequently.

85 gts coupe 105whp
91 civic si sohc vtec
http://www.whyturbothat.com for pics and dyno's of my old cars
- turbo del sol, turbo mr2, turbo ae86, 6cyl. 77 celica, 88 Mr2 SC





This post has been edited by nik: May 4, 2005 - 12:37 PM