7AGE

[nomuken]

Hi,
even that I still don't have my 16V running, I'm planning for the next winter already.
I want to build myself an 7AGE with
AFE crank and block
Belfab or Spool 7AFE conrods
Highcomp 4AGE pistons (probably OEM ones)
Haltech Engine Management
ITB's.

How do you solve the problem of the AGE pistons being floating pin and AFE rods being press fit? What mods have to be made to mount 4AGE pistons on 7AFE rods?

[mooreofit]

sounds like a good combo,

i have the belfab h beams on my 4afe and im running wiseco forgies.

i ordered my rods first then i ordered my pistons and when i did i stated i wanted it fully floating and gave them the i.d. of the con rod wristpin bore.

[Sam-Q]

have you considered the rate of compression ratio increase from the extra displacment?

[nomuken]

Hi Sam,
I'm sure you can tell me the compression ratio this setup will result in. 7AFE Block/Crank/Rods and 4AGE 10.3 pistons and a largeport 4AGE head?
Would appreciate it

[Sam-Q]

in theory 11.3:1

http://s-86.com/s-cr-chart.html" onclick="window.open(this.href);return false;

and you will probably regret clicking on this one:

http://s-86.com/s-cr.html" onclick="window.open(this.href);return false;

[nomuken]

Thanks for the reply, I knew your chart, but the combination of largeport an 7A was mentioned as *NA
And as I'm gonna run largeport head/smallport pistons/7Acrank,...

11.3 wouldn't be that bad. I've got fuel and Haltech ECU to deal with. Possibly I can run a 1.00 or 1.20mm headgasket to get the compression down a bit. Since my head is skimmed by 0.4-0.5mm already :-/

Goal was to get a CR of 10.5-11.0.

Still have to figure out:
- how much mods there are to het the 4AGE pistons in the 7A block?
- what the best rod and main bearings are for the 7A block? OEM ones are only 2layer
- optimal injector sizes
...

[Sam-Q]

yes with the large/big port I have n/A because it has a 18mm gudgen pin so it's incompatiable. However the chamber size is the same between the two 16 Heads so you can just look up the small port head. The standard gasket is 1.2mm and it's not a good idea at all to use thicker and it messes up your combusion chamber process. 11.3:1 is fine however with 0.5mm taken off it your looking at closer to 12:1 which is getting pretty high. You can keep this CR but I suggest some decent duration cams to make up for it.

Now there are no mods to fit the 4age piston into the block

- Bearings I can't help you with as I dont know much about the subject

- Find out what the standard 20V injectors are and use the same flow rate in something that's 16V compatiable, I think they are 270cc/min? I say this because in my own testing I only get at the very most a 75% duty cycle with my modified 20v with maximum revs and load.

[nomuken]

Standard Blacktop injectors are 295cc. Smallport 16V are 250cc.

Is your CR calc of 11.3 (or 12:1) with a 1.2 or 0.8mm headgasket.

I know that I need other pistons (because of the 18mm pin). So what could I do to lower the compression a bit to get closer to the 11:1?
If your calcs are based on an 0.8mm HG, I could use an HKS or TODA 1.0 or 1.2 to compensate a bit for the skimmed head. I could also buy some GZE pistons instead of the hi comp pistons.

[Sam-Q]

I better clarify that chart, because the 7A section is with a standard 4A 1.2mm gasket. The ZE pistons are a bit on the heavy side and the compression would be too low unless you have boost.

[nomuken]

Just did some calcs, 8.0 GZE pistons and 0.8mm HG should result in 9.9
But if I could find AE101 8.9 GZE pistons (the ceramic coated ones) I would get to about 11.0:1 wich should be pretty much perfect for my built

[Sam-Q]

I worked out 8:1 pistons with a 7a bottom and a 0.8mm gasket works out to 9:1

and 10.1:1 for 8.9:1 pistons

allowing for a 0.4mm shave its 10.5:1, but as I said before they are not light pistons. If you decide to go that way I say shave the head more

how did you work it out?

[nomuken]

Used this: http://www.csgnetwork.com/compcalc.html" onclick="window.open(this.href);return false;
With the following values:
bore: 81mm
stroke: 85.5mm
HG bore dia: 82.5mm
comp HG thickness: 0.4mm (0.8mm TRD gasket)
chamber volume: 36cc
piston dome: -4cc (for the 8.9 pistons ; -10cc for the 8.0pistons)
piston to deck clearance: 0.3 mm
All values taken from different internet sources

But I never thought about piston weight. This could possibly change my opinion on using GZE pistons

[Sam-Q]

well I think that was is theoreticly good however I use the original specs as a basis to work it out. Also the original chamber volume is 39cc or near to it before being modified.

Either way the result doesn't seem close to being right at all.

[mooreofit]

awesome webpage sam.

[Sam-Q]

thanks I get surprisingly little feedback on it