4A-GE engine mix - question

[Uzelac]

Now i got fear that stock rods won't be enough :/

Wiseco pistons have 18mm pins, really don't like idea changing them.
Also, it's said many times that crank can withstand 8500rpm and 180hp with no problems.
Not sure about stock rods.

What are the options for 18mm pin 40mm jurnal forged rods ?

[NoHachi]

HP doesn't kill stock rods, but those 500 extra RPM will. Stick to a stock rev limit and you'll be fine.

[Uzelac]

NoHachi Wrote:HP doesn't kill stock rods, but those 500 extra RPM will. Stick to a stock rev limit and you'll be fine.

It's a pitty I can't find 18mm forged rods.
They shouldn't be to expensive to buy, and since i plan to open engine and disassemble block (friend mechanic, not me of course ) it would be fail not to change rods.
I already have a plan to buy ARP head bolts, those for rods are just 50$ extra.

So.. what 40/18mm rods ?

[Uzelac]

Are oversized valves good choice for 4AGE's developing 180 or more hp ?
Where is the point when bigger valves are a must to keep on developing more power ?

[totta Crolla]

Uzelac Wrote:Are oversized valves good choice for 4AGE's developing 180 or more hp ?
Where is the point when bigger valves are a must to keep on developing more power ?

Look up 'valve curtain area' there is a basic formula for working
out valve diameter and valve lift.


http://www.nasaforums.com/viewtopic.php?f=39&t=14873
http://www.wallaceracing.com/curtain-area-calc.php

[Uzelac]

Thanks, i've read all of this, but still not sure if going oversize is good way for ~200hp 4AGE.

I see people have managed 200hp with stock valves, but also 4AGEs developing less power even though they have bigger valves.

For me it seems like O/S valves, as all parts that enlarge intake will give higher end power and loose some low end torque. That's just coming from common sense, not really sure.

[Uzelac]

Work in progress, still.... having hard time gaining volume in chamber.
ATM it is 32cc.
Valves are sinked 0.5mm with 3 angle job.
Piston dome is 5.9cc, gasket is 83mm/1mm. Squish would be .8mm

Static CR is ~13:1 by our calculation.

Race fuels and similar stuff is not on wanted list.
Trying to find few more cc and lower it to ~12:1.

[Bean]

What pistons do you have with that high cc for the dome?

I assume your head has been cut down quite a bit as stock is around 37cc

[Uzelac]

Who knows how much the head is cut, but it's certanly a lot.
Pistons are Wiseco.

[Bean]

have you tried to check if you could mill some of the dome down - as it's pretty high anyway?