I know they wont fit on an AVCS head. I'd assume that if you are using EJ20 heads on an EJ25 bottom end then yes.
Actually I think they will fit on the AVCS Head. I'm almost posative, you have to plug the oil holes in the avcs cams and you would lose the AVCS but they should fit
Really? SS doesn't think they will. What exactly is avcs? I know to do the swap I'd have to get the adapter, if I can use the gears and dissengage it would I not need the adapter? How would this effect the performance of the long block?
AVCS is like a really advanced version of VTEC. that's the easiest way to explain it. except it works all the way across the RPM range instead of just from one set point upwards like VTEC. helps with torque and gas mileage/emissions. if you're going with an STi long block then finding some stock STi cams shouldn't be hard/too expensive. edit: and check your thread on 4touge. who told you that you can put LGT gears in a 5 speed?
i would just do a hybrid dana... get a sti shortblock and use your existing heads with some sti cams inside.
Keegan I'm also considering that but am concerned about reliability. I read around on Nasioc and its been mentioned that since the compression is so different I'd also need different pistons after 20,000 miles. The reason im inquiriny about the longblock is because I'm in talks with a guy who has one for a reasonable price that's just missing the cam gears and turbo
just get the AVCS gears and be done with it. The exhaust gears are the same physical part as found on the EJ205. otherwise, w/out the AVCS gears...you'll need to plug the oil holes in the cams and then get the proper EJ205 spec cam oil seal for the intake cams. A waste of time and energy when you can just use the AVCS gears and be able to use AVCS in the future. AVCS rocks. Me. Lots of people have done it. the 4WD/FT4WD/AWD 5MT from 1985 to present is pretty much unchanged. Most items (90%) interchange.
AVCS is the Subaru flavor of Variable Valve Timing. Just about every company has a form of variable valve timing: Honda has VTEC and iVTEC, BMW has VANOS, Mitsubishi has MIVEC, Toyota has VVT-i ect. Basically the timing of your valves is dictated by the lobes of your cams spinning above your valves. Ideally you would want to have the valve timing to be tuned for different load conditions (like WOT at 3000 RPM). However, cams have the constraint of being a mechanical part that has to be smooth enough to spin thousands of RPMs. This means that a motor with a standard cam has a limited design range where the motor is operating under optimal timing. Variable valve timing attempts to vary the valve timing to make the motor run more efficiently (better power/emissions/fuel consumption). Systems such as iVTEC and VVT-i vary both the intake and the exhaust valves in relation to RPM. AVCS varies only the intake valves, but basically makes the motor make more power and burn less fuel. So, if you can afford to use the AVCS heads, you will have a better motor, but it will cost more in parts and probably more to tune. To find out more about AVCS and Variable valve timing in general, check out this link: http://www.drive.subaru.com/Win05_WhatsInside.htm There are currently prototype engines that use electronic solenoids to drive valves, which would eliminate cams completely. This would mean almost limitless tuning capabilities. The problem is that right now they don't have solenoids that are sturdy enough to last the lifetime of a car, and the current 12V electric systems in cars is not sufficient to power such a system. There has been talk of changing the standard to a 42V system, but that would mean you can't put 12V electronics on a 42V system and visa versa. Anyway, sorry to nerd out on everyone but sometimes I can't hold back the mechanical engineer in me...