Austarion

Although I've only had my SOHC for a short amount of time I'm planning to build a twin cam motor for a whole bunch of reasons including: drivability, economy, reliability, tuneability and opportunity. I've done a heap of research and this is what I've come up with so far. Please let me know if you experienced anything in your build I should be prepared for or if I've missed something

The Motor:

• - Starion block - bored, honed and decked
  - Long nose crank (6 bolt)
  - New bearings ect
  - 6 bolt DOHC rods
  - 9.0:1 compression pistons (turbo) maybe forged maybe not
  - VR4 head - machined - STD cams lifters ect
  - Drilled head to suit water jacket for water outlet relocation
  - Front outlet Thermostat relocation (4gpwr)
  - Cyclone manifold (modified) and I'm going to attempt to keep the butterflies if I can
  - EVO III coil packs
  - DOHC front cover, oil pump and pulleys
  - Balance shaft delete
  - DOHC timing cover
  - VR4 throttle body
  - VR4 alternator,
  - VR4 multi grove pulleys / harmonic balancer

Computer:
EMS stinger v3 ECU, already wired running MPI so hopefully most of the loom will swap straight over, with the addition of a few new plugs and an output to Idle control Valve

Questions:

• 1. Is it best to relocate Starion P/S pump or use VR4 and make custom lines?
  2. Should I use the Starion water pump and file it to clear DOHC stuff, or use VR4 pump?
  3. Have I underestimated this swap and am I going to run into a heap of unexpected hiccups?
  4. Are there any other areas you recommend I look into for reliability, power or future modification potential?

Thanks heaps
Max

Have you thought about a stroker or getting the later lifters with the bigger bleed hole to prevent the ticking noise ?
If you have to relocate the power steer pump why not use an electric pump .

Balance everything

RX7 gearbox

I have an exhaust manifold for you :D

I strongly considered a stroker but decided the trade off's aren't ideal for a daily, if I were to build a race motor it would be stroked all the way.

I did read about the newer lifters and I definitely don't want my fresh motor to tick so they will be worth the investment, I will get the rotating assembly fully balanced as I did with the SOHC and can barely feel any vibration caused by the balance shaft elimination.
I don't particularly like the idea of my powersteering pump shorting out whilst on the track, the road or even in my driveway for that mater so I think ill stick to the mechanical pump

Not completely sure what to do with the exhaust manifold yet, I have a stainless one to cut and flip but I still might have to hit you up for yours thanks Oldie
:beer

SR20? lol

I threw in the leccy PS pump as an option .I have an SR20 PS pump mounted on the AC bracket and no AC but you will want to keep it in a DD.
FWIW if the SS mani is a thin wall then it will eventually crack :(

I'd recommend an EVO/RVR small port head instead of the big port VR4 head. The VR4 had to use a tricky dual runner manifold to get the torque back up to where it should be at low RPM. Going with an EVO head you'll avoid this problem, but plenty of EVO's still make great power up top! Better drivability all around.

If you did use an EVO head though, you have to drill out the head stud holes to the same as the VR4/Starion ones to maintain oil supply.

Yep, the ports on the VR4 head are way oversized. Much better response from an EVO head. I run the VR4 head on my motor and it's good, but it would be even better with the smaller ports.

Highly recommend the later model lifters - my engine ticked like a bastard with the VR4 lifters and sounds sweet ever since I swapped over to the larger bore ones.

Lummy, more details on the large bore lifters you describe please...

Here you go :)
http://www.meek.com.au/index.php?_a=pro ... uct_id=112

What size bore hole are the standard lifters on a VR4?

Tiny - I don't have any here to measure, but at a guess, 1mm.

It's amazing how quiet the top of the motor is with these lifters compared to the old ones.

Enthuzed, your motor already has the big bore lifters