My 4AGE Story... (56k Warning)

[PazzaAE86]

So, my 86 has been off the road for a few months now but its nearing completion and you guys might be interested in the story of whats happened over the last few months.. So here goes!

I finally got my Toda Cams (304/288 8.5) and ITB kit on the engine and sent the car off for tuning with my Engine guy, a few days before a drift day.. Here is how it looked at the time after some fettling:



The car was ready for tuning on the dyno and it made 150hp, with a little more to go (compression issues due to bore wash was hindering power a bit).. Then...




Damn, spun a crank bearing while making a power run So we abandoned the tuning plans and drew up a full rebuild plan and set about gathering the parts we needed, and the custom Angel Works parts were developed. The Toda Cams were sold, to be replaced with some altogether improved Angel Works cams and i located a redtop AE92, a new oil pump and a few other bits and bobs along the way, and work finally started!

Final spec of the engine is:

AWT (Angel Works Technologies) competition high torque port development, hand blended valve seats with compound radii, extensive chamber work to match piston crown and quench area and allow good flow at low lifts and with piston at TDC.

AWT custom Camshafts. 282/278 deg duration, 106 deg LSA/peak timing, 3.8mm @TDC inlet, 3mm @TDC exhaust and 12mm lift total (50%more than the old todas!!!).

Arrows F1 Team solid lifters with daimond like coating

AWT custom forged 1mm oversize pistons with custom crown design to best enhance burn propagation, compression ratio, quench area, valve reliefs which aid flow at low lifts and active mixture conditioning, coated skirts. Note in the pictures the before pic which is the bare machine finished piston, they are then hand finished and blended and textured, otherwise alot of tuning potential is lost in terms of EGT, ignition timing (run as low as possible) and how lean we can run it. It really helps starving off det/knock/pinking, you turbo boys should all be doing it!

Rods, crank, pistons, flywheel, clutch camshafts all lightened and balanced by the best in the business, not your average balance job.

All this running though the existing OER throttle bodies, which have been modified to flow much better with less turbulance and expansion pockets, loosing less energy in the process.

The Pistons:







After the Block was bored out and all the components installed, 12 thou was taken off the deck because of water damage from a blown head gasket. The head work was started the day after....

[PazzaAE86]

Freshly carbostripped, hot tanked, stripped, degreased, TFR'd (yes TFR!), scrubbed, soaped and washed head just about to get attacked on the AWT porting bench. It really does take alot of cleaning to get a head to come up nice if your dont bead blast it.



The combustion chamber is std trim. Not ideal at all. Relatively small quench area (matched by the piston crown design) so mech octane is not superb. Actual chamber isnt too bad, nice and shallow, but horrid horrid machining around the valve seats which in std trim will really hurt the combustion process and provide pre-ig points and hamper flame propagation, hide end gasses yadda yadda yadda.

For a std engine, the valve seat configuration isnt too bad, a true 3 angle cut with 2 lead ins, so a simple bottom cut would effectively leave you with a 4 angle seat, a thin one none the less. However, on this application the seats will be all ground down and hand blended to form a compound radii from port to chamber, with only a very thin seat cut into it. The seat will be come part of the port and it wont be concentric or even round, it will be shapped to flow the best quality possible, although the seat will be concentric to seal the valve.

Chamber will be heavily modified to match piston crown and create a better shape for flame propagation to work in, allowing less peak ignition timing to be run, a faster burn under higher CR's with less knock sensitivity, wasting less energy from starting the burn too early.



Std inlet port. Its crap, volume too big, valves too small, casting quality is not great and there is alot of shift below the seats, horrible machining in the throats (visible at the back below seats). Port runner (manifold side) is actually offset and there are 2 port designs, one a left hooker, one a right, mirrors of eachother. So each valve has to have its half of the port designed and modified differently as flow reaching the bifurcation is comming from different entry angles (guide bosses give a clue).



Short side has nice amount of material to work with, this port will be running a flattened and widened short side turn to drop velocity over it. Each port will flow into the cylinder at different angles to promote swirl and mixture conditioning.



Exhaust ports arent too bad, just tiny! The work begins!



Just another pic of how bad the std ports are around the valve seats.....pretty apalling stuff.




Initial grinding starts around the bowl/short side and seats and this is what makes the port work. Blending of throat into seat and bowl, and bowl walls belnded into short side. It starts off looking pretty rough, and you have to be careful not to grind away areas where it will hurt flow, despite it not looking 'prety'. Not all areas of the port require touching, and this is down to core shift of the casting, primarily around the underside of the seats, you get little pockets, which if you touch destroy flow quality and quantity. Its very important to know what to touch and why.




Apologies for the poor lighting.
Pics illustrate the development of the short side, and the flattening of the turn....the floor becomes squarer with tigher radii on the corners, effectively 'D' shaping the ports. Final finishing is done once the guides and bosses and port floor is roughed out.







Development of the guides shape, profile, taper is very important. Most people grind them down, but they can be used quite effectively to direct, condition, energise and aid mixture condition. In this head the offset ports require the guide bosses to direct flow around different entry points and through the throat in different directions, so you can see quite easily that they blend and taper in different directions. Blending into the guide so the flow doesnt actually 'see' the guide or the boss is vital to making it work.



The OER ITB's flowed.

Point to consider is that at no point is a 'polished' finished ever used. Using correctly textured surfaces are better at supporting neat raw flow because the boundary layer thickness, or the actual layer of still air between mass flow and port wall, that flowing air floats on can be controlled to reduce losses, turbulance. Texture also aids mixturing and prevents fuel drop out as fuel never really comes into contact with the surface, and if ti does a shear state can be generated. Changing texture from near satin to rough can be used to energise the flow in directions.

More to come as it happens, all work and pics thanks to my Sponsor, Angel Works Technologies.. http://www.angel-works.co.uk

[Ivan141]

Great write-up...cant wait to see how it turns out on the dyno and how it will work out with your drifting.

[adomz]

nice!
really nice to read such a writeup...
;]

[PetzK]

Redtop head?? Dunno, but those look like largeports to me...

Otherwise, great work - what engine management do you run? As I see, those are not 20V TB's? If not which make, what do they cost and do they mate a Weber manifold or custom...?

I'd be interested in final power output of this nice engine, if done right you should get to 180hp+

[PazzaAE86]

Yeah its a large port head, running the red top bottom end.. Using the large port because of the manifold, only fits large port as you all know. The Throttle Bodies are made by a company called OER in Japan, as is the manifold. We are also hoping for 180+hp from the build.. More pics!

"After begging and scrounging the machine was done in double quick time, and the engine balancing in a 4 hour period, although i had to pickup the nxt day as it was a 120 mile round trip just to get the crank/rods/pistons balanced by the only person i really trust.

The Engine is running Total ARP for Rods, mains and headstud. Cometic head gasket (yet to arrive), my cams still havent arrived!..........they promised monday, but things like this always happen. Arrows Lifters arrived and so did the RPS clutch assembly, never used them before but i'm assured that they are 'good' so see how they go.

The cylinder head is completed. Apologies for the dirt on it, i've not had much time to make things picture pretty.








The oil pump is also modified for inclreased flow without a pressure increase."

[Richie]

Awesome project man, keep us posted.

[ZaX]

Nice project Paz. Wish you 180+hp

[PazzaAE86]

More..

short motor essentially done, tight as a virgin, ARP everything......god those pistons look sexual if i dont say so myself lol.

[Mux213]

Owh mama! I need to do that some day to