Der_Idiot

iTrader: (2)

Do you know what the duration is on the cams? I'm guessing if the base circle wasn't shrunk they must be above 270 to keep the rates down. IIRC someone had similar lift and was around 284 duration?

shifti

I don't remember what they were. i delivered the paper work on the cams to the builder with the cams.
But i think they were around 380 something on the intake cam and a bit less on the exhaust cam.

shifti

It's been a while since the last update. But i have been busy on other projects.
I finaly got time to make a torque plate at work, and the block is now at the machine shop for boring, decking and line boring.
The last post i wrote had a typo. the intake cam is 285° not 380. Haha.. And the exhaus cam is 277°
Found out that i had to make some room in the valve cover to clear the cams. So here are some pics.

ridethecliche

iTrader: (2)

Any updates? Curious how this is going!

shifti

The block tok forever at the machine shop, but i told them i was'nt in a hurry, when i delivered the block in april, they have decked It, bored it and line bored it. the block was finiched last week, but i am still on My holyday, will pick it up in To weeks, then mesure the bearings and order them and the remaining parts i need to Build the engine.
Since this has taken so long i don't think i will run it as a N/A first since this summer is almost over, and just start to make the intake manifold and turbo manifold when the engine is finiched.

shifti

Update.
Have finally got time too start work on the miata, and i have started a build thread Here:

ElyasWolff

I remember about 2003ish reading about motorcycle engine builders using JB weld. To do port work to make the ports have a straighter shot to the valves and increase port velocity. I also recall Yamaha (Toyota-ish) decreasing the port size on the 4AGE heads to make more power.

Midtenn

iTrader: (15)

The original 4ag had massive ports to support the TVIS system (2 runners per cylinder with a butterflies to open/close a runner for increased flow at higher RPM). At some point they ditched the TVIS system and went to the small port motor that made better HP and was more drivable.