Dismantling 20v Head

5th July 2003 9:45pm till 12:45am

Location - back kitchen :)

The 4AG-E 20Valve Engine Repair Manual instruction was followed carefully and rigorously concerning the correct procedures to dismantle the engine. If done wrongly, the head may wrap and render useless, or that the cam shaft may bend and again useless after that.

The engine was in-effective since 1st transplant, which was May 2002 because the installer made allot allot of mistakes on the EFI wiring loom. However the engine's mechanical is "believed" to be fine, just that without a proper "brain" it cannot function as a whole.

The entire transplant was taken out and replaced by another complete half-cut since 9th September 2002. Please see Restoration 2 

It has been running fine ever since apart from some unexpected wear and tear situations and not to mention bad luck. Please see Sudden Bad Idle and Sudden Death. The mechanic and my self put in extra effort and attention to the "complete" wiring loom to ensure it's success.

After so long, suddenly I have the free time to dismantle the old engine and rebuilt it for higher efficiency hence power output and hopefully fuel economy.

The usual modifications will apply: - (whatever standard from the book will not be mentioned)

  1. Port intake without polish.

  2. Port and polish exhaust (probably with polish too???)

  3. Port not to increase size, but only to remove small blockage that causes uneven flow.

  4. Valve springs may change to 3S-GTE??? depending on costs.

  5. Cam shaft to be re-profile for slightly higher durations??? depending on costs.

As for the engine block: -

  1. Grind to even all 4 weights of the pistons without rings on.

  2. Grind to even all 4 weights of the con-rods.

  3. Crank shaft to be balanced by rotation.

that's it I think, so on with the show of dismantling the engine head: -

Engine on skateboard for easy movement :)

That's me stripping the engine without proper tools :(

4 throttles taken out as a whole.

Nearly all top bits removed following procedures from 4AG-E 20Valve Engine Repair Manual. Look at how dirty the head is stained by old engine oil not being change on a regular basis and probably over used period. It is going to be a nightmare cleaning this head.


VVT sprocket stuck. Next time I'll remember to remove it 1st before remove the cam shaft from the engine :) haahhaha

After 3 hours only so little is done, mainly due to lack to tools, where a nut keep slipping and could not release the bolts holding the cam shaft. It's 12:45 am and I'm tired, give up, go to sleep, continue tomorrow.

  1. Dismantle 4A-GE 20v Head
  2. Dismantle 4A-GE 20v Head - Part 2
  3. Remove 4A-GE 20v Valves



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