What work should be done to a head in a rebuild?

[3sgte]

That's an exhaust valve, and the cooling passages look more than a little suspicious.

I would strongly suggest some professional help.

[Howieau]

Haha yeh, I realised that today when I looked at the head again. Its an exhaust valve, doh!

Cant they just run some acid stuff through the cooling passages to clean out all the crap?

Add: I was just checking out my head and rotating the cams with a ratchet. The cam lobe always touches shim through the whole rotation? Is that normal?

[3sgte]

It depends on what you mean by touching. With the valves closed, there should be clearance measurable using a feeler gauge between the base of the cam lobe and the shims. If there isn't clearance, then that is a problem.

As an approximate range, somewhere between .008 to .014 inches (eight to fourteen thou). this is not an exact spec, just a ballpark for looking at the head while it is off the car.

To clarify my previous point, I am a little worried that there might be a crack in the head.
Can you post a better pic of here:


What generation is the motor? (what was it originally fitted in?)
Do you have specs on what the welded/ground cams are supposed to be?

[Howieau]

The car is a ST185 Celica GT4, and the engine is a Generation 2 3S-GTE.

I had a closer inspection with a feeler gauge and there IS in fact a clearance between the lobe and shim so all is good.

As of today the head has been put in to get machined and I was able to talk fluently with the machinist as to what might need doing thanks to all of your help. Much appreciated!

Next up the block will need machining, so to start a new line of conversation, what things should be done there? Top shaved off, water gallery acid washed, cylinder rebore?

[allencr]

Next up the block will need machining,...what things should be done there?

The block surface/deck needs to be absolutely clean & straight/flat, so other then cleaning and inspecting/checking, nothing needs machining unless you know What & Why!

[Howieau]

Thanks for everyone's inputs, the head has returned look shmick as.

Heres a few pictures;


Old combustion chamber verse new;



Port and polish;


Lumpier cams;




Top down view of head;


Now ill CC the chambers and get ordering for some forged pistons, bearings, arp crap. Going to shotpeen the crank and rods too. Its all happening!

[fixeruperer]

do you have a pic of the old port just for comparison ?
and id smooth of those edges around the combustion chamber, what specs did ya get ya cams ground to ?

[Howieau]

The porting was already done by the previous owner, as were the cams.