basic 20v blacktop head rebuild / mods

[Shifty]

Guys

I'm building turbo 4A, with a blacktop 20v head. Currently the plan is just a thorough rebuild to standard specs.

Are there any weak points that should be addressed while it is apart?

[Bazda]

Valve springs

[CHB]

2nd That, valve springs.

[DreadAngel]

Perhaps the shims if the head is quite old...

They make a racket =|

[BLK_20v]

Any particular brand?

[Bazda]

Supertech valves springs are good.
Shims, well you will need to assemble and measure first, but normally they are not out unless somethings really worn.

[beerhead]

Rattly shims aren't a problem if you're planning on rebuilding a head. If the valves are being ground then you'll tighten the tolerances of all the buckets. A good machinist will check the tolerances after the valve grind and then skim the top of the valve stem the right amount to get the tolerances perfect, if they're a guru tolerances will be better than off the shelf shims.

[RT40Corona4AGTE]

agreed, valve spring replacement +1

and brand supertech +1

[allencr]

Adjusting the valves,SHIMS, is your job not the machinist! Neither is removing & replacing them in the head IMO, just cleaning & machining.
Rebuild/replace that VVT thing on the intake?

[beerhead]

Must be done differently in the USA, maybe too many pushrod engines? There is no re-shimming at all if the machinist lapps the valves after a valve grind, that's the point It saves you packets of time and money, done right the tolerances turn out more true than the step between the shims available off the shelf.

[RT40Corona4AGTE]

correct you are mr beerhead!

[Bazda]

If the heaed needs a valve grind it usually takes up 5-10 thou.
If the valves looks really good you only need to hand lap them in with grinding paste then check for seal.

If they are ground and your tolerances are too tight, taking material off the top of the valve is VERY time consuming. You just take material off the shim. This is what I do and works perfect, but you will need a valve grinding machine, I just make up a dummy valve which the shim fits on quite tight and run it through the valve grinding wheel.

[knightrous]

Supertech valves springs are good.
Shims, well you will need to assemble and measure first, but normally they are not out unless somethings really worn.

http://www.ipg-supertech.com/cart.ph...=Ret-tc50%2Ft1
This is the correct package from SuperTech?

[Shifty]

Thanks for the feedback kids. With the supertech valvespring kit, and standard head/cams, what kinda revs is the engine good for?