Cylinder head mishap

[Tractionman]

If the heads are not to be machined, and are a throw away item, why are there "so many thickness head gaskets" made ?
Correct me if I'm wrong, but that's a choice for when the head is machined, so that tolerances can be maintained ??
I think the job is done by now anyway.

 

[Davet]

Yes its done but the different thickness head gasket's is to allow for correct piston to deck protrusion tolerances and i did not discover this until i had to replace a cracked piston from no1 Head failure it got to hot and cracked from top of piston to first ring land and caused a minor miss at idle no 2 piston so here goes you can only use genuine pistons on the late model 1kz-te
As the engines can have 4 different piston no,s
And if that aint crazy enough they also have 3 different no con rods which makes for a whole lot of hassles if you dont know so i have inorder from no1
Pistons 2 .1 .2 .2
Con rod 1 2 1 1
And each rod has a different main bearing and each piston a different protrusion height
The specs say no more than 10 thou protrusion or it will collide wth the head
We worked that out the hard way aftermarket ones
Go whacky smack
So after a phone call to a toyota guru friend we replaced pistons and rings genuine and correct numbers from japan luckily i over service and the bores and bearings were like new so honed and put in pistons now with a 5 hole head gasket as from oe assembly the height was 11 11 13 13
So it should hit from factory so get this the aftermarket pistons only protruded 15,3 thou
That means with a 4 hole head gasket it would hit
Plus two different piston crown used so could easily smash valves if not correct
My toyota guy actually was a top mechanic at a large dealer but now is in spare parts due to hand damadge wow was i lucky to get him on the phone mire than once
Lesson buy a bottom end rolling assembly new from dealer or use some one who knows this engine backwards
I have no idea what the big Mr T was thinking when they put this stuff together
I know i will not do another one