[Tigerstripe40]

I've done alot of research on the 3VZ-E motor (not to be confused with the similar 3VZ-FE motor).

The 3VZ-E motor was designed in a day and age when a material called asbestos was the material of choice for head gaskets, brake and clutch linings and lots of other automotive stuff.

However. When the 3VZ-E motor was introduced to the US, Asbestos has been banned because of certain health problems associated with it. Toyota scrambled to come up with a suitable alternative. This alternative head gasket is the reason the 3VZ-E had head gasket issues.

The cylinder wall and water jacket thickness at the number 1 and number 6 cylinder is VERY thin. When an asbestos head gasket was used, this wasn't a problem, however these newer materials aren't able to really cope with the forces, and heat that they are subjected to in the motor caused these gaskets to blow.

What you can do about it:

The machine shop that did the machining of the block had done A BUNCH Of these blocks for the various toyota dealerships. They were able to weld in extra material on the outside of the number 1 and number 6 cylinder walls, as well as extra material onto the water jacket. Then they machined the whole block to make it all flat. This gave a wider area for the head gasket to seal to and will resolve the problem. This added $300 to the cost of my motor rebuild.

There is another problem with the exhaust valve in the number 6 cylinder burning up because the exhaust gases from the passengers side is dumped into the exhaust manifold on the drivers side right at the number 6 cylinder exhaust valve.

An easy way to solve this is to run an exhaust header.

In the end, I would say get a 3.0 V6 and drive the snot out of it.
In the mean time, save up the money for a 3.4 conversion for when the 3.0 dies.

FWIW, after all the problems and headaches associated wth my 3.0 rebuild, I REALLY REALLY wish I would have just done the 3.4.