2UZFE VVTI Head Decking Question

[khanguyen93]

Has anyone here had their cylinder heads resurfaced? The factory manual recommends replacing the head if warpage exceeds 0.0039", but I wanted to check in first. I’ve already removed the heads and am about to send them to the machine shop, but I’m curious, has anyone run into issues after resurfacing heads that were slightly out of spec?


Cheers!

 

[white_lx]

In the factory, the cam shaft bearings are bored with the flat cylinder head surfaces as a reference plane. This results in a straight cam bearing bore when the surface is flat.

Unless the machine shop clamps the heads so that the cam bores are straight first and then decks the heads, you will end up with a deformed cam shaft axes. After installation, the cam shaft will now flex with each revolution and might eventually break. I've seen at least one example of that happening over at the 100 series forum. I would certainly ask your machine shop how they are insuring the straightness of the camshaft bores.

If the warpage is minimal the head bolts will probably straighten out the heads. The cam bores will then automatically line up again as well. That would be my choice. If badly warped, then new heads or used flat heads.

 

[khanguyen93]

In the factory, the cam shaft bearings are bored with the flat cylinder head surfaces as a reference plane. This results in a straight cam bearing bore when the surface is flat.

Unless the machine shop clamps the heads so that the cam bores are straight first and then decks the heads, you will end up with a deformed cam shaft axes. After installation, the cam shaft will now flex with each revolution and might eventually break. I've seen at least one example of that happening over at the 100 series forum. I would certainly ask your machine shop how they are insuring the straightness of the camshaft bores.

If the warpage is minimal the head bolts will probably straighten out the heads. The cam bores will then automatically line up again as well. That would be my choice. If badly warped, then new heads or used flat heads.

Thanks for the info. I’ll check with my machine shop guy and ask about his full process.

Would it be reasonable to assume that if he checks the cam bores for straightness with the head off the engine or clamped to anything, and they’re perfectly straight, then it should be safe to deck the head from there?

 

[aztoytec]

I have never had a problem getting heads resurfaced for a 2uz. I would make sure your machine job has experience with them. If not find one that does

 

[khanguyen93]

I have never had a problem getting heads resurfaced for a 2uz. I would make sure your machine job has experience with them. If not find one that does

What's the most you've removed off a head?

 

[aztoytec]

Honestly don’t remember the numbers.