what causes aluminum heads to warp (and need a cleanup mill)

[rockin_rick]

Does this typically ONLY happen when you've overheated the car? Can it be needed when you've blown a head gasket and not overheated it (like I've done)? How many thousanths are typically taken off for a cleanup?

Rick

 

[fastf50rd]

Well, do you know the heads are warped for sure? If not, get a straight edge and a feeler gauge to find out. My buddies TFS's got warped, they were only out about .005" so it wasn't to bad. I just blanchard ground enough off to clean about .006"-.008".

 

[5literstang]

my car is the shop gettin a DSS put in, nad the guy told me since i had blowby my heads could be warped from the heat, if they are he said he is goin fix em some how, how do they fix em?

 

[Joes95GT]

Obviously aluminum is much less resistant to heat than cast iron is. At about 200* C (about 400* Farenheit), aluminum starts to become much more malleable. So, considering an explosion is going on inside of the cylinder, temperatures get quite hot, any thing that could have been slightly misaligned or installed incorrecly could result in a (slightly) warped head.

Overheating is a main cause, but bolt torque can also kill a head. What were the heads torqued to? You did use the dowels when installing the heads, right?

I'm tired, and I'm out of thoughts...

Joe

 

[rockin_rick]

my car is the shop gettin a DSS put in, nad the guy told me since i had blowby my heads could be warped from the heat, if they are he said he is goin fix em some how, how do they fix em?

It's my understanding that the block-to-head surface of the head becomes warped. They just mill them until they are flat again.



What does blanchard mean? Is it a name of the milling machine?

Rick

 

[fastf50rd]

Nope, its actually a grinding machine. It has a HUGE magnetic turning table and large grinding segments that move down on a head. Any flat plates or anything you see with real uniform, nice looking swirly marks are blanchard ground.