resurfacing head. is .008 too much?

[dsphil]

My machine shop told me that my m20 i head need to resurface the head at .008. Is it doable or I need new head? I think .006 was the max. any thoughts will be appreciated.

[Cabriolet]

My machine shop told me that my m20 i head need to resurface the head at .008. Is it doable or I need new head? I think .006 was the max. any thoughts will be appreciated.

you should be ok. there are 3 dimples on the bottom of the head. if they are gone then you will need to get a thicker gasket.

[AndrewBird]

.005-.010 is pretty standard for decking a head. You should be fine.

[barbierij]

I always thought that you could only shave until the "shave dot" is completely flush with the rest of the head (gone).

circled in red here:



any more and you need a thicker gasket.

[TobyB]

.008 is like, just a mild polish... You're in good shape.

You CAN cut it as much as you want- it's just that you then have to make sure all
the rest of the stuff is ok (valve clearance and timing, compression, etc)

t

[dsphil]

For some reason they think is too much. I told them to proceed and I will have to get a thicker head gasket. Will see what it was like when I pick it up. Thanks for the inputs.

[Hawk]

I have taken an M20 head down that far with no issues after a timing belt tensioner failed.

You should be fine.

[AndrewBird]

I think some Pro3 guys shave it down like .015" or some crazy amount. At that point though, the head is one time use only.

[getouth]

You're good!!

[TobyB]

jeeze, I run M10 2002 heads cut 0.100" in the race car just as a matter of course-

I can't see such a mild cleanup making enough statistical difference to notice on an M20.

It's just not that much...

t

[dsphil]

I have a little concern about this machinist now. They are telling me that the head is warped and they are putting it in the oven before they can resurface it. When they said oven, they don't mean cleaning it.

[TobyB]

Yeah, you can heat and twist a head to try to straighten it.

I could never figure out how...

t

[gwb72tii]

Heat can release internal stress from manufacturing that will cause warping

[steve68]

My S14 head was straightened in the oven then surfaced, don't remember how much,

[dsphil]

All these stuffs the machinist said is new to me. Maybe I shouldnt worry too much.