Whats up guys I'm in the middle of doing a rebuild. I was wondering about how many times can you take you're head in to have it resurfaced - before too much is taken off and its not usable? The head is from the eBay exchange program so I know its been milled at least twice; and I need it milled again.
Thank you :)

If I remember correctly .040" is the most you can take off the 420a cylinder head. Maybe on the safe side .032" is too close due to what can happen. By the time you get to .020" though the timing may need to be adjusted due the the c/r jumping up.

Originally posted by BoostedEclipse
If I remember correctly .040" is the most you can take off the 420a cylinder head. Maybe on the safe side .032" is too close due to what can happen. By the time you get to .020" though the timing may need to be adjusted due the the c/r jumping up.

Thank you. But how can I measure the head, I have no idea how much has been already taken off. How much do they take off by milling? I will be using a MLS head gasket.

A good machine shop maybe able to measure it for you. If your really good at surfacing/milling and the head isn't warped really bad, then it shouldn't have to be milled very much. Just enough to get the surface flat.

I would be cautious though as the head gets milled it closes the distance between the piston and valve. I would talk to an experienced person at a machine shop and get their opinion, or maybe someone else more experienced will chime in.

Originally posted by TheRedBarren
How much do they take off by milling?

Depends on the mill job. That is asking how big of a piece of pie does one cut with a knife? Who knows... depends on much of a fat ass they are.

Do you have receipts proving this head has been milled twice prior? I am not familiar with the ebay exchange program you speak of but I would be skeptical of having it milled a third time if you were not the one ordering the first two jobs.

Originally posted by CODE4

Originally posted by TheRedBarren How much do they take off by milling?

Depends on the mill job. That is asking how big of a piece of pie does one cut with a knife? Who knows... depends on much of a fat ass they are. Do you have receipts proving this head has been milled twice prior? I am not familiar with the ebay exchange program you speak of but I would be skeptical of having it milled a third time if you were not the one ordering the first two jobs.

For what its worth:

I have had three heads milled, and each time they took off .006. Also a friends head was milled as well, and .006 was taken off as well.

Different machine shop told me that .006 is about the "standard".

Now take that with a grain of salt, but IMO a third time should be safe.

Like Dave pointed, depends on the machinist though.

These heads have been cut as much as .060 with stock set-up. Your machinist will be able to pull up the unmilled number and compare it to the current dimension to see how much was already taken off. I do have to admit that with .020 taken off my head, my timing marks give me a little different visual than regular stocker.

Great! Thank you so much guys! Good info. Sounds like I just need to go to the machine shop