mhuppertz

Ok, my machinest advised that we do not mill the head because it has conformed to the block. Thoughts?
-mark

torquefan

Wow, never really heard that line of thinking before. I generally go over each surface carefully with a straightedge and feeler gauges first, before I decide whether a head needs to be sent for machining. Have seen many heads that needed straightening, but can't remember a block that needed resurfaced.

schamran

Did he go over the head with a dial indicator?

mhuppertz

He said if you are not going to mill the block (which I obviously can't do in frame) that milling the head is a mistake. I'm a little worried about the front passenger corner of the head where it tends to leak.

mhuppertz

Haven't pulled the head yet, waiting for the studs. He worked for Rocky mountain Cummins for a number of years back in the day. Like I have said elsewhere, he is one of the best engine builders/machinests in the country, and I really respect his opinion.... but he doesn't do performance diesels!

jimbo486

if the head comes off, i recommend it get machined. it will always be warped on the exhaust side, naturally, due to excessive exposure to heat. even if it only needs .001" to get it flat, it's worth it.

Riesenbr549

Yes i agree, if in doubt Mill it!! Just get a .020 over marine gasket and you can take up to .020 off the head and still be at stock comp. Not to say that your guy is wrong . For a in chassis thats the norm. Mainly big truck motors thou. If he argues then ask him what 2 do if you put a new head on?? just saying...

JD730

Tell him to take off just enough to straighten it, according to the book your allowed to take off up to .020". If he doesn't want to do, find another shop that will. Don't forget to check if for cracks before you do any machining.


Wrong, .020" over gasket is used if you have to mill the block deck down to straighten it out. Thats why there are .010" and .020" gaskets, so you can cut the block twice if you have to, chances are you won't, but there's always the chance.

mhuppertz

I'm at high altitude, so a small bump in the static compression ratio would be a blessing.