Hi,
I am new here, so hopefully I elaborate enough. I have a 94 civic 1.4l engine. I blew a head gasket a few months back and I'm going to be replacing it soon. I've talked to numerous people about doing this and some say I should have the head milled and others say its unnecessary. I'm conflicted on what I should do any advice would be great.

 

Didn't overheat: Slap in a new gasket.
Overheated but the driver kept going until engine stopped: Replace the whole engine.
It's that gap between the two cases where there is uncertainty. I would tend to try a gasket slap first, if the new gasket blows, machine the head or consider a new engine.

 

The easy way to decipher the in between gap is when you pull the head (to do the head gasket) you check the head with a precision (mechanics) straight edge. If it's not warped, replace the gasket, if it's warped, send to machine shop for milling. Could also have a full valve job done on it at the same time and then the head will be fresh and new.

 

The engine did overheat; however, I pulled over because of the white smoke pouring out my exhaust. So from what I'm hearing is I should use precision tool to determine if its straight, if it is slap the new head gasket in and I should be good. If not have it milled. Now what does having the full valve job done entail?

 

It's a job the machine shop would do for you. A full valve job is replace the valve guides, replace all the valves and do a 3 angle cut of the valve seats, replace all the valve seals and verify the valve height is still in spec after all of this is done. Usually you also replace all the retainers and springs at the same time.

That is a complete valve job.

 

Jeez, that's insane. Don't think I'll need to do that (hopefully). Thanks for the info!

 

In town here, there is a machine shop that surfaces heads. They basically have a giant belt sander with a fine grit belt that they drop heads onto and surface them and it's $30 for a Honda head so it's a no brainer compared to taking a risk and doing the job all over again.
Something VERY important however. Neither Honda nor the machinist ever really debur the edge of the combustion chamber inside the firing ring of the head gasket. Sharp edges left here can cause pre-ignition and head gasket failure. Lay your new head gasket over the head while it's upside down on the bench, line up the bolt holes and carefully use a sharpie to color the area inside the firing ring of the head gasket. Then you can use an exacto knife, 400 grit sandpaper, or whatever you like to round those edges. But, be super careful not to scratch or nick the sealing surface of the head where the head gasket goes.

 

This is on a SR20DE, but same principle applies.

Nissan SR20DE Engine Build Up - Turbo & High-Tech Performance