FOCUSHERE

Ok a co worker and my self were talking about heads and stuff were both big gearheads (were engine mech in the usaf on blackhawks) and he told me that i should have my block milled becasue im doing a head job, timing chain, ect and i argued no way just clean surface and bam im in business what do you think? now my head i will cause that will be off so duh and i think the mechiune shop does that anyways when your doing a pressure test after port ,polish, springs, ect

Azusacanyonbogger

called decking the block and you should do it just to make sure you have an even surface, especially if the engine has been overheated. as well as resurfacing the head (which technically milling the head but only a small amount to ensure a completely level surface.) and if you had a port job on the head then most likely they asked you if you want to resurface but i doubt they will just do it for free.. i would double check what you are getting done at the machine shop. if the block is out it would be a good idea to deck the block and resurface the head to make sure you have a good surface for the headgasket to seal. really sucks to put it all together and then have a leaky headgasket due to an uneven head / deck. and what do you mean clean the surface?? if you mean clean it like resurface then yes, if you mean clean it like with a rag or something then its not recommended unless you want to take a chance with it sealing. just my opinion from experience.......

FOCUSHERE

thanks i know its called decking and i know that reserfacing is recommed but my truck is a 92 pu with 116k and never been over heated and my block wont be out of the truck just the head to do the timing chain/ head work and what i mean by cleaning the surface is is making sure no old gasket is stuck to the block when the new one is placed and maybe take some emery cloth to it

so your telling me every person that does a HG pulls there motor to deck the block i think you are confused like my co-worker

mr toytech

check it with a straight edge to see if it is within specs. for warpage. then go from there. if it is ok then clean it and put it back together. you only deck them if it out of spec. for warpage. thats from a mstr yota tech.

ewong

Make sure your straight edge is STRAIGHT....

Dont use a Home Depot T square thats been banged around in a tool box for 10 years...

I was told to get a hunk of STARRET steel bar in stainless. Those are STRAIGHT and pretty stable.

Use a feeler guage and go at it in as many direction as you can as well as the FSM positions...

My HG went at 225K, the block was straight.
I did the head with the block in the truck.
At 350K Im thinking maybe I shoulda done the rings too..

InternetRoadkill

I always had my blocks decked whenever the cylinders were serviced. Even if the engine has not been overheated, the temperature cycling can still cause some minor warpage in the block. This is less of a problem in an old block since it's likely that its already done whatever warping it's going to do. Old blocks are said to have been "seasoned". Once a seasoned block is re-machined, they tend to be more stable than new blocks.

So the general recommendation is that if it's an old block that hasn't been decked yet, it's a good idea to go ahead and get the machine work done on it. You might want to check the cylinders for roundness too.

The machining leaves a nice surface for the new head gasket too.

RustBucket

iTrader: (1)

But if your engine is still in the truck, that doesn't make sense to yank the whole things out just to do the head!

What I have done in the past is to get a large, fine whetstone (like for sharpening knives) with some lube and, using a swirly pattern, take off just the tiniest bit of metal off the top of the block. It leaves it smooth and clean if you're patient. The recommendation to use the straightedge and feeler gauge is a wise one too.

CJM

Yep, check it out and only then if its out of spec should you mill it.