How to Surface a 4G63T Cylinder head for a MLS head gasket

[BogusSVO]

How to resurface a 4G63T Head For a MLS head gasket.



I use a Comec Auto I 1000 High Speed Milling Machine with CBN insert for Cast Iron OR a PCD Insert for Aluminum Heads
This machine is double adjustable, I can adjust the spindle speed and the table travel speed to achieve the surface finish that is required.
Auto I 1000 CBN Surfacer


The first thing to do is check the valve cover surface for any burrs and remove them.

Next is to mount the head in the machine and check the level of the head in both directions.

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Then the other way, this head was not out that bad from the last time it was milled.

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I did a "getting to know you" pass of .002 to see how square the head was. This was done on a faster setting.
Notice the upper and left side of the head is dull, this is a low spot. The head was not index properly and did not maintain a proper "square" to the valve cover surface.

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I made another cut of .003, I sped up the cutter, and slowed the table speed.

This is the end result.

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Another different view.

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Now with a proper surface, and the head re-squared, The customer will have no issues with a MLS gasket sealing, and also having a closer to equal combustion chamber size.


this is a good vid to watch, it shows BOTH the belt sand method, (NOT TO DO) and it shows the method I use, A high speed milling with a .500 insert. (THE ONE TO USE)

[ame=http://www.youtube.com/watch?v=I-mHiuOyR4M]YouTube - Resurfacing an Aluminum Cylinder Head[/ame]

 

[efrainz28]

I have my head and block resurfaced. To install an MLS, do I have to have the surface clean? (No oil or grease on the surface) what do I clean it with?

 

[sledge42hammer]

I have my head and block resurfaced. To install an MLS, do I have to have the surface clean? (No oil or grease on the surface) what do I clean it with?

brake clean and clean rag(s)

 

[Colt4G63 also]

I have my head and block resurfaced. To install an MLS, do I have to have the surface clean? (No oil or grease on the surface) what do I clean it with?

brake clean and clean rag(s)

But be careful! You're in California, and brake clean is known to cause cancer in California.

 

[AG 305]

stock valves need to be removed before resurfacing?

 

[BogusSVO]

efrainz28.... yes a quick wipe down of the gasket mating surface with brake clean/paint thinner ect will remove all oil residue.

AG305... it depends on how thin the head is, and how much will be cut off, sometime after a head has been milled a time or three and the head is thinniner than 5.185 the intake valves will have to be removed so they do not get cut when surfacing the head.

 

[Fehrion_sit]

BogusSVO, i drove the car back to my house, about a mile with the heat gauge buried, im taking the head off and intend to measure everything professional, i am a tech, though this is my first 4g63. im planning on using a mls headgasket, do u think im going to need to have the block milled, i really not looking to remove the block from the car. personal / professional Opinion ?

- mike

 

[LiquidX]

You will need to get it checked for flatness.

The head surface optimally is to be a mirror smooth finish to remove any crevices, over hangs that will not allow the MLS gasket to seal. If you can catch your fingernail on the block surface then it needs resurfaced. If you do not want to go through that then use an OEM composite gasket.

The OEM composite gasket is able to withstand 40psi with L19s and an o ringed block. Others DD at 30psi with ARP studs.

 

[Fehrion_sit]

LiQUiDx, when you say run my finger nail for hangs, you mean perpendicular to the block, actually on the mating surface?, im having the head resurfaced, im trying to do the best quality job that i can

as for the type of HG, i have a e316g setup, 550cc injectors, i can give more details if needed

 

[LiquidX]

If you drag your nail/s across the mating surface of the block and head where the head gasket will meet and you catch a groove, it's not surfaced well enough for a MLS gasket.

As mentioned, pushing a E316g at 25psi will be fine with a composite gasket using ARP head studs.

 

[AWD Devious]

I always wondered what kinds steps to resurface the block. This is was very informative.

+1 internets for you

 

[wcassar]

Is there an indicator of head surfacing limit?
how many times shall a head be resurfaced?

 

[BogusSVO]

Is there an indicator of head surfacing limit?
how many times shall a head be resurfaced?

No, ,there are no indicator or surface limit marks cast into the head.

The only way to know is to measure the head thickness.

http://www.dsmtuners.com/forums/cyl...how-measure-4g63-cylinder-head-thickness.html

If you look in this thread

http://www.dsmtuners.com/forums/cylinder-head-short-block/471805-head-inspection-10-a.html

You will see how the head has been milled way past the limit.
Some call the spots in the pics, wear/mill indicators, that is incorrect, those are the points that the molten aluminum is injected into the casting to make the head.