G4CS Coolant Passages

[Jhoe]

I am having trouble my head sealing. The head is going to the shop to get tested tomorrow. I have 2.4L G4CS and ended up drilling 2 extra holes for coolant. The head is leaking in the front of the block, left and right sides, whereas the holes were drilled more on the back side, between pistons 4&3 and 2&1. I've tried various gaskets so far, would drilling these extra lines really have any effect on lifting the head to cause a leak? I mean even if it is 15psi of coolant or an extra 100psi of oil, would this cause a leak? Using ARP hardware. I don't think it is causing the leak but wanted to know what you guys thought. Thanks.

 

[oddrob]

Did you check to be sure the head was flat? Does the HG match both the block and head perfectly?

 

[cornbread]

There was no reason to drill those 2 holes in the first place. I run the G4CS block as well and i dint drill anything and haven't had any problems. But since you already drilled it did you drill it after the head was machined?

 

[Jhoe]

The holes were drilled then the block was machined. The head was flat and I am taking it to have it checked out tomorrow. The gasket has two holes if I remember correctly but the head does not (so no the gasket does not match perfectly). So basically I have two holes opening up to the head from the block. I'll triple check tomorrow when I take it to the shop.

 

[Injected]

The holes were drilled then the block was machined. The head was flat and I am taking it to have it checked out tomorrow. The gasket has two holes if I remember correctly but the head does not (so no the gasket does not match perfectly). So basically I have two holes opening up to the head from the block. I'll triple check tomorrow when I take it to the shop.

Let us know how this turns out. I have a great G4CS shortblock (stock hyundai block and crank) and am contemplating the build or selling it.

 

[Lunch_Box]

I don't understand why you drilled holes, I did not need to on my G4CS block.

 

[Jhoe]

Finish your build! Works great for me when it doesn't leak! This combo works great for many people I am just having some issues I am sorting out.

Holes were drilled because some older posts said they needed to be drilled. This was because they didn't know what they were talking about and only read that else where without checking up on it. Some people thought the 4g64 block was the same as the g4cs. I was in a rush and took their word for it. Head is at the shop awaiting inspection. More soon later this week.

 

[Turbocharged]

The g4cs does not need to be drilled. All oil and coolant passages lined up from my block to the head gasket to the cylinder head. You did you an 87mm or 88mm (size depending on chamfer) 4g63 head gasket, right? The 4g64 head gasket is different. If you drilled holes to match a 4g64 head gasket, they do not corespond to holes in the cylinder head. That is probably your problem.

Where are you guys locating your knock sensor on the g4cs. I have mine threaded in the long boss above the AC compressor between cylinder number 1 and 2. I think its the boss used to mount the intake manifold hanger/mount (which I dont have). I have some random knock issues and am considering relocating the knock sensor...

 

[sunflashx]

Where are you guys locating your knock sensor on the g4cs. I have mine threaded in the long boss above the AC compressor between cylinder number 1 and 2. I think its the boss used to mount the intake manifold hanger/mount (which I dont have). I have some random knock issues and am considering relocating the knock sensor...

Mine is in the same place. My knock sensor seems to behave exactly as I've always expected it to.

 

[Jhoe]

Using the right size head gasket, I doubt the extra passages are the problem considering all the force that the pistons produce is being sealed. Checking the block soon, head turned out okay.

 

[Hooah]

Ive looked everywhere...noone seems to every say what headgasket you run with a 4g63 head and g4cs block, can someone inform me please?

 

[JeffGST]

4G64 Block = 87+mm

You will need a HG that is at least an 87mm bore. Options are...

1) The expensive HKS gasket
2) Cometic 87mm
3) Felpro HG (Always drastically oversize and this is what I use on my Talon)

I would not recommend the Felpro unless you are running low boost or if you have your head or block O-ringed. I personally like the cheap Felpro because I have stainless O-rings machined into my head. The O-rings can dig into the soft composite HG material and it provides a great seal. I don't push any coolant at all and all the combustion gases are trapped in the cylinder.

I like running a cheap composite head gasket on my 4G64. I rather blow my head gasket than blow my motor. The HG is suppose to fail when there is a problem with the motor. It's my FUSE. Head gasket install is only 2 hours of work. Rebuilding my short block is a few weeks of work.

 

[Hooah]

I ordered a g4cs headgasket from cometic and was sent a copper hg. i was looking for running a MLS, its a 10:1 comp motor, and i dont feel safe with this copper gasket cause i never ran one before, dont really feel like doing another hg. what are your opinions on it?

 

[TurboAnything]

You need to be O-ringed for a copper gasket. You also need to slather it in rtv to keep it from leaking coolant.

 

[Savage Talon]

I push coolant with my copper head gasket even at low boost and my head is O-ringed. I'm going to try a Felpro gasket and see what happens. And the copper gaskets seaps oil on the outside down the block. More of a pita then they are worth.

 

[need2boostpsi]

does anyone have a deck picture showing these coolant holes?

 

[1fastlaser]

There is two holes on the deck of a g4cs beside cylinder 1 that need to be drilled to match the 2.0 block.