cylinder head modification idea

[banishedmunk]

Well I recently had a coolant leak coming from between the head and the block. it was coming from the intake side on the trans side. well when I get the head off I notice something and get an idea. on the block there is two large holes as seen here hole circled is hole in question.

You must be logged in to view this image or video.

when I looked at the head there was no hole to corespond with the jackets in the block. but there is room in the head for a hole to be drilled with no initial draw backs to my knowledge. I can feel inside the hole where the thermostat housing that it would go directly into the jacket. here is where I would like to drill the hole.

You must be logged in to view this image or video.

will there be any negative effects from drilling this hole and having my gasket pressed to accompany the newly added hole. It seems as if it would allow for added flow through the head and allow for slightly better head cooling.

 

[PieEyedPiper]

You might try PMing bogusSVO to get see if he has any input.

 

[LiquidX]

You might try PMing bogusSVO to get see if he has any input.

He hasn't logged on since January.

 

[knochgoon24]

IMHO, if it would have helped cool the head, Mitsubishi probably would have drilled the hole.

 

[banishedmunk]

with no fluid moving through that area it creates a path of resistance which I believe with the hole drilled the coolant wouldnt have a chance to build up in that area creating a hotspot in the head.

 

[2slow4now]

I think its made like that so you get more flow on the exhaust side of the head because thats where most of the heat is generated. More cooling is needed on that side so it makes sense to have more flow on that side or as they designed restrict the flow to the intake side.
If I would drill the intake side like your saying I would also enlarge the exhaust side hole to balance the flow. Then the question is would that slow the flow of coolant with added holes and harm cooling?

 

[19Eclipse90]

I wish I had a better picture, but here's an original 2G turbo head. There is a hole on the intake side and it also appears larger than that on the exhaust side. I'll snap some better pictures later this week and take a good look at what exactly is going on.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

It is interesting because all 4G63s use the same head gasket and, regardless of the head being with or without that hole, none of the head gaskets I've seen have a hole for coolant flow at that point on the intake side. So why did Mitsubishi keep the passage on the head gasket blocked off even after putting that particular hole in the head? I'd also like to believe they had their reasons.

 

[banishedmunk]

I talked to Bj from BJ's cylinder heads and he explained that drilling a hole there would actually hurt the cooling effect of the cooling system. If you notice on the head the cooling jackets on the head actually get smaller from the cam side over. he explained this is to maintain pressure in the system as it is pressure that cools as opposed to flow. without the pressure from the coolant it would actually boil much faster and create a foamy layer between the cylinder and the coolant. it is pressure that keeps the coolant cooling the cylinders not flow.

 

[2slow4now]

That makes sense. When you build more pressure it raises the boiling point of the liquid. The higher the boiling point the more heat it can absorb. Flow carries the heat away for the radiator to get rid of and pressure keeps the coolant from boiling.
I looked up a chart for superheated steam and @ 15.3 psi the boiling point is 250 degrees. If you bumped the pressure to 25.3 psi the boiling point would be 267 degrees. Sounds like a higher pressure radiator cap would be the ticket to better cooling.

 

[PieEyedPiper]

More pressure will raise the boiling point but I don't see a reason to bother increasing my coolants boiling temp from say 250 to 267 since if I'm that hot anyhow boiling my coolant will be the least of my worries.

 

[nitrouskris]

I talked to Bj from BJ's cylinder heads and he explained that drilling a hole there would actually hurt the cooling effect of the cooling system. If you notice on the head the cooling jackets on the head actually get smaller from the cam side over. he explained this is to maintain pressure in the system as it is pressure that cools as opposed to flow. without the pressure from the coolant it would actually boil much faster and create a foamy layer between the cylinder and the coolant. it is pressure that keeps the coolant cooling the cylinders not flow.

bj ???? you mean in the past right ?

 

[Colt4G63 also]

It's made that way to direct the flow of coolant. If you open that side up too much the coolant will have no reason to cool the opposite side of the head.

You have plenty of flow through that side of the head because all the coolant flows out the T-stat housing directly above those blocked holes.

 

[banishedmunk]

bj ???? you mean in the past right ?

if by PAST you mean two weeks ago then yes

 

[nitrouskris]

if by PAST you mean two weeks ago then yes

really well if you could can you pm me his contact info