4G63T Head oil port mod

[BogusSVO]

4G63T Head Oil Port Modification


This is a simple and effective mod done to the oil port from block to head.

I have found out a restriction can occur when excessive milling of the head has been done.
Resulting in low/poor oil flow through the cylinder head that can cause lifter tic, cam tower gaulding, and in some cases on turbo engines that feed the turbo oil from a port on the head, to cause the turbo to fail.

Appox mod time with head of engine is 2 mins.


Stock oil port….

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

Take a die grinder with an aluminum burr and grind and chamfer the oil port, while staying inside the gasket-sealing ring. (I find a ¾ base tree burr works best)

So the end result looks like this.

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

I prefer this to be done before the head is resurfaced.

I hope you find this useful.

 

[chaggard27]

So I have read both threads and it got me thinking about the build I am planning on doing. So as far as the first mod it works no matter what head/block you are using. However as far as the second mod I believe I have an idea as to save some money/work and get the same results. In my build I plan on putting a 1g head on a forged 7bolt block. So if I were to use all 1g studs except for the one with the oil gallery and use a 2g stud there wouldn't I get the same result? Possibly better since it would be a 1mm difference?

 

[BogusSVO]

So I have read both threads and it got me thinking about the build I am planning on doing. So as far as the first mod it works no matter what head/block you are using. However as far as the second mod I believe I have an idea as to save some money/work and get the same results. In my build I plan on putting a 1g head on a forged 7bolt block. So if I were to use all 1g studs except for the one with the oil gallery and use a 2g stud there wouldn't I get the same result? Possibly better since it would be a 1mm difference?

yes that would work, but the 2g 7 bolt blocks are 11mm studs/bolts with the 1g head that is factory machined for 12mm studs/bolts you have already have the larger bolt holes so the oil flow around the stud is "built in" with the combo your talking about.

 

[gorf]

This is an interesting thread - thanks for the idea.

I currently am running a 6 bolt block with 2g head and just had the bolt hole reamed to fit the 1g arp head studs. Now I am concerned about oil flow to the head. Seeing as this appears to be a new idea, I would be interested in hearing from other people running a 6 bolt block with 2g head without this mod. Is anyone seeing signs of oil starvation to your head?

I would also be interested hearing from others about what difference this mod makes on oil pressure in the above 6 bolt / 7 bolt combo.

 

[Fabian]

this is great information seeing that I'm getting all my stuff together to do a 6bolt swap with a 7bolt head. THANKS for posting your info!

 

[Jeff99GS]

In my build I plan on putting a 1g head on a forged 7bolt block. So if I were to use all 1g studs except for the one with the oil gallery and use a 2g stud there wouldn't I get the same result? Possibly better since it would be a 1mm difference?

The only problem with that is, how would you get the 12mm bolts to thread into the 11mm holes on the 7 bolt block tho? You would have to drill and RE-tap all of the head bolt holes in the block.

Remember guys...ITS NOT whether its a 1g or 2g but whether its a 6 bolt or 7 bolt.

6bolt was made - 1989-92.5 and had 12mm head bolts

7bolt was made - 1993-99 and had 11mm head bolts

..... I have all stock junk. 93,000 miles on the odo. Is my head starving for oil? I hope not.

And lifter tick... does that have anything to do with my car being 14 years old? I hope so, I'm sure these didnt tick from the factory.

If you have a factory head with factory bolts then you are fine. If you have lifter tick it is probably from OLD gummed up lifters. Oil turns to sludge causing the Hydraulic lash adjusters (lifters) to stick or collapse.

This mod in the original post is great for us guys with shaved Heads and ARP studs. I have 3g lifters and NOT one peep of lifter tick so far...but if I ever do get lifter tick I will be sure to do these 2 modifications!

 

[rare1]

I'm gonna do this mod in addition to my bse.Thanks for the info.

 

[BogusSVO]

Gald you will put it to use rare!

I hope some of you guys will post before and after oil pressure readings!!

I would like to see how it dose effect your over all oil pressures.

 

[ToughTalon]

WOW, BogusSVO- thank you for all your great tech threads lately, I really appreciate reading your posts! The fact that you dont even own a DSM makes your work even more appreciated!

My classic goodluck struck again, I just got done installing a re-worked head on my car and I dont want to buy another HG right now dohh, thats my luck.

And if any one is taking oil pressure readings or having oil pressure issues, PLEASE post what oil type and weight you are running. For example I am running Amsoil 5W-40 oil with no balance shafts, when my car is warm I do not have oil pressure issues. I do have a re-located oil filter and an external oil cooler too, incase your curious.

 

[chaggard27]

The only problem with that is, how would you get the 12mm bolts to thread into the 11mm holes on the 7 bolt block tho? You would have to drill and RE-tap all of the head bolt holes in the block.

Haha. Should have proof read. Yeah that or even just using all 2g studs. The alignment pins are what align the head so I would be fint with it that way. However since I am aiming for 550-600 whp I may drill and tap for the 12mm bolts. All except the oil gallery which I will keep 11mm.

 

[enos1010321]

Now for the 7 bolt engines the Head bolt is noticeably longer and thinner.
I'm sure these aren't accurate measurements but they give you an idea.

10.12mm just below the washer.

9.48mm in the center

10.92 on the threads

Would that mean that if you run a 6 bolt head with a 7 bolt block that you don't need to do this? Since the 7 bolt head bolts are thinner?

I wonder what the passage way looks like on an evo 8 head(newer 4g63 design). The 9 might be a different configuration because they need more oil for MIVEC.

 

[BogusSVO]

I would not think you would have to ream the head bolt hole larger with the 1g head on the 7bolt block, but i would say still port out the oil trough.

 

[Black_Bullet]

What about on cars with the revised lifters, is this still a good idea to do? Sorry if im off track a little, I just skimmed through the thread.

 

[Jeff99GS]

What about on cars with the revised lifters, is this still a good idea to do? Sorry if im off track a little, I just skimmed through the thread.

I don't see why it would be a bad idea. All it can do is help flow MORE oil to the lifters (HLA's)

 

[BogusSVO]

What about on cars with the revised lifters, is this still a good idea to do? Sorry if im off track a little, I just skimmed through the thread.

well it depends why you have the revised lifters? did you have your head rebuilt? or surfaced? and just suffer from lifter tic? if so then Oil mod #1 would help.

did you do the 6bolt 1g block with the 2g head? then you would need to do BOTH oil mods.

were your lifters just wore out from high milage?

 

[Black_Bullet]

No just lifter tick on the 6bolt so it got revised lifters. Ive never had oiling issues to the head or turbo ( tapped at the oem location) so far and the bottom end is being rebuilt right now and Im planning on having good clearances for good oil pressure, it already doesnt have balance shafts. Just trying to further understand this modification.

 

[BogusSVO]

when the head is milled, it closes up the oil transfer trough that is cast into the bottom of the head, a smaller trough means less oil flow to the oil galley thet is in that one head bolt hole.

This mod opens up the oil trough and promotes better oil flow to the head.

From what I have heard and read on this board, your oil pressure will go up beacuse of the BSE. around 100psi most have claimed.
IN THEROY, this mod may also help reduce the excessive oil pressre that is caused by the BSE, by allowing more oil to flow to the head, and alowing some of the oil pressure to bleed off.

How much has been surfaced off your head? how many times has your head been surfaced?

The reason for the lifter tic may be beacuse the lifters are not getting enough oil to keep them fully pumped up.

From what I have been measuring, combined with the "New Thickness" of the head, that oil trough should be appox .080 deep factory.

Now with the head being surfaced, lets just say twice in its life, due to being rebuilt, or blown HG, at an avarage of .010 each time, that means the oil trough is now .060
Now the head has a .020 built in oil restriction.

Do you think the same GPH/LPH will be mantained in a .060 oil trough as it was new with a .080 trough?

How do you Know you do not have oiling issues? have you checked the pressure or flow on the head?

 

[Black_Bullet]

If your referring to me^ im saying after doing revised lifters there was no more lifter tick and the turbo never had oiling issues so that is what I was using to judge. I will show some other people in the dsm scene out here and see if they've ever seen this mod. If its not too much of a hassle I may give it a try.

 

[pneumo]

I knew there was a good reason I used a thicker head gasket when I rebuilt my motor.

 

[cardot33]

I knew there was a good reason I used a thicker head gasket when I rebuilt my motor.

that just goes with the whole "do it right the first time" thing.

 

[BogusSVO]

Black Bullet, I doubt you will find that this mod has been done before, but if you have, cool, let me know what you find out.

 

[Black94DSM]

Kiggly has a regulator you put in the head to only allow a certain psi of oil pressure to the head. This makes sure you have more oil in the pan. So with this mod that you are doing, you are trying to add more oil to the head and its not really necessary.

I would say its just more necessary if you are doing the 7 bolt head on 6 bolt block to make sure you are getting at least the recommended amount to the head.

 

[Sarge32]

Has anyone run into the 2g heads that already have the larger headbolt holes from the factory, not enlarged. Don't laugh, I accidently bolted a 7 bolt head down on my 6 bolt. The head slipped right down on the headstuds. I did not do any of the oil mods stated in this post. Does anyone know if I am going to run into issues?? The head was milled some, but I am using a mitsu mls gasket.

 

[Strm Trpr]

Anyone know the compressed thickness of a Mitsu MLS Head Gasket?
And does anyone know the compressed thickness of an OEM Composite Head Gasket?

JNZ Tuning states that the FelPro Perma Torque Head Gasket has a compressed thickness of .055".

 

[sophat34]

ok, so lets see if i'm thinking correctly here. so, the only oil feed for the head is threw the head stud and most people are increasing the size of their head studs restricting the supply flow. now if we put a tee in the turbo feed line off of the oil filter housing and ran the extra side of the tee in to the oil feed port on the head would this balance out the flow? just some random thoughts here, I'm not crazy about the idea of tearing my head down again.

 

[TSIfreek]

Anyone know the compressed thickness of a Mitsu MLS Head Gasket?
And does anyone know the compressed thickness of an OEM Composite Head Gasket?

JNZ Tuning states that the FelPro Perma Torque Head Gasket has a compressed thickness of .055".

I have read that the compressed thickness of the Mitsu MLS is .060'' and you are correct with the thickness of the felpo perma torque of .055''

ok, so lets see if i'm thinking correctly here. so, the only oil feed for the head is threw the head stud and most people are increasing the size of their head studs restricting the supply flow. now if we put a tee in the turbo feed line off of the oil filter housing and ran the extra side of the tee in to the oil feed port on the head would this balance out the flow? just some random thoughts here, I'm not crazy about the idea of tearing my head down again.

I wouldnt worry about it. Guys have been running unmoded heads for years with no problem. Keep it simple.