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….

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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.

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

I hope you find this useful.

 

[BogusSVO]

If it helps the argument/discussion, I recently installed a 2G 7-bolt head (small ports) on a non-turbo 1G 6-bolt block and didn't touch the head bolt holes.

Car's still on the road, about 8k miles later.

Did you use head bolts? or head studs?

 

[JusMX141]

We re-used the OEM 6-bolt head bolts.

We're not talking about a high-boost application here....it's my buddy's P.O.S. daily driver.

 

[Jeff99GS]

Where do you get this "fact" from? I have personally seen a stretched head bolt out of my 6 bolt. Any head bolt can stretch.

The Factory Service Manual. I suggest you buy a copy. Of course they can stretch, but 6 bolt head bolts are NOT "torque to yield" bolts.






As for the differences in bolts here are some pics. 6 bolt head bolts and 7 bolt head bolts BOTH have a slight taper to them.

I tried to measure them but my caliper is kind of a POS.

6 BOLT- 12mm just below the head, 12mm at the threads, 11.21 at the center of the bolt

 

[BogusSVO]

We re-used the OEM 6-bolt head bolts.

We're not talking about a high-boost application here....it's my buddy's P.O.S. daily driver.

This leads me to wonder what the factory diameter of the 1g bolts are.
If they are undercut bolts with shoulders, I can see the bolts working, but the ARP studs binding up.
Time to do some more reaserch.



Heres a link to what is now the 2nd part of this oil mod.

http://www.dsmtuners.com/forums/cylinder-head-short-block/341885-oil-port-mod-2-4g63t.html

This has been the mosted debated and talked about "how to" I have posted.
I am glad to know some of you will (and already have) put this mod to use.

 

[Jeff99GS]

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

 

[Jeff99GS]

If it helps the argument/discussion, I recently installed a 2G 7-bolt head (small ports) on a non-turbo 1G 6-bolt block and didn't touch the head bolt holes.

Car's still on the road, about 8k miles later.

No lifter tick? how is the oil pressure?

 

[cardot33]

If it helps the argument/discussion, I recently installed a 2G 7-bolt head (small ports) on a non-turbo 1G 6-bolt block and didn't touch the head bolt holes.

Car's still on the road, about 8k miles later.

non-turbo would possibly explain why there's no oil starvation. that much less demand for oil.

 

[rEclipserGST]

No lifter tick? how is the oil pressure?

I would also like to know if the oil pressure is higher. Since there will be more oil flow, but volume and pressure are not the same. Anyone who did this mod notice any difference in higher or lower pressure in the oil??? Dont want to hurt that turbo.

 

[EagleTSIawd]

Wish I knew about this mod 20k miles ago, my turbo oil is fed from the head and it's starting to go out (I can hear the fins hitting when the engine is cold)

I am seriously thinking of doing this mod, would I need to resurface the head or get new studs, H.G. if I do this right? I have ARP bolts and O-ring H.G., my entire head has pretty much about 20k miles on it.

 

[BogusSVO]

if you are careful, with the porting and if everything else is fine with your head, I would not see a reason to have it resurfaced.

If you gan get your hands on an old HG, I would lay that over the head deck to protect it incase the burr skips out on you.

As far as new studs and/or HG, that is up to you, if you have ARP head bolts, and they been working well for you, stay with them, unless you have a mod in the future that will make them the weak point, the same for your HG, if it is a MLS style that is reuseable.

rEclipseGST... to what you have asked, I have one close friend who is big into DSMs, and the whole reason this mod came about, I can say it cured his lifter tic. But to start off the short block was a high mileage, and well wore. We did not take before and after oil pressure readings, and only oil port mod #1 was done. He has appox 10k miles on the rebuild and the oil pressure still looks good and no valve train noise.

 

[empie1]

The Factory Service Manual. I suggest you buy a copy. Of course they can stretch, but 6 bolt head bolts are NOT "torque to yield" bolts.

I have a factory service manual and Im aware of what torque to yield means.That has nothing to do with the fact that you claimed "they dont stretch" and can be reused.I would never reuse a factory headbolt when doing the hg or equivalent. But I guess I just dont like doing things twice.

 

[rEclipserGST]

I have a factory service manual and Im aware of what torque to yield means.That has nothing to do with the fact that you claimed "they dont stretch" and can be reused.I would never reuse a factory headbolt when doing the hg or equivalent. But I guess I just dont like doing things twice.

Lets be the "better man" and end the dicussion about the head bolts. This is a thread dedicated to the Oil Port Mod. Lets conserve space, I've read most of this thread only because I am in the middle of a 14b swap and I'm curious if this will increase the pressure or not. Lets keep this clean. We all drive DSMs so that means we are all friends and have the same goal in life.... keeping our sexy cars running strong

 

[Jeff99GS]

I'm curious if this will increase the pressure or not.

I think if anything these 2 mods will decrease overall oil pressure, but RAISE the flow of oil to the head.
Because if the port/bolt hole is too small the oil will STILL go through, but the larger stud may act as a blockage. That would in fact increase pressure to the other areas of the engine, yet starve the head/HLAs/Cams.

I hear a lot of guys running no Balance shafts saying they still hit 100+ oil psi at 6000 rpm. So I think these 2 mods mentioned earlier would help lower that psi. This is just a guess I have NO evidence to back up these claims. Just a thought.

 

[rEclipserGST]

I think if anything these 2 mods will decrease overall oil pressure, but RAISE the flow of oil to the head.
Because if the port/bolt hole is too small the oil will STILL go through, but the larger stud may act as a blockage. That would in fact increase pressure to the other areas of the engine, yet starve the head/HLAs/Cams.

I hear a lot of guys running no Balance shafts saying they still hit 100+ oil psi at 6000 rpm. So I think these 2 mods mentioned earlier would help lower that psi. This is just a guess I have NO evidence to back up these claims. Just a thought.

Doesnt removing the balance shafts increase the oil pressure?

 

[Mr PopUps]

Im done with this thread.

Ok i AM coming back to this. Reread my posts, i always said that there is no way the oil will flow past the locating pin in the block. Now, after seeing his 'other' mod, it seems that he bored out the bolt hole making it look like the hole that is stepped for the block pin. I am not handing out misinformation, rather due to the pics, i was mislead, and after seeing a pic of a short block realized what was wrong, it was the wrong hole.

 

[95420A]

I will definitely be doing this mod when I get my engine rebuilt. Thanks for the idea.

 

[Jeff99GS]

Doesnt removing the balance shafts increase the oil pressure?

YES it does INCREASE the pressure cause you are BLOCKING the oiling holes off.

Similar to a head with too large of a stud in it. If the hole is partially blocked off then the oil pressure will INCREASE indeed........ EVERYWHERE but in the head. The head will LOSE oil pressure to the point where it obviously causes lifter tick.

So by doing these 2 mods you are relieving a restriction to the head and to the oiling system. That should lower the overall oil pressure. For most of us that is a good thing. I know my Oil pressure is pretty high...and I already ported my oil filter housing.

 

[BogusSVO]

Doesnt removing the balance shafts increase the oil pressure?

That is the theory Jeff99GS has, and seems to be common knowlage, that the Blanceshaft removel will INCREASE oil pressure, I would have to say that would be correct with the blocking off of the oil feed ports to the BS, the oil that would normally flow around the BS and then be dropped back down into the oil pan, has to now find a new place out, therefor, that "extra" oil in the oil passages is now backed up, rasing the oil pressure.

Now, from what I am getting, and the theroy seems sound to me, that with the mod, oil flow will be increased to the head, due to less of a blockage caused by the head bolt/stud.
Inturn with the increased oil flow, the pressurized oil will have other places for the oil to escape which inturn should drop overall oil pressure.

I would like to ask any of you that do perform this mod, if you are able and have the time, check the oil pressure BOTH before the mod is done, and after. Also if you can let me/us know the mesurement of the bolt hole, and if you use a head stug or head bolt and if the head is a 1g or a 2g.

 

[empie1]

I think if anything these 2 mods will decrease overall oil pressure, but RAISE the flow of oil to the head.
Because if the port/bolt hole is too small the oil will STILL go through, but the larger stud may act as a blockage. That would in fact increase pressure to the other areas of the engine, yet starve the head/HLAs/Cams.

I hear a lot of guys running no Balance shafts saying they still hit 100+ oil psi at 6000 rpm. So I think these 2 mods mentioned earlier would help lower that psi. This is just a guess I have NO evidence to back up these claims. Just a thought.

I ported the ofh and still hit 100 psi...Im thinking of doing these as well.Hopefully someone can confirm its worth the hassle.

 

[BogusSVO]

I ported the ofh and still hit 100 psi...Im thinking of doing these as well.Hopefully someone can confirm its worth the hassle.

it seems that this a "new" mod and not many have been"guinie pigs" with the exception of about the 15-20 that I have done in my shop.

empie1.... sounds like your goin to be one of the first, if you decide to go through the "hassel" of pulling your head and trying this mod.

 

[Jeff99GS]

Well one thing is for sure, if you have a milled head and ARP studs you have definitely decreased oil flow to your head. And for guys getting the oil feed for their turbo at the head then you are also decreasing oil flow to the turbo. Maybe NOT much, but it can't hurt to do these 2 mods next time your head is off! I know I will.

 

[rEclipserGST]

Well one thing is for sure, if you have a milled head and ARP studs you have definitely decreased oil flow to your head. And for guys getting the oil feed for their turbo at the head then you are also decreasing oil flow to the turbo. Maybe NOT much, but it can't hurt to do these 2 mods next time your head is off! I know I will.

How would we be decreasing oil flow to the turbo if we are feeding from the head? Feeding from the head is directly under that hole that everyone in the thread is trying to mod up. Please explain. I think you are trying to say We are decreasing flow everywhere else BUT the turbo. Clear that up for us please. I'm sure from the factory everything checked out fine.

 

[BogusSVO]

How would we be decreasing oil flow to the turbo if we are feeding from the head? Feeding from the head is directly under that hole that everyone in the thread is trying to mod up. Please explain. I think you are trying to say We are decreasing flow everywhere else BUT the turbo. Clear that up for us please. I'm sure from the factory everything checked out fine.

The oil flow is decreased without the mod, the head bolt/stud blocks the oil from getting to the oil galley that goes up the side of the head and then feeds the turbo.

This mod helps getting the oil to flow around the stud, and thu the oil trough from block to head.

 

[Jeff99GS]

How would we be decreasing oil flow to the turbo if we are feeding from the head? Feeding from the head is directly under that hole that everyone in the thread is trying to mod up. Please explain. I think you are trying to say We are decreasing flow everywhere else BUT the turbo. Clear that up for us please. I'm sure from the factory everything checked out fine.

I'm saying WITHOUT doing this MOD you may have CUT some oil off from going into the head/turbo. Why do you think the LIFTERS tick?? Cause they are starving for oil. And where are the lifters located? That's right....THE HEAD! Now for example, if you're running a Brand new head that was NEVER milled and stock head bolts then you likely don't have an oil issue to the head. But if you're like most of us running a head that has been resurfaced a few times and ARP studs, then you are effectively reducing the amount of oil flow to the head as shown by Bogus SVO

The oil flow is decreased without the mod, the head bolt/stud blocks the oil from getting to the oil galley that goes up the side of the head and then feeds the turbo.

This mod helps getting the oil to flow around the stud, and thu the oil trough from block to head.

Thanks for explaining it Bogus...these guys don't understand a FU*KING word I type?!?!?! Everyone just wants to argue with me??!?!?!

 

[rEclipserGST]

...Im saying WITHOUT doing this MOD you may have CUT some oil off from going into the head/turbo. Why do you think the LIFTERS tick?? Cause they are starving for oil. And where are the lifters located? That's right....THE HEAD! Now for example, if you're running a Brand new head that was NEVER milled and stock head bolts then you likely don't have an oil issue to the head. But if you're like most of us running a head that has been resurfaced a few times and ARP studs, then you are effectively reducing the amount of oil flow to the head.

If you want to try and experiment...take your sink faucet and turn it on HIGH...NOW JAMB you thumb right in the middle of the faucet opening....what happens?? the water get restricted right?? Or does it flow the same amount of water and go right through your finger?




Thanks for explaining it Bogus...these guys don't understand a FU*KING word I type?!?!?! Everyone just wants to argue with me??!?!?!

..... Thats not a very good explanation with the "thumb in the sink" thing. Haha. But I get what your trying to say. 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.