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]

well to help remove some of the restriction where that entry point is to the oil galley from the boly hole, I did some measuering and found out some intresting things....

http://www.dsmtuners.com/forums/cyl...41885-oil-port-mod-2-4g63t.html#post151916894


For your guys that do not belive that is the block to head oil trough, well ok your intitled to your opinions.

I still do this mod TO ALL the 4G63 heads that come through my shop. I have yet to have any of them come back for oiling issues/lifter tick.

 

[Jeff99GS]

well to help remove some of the restriction where that entry point is to the oil galley from the boly hole, I did some measuering and found out some intresting things....

http://www.dsmtuners.com/forums/cyl...41885-oil-port-mod-2-4g63t.html#post151916894


For your guys that do not belive that is the block to head oil trough, well ok your intitled to your opinions.

I still do this mod TO ALL the 4G63 heads that come through my shop. I have yet to have any of them come back for oiling issues/lifter tick.

I bet these 2 mods would also help some guys that removed their balance shafts with the HIGH OIL PRESSURE problem. Some guys still have High pressure even after they port the oil filter housing.

And this is also a great reason why not to put those 2g heads on a 6 bolt block with out getting the head bolt holes bored out. I have heard some guys saying they stuff the 12mm bolts in the 11mm holes of the 2g head. I bet doing that cuts MOST of the oil off from your head.

 

[Strm Trpr]

I really don't think it's possible to put a 2g head on a 6-bolt block without enlarging the holes for the 12mm studs to pass thru.

I have a spare 2g virgin head that I'll take a look at and measure how deep the relief is
and I'll also check to see if that hole is actually larger than the other thru holes for the studs to pass thru.
Beveling the inner surf like the OP mentioned is an excellent mod, and I bet even the most experienced guys over looked this mod, and it was proven in a few posts.

 

[RipperXX]

Funny how this has panned out. More so as I have known it's common for some of the top V8 engine builders do this. But I kind of always thought that was because there castings were so rough and well crappy.


+1 to OP










Hopefully I will recall this thread when the time comes to pull my engine out for a rebuild.

 

[empie1]

I have heard some guys saying they stuff the 12mm bolts in the 11mm holes of the 2g head. I bet doing that cuts MOST of the oil off from your head.

No, this is not true at all.
Funny how everyone turned on the guy who simply made a post trying to help us out... at the idiots that talked smack when they really had no idea what they were talking about
Good info here.

 

[Rob10_99]

I need someone who has their head off atm to put about 10qt's of oil in the pan, and spin the oil pump with a drill until its empty, I'll wait for it to turn up on youtube.
My bet it would be like the sludge commercials, it would be great.

Yes, that is the only oil passage, end of story.

 

[Jeff99GS]

No, this is not true at all.
Funny how everyone turned on the guy who simply made a post trying to help us out... at the idiots that talked smack when they really had no idea what they were talking about
Good info here.

Um do you know how to read boss?? Im agreeing with the guy?!?! We figured out that was the oil hole and BOLT hole WAYYY back in post #9 bro. READ the THREAD. Im not sure who all these dudes are saying NO OIL could flow around the bolt???

What I was saying is If you DONT bore the BOLT/OIL hole like the op states in the oil port #2 thread, you could starv the Head for oil. Wow you lads need to take reading comprehension classes or something....I never TuRNED on the guy?!?!?! I have been saying it was a good Idea since post #9

Why are you quoting what I said about guys using 6 bolt head bolts on a 2g head?? What does that have to do with anything you said?!?! Im so confused why you' think I am against this oil porting mod??? Are you even reading my posts?!?!?!

 

[empie1]

Hahahahaaa hells yeah MR T.

I just can't figure out why he quoted me of all people?? I mean what the hell did I say that was negative towards this mod??

Take it easy "boss".I quoted you about your statement over the 2g head.Clearly since you didn't say anything about the op, than my statement wouldn't pertain to you would it?

 

[tkelly27]

Blingstatus on here starved his 2g head of oil by using the 1g studs with his 6 bolt block. He even drilled out the holes, just not enough, they need the proper clearance.

 

[Korndogg]

Huh, this is very interesting. Good piece of knowledge here. Thank you OP.

Also, for what it's worth, we had a 6-bolt motor with ARPs in it. One stock 2G head would (barely) slide over the studs. One didn't have a chance in hell and had to be drilled. Same block, we were just deciding which head to use...

Kind of hit or miss on that, I think.

 

[99gst_racer]

Ever wonder how the lifters could shoot oil 5ft in the air?

That oil is not shooting up from the HLAs.
What good is a lifter shooting oil directly at the VC baffling?

 

[BogusSVO]

Huh, this is very interesting. Good piece of knowledge here. Thank you OP.

Also, for what it's worth, we had a 6-bolt motor with ARPs in it. One stock 2G head would (barely) slide over the studs. One didn't have a chance in hell and had to be drilled. Same block, we were just deciding which head to use...

Kind of hit or miss on that, I think.

well it sounds like both 2g heads need to have the head bolt holes reamed for the for the 1g studs.

From what I have come to understand is, the 1g heads use a 12mm headbolt/stud and the 2g use a 11mm head bolt/stud.

I am trying to get my hands on a few 1g heads so I can measure the the factory size of the 1g head bolt holes.

 

[empie1]

From what I have come to understand is, the 1g heads use a 12mm headbolt/stud and the 2g use a 11mm head bolt/stud.

Correct.

 

[Jeff99GS]

I believe the difference is whether its a 6 bolt engine or a 7 bolt engine.

The 6 bolt engines had the 12mm head bolts and the 7bolt engine had the 11mm bolts.
That is why I was saying I have heard guys SAY that they fit the 12mm bolts in the 7 bolt head without boring the holes. So my point was that by doing that you may also be cutting off most if NOT all of your oil to the head.

So Basically for those who don't understand me well, I am saying this Oil port MOD is a GREAT IDEA! And you should NEVER EVER try to put 12mm bolts in the 7bolt head without reaming the holes and enlarging the one that oil flows through. There is MEANT to be a gap around the bolts. The Dowel pins are what center the head on the block. NOT the bolts.

6 Bolt 4g63's were made from 89-92.5ish 12mm bolt

7 Bolt 4g63's were made from 92.5-99 11mm bolt

 

[race_me89]

my head is already off I am def getting this done before the whole assembly process starts

 

[deflator]

Correct.

Close, the 6 bolts have headstuds don't they, while the 7s have headbolts.

OP: I am going to do this, but the only porting bit I have that size is carbide. Bad idea on alum? I know I'll need to keep the bit cool to prevent it from binding the alum. to it.

 

[Rob10_99]

All dsm's(1g/6bolt) use headbolts. they are a 10mm allen head
Correct about the 11mm/12mm being 7bolt/6bolt difference.

 

[BogusSVO]

Close, the 6 bolts have headstuds don't they, while the 7s have headbolts.

OP: I am going to do this, but the only porting bit I have that size is carbide. Bad idea on alum? I know I'll need to keep the bit cool to prevent it from binding the alum. to it.

I use a single cut bur which is for non-ferrous metals, if all you have is a doubble cut bur, you can get away with using it, just be very carefull, and keeps lots of oil on the burr.
also you may want to put the old HG on the surface, so if the burr skips off it will hit the old HG and not the head itself.

Not much has to be taken off, appox .030 - .040 in depth should do it. the radii into the head bolt hole is where most of the grinding will be done.

 

[Jafro]

Wow, this thread went all over the place. Good info BogusSVO. I'm sure the machine shop that worked my head did nothing of the sort. Had lifter tap, but so-called "3g" lifters fixed it.

I have a 6-bolt shortblock and a 7-bolt head, disassembled, as well as a set of digital calipers to measure with. Would measurements of any of those parts help? I don't currently have a 6-bolt head that isn't bolted to anything, but can probably find one at a friend's house.

I would also be curious to see if there is much difference in the threads of ARP studs vs. factory studs' threads. A deeper cut thread or variance in the OD would certainly change the characteristics of the oil flow.

 

[99gst_racer]

I would also be curious to see if there is much difference in the threads of ARP studs vs. factory studs' threads. A deeper cut thread or variance in the OD would certainly change the characteristics of the oil flow.

The oil doesn't flow through/around/near the threaded portion of the studs/bolts. It flows around the necked-down shank of the stud/bolt.

 

[BogusSVO]

from what I looked at as far as the studs and bolts go, the ARP studs should be fully in the block, maybe one or 2 above the surface, but the shank is smooth,
What I would like to find out is if the shank of the factory head bolt is necked down/under cut then flares to the threads with a stepor shoulder built into the underside of the bolt head.

 

[Jeff99GS]

What I would like to find out is if the shank of the factory head bolt is necked down/under cut then flares to the threads with a stepor shoulder built into the underside of the bolt head.

I can run up to my shop in a few minutes and take some comparison pics and measure them where they neck down.

Close, the 6 bolts have headstuds don't they, while the 7s have headbolts.
.

NO, none of the 4g63 DSM engines have studs. However the 6 bolt head BOLTS are REUSABLE indefinitely unlike the 7 bolt head bolts which are "torque to yield" Meaning they stretch and need replaced every time you remove them.

 

[Jafro]

If the 7-bolt's head bolts neck down... the ARP 11's don't. The bolt diameter is the same as the thread diameters. Here's a horrible photo...

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but you're right... the threads aren't continuous throughout the length of the stud. Had forgotten about this. I have the old head bolts in a box at home and will check 'em out.

I'm just glad my turbo's oil feed is from the filter housing rather than the head. My CH was resurfaced and I'm sure the machine shop didn't tweak that passage.

 

[empie1]

Close, the 6 bolts have headstuds don't they, while the 7s have headbolts.

OP: I am going to do this, but the only porting bit I have that size is carbide. Bad idea on alum? I know I'll need to keep the bit cool to prevent it from binding the alum. to it.

Wrong.They all use bolts.

However the 6 bolt head BOLTS are REUSABLE indefinitely unlike the 7 bolt head bolts which are "torque to yield" Meaning they stretch and need replaced every time you remove them.

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.

 

[JusMX141]

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.