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.

 

[loco4G63]

I just to get my facts/ ideas right. I am building a 6 bolt with a 2g head. I want my head holes drilled for a 12mm stud which means drill them out with a 12mm bit? I am gonna ask for the oil port to beveled out as well as drilled .500 up to .250, is this correct? Should I drill the oil galley straight thru at .500? I hope you guys steer me in the right direction on this. Thanks in advance for any input.

 

[pneumo]

I just to get my facts/ ideas right. I am building a 6 bolt with a 2g head. I want my head holes drilled for a 12mm stud which means drill them out with a 12mm bit? I am gonna ask for the oil port to beveled out as well as drilled .500 up to .250, is this correct? Should I drill the oil galley straight thru at .500? I hope you guys steer me in the right direction on this. Thanks in advance for any input.

Use a 1/2" drill bit on all the head stud holes. The head studs for a 6 bolt are 12mm thick, so you need a little room around it so the head slides onto the block freely.

 

[Purple_Demon]

Edit.


Never mind. I missed an entire page in this thread.

 

[BogusSVO]

Since I have posted this almist 2.5 years ago, I would like to know how many have done it, and what results they have noticed.

 

[kchaazz]

That before an after pic shows the INCORRECT way to port an OFH.. Holy crap people do not expose the sides of the piston like that

Indeed, it does and Im curious to know who did that!! Not my pics, just some I found to post haha. I only enlarged the hole diameter on my own housing by approximately .0625" overall, and my oil pressure has always been within normal range, vs. on the high side before I ported the hole. This is on a block without oil squirters and of course the bse.

 

[chewrawka4g63]

so just had my head rebuilt, among other upgrades, aloso had ticking problem before so I bought the revised lifters, sure enough stumbled on to this thread late,...........head still tick almost sounds worse, so getting ready to pull the head off next couple of weeks, also getting new tensioner and head studs. I will post my results when she's up again.

the car is my daily, by NOT doing this mod, am I in risk of my head failing?? hope thos resolves my issue....

 

[BogusSVO]

All this mod is for is restoring oil flow to the head.

Unless the head is extreamley thin, as in the trough is about milled gone.

 

[chewrawka4g63]

so heres a pic of my head, If you look at the corner where the mod is going to be performed, seems a bit shallow. Is it possible for this lack of oil flow to cause high oil consumption?

 

[BogusSVO]

No poor oil flow will not cause oil consumption.

 

[kchaazz]

If youre losing oil and its not leaking out of the motor, its not too difficult to find where its being burned. Take the O2 housing off the turbo- if the turbine is white, the oil is bypassing the oil seal in the center section. Take off your exhaust manifold- if youre losing oil through guides/ valve stem seals- your valves will be wet. If its rings, the valves shouldnt be wet cause the oil is mostly being burned in the combustion chamber before exiting the exhaust valves.

 

[chewrawka4g63]

Been doing my homework as much as possible, just had turbo rebuilt ,head rebuilt, piston rings have no more than 10k on them, valve stems were replaced....

was fixing the leak from my oil return line, noticed that my oil feeds turbo from ofh, I also have my balance shaft removed. now I know (after emmence reading) that I should feed oil from the head, plus do the ofh relief port mod to get my pressure in check. as I'm doing this mod as well, seems ove completely looked over this issue,..... ignorance, gotta love it.

 

[kchaazz]

Why not attach an oil pressure gauge to check your oil pressure, if youre curious about where its really at? Itll possibly save you some work. Also, if youre still using the 16G in your profile, its actually recommended to feed MHI turbos from the oil filter housing by Forced Performance themselves, so you should be fine there. Stock boost levels on 1G cars may have been ok for feeding the turbo from the head, but cranking the boost spins the turbo far faster than it did from the factory, which requires more oil to keep the turbo happy and if you notice, the 2G cars all fed the turbo from the OFH. While this could be considered an apples to oranges comparison because the T25 on a 2G is a Garret unit vs the 14B being an MHI unit on manual 1G cars, I trust FP's judgment on this.

 

[chewrawka4g63]

I've read the opposite, the member justmx (or something) says to feed from the head, or install a restrictor. I feel flowing from the head is better than restricting anything. he's a known member and says the mhi were factory installed with oil fed from the head.

 

[rhtwng2]

I had ran my water supply dry???? I know how does someone drive their car for 12 yrs and then take it in for upgrades and all of a sudden the very next day warp the head. They milled the head and the mechanic pointed out that they didn't mill the oil passage. Man the machine shop copped a major attitude when I took block/head and wanted them to machine matching oil passages...I do know that I feel better with this mod done...

 

[kchaazz]

I know who Jusmx is, and hes highly respected for his knowledge, and I dont doubt him one bit. I did forget to mention that youre supposed to use a restrictor when feeding from the OFH Ive got the OFH feed setup, mostly cause I happen to work at a place where Ive got all the crap to make the setup right here at work, and my boss just gives it to me usually...

 

[Boomdeeze]

I decided to do this mod since I am replacing my hg. I had higher oil pressure and some lifter tick even after porting the relief on the ofh. I know I did touch the edge with the bit but the gasket doesnt come close to that part so it will not affect sealing. Here are a couple pics, did I go enough and how does it look?

 

[dsm-junkie]

This is my oil port mod!! Sorry for the crappy pic!

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[turbotalon1g]

This is my oil port mod!! Sorry for the crappy pic!

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That looks awesome, what did you use?

 

[dsm-junkie]

That looks awesome, what did you use?

I actually had my machine shop do it when I got my head stud holes drilled out!

 

[BogusSVO]

Boomdeez.... looks ok, but champher it a touch more where it makes the turn into the HB hole.

Junkie... that is about the prettiest one I have seen!

 

[Boomdeeze]

Ya yours looks really clean, I did mine with a dremel which is why it isn't as smooth but should still get the job done.

Bogus- do you mean round it off more or go further down?

 

[dsm-junkie]

Junkie... that is about the prettiest one I have seen!

Thank you sir!!!

Ya yours looks really clean, I did mine with a dremel which is why it isn't as smooth but should still get the job done.

Thanks alot!!!

 

[Boomdeeze]

Ok I rounded it off a little more and gave her a small clean up, look any better?

 

[BogusSVO]

That sould work just fine, not as pretty as Junkies, but will do!

 

[Boomdeeze]

Ok let's not compare to junkies, his was done by a machine shop!