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.

 

[woooop]

How do you know that the pressure isnt to high with a stock guage, you dont ! Get a guage and come back.

 

[snooopy365]

I`m not getting why my head/cams are still fine.
If I understand it right my head should be low on oil and also pressure (in the head).

I used 12mm APR studs, 6bolt block, and 7bolt head with everything stock.
It is a very tight fit.
But I`m running this combo about 10.000 miles now without any problem?
Fedding a 16G evo3 turbo directly from the head.

Turbo is also in great shape.
Car had a crash, so now I wanted to port the oil relife valve because oil is leaking everywhere. (high oilpressure because no BS)
WILL this kill my head? because pressure will drop and the oilport to the head is way to small? I really have no intention in pulling the head again.

Idea was to just port the oil relive valve, throw some FP2 cams in the head and get the engine into my second DSM.
It would suck to get damage the engine after all, but also would suck to pull the head again.

 

[BogusSVO]

best thing I can say to do, is T into the turbo oil feed port and install (even just for temp) whet the oil pressure is there.

with the BSE done, and the rasie in oil pressure that happens, you may be forcing more oil thu, but at lower RPM the flow may be low also.

 

[1bad4g]

i did this mod....and i have to admit. and so will my bro and several friends.

THIS IS A GREAT MOD. i have never heard a more silent valvetrain in a 4g63.

yes iam considered a rookie on the forms here. but iam no stranger to high HP DSM'S. i have ouned my first 4g63 sence 2000.

this mod. with some new 3-g lifters and good oil. made a world of differance
i will for sure be looking for more bogusSVO. tech write ups.

 

[modifyer]

Perfect timing for me, I am building a 6 bolt right now and just picked up all the parts from the machine shop yesterday. Thanks SVO

 

[iceman21221]

This mod was done to a fresh head. Cut maybe one time. Since i have installed this head im having trouble with oil being pushed out the oil cap. I have tried 3 new caps and seals with no luck. Even tried to install 2 new seals on one cap. still no luck.

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[BogusSVO]

Iceman, sonds like a blowby or PCV problem.

This mod should in no way effect the way your oiler filler cap seals.

 

[Mitsuturbo]

Awesome info. I can't believe we didn't notice this and do something about it before. It's so dang simple!

I'm getting my head and block back from the machine shop pretty soon. Before i assemble it, i intend to clearance this area out a bit as well.

Thank you for bringing this to our attention and sharing!

 

[jimbob_843]

Im in the process of doing frankentein build and im deffinately going to do the mod. Im getting oil squirters installed and of course a bse. Do you think if i do this mod it will rob too much oil from the crank because of the squirters and all? Thanks

 

[ontario AWD]

Thanks for providing excellent info BogusSvo.My already cut head is going to the machine shop tomorrow so i am very glad i found this.

 

[chronister76]

dang!i wish of read this 3 weeks ago i just had my head put back on from napa and waiting for my ecu and ill be boosting again!

 

[gsxeclipse97]

I'm about to reinstall a 2g head on a 7 bolt block using ARP studs. I have removed the BS also, but it seems that all of you are doing this mod to a 6 bolt head. My question is can it be done to 7 bolt heads? I have 3g lifters in there also.

 

[Jafro]

Exact same principles apply. Only difference would be the diameters of the head stud holes. The 6-bolt uses 1mm bigger studs than a 7-bolt does. Aside from that, all the coolant and oil return passages line up between the head and the block, and they all work the same.

 

[BogusSVO]

this oil mod will work for both the 1g and 2g head... it has more to do with milling the head/head thickness and the cross over port from block to head.

if proper oil flow is not mantained, then it will not matter if you have 3g lifters or not.

 

[66ss]

feeding from the oil filter housing is still the best spot

 

[BogusSVO]

feeding from the oil filter housing is still the best spot

yes to a point, but if you do not have the proper sized restrictor from the OFH then you ach over presserize the turbo and blow the oil seals.

 

[Ghostcrafter]

Wow ... I can't even describe how happy I am, that I just found this thread. I have the engine out of my '92 right now, and this is something I can do while I'm waiting for all my rebuild parts to show up.

That is, as soon as I find a non-cracked 1g head for my 6-bolt. =(

 

[dented_coffee]

I have a brand new oem 6-bolt head with under 500 miles on it laying arround and I'm in the process of porting it out to a mirror finish on the exhaust side and leaving a bit of a ruff port work on the intake side for my daily driver. I will be sending it out for a flushing and hot tanking because I did a few coolant port mods on it, de-casting flashed the holes and passages, and I just finished the OIL PORT MOD #1 to it.

I have a 7-bolt 1G block in my talon right now and I'm gonna be putting a 6-bolt 1G head on it. I think the extra clearances of the 6-bolt head stud hole in the head beeing used with a 7-bolt head stud will make it to where I don't have to reem out the hole for oil clearances.

BogusSVO, I will be posting before and after oil pressures for everyone to see at both the OFH and the head. My engine in my talon right now is still running perfect and it's a freshly built engine with all OEM parts and it still has the BS's so It's as close to perfect for OEM new readings that your gonna get in a 1g DSM. It has under 10k miles on the engine so it's fully broke in, rings are fully seated and not burning oil at all.

I would like to go with ARP studs but can't find substancial proof that the 1g's 6-bolt and 7-bolt have different oem head bolts. I have been told that they are exactally the same and that for my 1g 7-bolt I should buy 6-bolt studs. I know it's been argued but I have yet to see proof that they are the same or different.

CAN ANYONE PLEASE POST SUBSTANCIAL PROOF THAT THEY ARE DIFFERENT?
^ no 2g junk im talking all about 1g factory head studs. i know the 2g block has alot of differances from the 1g block and the 11mm studs might just be a 2g 7-bolt thing.

 

[Strm Trpr]

6-bolt block = 12mm Head Studs
7-bolt block = 11mm Head Studs

All 7-bolt blocks use a 11mm Head Stud, period, end of discussion!

Can someone with CAPS put this to bed for this guy.
I'm on a 64bit PC right now, so CAPS is not an option.

On another note, I was perusing the 2011 ARP Fasteners Catalog and noticed the following:

OEM 6-bolt rods use a 9mm rod bolt.
OEM 7-bolt rods use a 8mm rod bolt.

Although it's only 1mm difference, this is enough of a difference to give the 6-bolt bottom-end higher power handling capabilities, stock 6-bolt vs stock 7-bolt.

Most 6-bolt and 7-bolt aftermarket rods, run 3/8" ARP 2000 series rod bolt.
3/8" is 9.5mm so they are larger than stock and equal between 6 and 7-bolt rods.

There are a few rod manufacturer's that run a 7/16" ARP 2000 series rod bolt; Howard's Rods thru MAPerformance, and RACE Eng. has their own 4g63 Billet Rod that utilizes a 7/16" rod bolt.

 

[pneumo]

up to April 1992 uses part # MD121887 12x84mm,
from May 1992 to 1999 uses part #MD191470 11x97mm.
It's no coincidence that they changed from 6 bolt blocks to 7 bolt at the same time.

The size of the headstuds depends on the block. If you have a 7 bolt block, use 11mm studs.

 

[Strm Trpr]

up to April 1992 uses part # MD121887 12x84mm,
from May 1992 to 1999 uses part #MD191470 11x97mm.
It's no coincidence that they changed from 6 bolt blocks to 7 bolt at the same time.

The size of the headstuds depends on the block. If you have a 7 bolt block, use 11mm studs.

Thank you sir!
I forgot to use CAPS when I got home this evening.

 

[colt2096]

Thanks for this great info, i am going to rebuild the engine of my Eagle Talon TSI AWD 91 and i will make this mood before install the head, thanks

 

[rtincher22085]

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.

Since these stock 6 bolt head bolts are ok, I never compared my after market top lines to the stockers, so people may think I'm crazy for saying this but, why not notch the head bolt 1mm around where the oil comes through the block to the head. or 2mm either way you will be doing the sam
e thing if you have persay a 6bolt head and block. I just rebuilt my engine with BS elimination and my block was decked not my head and it sounds like the lifters are starved. I have topline head bolts should i change out one of my topline with my stockers in that hole to see my results? I don't wanna pull the head it has 200 miles on it.

 

[GIRman67]

Because by doing so you effectively make that headstud a weak point in the head assembly. It's strength is no longer going to be the same. ARP specifically says to torque to 75% of it's yield strength, which 1g headstuds is about 90ft/lbs. When you cut pieces off, it cuts part of the strength of the stud. Milling into the actual bolt hole keeps your stud as strong while giving proper flow at the same time, because you are not drilling all the way just a short distance starting at the bottom of the head.

 

[rtincher22085]

Thanks for the tips guys, my problem doesn't lie here I'm getting plenty oil to the head its rod knock unfortunetly. Whats the best way to figure out which cylinder? Drop the pan and wiggle?