Drilling 2g head for 6 bolt block

[highboosted98]

I Just wanted too know what size imperial drill bit to use for drilling the head stud holes for my 2g head so that i can bolt it up to my 6 bolt block. Also is there anything elese i should be aware about when drilling the holes.

 

[kiggly]

You don't need to drill the holes in a 2g head to fit M12 studs. Just slide it over the ARP's and bolt it down.

Kevin

 

[highboosted98]

What do you mean by just sliding it over? i`ve researched a few places and everyone was saying that you need to drill the holes bigger. can anyone Else confirm this?
thanks.

 

[kiggly]

By 'slide it over' I just meant it fits. The bolts won't have much clearance, but they definitely fit just fine on the 2 engines I have like this. I had the one 2g head on 3 different blocks while mocking stuff up for the race car. The other street car has normal 1g dsm head bolts on a 6-bolt block with a 2g head and it fit fine as well.

Kevin

 

[highboosted98]

I was just informed by a machist that they need too be drilled bigger because there needs to be clearance for oil.

 

[TargeT]

I was just informed by a machist that they need too be drilled bigger because there needs to be clearance for oil.

clearance for oil? are you serious? lets think about this.... the STUDS that have 80+ ft/lbs of torque on them need to have oil pass, what,,.. under them? around them? did he tell you to replace your muffler bearings too?


My 2g head fit just fine on my 1g block, infact i bought a freaking drill bit set JUST soi could drill out the holes for the larger studds & when i got all ready to drill the bit just slid down into the hole...

 

[highboosted98]

hhmmm i am very confused at this point but that what i`ve been told. How long have a had that 2g head on there for?

 

[fp-green-95tsi]

You do not need to drill the head! Like they said above. I have over 20k on a 2g head 6 bolt bottom end this way.

 

[Burnett03]

I was just informed by a machist that they need too be drilled bigger because there needs to be clearance for oil.

three people have told you you don't need to do it. Incuding a guy that has a 9sec race car. How about you shut your mouth and listen to them.

 

[highboosted98]

First of all not everyone I have spoken to has told me the same thing including a machinst as i have mentioned before who owns and builds dsms. Just because somebody owns/races a 9 sec talon dose not mean their automatically right. How about you stay out of the thread unless you have something to good say.

 

[kiggly]

Oil passes around the passenger side front head bolt to oil the head. This is how the entire head is oiled. There is still enough room around the M12 bolt to supply oil to the head without problems. Verify this in your motor, but you will be fine. I haven't used the straight shank M12 studs with the 2g head and as far as I know, ARP doesn't even sell them anymore. The OEM head bolts are also cut down along the shank to achieve more stretch with less clamp load (which is a desirable thing). This design also frees up more oil flow area around the bolt.

And no, I'm not automatically right and I hope people who read things I post (or anything anybody posts) do a reality check on what is said and don't take anything as gospel for any reason.

Kevin

 

[TargeT]

Oil passes around the passenger side front head bolt to oil the head. This is how the entire head is oiled. There is still enough room around the M12 bolt to supply oil to the head without problems. Verify this in your motor, but you will be fine. I haven't used the straight shank M12 studs with the 2g head and as far as I know, ARP doesn't even sell them anymore. The OEM head bolts are also cut down along the shank to achieve more stretch with less clamp load (which is a desirable thing). This design also frees up more oil flow area around the bolt.

And no, I'm not automatically right and I hope people who read things I post (or anything anybody posts) do a reality check on what is said and don't take anything as gospel for any reason.

Kevin

I'm trying to wrap my head around this,. your saying that oil passes along side the bolt its self (through the hole that the bolt sits in while holding the head to the block) or around the bolt at the base of the head, where it contacts the headgasket/block ?

oil traveling through the "bolt hole" itself seems like a really poor design. I dont recal any thing that indicated oil would flow there or have anywhere to go if it did.

 

[kiggly]

Oil flows along the shank of the bolt. There is an oval-shaped area on the head gasket where the oil comes out of the block. This has a pocketed area in the head that directs the oil around the shank of this bolt. Oil then flows up, between the bolt shank and the bore in the head, then goes into some cross-drilled passages that feed the cam journals and the oil distribution block that feeds the lifters (early 1g's had a pressure regulator here). All these oiling holes are below the bolt head. Remember also, lots of cylinder heads out there have restrictors feeding the entire head that are in the range of 0.040".

Kevin

 

[TargeT]

Ahh, ok i didnt see the holes cross drilled in that particular location, i checked a couple of the others (apparently not the right ones) now i'm a bit parinoid, those bolts fit real tight in there,... though i supose your right, the head doesnt need an extream amount of oil, but when your feeding a turbo from the head.... thats when i get worried

Now i almost want to go back from my oil filter housing feed point,.. even though thats way too much oil, I guess i can just add a few inline restrictors

 

[timloomis]

thats weird.i noticed on my 6 bolt head,the oil feed for the head is between the last 2 head bolts right in front of the tranny.theres an oil passage there from the main oil galley.

 

[TargeT]

thats weird.i noticed on my 6 bolt head,the oil feed for the head is between the last 2 head bolts right in front of the tranny.theres an oil passage there from the main oil galley.

I glanced at the two heads while they were laying upside downside by side & really didnt see any difference (except that the 2g had a MUCH better combustion chamber area & different port shapes etc ) now i almost am tempted to pull my head b4 i start the car just to make sure..

bah, screw it, i'll do the cas rewire tonight and hope for the best

 

[timloomis]

the 2g is much smaller then the 1g head.smaller intake and exhaust ports.plus they use smaller lift cams.but the bolts your using should be ok.many people have done head swaps with no drilling at all.

 

[kubix]

when i did my swap with a 2g head and 1gblock, my machinist drilled the block to 12mm as it was 11mm from what i was told. or it could be the other way i forgot. but i do know they drilled.

 

[TargeT]

when i did my swap with a 2g head and 1gblock, my machinist drilled the block to 12mm as it was 11mm from what i was told. or it could be the other way i forgot. but i do know they drilled.

I purchased a 12mm DRILL BIT and it slid right into the bolt holes.. no drilling needed. maybe different yeard had different sizes?! mines a 99


*edit, i ment drill bit, not bolt

 

[Big Woo]

I have seen this several times before, and seen it go both ways. Sometimes you will not need to drill out the holes, sometimes you will.

There are many factors that need to be considered here, for example here are a few.
1: style and version of head bolt or stud being used
2: straightness and perpendicularity of the head studs when installed into the block. ( just because the studs are installed hand tight, and seated does not mean that they are perpendicular to the deck surface. After they are installed try checking them with a machinists square.)
3: wether or not the cylinder head has been warped in the past, and how it was resurfaced. (some shops will just resurface the head based solely on removing the minimum amount of material, this can result in a perpendicularity problem between the head bolt holes, and the deck surface on two axises)
4: The shanks of the head bolts or studs should not bind or drag within their respective cylinder head holes at all. If they do then it will effect the torque or stretch needed to attain the proper clamping load.

 

[eclipse08]

I also had to have my 2g head drilled out to 12mm to fit on the six bolt block. When I tried to just slide the ARP head studs (1g) in my 2g head they wouldn't even go in. So from the sounds of it you just need to measure the clearances for your specific setup and then do what you think should work, after all you're the one that's driving the car.

 

[jltcat]

the head will fit. No oil in studs so dont worry about oil flow. Only have to drill hole if they are extremely tight meaning that the head needs the assistance of a hammer to go on because of heat expansion. But that shouldn't be the case, mitsu does a good job with keeping their parts to blueprint specs.

 

[highboosted98]

Ok i just installed the head on my 2g head on my 6 bolt block. I am using arp studs and have not drilled the holes. It was tight and needed a mallet too tap it down. Should I consider removing the head for drilling? or just leave it. I`m just wondering what will happen when the engine warms up being a tight fit with heat expansion. One guy says oil travels around the head stud the other says the opposite. For you guy who have been using the stock size 2g head on 6 bolt block are you using arp head studs?

 

[TargeT]

maybe its just an ARP headstud thing, i used stock 1g headstuds, fit fine.