Head ID question 1.6 vs. 2.0 DOHC

[iceman69510]

I have a DOHC that I got from someone, and I was told it was from a Talon. It has been gone through because it has some new valves in it. He told me it was "rebuilt". Question I have is this: I have never noticed this before, but it has "1.6" essentially scribed (looks like light welding) on the front of the head. Would this be a 4G61 head? How are they different from a 2.0 head? Head volume? Valve sizes? Cams? I was planning to use this on the rebuild for my '92, but now not so sure. Maybe it was a core at some rebuilder and it has been made into a 2.0.

I can post a pic if someone needs to see this.

Thanks.

 

Did it come with cam's? , I could also check real quick but I'm pretty sure valve size would be differernt in the 1.6, other than that cam lobe size would be a dead giveaway

 

[iceman69510]

It did come with cams. Is the lift different, or base circle? I can check them against another head I have here.

 

[89Mirageman]

Are the intake ports the same as 2.0 ports? If so that rules out it being a 4G61 head (from a Mirage) because the ports are much smaller on those. If I had to guess, it came from a 92-95 Hyundai Elantra. Even though the head was marked as 1.6L, they were available on the 1.6 and 1.8's. The CC is smaller on these and they will slightly raise the compression when you bolt one on a 4G63. Its pretty much identical to the 1.6 Mirage head but it has the larger intake ports. Valves are all the same on the 1.6, 1.8 and 2.0 heads. Cams are all different. Here is a good post over on 4G61t.org with some pics of the differences on page 3.

click

 

[iceman69510]

Revival time.

I have not messed with this head for months, but did yesterday. It definitely says 1.6 L on both ends, but looking at the head specs in the Mitsubishi Engine manual, nothing I could find in the specs appears different between the 1.6 and a 2.0 l heads other than the camshafts. It say in the book they are marked, and I did find a marking on the intake camshaft before the final cam journal bearing that says "D", which according to the book should a 2.0 turbo cam ( but it does not clarify if the D is the exhaust or intake designation). The exhaust cam I can find no similar letter in that location. Is that where they are marked? I have another head I have to look at but will do that tomorrow.

Prior comments indicate people familiar with these heads believe there are differences such as port size or valve size, but the Mitsu engine manual does not reveal this.

 

[toybreaker]

Do you have a 2.0 head gasket you could lay on the 1.6 head to see where the chamber casting lines up relative to the 2.0 head?

I vaguely remember the chamber size was different...

 

[brisvr4]

1.6 chamber should be 43cc vs 47cc for the 2l head from memory.

 

[mitsuturbo]

There's a big thread about this over on the Link forum.
Some have been comparing the 1.6, the Hyundai, and the 4g63 heads. Apparently one is 4cc smaller, as mentioned above. This increases compression.
Kind of like the honda guys with the b16/b18 thing.

WTF. It took us this long to figure it out?!

 

[mountaineerjeff]

this info has been floating around since before I had ever owned a mitsubishi. Its one of the first things i found out. The info is out there if you look. People just dont always apply the ideas until 1000 other people have good results.most of the discussions on head choice/ head swaps always end with some ass saying well so and so ran 8s and made 1000 hp on a standard head so why swap?

I always think that that is the worst answer you can give when trying to find new ideas. but back on subject, yes this is old news, and yes there is a chamber difference which would increase CR. I do know that the 4g61 has a much smaller bore, which may effect the flow on the 4g63. I also know that swapping a 4g63 head on a 4g61 is a HUGE improvement, as I have personally done it. now whether that's simply because the cams are different, or if there is an actual design change I dont know.

 

[FlyingEagle]

Cams are interchangeable between the 4g61/67/63/64 heads being that they are also, all from this generation of motor.

Here is what I have found from alot of overseas threads, and local stuff from North America as well.

click

Most of that information was gleaned for reputable members who had very successful builds or just a good knowledge about these heads.
Just be aware that the thread is open to interpretation and if you find any differences here, just let me know.
4g61 heads have smaller CC, same valves, smaller intake port sizes, large exhaust ports like 1G heads.
4g67 heads have smaller CC, same valves, larger intake port sizes, large exhaust ports like 1G heads.

43cc vc 47 cc. This would probably explain the difference in compression ratios between the 4g63t and 4g61t, considering the piston and deck heights leave the pistons at exactly the same height in their respective bores. If using a 4g61 head, it would stand to reason that you have to use the 4g63 head gasket option.
For anyone putting on a 4g61t head gasket kit from Fel-Pro, it is made to accomodate piston sizes up to the 4g64 sizing and IIRC, maybe an overbore. Not sure if the OEM gasket has any extra girth to accomodate an overbore. That is off topic, but when people are mixing and matching parts, it helps to know about a few hurdles depending up on their available options.

 

[mountaineerjeff]

^ good point on the head gaskets. this is the reason I had to part with my mirage build. the previous owner put a 61 bore size head gasket so it did not seal against the 63 head, causing the gasket to blow out and leave me stranded

 

[turboaddict]

Ok, I have a usdm 4g61t and jdm 4g61t, the usdm have smaller ports that are smaller than a 2g even and more rounded with the smaller 43cc chamber, the jdm has 1gsize intake ports with the 43cc chamber, but my jdm 4g61t even though having the larger ports in the head, still has a cyclone singlerunner intake manifold with the usdm size more rounded runners in it. the cams in both 4g61t motors were small and I picked up a good bit of power with gvr4 stock cams. Valves are all the same, also the jdm 4g61t has a 1.8 cast into it where he usdm has 1.6. if you look at the intake ports you will see a HUGE difference and know right away what you have. I also know that my stock composit gasket was sized to the 4g61t pistons (smaller cyclinder holes for the 82.3mm bore pistons) I also know that if torqued correctly that mine never leaked even running 40psi on e85.

 

[mountaineerjeff]

so you said usdm 4g61 and jdm 4g61t, is there a difference between the usdm 4g61 and usdm 4g61t? because the difference might be the fact of whether or not it was turbo not on its location.

 

[iceman69510]

Yesterday I managed to get my 2.0 head pulled for comparison purposes. The intake and exhaust ports and valve sizes are all the same on both heads. The chamber size is definitely different.

So, I have to conclude that this head marked 1.6 L is in fact exactly that.

Now to decide if the compression increase will be a problem or not. What is the piston dish volume on a stock 4G63T?

 

[mountaineerjeff]

if anything it should help, instead of hinder you. without any actual equation, it should only raise your CR by .5 at tops. you can run the 4g6x motor on 9.5:1 CR with pump gas and a good tune. the higher the CR the more power, and better spool. the head swap is a common way to increase CR inexpensively

 

[mitsuturbo]

Quoting iceman69510:
Yesterday I managed to get my 2.0 head pulled for comparison purposes. The intake and exhaust ports and valve sizes are all the same on both heads. The chamber size is definitely different.

So, I have to conclude that this head marked 1.6 L is in fact exactly that.

Now to decide if the compression increase will be a problem or not. What is the piston dish volume on a stock 4G63T?



I'm not sure about stock 1g pistons, but i believe 2g pistons dish is 13cc

(correction, found this on google: The 1g piston dish + headgasket volume is 26.42cc)

 

[FlyingEagle]

So, this would mean that you have a 1.6L head that was ported to match 1G head port sizes by the sounds of it. Stock 1.6L turbo intakes had small runners and heads had small intake port sizes to compliment the high revving nature of the 1.6L (bore/stroke/rod). Wish I could add more about the dish on top of those pistons plus head gasket volume.

 

[turboaddict]

Quoting mountaineerjeff:
so you said usdm 4g61 and jdm 4g61t, is there a difference between the usdm 4g61 and usdm 4g61t? because the difference might be the fact of whether or not it was turbo not on its location.



sorry for taking so long, anyway yes my usdm has smaller intake ports (roundish) and my stock jdm4g61 had the same size as my 1g this was unported as you could se the casting flash,marks and whatnot. the exhaust is the same on the ports in the head, the exhaust manifold is a joke.

 

[mitsuturbo]

I saw a 1.6 head in the junkyard today. Looks like it's never been molested, and the VC and hood is still on the car.

Anybody interested for a decent price? I could go pull it.

 

[iceman69510]

Quoting FlyingEagle:
So, this would mean that you have a 1.6L head that was ported to match 1G head port sizes by the sounds of it. Stock 1.6L turbo intakes had small runners and heads had small intake port sizes to compliment the high revving nature of the 1.6L (bore/stroke/rod). Wish I could add more about the dish on top of those pistons plus head gasket volume.



Doesn't look ported at all. Surface finish looks as-cast, so maybe it is one of the Hyundai heads.