1800cc Twin Cam head

Junkers · Post by **Junkers** » Wed Feb 04, 2009 2:36 pm

Hey fellas and fellettes (hah who am I kidding)

Bought a 1800cc galant today with a twin cam engine 4g62, wondering whether I can use the head off this for my twin cam conversion? Got it for the right price so thought I would take a gamble. Not fussed if the ports are smaller, just curious about the holes lining up and the cc of the combustion chamber.

Cheers

FST4RD · Post by **FST4RD** » Wed Feb 04, 2009 2:41 pm

I think I read on either Msport or NZmmc that they do... but not 100%.
I'll try search out the article for you.

S0LJAH · Post by **S0LJAH** » Wed Feb 04, 2009 2:54 pm

dirtygalant will be the man with the answers for you
but i do believe as FST4RD said they are the same

palmystar · Post by **palmystar** » Wed Feb 04, 2009 3:43 pm

I think the 1800 might have the big port head. apart from that should almost be identical to the 2l dohc heads. May also be higher compression but not sure. As mentioned dirtygalant will be the one to ask.

dirtygalant · Post by **dirtygalant** » Wed Feb 04, 2009 4:16 pm

Junkers wrote:Hey fellas and fellettes (hah who am I kidding)

Bought a 1800cc galant today with a twin cam engine 4g62, wondering whether I can use the head off this for my twin cam conversion? Got it for the right price so thought I would take a gamble. Not fussed if the ports are smaller, just curious about the holes lining up and the cc of the combustion chamber.

Cheers

It wont be a 4G62 they are only SOHC and 1795cc (80.6mm bore x 88mm stroke) - what you have is a 4G67 which are only DOHC and 1834cc (81.5mm bore and 88mm stroke).

I happen to have a 4G67 head in my garage which has bent valves from a snapped cambelt - they are indeed big port just like the N/A 6 bolt 4G63 DOHCs, and I'm pretty sure the valve size and combustion chamber sizes are the same for 4G67 DOHC and 4G63 DOHC also, but I'll have to confirm that.

It will definitely bolt on and you can definitely use it for a DOHC conversion on your Starion block - they even have the same oil feed on the cylinder head for the turbo.

I ended up using a 4G61 turbo head on the 4G67 block which snapped the cambelt - the heads are identical between those two, just swapped over the cams. Honestly Mitsubishi is like lego.

Here's a pic of the EvoIII head side by side with the 4G67 head I snapped for OLD FART to show the oil feed. You can see the thermostat housing flange is a little different but that's only the difference between 6 bolt the 7 bolt heads

groupAralliart · Post by **groupAralliart** » Wed Feb 04, 2009 7:24 pm

Maybe Redzone can confirm this but I was of the understanding (compared it physically myself and also via mitsubishi parts microfish catalogue) that the NA and turbo version of the 4g63 twin cam head on a 7 bolt crank are identical. The main difference is in the inlet manifold with split runners?, valves are identical only camshaft profiles are different, with higher lift cams in the NA version? I think? the ports are all big on 4G63 TWIN CAM heads even the Hyundai versions?

dirtygalant · Post by **dirtygalant** » Thu Feb 05, 2009 4:22 am

7 bolt crank heads have SMALL ports and no split runner 'cyclone' system like the 6 bolt VR-4 does. All 6 bolt DOHC heads are BIG port (except the 4G61 which has slightly smaller ports but not as small as small port 7-bolt 4G63)

www.18u · Post by **www.18u** » Thu Feb 05, 2009 7:48 am

I was always told that vr4 is a big port, 4g61 and hyundai are in between and evo 1-3 are small. It is also interesting to look at the turbo matching to the port size. Bigger ports had smaller turbos

dwlee · Post by **dwlee** » Thu Feb 05, 2009 3:52 pm

The inlet port area of a 4g61 is approximately 1430mm^2 while evo 1-3 is approximately 1454mm^2. So there is very little difference when you compare the big port 6bolt heads at approximately 1750mm^2. If you look closely at the port size about 50mm or so into the port there is significantly less difference in port cross sectional area between heads.

redzone · Post by **redzone** » Thu Feb 05, 2009 8:20 pm

groupAralliart wrote:Maybe Redzone can confirm this but I was of the understanding (compared it physically myself and also via mitsubishi parts microfish catalogue) that the NA and turbo version of the 4g63 twin cam head on a 7 bolt crank are identical. The main difference is in the inlet manifold with split runners?, valves are identical only camshaft profiles are different, with higher lift cams in the NA version? I think? the ports are all big on 4G63 TWIN CAM heads even the Hyundai versions?

nah you got 6 and 7 bolt mixed up steve.

Junkers · Post by **Junkers** » Fri Feb 06, 2009 10:46 am

Cheers everyone, appreciate the response.

Dirtygalant, do you know what the second hole next to the oil feed is?

dirtygalant · Post by **dirtygalant** » Fri Feb 06, 2009 3:17 pm

On the evo head? looks to be castings for something to mount off - but can't think of what will mount there off the top of my head

Austarion

1800cc Twin Cam head

1800cc Twin Cam head

Re: 1800cc Twin Cam head

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