4g61t.org

what does this mean

I have this on my cylinder head only it has a 4 under the 1.8 instead of the 5 that is shown.




I saw this and the picture says it is a 1.8L head. Does this mean that the cylinder head on my engine is not the origional?? or is that what the 4 means?

Thanks

casting revision?

soe cars came equipped with 1.8 heads. the ports are way bigger than the 1.6 intake and exhaust ports.

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wait wait... are you asking what does the 18 mean or the 4/5?

18 = 1.8 head
4/5 = ???

I'd be interested to know if the ports are indeed large 1.8-2.0 head ports on the intake and exhaust side. That 5 shouldn't say much more than the 4 did ......hmmmm ..... I don't hear anything so it's not saying much.

theres a chance that 1.6 might be a jdm, i hear some of them come with 1.8 heads if not all

sorry, what is a jdm? is it good that the engine has a 1.8ltr head instead of the standard? would anything else be differant? invectors, cams etc? would they be from a 1.8 too or standard 1.6?

sorry for the q's, but is the 1.8 head better than the 1.6?

I will try to comprehend all known info about the different head versions to make a sticky out of it or move it to the archives:

casting marking "16" head:
- came stock on the 4G61 (1.6L)
- has a 43 ccm combustion chamber
- uses smaller ports (in comparison to a "20" head)

casting marking "18" head:
- came stock on the 4G67 (1.8L) and some JDM 4G61
- has a 43 ccm combustion chamber
- uses lagerer ports (like the "20" head)

casting marking "20" head:
- came stock on the 4G63 (2.0L)
- has a 47 ccm combustion chamber
- uses large ports

The "4" or "5" below the casting marking is some sort of revision. It's function is unknown.

Edit: volumes are approximations.

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Nice work The Ethereal, I think the next breakdown we need to know for those few engines that got the "18" head on a 1.6L engine also had any difference in the type of transmission bolted to them, and or it they were Turbo or N/A. I've seen this info around earlier but not all inclusive. Trent's post archive showing the port differences including the TB differences is already a good place to start for visuals but if we now have the tech data, that's even better. Once we know which set of countries got what (ie. New Zealand, Australia, Japan, and America's (although there may be more breakdown there too), then we can tell the major differences that the Mitsu head hancho's were catering to at the time of production and shipping. Some markets got fun stuff and other's just got daily drivers.

Well, I've heard rumours, like the higher compression European engines have different heads w/ a smaller combustion chamber than USDM heads. Could that be an explanation for that "4" and "5"?

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So, are we talking about 1.8L NA heads fitted to 2.0L NA engines in Europe? That would explain the smaller combustion chambers but the larger port sizes. Also OTOH would we be looking at these engines as being shipped to their respective countries?

Europe: DOHC - NO turbo options from Mitsubishi
4g61 1.6L with "16" Head casting featuring 43 cc combustion chamber 10:1 CR small ports No "18" head option ever installed by the factory, or turbo option either
4g67 1.8L with "18" Head casting featuring 43 cc combustion chamber 10.5:1 CR big ports
4g63 2.0L with "20" Head casting featuring 47 cc combustion chamber 10.5:1 CR big ports
4g64 2.4L with "18"("20"?) Head casting featuring 43 cc combustion chamber small ports

North America: DOHC
4g61 1.6L with "16" Head casting 43 cc combustion chamber small ports
4g61 1.6L T with "16" Head casting 43 cc combustion chamber 8.0:1 CR small ports
4g67 1.8L with "18" Head casting featuring 43 cc combustion chamber big ports
4g63 2.0L with "20" Head casting featuring 47 cc combustion chamber big ports
4g63 2.0L T with "20" Head casting featuring 47 cc combustion chamber big ports 1st Gen
4g63 2.0L T with "20" Head casting featuring 47 cc combustion chamber medium ports? 2nd Gen
4g64 2.4L with "18"("20"?) Head casting featuring 43 cc combustion chamber small ports

Australia + New Zealand: DOHC
4g61 1.6L with "16" Head casting featuring 43 cc combustions chamber small ports (some heads came with large intakes/small exhaust ports)
4g61 1.6L with "18" Head casting featuring 43 cc combustions chamber big ports (2 users report the #4 printed beside the 18 reference)
4g61 1.6L T with "16" Head casting featuring 43 cc combustion chamber 8.0:1 CR small ports
4g67 1.8L with "18" Head casting featuring 43 cc combustion chamber big ports
4g63 2.0L with "20" Head casting featuring 47 cc combustion chamber? small ports
4g63 2.0L T with "20" Head casting featuring 47 cc combustion chamber big ports 1st Gen
4g63 2.0L T with "20" Head casting featuring 47 cc combustion chamber medium ports? 2nd Gen
4g64 2.4L with 43 cc combustion chamber small ports IE DOHC Galant 1994 uses small style ports, same as a 2G DSM head

JDM Japan + Caribbean: DOHC
4g63 2.0L with "18" Head casting featuring 43 cc combustion chamber big ports
4g63 2.0L with "20" Head casting featuring 47 cc combustion chamber big ports
4g61 1.6L with "16" Head casting featuring 43 cc combustion chamber small ports
4g61 1.6L T with "16" Head casting featuring 43 cc combustion chamber small ports
4g61 1.6L T with "18" Head casting featuring 43 cc combustion chamber big ports




If we have all the applicable years for each type of motor, the type of car and the revision numbers as they apply to the head, then that would pretty much seal the deal.
I'd love to see a quick reference on this if we don't have one already lurking around the archives somewhere. Feel free to critique the specs I've posted, there are sure to be numberous errors as I am not up to par on my off-continent cars. Post up revisions to the list please.
Also compression ratios would be great to see listed as well.

I never heard of a 4G63 coming w/ the 1.8 head stock.
European 4G63 ("20" head) and 4G67 ("18" head) have a CR of 10.5:1 while the 4G61 ("16" head) have a CR of 10.0:1. We got only NAs here and apparently no 4G61 ever came w/ a 1.8 head.

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in the caribbean...we get all the JDM MODELS of engines

there are many 4g63 n/a engines that came STOCK with teh 4g67 ( 1. 8 ) head, hence the abundance.
4g63T's (6bolt 1G) came with the 1.8 head as well..i confirmed this in quite a few engines...

likewise many of the 4g61T's came down with the 1.8 head too, but a few came with the 4g61 standard too...

but as was mentioned, no 4g61 n/a engine came with the 1.8 head. EXCEPT MINE but that was not stock...i had to get a replacement and the 1.6 heads are non-existant here...

so u can add these specs to ur list...from Caribbean/Japan...same models basically..

Updated thus far.

xlr wrote: November 27th, 2007 from Perth, Australia.

Another thread to reference to here:
http://www.gsrcyborgclub.com/viewtopic.php?p=25423