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 Post subject: newbie
PostPosted: Tue May 13, 2008 11:02 pm 
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Joined: Tue May 13, 2008 5:57 pm
Posts: 9
Location: Melb Aust
I was looking for info on 4G61 and this forum come up on google

so my car is a 1979 chysler sigma that is circuit raced here in aust
atm is running a 4g54 Na with 160 hp atw

future mods ( and why I've been looking at 4g61 info )

ether a bored out *61 or a destroked *63
engine can be no larger than 1764 cc
so a 85.5 bore x 75 mm stroke = 1723
that will run a garret GT2860 BB turbo fitted with a 36 mm restirctor ( class rule ) running 25 + psi which will drop off badly over 7000 rpm
head not sure I have a few to pick from but will get the normal treatment
stainless valves - bronze guides some port work
not sure on cams as yet cant be to wild as air flow is restricked and is worse at higher revs
rod and pistons will be after market 4g63 bits all being well priced
flywheel I will machine myself the last one made for the 2.6 weighs 2.9 Kg (6.4 lb ) from 4140 steel
clutch 7 1/4 Tilton
this is to fit a rwd so a new baffled sump will be made to stop surge
I have an EMS after market ECU for it

anyway thats the project most machining and the engine build will be done in house

cheater


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 Post subject:
PostPosted: Wed May 14, 2008 8:45 am 
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Joined: Tue Nov 06, 2007 7:29 pm
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Location: North Idaho, USA
Oh my.......you've got a big project going on, I see. Good luck to you, and keep coming back here to let us know what's happening with it. :D


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PostPosted: Wed May 14, 2008 10:00 am 
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Joined: Wed Dec 24, 2003 3:32 pm
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Location: Ottawa, ON, Canada
I would suspect that the rod ratios of the 1.6L would be better for elevated RPM's for extended periods, but the 2.0L still held it's ground in competition nonetheless. I think you will have a solid foundation with a built 4g61t, but see if you can get some stronger pistons made up. Ringlands are smaller on teh 4g61t design and we're pretty confident that there should be a way around it. Contact "dragstr4g61t" with the PM function, see what he has to say on this subject. His stock bottom end 4g61t just broke the 10's in the 1/4. 8)
Enjoy your stay, and let us know what you end up doing with your build, assuming you aren't giving away too many hints to the competition. :wink:


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 Post subject:
PostPosted: Wed May 14, 2008 5:43 pm 
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Location: Melb Aust
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I would suspect that the rod ratios of the 1.6L would be better for elevated RPM's for extended periods, but the 2.0L still held it's ground in competition nonetheless.
Contact "dragstr4g61t" with the PM function, see what he has to say on this subject. His stock bottom end 4g61t just broke the 10's in the 1/4. 8)
Enjoy your stay, and let us know what you end up doing with your build, assuming you aren't giving away too many hints to the competition. :wink:
my main concern with my move from N/A to turbo in the class I run is that the engine needs to be 1.7 times smaller or I would have just fitted a VR4
I still wish to run 2000 -3000 cc but a 2l x 1.7 = 3.4
so a 4g61 came at the right price in fact was given to me by a guy that I build engines for it also comes with an EMS ecu
so 1595 x 1.7 = 2712 that will prob go in to start and std but I will make a sump and a new tube exhaust manifold of cause the T/B will need to be moved to the other end of the plenun ( rwd car )
I however had thought of using 85 mm pistons
and since joining the forum have picked up some hints ( dragstr4g61t ) being one that point out things
so it looks like I will destroke a 4g63
my plan goes something like this
a 4g63
85.5 mm 9:1 forges some 4340 H beems but using a 4g61 crank
1723 cc x 1.7 = 2929
I will have to do a little machining to the block mainly the deck will need some removed about 4 mm it seems
as I have a 1.8 hyundai engine use the head off that it has 1.6 cast in it so it should be a small chamber
I will fit 1 mm os stainless valves with bronze guides and give the ports a tickle
the turbo will be a gt2860
I use a couple of different cam grinders here so I'll chat to them when the
time comes

as for the competition I have not seen anyone use a 4g61t in our comp
there are a few 63s in evos


cheater


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 Post subject:
PostPosted: Wed May 14, 2008 9:20 pm 
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Location: Ottawa, ON, Canada
Quote:
I will have to do a little machining to the block mainly the deck will need some removed about 4 mm it seems
as I have a 1.8 hyundai engine use the head off that it has 1.6 cast in it so it should be a small chamber
What plans do you have for the head: stock 4g61t combustion chamber size, as shared with the 4g67 heads?

You would need a 4g67 (1.8L Hyundai head) with the 1.8L stamped on the side. Just make sure you are getting large inlets and large outlets that are roughly 2.0L 4g63 sized. There are some heads that are small inlet (1.6L sizing) and large outlet (2.0L sizing). It would seem that some of the Aus and or NZ stuff suffers from these hybrid part issues.

Fantastic thread where another bit of useful info was gleaned from:
http://www.gsrcyborgclub.org/viewtopic. ... ght=#19838
Quote:
Flying Eagle wrote:
I need to update the listings that are posted above, as there are lots of changes that have recently, well in the last few months, come to light.

All 4g61t's that came to north america are small port heads from what our members have seen and used. Adding a 4g67 head setup, which was delivered to motor in JDM land and NZ/AUS is the only ways to get big ports from the factory.

What I need to know is when the big intake port and small exhaust port showed up, and when the defining time period was for finding large port intake/exhaust 4g67 heads versus the stop date for small port intake/exhaust 4g61t style heads as to how they were delivered on 4g61t motors over here (NZ/AUS). Was the facelift time period the defining time for most to find that they had 1.6T DOHC large port in/out setups from the factory?

ticklenut wrote:
I believe the head change occurred in 90 or 91, as far as I know no 61t's were delivered to AUS and all 4g61's delivered were post 90 and therefore the large port or 18 head. I have a 61t with the small port head and a 61 NA which has the larger ports. Just holding on to the NA head for future plans . The 61t is an 88-90 engine personal import.

mrcyborg wrote:
have a NA61 engine with the the stamped as a "16" and it surely has big intake ports, i sold the intake manifold to a dude that used it on a vr4 head in place of a dual runner.
Thought I would add some food for thought, if this hadn't already come across your plate in your line of work. 8)

If you are not a member there yet, sign up and also check out the NZ board run by Jarred "GSRWRC":

http://4g61nz.co.nz/


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 Post subject:
PostPosted: Wed May 14, 2008 9:52 pm 
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Joined: Tue May 13, 2008 5:57 pm
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Location: Melb Aust
Quote:

You would need a 4g67 (1.8L Hyundai head) with the 1.8L stamped on the side. Just make sure you are getting large inlets and large outlets that are roughly 2.0L 4g63 sized. There are some heads that are small inlet (1.6L sizing) and large outlet (2.0L sizing). It would seem that some of the Aus and or NZ stuff suffers from these hybrid part issues.


If you are not a member there yet, sign up and also check out the NZ board run by Jarred "GSRWRC":

http://4g61nz.co.nz/
the 1.8 hyundai engine that I have here has marked 1.6 on the head but the ports do look much the same size as a 2.0Lt head
I had one sitting beside it and both inlet and exhaust look the same on both heads
if I get a chance this W/E I'll tear the 1.8 down so and measure it up

I'll have a look at the NZ forum

thanks
cheater


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