4g61t.org

Hey everyone,

Sorry but I'm in a hurry for answers as my engine builder is waiting on me lol.

I have a 4g61 Turbo block that I pulled out of a 1992 Plymouth Laser RS that I parted out years ago, it has oil squirters and no balance shafts.
I did not find a vin# in the normal spot but it is stamped 4G61 under the water pump coolant tube.

I've been searching the forum and found out that it's a rare block and still in great shape (it was running)
I have no plans to use it as I want a 2.0l turbo engine back in my 1990 Eagle Talon.

The head that was on that motor is a 1.8L dual over head cam 16v the only difference I see between it and the 2.0L head is the cc of the combustion chamber.The Valves have the same part #'s

Here are my questions:

Would that head have been on that block from factory and or could this block actually be a 1.8l and not a 1.6L?

I already did a stage 2 port and polish job on the head and it's been decked and ready to reassemble.
Is there any thing I need to worry about or change if I was to bolt this 1.8L head on to a 2.0L block that will be pushing 15-18 psi and 300 plus hp?

Here are my go fast parts:
16g clipped turbo.
boost control
3" exhaust.
Walbro 255 fuel pump.
550 injectors.
Gm maf.
Front mount intercooler.
exedy stage 2 clutch.
Fidanza aluminum flywheel.
DSM link.
Every thing has been ported and polished on the intake side and the exhaust side.

A lot of the 4G61 heads say 1.8 on them, even though they are really meant for the 1.6L bottom-end. I don't have an explanation for this.

The 1.6/1.8 head has smaller intake ports, similar to a 2g head, so unless you ported them THAT much (I hope you didn't), you'll have to get creative with your choice of intake manifold. Other than that, it should bolt on to the 2.0L block just fine, as long as it's a 6-bolt bottom-end. The 7-bolt bottom-end has different size head bolts. The CC is smaller on that head, so your compression will go up a tad.

Welcome to the forum. Please put a location in your profile.

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91 GSX - 511fwhp and 352 lb/ft 25psi 110 octane, 7.68 @ 95.9mph 1/8th 21psi 91 octane, 11.93 @ 112.9mph, 117.7mph best trap speed, 20psi 91 octane
98 Volvo S70 T5 - DD

http://www.facebook.com/captaintonus

The head from the 4G61 would likely be from a 92-95 Hyundai Elantra as that is the most popular head swap for the 4G61 but those head stamps may not be an accurate way to judge which head you have though.

Like you said the combustion chambers are the same size as the 4G61 head so you would be increasing compression buy using the 1.8 Elantra head on the 4G63 block. Although I have never seen anyone do a 1.8 head on a 2.0 block I don't see why it wouldn't work.

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89 Mirage Billet 20g 63t 12.4@120 417whp 400wtq @ English Racing.
89 Colt GT E316g
06 Silverado SS
07 ZX6R

The 4G67 (also 1.8L) is a common head swap for 2.0L blocks. It has the correct size intake ports, but a slightly smaller CC.

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91 GSX - 511fwhp and 352 lb/ft 25psi 110 octane, 7.68 @ 95.9mph 1/8th 21psi 91 octane, 11.93 @ 112.9mph, 117.7mph best trap speed, 20psi 91 octane
98 Volvo S70 T5 - DD

http://www.facebook.com/captaintonus

^Do you know of any good threads with a head swap and results? People talk about it and I know it will work but I just haven't seen it done yet.

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89 Mirage Billet 20g 63t 12.4@120 417whp 400wtq @ English Racing.
89 Colt GT E316g
06 Silverado SS
07 ZX6R

Not really, no. The gains would barely be noticeable, if you ask me. I definitely wouldn't go out of my way to use that head over a normal 2.0L head.

_________________
91 GSX - 511fwhp and 352 lb/ft 25psi 110 octane, 7.68 @ 95.9mph 1/8th 21psi 91 octane, 11.93 @ 112.9mph, 117.7mph best trap speed, 20psi 91 octane
98 Volvo S70 T5 - DD

http://www.facebook.com/captaintonus

Hey Guy's thanks for the info so fast!
The ports on the 1.8l head are very close to the 2.0L head, matter of fact when I gasket matched the head I didn't remove very much at all and all I did for port work was remove the lost foam casting marks and clean every thing all up and knife edge the intake dividers and blended the casting into the valve seats so there isnt a ridge.
On the exhaust side I just smoothed every thing out.
The valves are exactly the same as the 2.0L and so are the head gaskets,I'm sure the only difference is a smaller exhaust cam and smaller combustion chamber.
As soon as I figure out how to post pic's I will.......

The intake ports are the same as the 2.0L on mine and it is a 6 bolt motor.

When I did the work I had no idea it was a 1.8L head lol...I have a few 2.0L heads I could use but I don't want to do all the porting work over again, that's the reason I'd like to use the 1.8L head.
My Engine builder can run a cutter into the chamber and remove the extra material beside the valves using the valve guide hole as a center point and then it will basically be a 2.0L Head

Here are a few pic's of the head...Details listed above the pic's.
Don't touch your mouse and the lower bar blocking the pic's will go away


http://s852.photobucket.com/user/74runn ... rch%202010

That's a 4G67 head. You'll have no issues bolting it on to the 2.0 bottom-end. People claim it will bump compression from 7.8:1 to around 8.2:1

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91 GSX - 511fwhp and 352 lb/ft 25psi 110 octane, 7.68 @ 95.9mph 1/8th 21psi 91 octane, 11.93 @ 112.9mph, 117.7mph best trap speed, 20psi 91 octane
98 Volvo S70 T5 - DD

http://www.facebook.com/captaintonus

That's great info Thank's!
Do people just turn down the boost with this combo?

No. You can run the same amount of boost. It's common to step up compression in these motors. The 2g cars were 8.5:1 from the factory. You can even go 9:1 and not have to worry about what boost you're running, in my opinion. It's all in the tuning. I'd recommend larger injectors for your setup. 550's are kind of small.

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91 GSX - 511fwhp and 352 lb/ft 25psi 110 octane, 7.68 @ 95.9mph 1/8th 21psi 91 octane, 11.93 @ 112.9mph, 117.7mph best trap speed, 20psi 91 octane
98 Volvo S70 T5 - DD

http://www.facebook.com/captaintonus

Can i have your 61 block

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Black 1989 Colt GT with 4g61t. 200k miles and climbing. Rebuilt 2.0 in the works.....
14b, 450cc's, 3" exhaust, small fmic, all running on megasquirt version: DIYPNP
White 1992 colt-vista wagon 2.4, awd, auto (daily)
Keane

LOL,I was going to rebuild it and just sell or trade it.How interested are you? It's in nice shape and freshly painted but the crank will need to be polished and new bearings installed but that go's with out saying.I have the whole motor less the head.(Shortblock)
Probably better to PM me this isnt the for sale/trade section