GT DOHC into a 97 Geo Metro
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Author:  codyb76 [ Sat Jun 13, 2015 5:28 pm ]
Post subject:  Re: GT DOHC into a 97 Geo Metro

That makes the swap much easier. I think every detail you need is in this write up. Any accessory that bolts to the block will bolt to the gt block. You will need to machine the cam sensor housing as fainya did, or have a machine shop do it. That is likely the hardest part and most costly. The next difficult part will be figuring out a way to reprogram and tune your ecu to get the most out of the gt engine. This isn't a swap for amateurs in my opinion, but it's a really neat thing to have seen done successfully. If you tackle it, expect to put in a lot of hours and have car down for a while.

Author:  Dillan03 [ Sat Jun 13, 2015 7:28 pm ]
Post subject:  Re: GT DOHC into a 97 Geo Metro

I understand that it's not the easiest thing to make happen. Was just concerned about the accessories. My best friend is a machist and has access to a lathe and mill at work every day. I know the blocks are the same and figured everything just bolted up but wasn't sure I plan to run a SAFC to tune the ECU if that don't work I will go stand alone because this motor is being built for turbo before it goes in the car so I may have to Standalone any way. I was just wanting details but your right he did cover pretty much everything.

Author:  fainya [ Sun Jun 14, 2015 2:30 am ]
Post subject:  Re: GT DOHC into a 97 Geo Metro

98 engine wiring harness.
98 throttle cable.
Made new bracket to hold the 98 throttle cable to the GT intake manifold.
GT intake manifold.
98 oil pump with crank sensor mounting hole.
98 oil pan with crank sensor mounting hole.
98 crankshaft sensor.
98 lower timing belt sprocket for crankshaft sensor.
98 crankshaft pulley for drive belts.
I didn't have the GT intake manifold to the engine bracket. I made one.
98 Cam sensor to make the engine run past 3,000 rpm.
Made new cam sensor housing to replace distributor.
98 coil packs to replace distributor.
98 cam shaft sensor.
Made coil mounting bracket that attached to back of head.
98 injectors with GT fuel rail. double up the rubber seals on both ends, rail bolted
to head with out spacers.
Longer fuel pressure and return lines.
98 throttle body bored to 47 mm with 98 idle air bleed solenoid.
98 map sensor with new rubber seal replaced the GT idle air bleed solenoid.
Made a new bracket to hold the map sensor to the GT intake manifold.
GT thermostat housing with old sensors holes plugged off.
98 temp sensor into back of head. 98 temp sensor replaces the 3 GT sensors.
98 alternator bracket, A/C compressor bracket, motor mount brackets.
98 intake tube and air filter. The GT air flow meter is not used.
Eventually I replaced the rubber air intake tube with a 3" aluminum tube and a K&N
air filter. This improved the bottom end response.
98 intake air temp sensor.
98 secondary fuel purge solenoid for carbon canister.
GT exhaust manifold with down pipe or header with hole for O2 sensor.
98 O2 sensors both front and rear.
Lower GT engine to bell housing bracket if you use a GT transmission.
I did not have to stretch the 98 wiring harness.
A new front O2 sensor came with longer wiring. The original 98 O2 sensor I would have
had to add a short harness to keep the wiring off the exhaust manifold.
New exhaust system. 2.0" from the header back through the 2.0" cat back to the exhaust flange that is close
to the shifter. 2.25" from the flange back to the end of the tail pipe. I have used smaller inside diameter
flange plates as exhaust resticters for tuning purposes. unrestricted engine runs rich.

Author:  Dillan03 [ Mon Jun 15, 2015 8:07 pm ]
Post subject:  Re: GT DOHC into a 97 Geo Metro

Thanks so much I should have my motor this week and plan to rebuild it before it goes in the car. I may need a little more detailed info on the can sensor housing just dimensions if you could help with that it would be great. So glad I found your post.

Author:  Tim Keith [ Sun Aug 23, 2015 1:06 am ]
Post subject:  Re: GT DOHC into a 97 Geo Metro

This is an interesting option. I have the GTI motor but I lack the PCM and wiring.

Author:  fainya [ Sun Aug 23, 2015 3:07 pm ]
Post subject:  Re: GT DOHC into a 97 Geo Metro

I have finished this car project. I have all the body and interior finished too.
I drove it up to GeoPalooza and back at 75 to 80 mph and got 35 to 37 mpg average.
3,000 mile breakin for the car.
Nothing broke or acted up on the drive up and back.
I am happy with the way the car turned out.
When I got up to GeoPalooza and parked the car, It was like I dropped a piece of
cake on the ground and the ants found it. I had people crawling all over and under the car
to see the work I had done. Lots of questions answered about the car.
3834 finished car.

IMG_3834 (2).JPG
IMG_3834 (2).JPG [ 340.99 KIB | Viewed 2278 times ]

Author:  CAMI Man [ Sun Aug 23, 2015 3:44 pm ]
Post subject:  Re: GT DOHC into a 97 Geo Metro

Very nice fainya :!:
You have done a fantastic job :!:

Author:  CAMI Man [ Sat Jul 16, 2016 4:28 pm ]
Post subject:  Re: GT DOHC into a 97 Geo Metro

Fainya any updates to your car ?? :D :D
You were mentioning Supercharging :mrgreen:

Author:  CMA [ Tue Jul 19, 2016 12:15 am ]
Post subject:  Re: GT DOHC into a 97 Geo Metro

geopat wrote:
Cami Man wrote:
It has been done .
fainya is the first to run it using the mk5 obd2 computer from the sohc 16valve.

This is what fanastic about this car!

ODB1 is pure garbage... IMHO. If it works then don't touch it. :buzz: heck, fainya did it... so impressive...

Author:  MarkZ28 [ Wed Sep 28, 2016 1:06 pm ]
Post subject:  Re: GT DOHC into a 97 Geo Metro

Fainya, I finally found your thread. T3 over on geometroforum directed me to you since you have done this swap. I have a 98 1.3 sedan with the 5 speed. I either want to put a dohc head on my sohc shortblock or do the whole engine. Be the same either way, just have to swap the oil pan, sensor, and oil pump from my sohc to the dohc engine for the crank sensor. My question is about the cam sensor. Will the cam sensor assembly from my sohc swap onto the dohc head? It would make it so much easier to swap. Will the cam connect to the sensor drive? You used your 97 distributor to use the sensor, did you try the 98 cam sensor assembly? If I can use my current sensor I wont have to modify a distributor or make a bracket for the coils. Thanks.

Author:  codyb76 [ Thu Sep 29, 2016 11:00 am ]
Post subject:  Re: GT DOHC into a 97 Geo Metro

You will have to have a housing machined and a piece built for the end of the cam to adapt it, think there is pics on here of what fainya built.
This is a really neat swap, but consider some factors before taking it on. Lots of work, and apart from the cool factor and amazing sound of the twin cam setup, there isn't a lot to gain in my opinion. The problem centers around the obd2 ECM not being easily altered or programmed/chippable. When you are done you have a gt engine running on a sohc timing and fuel map, and you lose 500 rpm in the process (rev limit with sohc is 6500, where gt is 7000). So you're adding high rpm power but the ECM won't allow you to use it.
Having had quite a few of each engine style, I'd really consider just putting a cam and free flowing exhaust on your sohc, it will add a fair bit of power and that engine makes more torque which is nice in the heavier late body styles. My car was as quick as a stock gt after I added cam, intake and exhaust to a 99 sohc 16V.
Your other option is to swap to gt ECM, in which case chipping the ECM becomes possible, but requires wire harness mods and swap.
Don't want to discourage you, just some things to think about.

Author:  MarkZ28 [ Thu Sep 29, 2016 12:22 pm ]
Post subject:  Re: GT DOHC into a 97 Geo Metro

Fainya had the 97 8 valve distributor. My 98 already has the cam sensor assembly ready to go. I was just curious if the 98 assembly would bolt in and work without finding a 97 distributor to modify. It appears from the outside that the camshaft sensor assembly would bolt in the same as the distributor, its the drive end that I am not sure about. I did have the valvecover off but not the assembly so didnt think to check it. I may remove it and try to see if it looks the same as the drive end of a dohc distributor.

As far as tuning and programming, its obd2, which normally can be tweaked and things changed fairly easily, if there is a tuner made that works with Suzuki programming. If its a Chevy program it may be even easier. I think the tool that the dealers use is called a Tech 2. Since its a "Chevy" Metro they should be able to use it to change things.
If I just swap heads out and get the tuning done, how fast can a G13bb spin before breaking? The G13b has a forged crank and rods, the sohc uses cast crank I think and weaker rods.

Author:  suprf1y [ Thu Sep 29, 2016 3:25 pm ]
Post subject:  Re: GT DOHC into a 97 Geo Metro

Cody's right.
There's no advantage and lot's of downside to this swap the way it was done. Dished pistons, GT head, less timing than a stock dohc, and 1000 less RPM is not a recipe for success. Cody's is, and a 4.39 trans is the icing on the cake.

Though I asked several times, fainya has yet to answer how he's going to tune the obd2 ecu, what parameters he's going to use, or what the stock ones are.

Author:  MarkZ28 [ Thu Sep 29, 2016 5:59 pm ]
Post subject:  Re: GT DOHC into a 97 Geo Metro

I have the exhaust manifold and larger throttle body you sold me. I will most likely stick with the sohc, was just curious how hard it was to do. Plus, it looks cool, lol. Who sells cams for the sohc? Anybodymake higher compression pistons? If not the dohc head, Id like the extra strength of the dohc's forged crank and rods. Cant afford to hop up a small blick chevy car anymore, Metro is a fun little car to mod and its easy to work on.

Author:  suprf1y [ Thu Sep 29, 2016 7:11 pm ]
Post subject:  Re: GT DOHC into a 97 Geo Metro

That's why your username is familiar.


Author:  MarkZ28 [ Thu Sep 29, 2016 9:18 pm ]
Post subject:  Re: GT DOHC into a 97 Geo Metro


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