Twincam back to G180 conversion !

Soop · backyard mechanic Joined: 30 May 2002 Posts: 748

Still thinking about going back to a stock engine since I can't really justify spending so much money on the car at the moment.

What would be involved in converting back to a standard G series engine from a twincam setup.

I am aware that the box is different, however can it be modified to fit a stock G series engine ? I know the stock box can be modded to fit a twincam but can u do it the other way around ?

Will my fuel pump need to be changed or is it ok to keep the high pressure fuel pump ? Remember I would be going back to a carby engine here.

Would I be able to keep all the ancilleries from the twincam engine ? May save me a bit of money.

Also I'm not smart enough to do this myself so would any places give me a trade in on my old engine when I get the new one installed. It still runs pretty good.

Also any idea how much altogether (approx) I'd be looking at to get my twincam removed and a stock reco'd g180 put in.

Questions, questions, questions. I would usually ring around but no where will be open thanks to new years and stuff.

Any help appreciated !

martin · backyard mechanic Joined: 04 Oct 2001 Posts: 900

can't say have done it but...

if you have a genuine twincam box, you will need an adaptor for the bellhousing BUT the starter motor is on the other side so that will be a bit of a pain

you'd be better off just finding a shitter of the same model as yours and replaceing the entire drivetrain

you going to bother injecting it or not? im not 100% sure if the injection setup from the twincams will bolt straight into the SOHC if my memory is right they dont... maybe a piazza manifold? or just get a carby and save the hasstles, you could leave most of ur injection shit in place anyway.

Soop · backyard mechanic Joined: 30 May 2002 Posts: 748

The reason I'm getting rid of it is because I don't wanna run injection due to the costs of getting a computer setup and stuff. So the sohc motor would be carby.

So basically I would need to replace the motor(duh) and gearbox ?

Stock TE · backyard mechanic Joined: 12 Mar 2002 Posts: 853

If you change it back you will regret it later on. Just get the twincam running.

martin · backyard mechanic Joined: 04 Oct 2001 Posts: 900

yeah or if worst comes to worst just carby the twincam.... they go pretty good i hear

Soop · backyard mechanic Joined: 30 May 2002 Posts: 748

Ok thats another option.. carby. Is it even possible to run like a single webber on the twincam ? I would do it if possible.

I just can't justify spending over a grand just to get it running when I could possible get a fully reco'd and running donk in there for not much more. I want reliability over speed for this car.

Soop · backyard mechanic Joined: 30 May 2002 Posts: 748

Prolly not. I had a g180 in my old gem and it was good enough for putting around in. I was happy.

I bought the gem with the twincam in it mainly cos the driveline/body and brakes were good. It had the twincam in there but I never went out of my way to get one.

gem · tinkerer Joined: 23 Dec 2001 Posts: 152

I would not bother changing back to a sohc engine.As for carbies you would need to find a twin webber style manifold.I have one (but its not for sale) if you need a picture of it I can send you one .If you are handy with a welder you could make one.
I replied to you in the R&D section a while ago. If you need some help getting your delco system working properly you can contact me gem@alphalink.com.au as I had my old race car running on the delco system for about three years without a single problem.There are also alot of people that can tune a delco system to suit any car. I have had experience with Haltech,Autronic and Delco and the Delco system is very good especially if you change the mapping.
Gem.