G200 DILEMMA HELP!!

Benjamin · backyard mechanic Joined: 05 Oct 2001 Posts: 525

Okay,

My G200 is in many pieces across the engine builder landscape, I want to be on the road ASAP and am starting to get really raggy about the situation. I think I need a hug lol

Anyways, it turns out the block has been bored 40thou over already and therefore the next option is to go 60thou (maximum). The engine builder tells me that for my intended use 60thou is not recommended.

I am using the car as a daily driver, also it will be undertaking many longer distance trips. I live in Central VIC, which can be warm, certainly not QLD warm but Summer can be hot. The head is an early TX item, shaved to buggery, increasing compression and heat.

The engine builder says I will need a 5 core radiator and a thermo fan, even then in Summer I will be watching the temp gauge to be on the safe side. Not only that, she will carry on like a bitch... on heat. I am fine with running extra cooling, but only to a point.

My question is: for my intended use, is 60thou over on a G200 waay risky and will it end up being too unreliable that I can't trust it?

I need a serious answer please. After this weekend I will have few transport options as I have to hand my mum's Hilux back Sad

not only that, the project has been dragging on waay too long and to be going without transport for another 2-3-4 weeks is going to be hard.

Thanx guys

Dave · tinkerer Joined: 04 Oct 2001 Posts: 322

A 5 core radiator? What are you going to be running in it? The blood of Satan?

The G200 is basically a G161z with more stroke and more bore - I would have thought the standard radiator, perhaps rebuilt to 3 core would have been enough, but don't quote me on that because I'm not an expert.

If you want an instantanously bigger radiator, get a Diesel radiator and get that rebuilt to, uh, 5 core as he suggests.

It's higher and wider, but fits into the petrol Geminis without any mount modifications, although you do have to get the pipes reorganised as the Diesel cooler had pipes in different areas on both the top and bottom tank.

Thermo fans are always good too - they increase horsepower a little bit as well because the engine don't have to turn it around.

With the head shaved, just make sure the timing chain is tensioned right - I had the head shaved in my old TD van and after about 3 months it dropped the tensioner. Shaving the head means that the top of the chain and the bottom are now closer together, resulting in some slackness.

Of course in a $500 dunger, spending that sort of dough to get a new timing chain tensioner kit into it was out of the question, so I bought a G180 instead!

Cheers,

Dave

DrIFtA · tinkerer Joined: 13 Mar 2003 Posts: 246

Multiple posts on this topic have advised against anything over 40thou on the G200. Cylinder walls and head gaskets will provide much pain and agony and wallet munching. Just get it honed at what it is now.

Benjamin · backyard mechanic Joined: 05 Oct 2001 Posts: 525

It is beyond honing at 40 thou, 60 thou is the only option. Thanx for the direct answer. I guess I go looking for a new G200 block and go from there.

Cheers

GasGem · backyard mechanic Joined: 05 Nov 2001 Posts: 755

Have you considered getting sleeves? they may work out cheaper, also I would consider O'ring's as with a 40thou and 60thou there is not much room between 1-2 & 3-4 and with a shaved tx head you can almost bet in 6 months you will blow a headgasket between cylinders. 3 core readiator will do just fine, either get a gemini unit re cored or something simular, celica, torana, diesel gemini...

cheers.
Eggy

Benjamin · backyard mechanic Joined: 05 Oct 2001 Posts: 525

Hey Eggy,

Yeah considered sleeves, $100+ per cylinder is fairly prohibitive and not really recommended for reliability. I have spoken to a few ppl about sleeves and they wear quicker, really only suited to race engines. $400 extra is not really in the budget.

I have called a few wreckers in my area, there isn't much chance of scoring a G200 at all.

Risking blowing a head gasket in 6 months is not my idea of reliability. I may have to go back to rebuilding the G161, unless I can find a G180 in the meantime, but then I start again.

Thanx m8.

GasGem · backyard mechanic Joined: 05 Nov 2001 Posts: 755

ring around I got a set of sleeves done for about $40 per pot... at worst get the G161 and out 1800 + 40thou slug's in it, it will go reallynice and you will not have any vicroads issues as the G200 is illegal...

cheers
Eggy

Benjamin · backyard mechanic Joined: 05 Oct 2001 Posts: 525

Interesting theory. So 40 thou over G180 slugs, or standard G180 slugs = G161 40 thou? No problems with stroke?

Hmmm. I thought the G200 was legal as long as it was NA?

Thanx

Ben Wight · backyard mechanic Joined: 04 Oct 2001 Posts: 946

Your compression ratio is the only worry. Optimax will only allow you to run around 10:1, depending on your cam, before ignition timing has to be retarded too much to get a good power gain. Maybe you should consider a lower compression head.

I dont see how your bore size is a big concern, its more the compression, as retarded timing is necesarry to avoid detonation which increases cylinder temps.

Work out your compression ratio, and then make decisions.

Anyway, you can get a brand new 3 core radiator, and you might be able to squeeze in a 12" thermo fan (10" fans fit no worries). New radiator core is usually about $200 or less.

Ben

Benjamin · backyard mechanic Joined: 05 Oct 2001 Posts: 525

Dished pistons Smile

I am not concerned about compression, and aim to keep it around 10:1 running on PULP. I am more concerned about the heat and wall thickness between slugs.

Thanx