G200 comp ratio

SHEEL · Posted: Sat Apr 12, 2003 5:55 pm Post subject: G200 comp ratio

Does ne 1 know the chamber volume for a g200 head in comparison to a g161. i.e what would my comp ratio b if i fit a g200 head to a g180 to de- compress?
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tx1975 · tinkerer Joined: 21 May 2002 Posts: 321

would be lower but y bother it doesnt have the best port design, get a early 1600 head and cc the chambers and make sure u tune it right and there wont be any need to lower the comp.

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

I dont know the volume for sure, but I do know that it must be about 55 or more cc's. Its hard to know factory volumes as every time a head is shaved, it reduces by a couple of cc's or more.

I have a heavily shaved TD head with 40cc chambers, and thats after I took a fair bit out to unshroud the valve seats. I also have a midly shaved one with untouched chambers which is 42cc.

I also have a TG pollution head with modified chambers that is 52cc.

Remember, you can always get factory dished pistons to lower the compression ratio on a 1800.

Ben Wight

SHEEL · Posted: Sun Apr 13, 2003 5:39 pm Post subject: Re: G200 comp ratio

thanx i should be able to get some rough figures from that, i will be building a g200 bottom end with pistons to suit so it will be easier then. the g200 head on the 1800 is just a temporary set up at the moment. hopefully the bottom will hold if i don't give it a hard time...
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Ben Wight · backyard mechanic Joined: 04 Oct 2001 Posts: 946

The bottom end should support over 350hp as long as it doesn't detonate. It might support a hell of a lot more too, but I have never measured it.

So feel free to give it as hard a time as you want!

SHEEL · Posted: Sun Apr 13, 2003 8:15 pm Post subject: Re: G200 comp ratio

no shit? with standard pistons?
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Ben Wight · backyard mechanic Joined: 04 Oct 2001 Posts: 946

Yes, with ACL cast pistons. They are structurally strong, but if your engine detonates, like from a lean out, engine overheat, bad fuel, too much ignition timing, or simply too much boost, then they will break. Usually crack a ring land clean off.

I once melted a hole clean through one though, that was strange. It was one of the few times I was running water injection though with methanol, might be realted somehow.

But foe a mild engine, forged pistons would be a bit overkill if the engine is sorted properly on a dyno.

Ben Wight