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Location:
Melbourne
Registered:
February 2005
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 2tg head on 3t block
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Tue, 12 April 2005 05:14
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Before I start I have searched for this topic and there is so many posts I was just going round in circles. Everyones opinion seems to contadict each other. Can someone please confirm some things for me.
I have a complete 3t bottom end, and a complete 2tg. The 2tg is not injected.
Am I correct in saying that to make a ~2L 2TG-3T hybrid, I need to:
- Fit the 2TG head onto the 3T block, or being a carbied 2TG will the cam bearings not fit?
- Bore the 3T block out to 89mm
- Flycut the 3T pistons, or use 2TG rods, or both?
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Location:
Ballarat, Victoria
Registered:
March 2003
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Re: 2tg head on 3t block
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Tue, 12 April 2005 06:24
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bore out to 88.5mm, 89 is very hit and miss- its trial and error if you get a block with enough meat to bore- you may be too close to the water jackets.
same trouble 'the untouchable' had. pm him for details. needless to say it was too much of a pain for him.
2tg head needs a dummy cam or something
you flycut the 3t pistons on the 2 rods, i think.
im sure someone can clear this up for you, im no 2tg expert 
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Location:
Brisbane
Registered:
July 2004
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Re: 2tg head on 3t block
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Tue, 12 April 2005 06:41
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I am in the same boat here...not sure which choice to go with. Have a complete 3tc and getting a 2tg. People say to use the bottom end of the 3tc, yet others say for the hybrid, use the 2tg block and just add the 3t pistons/crank - increase compression without really having to modify the head.
Best to use? because i settled on...2tg rebuilt with new carbs, new aggressive cams, port and polish, bored to 1800, 3t pistons/crank (maybe billeted - i think possible)making it 2lt (i think yes?)then lightened flywheel and heavy clutch.....keep with that idea, or use 3t bottom end?
Loan is coming though very soon, so ideas would be great.
Cheers,
crok.
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Location:
Melbourne, Australia
Registered:
March 2005
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Re: 2tg head on 3t block
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Tue, 12 April 2005 13:23
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The 2T and 3T rods are the same dimensions.
The 3T crank can only be used with 3T pistons (or pistons with 3T gudgeon pin geometry).
You get about 1940CC from 89mm x 78mm. It's not that hard to calculate. Hint: Pi = 3.14159
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Club President
I supported Toymods
Location:
Sydney
Registered:
May 2002
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Re: 2tg head on 3t block
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Wed, 13 April 2005 05:16
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Short Version
Use 3T Pistons and Crank, pistons will require flycutting
2T, 3T, 2TG rods - All the same length so interchangeable (Don't mix and match tho, they are different) - Keep an eye on rod bearing oil hole locations !!!
ANY 2T, 3T series block will do. early 2T-C blocks will need clearancing for 3T crank.
The Half cam drives the oil pump and Dissy, It goes where the std cam goes in a xT-C engine. remember to block the unused cam bearing oil holes to maintain oil pressure.
88.5mm is biggest "safe" bore size. Bigger is possible tho not worth the gamble IMHO
A xT-G reguires xT-G timing gear, timing covers etc !
Cams and Headwork etc etc depends on application.
Hope that helps !
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Location:
Kilsyth, Melbourne
Registered:
September 2004
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Re: 2tg head on 3t block
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Wed, 13 April 2005 13:03
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wot was that about a dummy cam? wot does this mean?
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Location:
Brisbane
Registered:
May 2002
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Re: 2tg head on 3t block
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Wed, 13 April 2005 13:16
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The dummy shaft goes in the block where the camshaft would go in an OHV engine. It's there to drive the distributor and oil pump. There are two timing chains, one goes from the crank to the dummy shaft and the other goes from the dummy shaft to the actual camshafts.
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Location:
Kilsyth, Melbourne
Registered:
September 2004
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Re: 2tg head on 3t block
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Wed, 13 April 2005 13:21
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oh yes thats rite i remember now
cheers, Calvin
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