Engine Boreing For 3t

[flamingheads]

I've got a 3T engine and it has to be bored out and I was wondering if it's worth getting it bored up to 2 litres.

The engine is stock with extractors and exhaust and will have a down draught webber. Would giving it a bigger bore give any performance gains?

And does anyone know somewhere good to go to on the sunshine coast? Cheap is good.

Thanks

[kiahn]

first of all is it even possible to goto 2 litres with a 3t without putting new sleeves in?

displacement is the best way to get power as it gives you a better base to start with, but why? what the car going to be used for?

id say go 20 thou over and buy some nice pistons and rings so they last

 

but long story short if your gonna bore it out that much you wont have room to rebore it when it comes time to rebuild,

that said a 2 litre will obviously have a heads up on a 1.8.

 

ask around here what is good to get done:

http://www.toyota3tc.com/

Edited August 21, 2009 by kiahn

[snot35]

I think most 3T's are supposed to bore up to 2lt quite well. I've seen 88.5 and 89mm piston options around, but I don't know of their availability. You may have to spend a bit.

 

It's a pretty common mod. It will make the motor less revvy, unless you change things to take full advantage of it. You may or may not want this. Coupled with other mods it should make quite a difference.

[kiahn]

yeh but that changing the stroke as well

stock they are 85x78 (bore x stroke) he is talking about just boring it out which is why i said that its a bit risky.

btw wiseco make some really epic pistons for 3t's 00, 20 and 40 thou over. possibly more things too so go check out their site, but their pricey

[styler]

the 2 litre 2tg, aka 3tg hybrid, is a combination of

2tg motor and 3tc crank and matching 89mm 3tc oversize pistons.

it works out at 89mm bore x 78mm stroke = 1940cc and is called the "2 Litre".

 

in the t series blocks - 2t, 2tg, 3t, 3tgteu families:

 

interchangable crankshafts at 70mm for 2t and 78mm for 3t

you must use matching crank and pistons though:

 

2t crank + 2t pistons

3t crank + 3t pistons

 

3t pistons in mm:

 

85 - cast

86 - cast or forged

87 - forged

88 - forged

89 - forged

90 - forged

 

85 for NA

86 cast for NA

86 forged for high boost or NA

87 for high boost or NA

88 for med boost or NA

88.5 med boost or NA

89 NA (suitable block recommended or liners)

90 NA (suitable block required or liners)

90 grout filled block for high boost drag (liners)

 

at 2 litre or similar you retain most of the oversquare characteristic

of the motor bore/stroke ratio which is often attributed to the how the motor

revs and the power curve, to a degree... oversquare is for revs and undersquare

is for torque.

 

3t crank has 8 counterweights and as such is heavier in weight and in

rotational inertia.

 

2t crank has 4 counterweights and as such is lighter in weight and in

rotational inertia.

Edited August 21, 2009 by styler