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Two liter 1725

B

Bill Blue

Platinum Level Sponsor
Been thinking about the Mitsu connecting rod with a 1.71" big end. When used with an offset ground crank and +.060" pistons would yield two plus liters. Question of the day, taking into account the lower rev limit due to the stroke and rod diameter, how would this shake out for use on the street? I'm thinking about a torquey engine (say with a "KB" cam) with a rev limit in the 5500 to 6000 range. Would such rpms even be advisable?

Bill
 
alpine_64

alpine_64

Donation Time
Bill the 2120 motors were reliable on street from the ones i knew.
They were carefully assembled.
1 owner who had 2 x 45 dcoe used to run it up to 6k.. But the torque it had meant at 3-4500 you had plenty of go for street driving.
Its been a long time since ive seen one.. But did spot on a messsge group one of the 2120 2x40dcoe cars recently .. Was hooked up in an automatic SIV alpine where the BW35 was replaced with a later BW40 iitc.. Current owner has it in same spec.. Car was built maybe 1999...
 
B

Bill Blue

Platinum Level Sponsor
Michael, I cannot find the particulars on the 2120 motor. Could you be so kind as to repeat them here? If possible, the source and critical dimensions of the components. Also, any block modifications needed.

Bill
 
alpine_64

alpine_64

Donation Time
Bill can only go from memory for the moment.
It used Mitsubishi starion turbo pistons and rods. The pistons fot machiened at thw crowns to reduce some of the dish (original low compression for turbo) the crank was offset ground.
The bore was 110 over iirc and requires a custom head gasket as stock HG won't go more than .060.
The heads chambers also need to be opened up a bit to lower the compression... Or maybe you could not modify the pistons...but guess you need to chefk deck height and piston to.deck clearance.

I might be able to get someone who used to have one of the motors to get the specifics.

UK guys and later in Australia and NZ did a just on 2ltr with volvo pistons too...
 
spmdr

spmdr

Diamond Level Sponsor
I have a 1592 with a (untested) BIG Bore of 3.425" (+.215 OVER Bore!)

And that got me wondering what the cylinder wall thickness is.

So I did a quick check of 2 stock bore blocks.

I found the 1592 had a minimum of .210 cylinder wall thickness

And the 1725 had a minimum of .180 cylinder wall thickness.

YMMV.

DW
 
bernd_st

bernd_st

Bronze Level Sponsor
... or work with cylinder liners. Then only the headgasket sealing ring/compression ratio would be the limit...
 
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