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Old 10-28-2024, 05:38 PM   #5
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Join Date: Apr 2016
Location: Norway
Posts: 199
Pictures will be great. Thanks. Measurements would be lovely.

The 2.7, 3.2 and 3.4 cranks are interchangeable, so should use the same bearings. The rods are the same for all, so use the same bearings. The incompatibility lies in the chain drive to the IMS which is different for cars with the late updated type chain. The 2.5 has the early dual bicycle type chain.

I'm expecting the 2.5 crank to fit the 2.7, 3.2 and 3.4 crank carriers, but not the other way round. due to the longer throw.

According to some photos, the bearing tang on the 2.5 is different/mirrored from the later engines, but that should be fixable by cutting a new notch on the opposite side. My 951 has Supra rod bearings which have the notch on the opposite side from stock bearing shells. I machined notches on the opposite side of the big end bores to make them fit. Was relatively easy in a cheap Chinese lathe. I just needed to make a fixture for them on the cross slide.

I'm wondering if the 2.5 crank carrier can be machined to accept the longer throw of the 78mm cranks.
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1990 944 Turbo
2007 Renault Clio RS 197 (Sold)
1998 Boxster 2.5L Track Day/ Race Car
2011 Mistubishi i-MiEV
Norway

Last edited by Bebbetufs; 10-28-2024 at 05:41 PM.
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