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Registered
Join Date: Apr 2012
Posts: 12
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2.2 L upgrade to 70.4 mm crank
Hi. I've got a stock 1970 911T that never has been apart and needs a rebuild. It leaks like a sieve. All the O rings have turned to dust.
While rebuilding, I have the opportunity to install a 70.4 mm crank and rods from a 2.7 liter. Lets assume the original pistons and cylinders are reusable. (Cast iron cylinders honed and new rings.) What compression ratio will this combination create? Also, will the original flywheel bolt up to the 70.4 mm crank. Thanks |
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Registered
Join Date: Oct 2008
Location: Nash County, NC.
Posts: 8,492
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Compression would change upward to 9.2 but youll need to modify the skirts of the Pistons to clear the counterbalance of the crank. You're pistons are castings and don't have the strength of the E or S Pistons.
I believe I would save the crank and build back "T" Flywheel will bolt up. Bruce |
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Registered
Join Date: Apr 2012
Posts: 12
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Thanks but why build back to T?
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Registered User
Join Date: Aug 2010
Location: Küsten, Germany
Posts: 175
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Assuming P/Cs are in good condition 2,2T upgrade to 70,4 works well.
Depends on the pistons you have check the skirts' clearance to crank. I did it it once with no need for machining. |
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Registered
Join Date: Mar 2002
Location: longbeach
Posts: 925
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Put solex cams in it also and this will be a great torque engine that will rev out too.S
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Registered User
Join Date: Aug 2010
Location: Küsten, Germany
Posts: 175
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In that case valve pockets should be checked for valve clearance.
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Registered
Join Date: Apr 2012
Posts: 12
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Should I use solex or E cams?
Thanks |
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