3400 Interchange Problem....Help!

[Andrew91PGT]

Hey guys/gals, I am new to the site, but a big fan of the 3100 3400 motors. I am in the middle of replacing an engine on a 2003 Grand Am GT.

I have always been under the impression that a 3400 is a 3400 when it comes down to the heads and block, no matter the year, with the exception being the Equinox.

I purchased a low mileage 2005 Buick Rendezvous 3400 engine. Everything externally looks near identical with the exception of the motor mount brackets and locations, alternator mounting, etc.

Well, I got everything swapped over that I needed from the Grand Am's original engine (including the oil pan because the rendezvous did not have an oil level sensor -wtf!) Then I got to the flywheel/flexplate. The new engine did not have one installed, so I removed the Grand Am one from the original motor. It does not fit the rear "snout" of the Rendezvous crankshaft? Has anyone ran across this or heard of it? It's a difference of .009-.010 of an inch so I planned on having a machine shop hone out the flywheel hole to fit it to the new engine. Just wondering if I missed something????

[Superdave]

Never heard of that, the snout should be the same.

I'd just take a die grinder to it if it's that small of a difference, that'll take a minute or 2 to clear up.

[Andrew91PGT]

Never heard of that, the snout should be the same.

I'd just take a die grinder to it if it's that small of a difference, that'll take a minute or 2 to clear up.

Yes, I was suprised too. I did exactly that with a die grinder. Just oversized the flywheel hole slightly. Took less than a minute. I was more concerned about a crankshaft difference that I could not see, like maybe a different trigger wheel, or something more serious. But, all went well and smooth, this was the only big issue that came up.

The 2005 Rendezvous crank was deffinately larger than the one
from the 2003 Grand Am. But, all worked out other than that, engine has over 200 miles on it in its new home.