I'm doing a rebuild on a 3800 V6 motor for a monte carlo and got the following out of round measurements for the rod journals on the crankshaft: 0.0004", 0.0003", 0.0005", 0.0003".

The tolerance according to GM is 0.0002" and I was wondering if the measurements I got are acceptable? I realize it is out of spec but how crucial is it that they are only less then 0.0003" over?

Can I reuse the crank or should I get it machined?

Thanks

 

did u use a reputable micrometer?

hey man will u come over on my thread about rebuilding a 3.8L and give me some pointers?

ive never messed with this v6 stuff before

 

Yeah the mics are brand new and measurements for everything else are accurate

Also, I wouldn't mind helping you out either but this is also my first time messing with this motor so we'll learn together i guess

 

Ouch. Ok, that was the wrong answer but you just don't realize it is.

Who is the manufacturer of the Micrometer and just because it is new is so the wrong answer I won't even get into it. The correct answer is - I have tested the micrometer on a set of gauge blocks of: .250, .375, .500, and .750.

As for the out of spec question, yes it is critical.

I would bring it to a machine shop, and more specifically a machine shop that specializes in race cars and performance vehicles. Otherwise bring it to a GM dealer and see who they recommend in the area.

 

That might have been harsh and it wasn't meant that way. Long day at work.

 

yank the pistons and rods and take it too a good machine shop!! one that won't lie to make money

have him mic it and he can put the rods back in round EASILY if he has the right machine tools!!

good luck

again i would appriciate some responces to my posts guys!!