350 rod orientation question

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Old June 29th, 2013, 05:42 AM
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350 rod orientation question

A resent comment on Seth's engine has me worried about mine. engine has been rebuilt but not started. The post states
. " Also, the connecting rods must be oriented on the crank in such a way that the bearing tangs face the CAMSHAFT, not the pan rails(as some other GM's do)".
I Rebuilt my engine with speed pro flat tops. I had the rods shot peened and resized at the machine shop. They also installed the rods on the pistons. I made sure the pistons were oriented correctly when I installed them but did not check the orientation of the rod on the crank although all rods were oriented the same. The machine work was done by a respected Chebbie engine builder. What are the odds he would have installed the rods on the pistons wrong?
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Old June 29th, 2013, 06:46 AM
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If your not going to sleep its only a pan gasket . or is it in the car ?
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Old June 29th, 2013, 11:29 AM
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A friend put them in "wrong" in a 455, beat the crap out of it for 5-6 years. Then found out when he tore it down for a freshen what he had done. He had no problems.
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Old June 29th, 2013, 11:40 AM
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Originally Posted by 380 Racer
A friend put them in "wrong" in a 455, beat the crap out of it for 5-6 years. Then found out when he tore it down for a freshen what he had done. He had no problems.
I heard the same thing a couple of times. I am not positive, but I don't think there is a radius/chamfer issur like on some cranks and rods.
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Old June 29th, 2013, 12:56 PM
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The other easy way to tell, if your rods have oil spit holes (not all do), is that the holes point towards the cam.
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Old June 29th, 2013, 01:12 PM
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When you mark the rods for removal...don't they all face the same direction?
Piston arrow facing front..rods numbered and facing drivers side of motor?
Meaning the numbers are showing on one side of the motor.
When you re assemble the motor...the numbers should match up where they were removed from.

Last edited by Nasty455; June 29th, 2013 at 01:14 PM.
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Old June 29th, 2013, 02:02 PM
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Originally Posted by Nasty455
When you mark the rods for removal...don't they all face the same direction?
Piston arrow facing front..rods numbered and facing drivers side of motor?
Meaning the numbers are showing on one side of the motor.
When you re assemble the motor...the numbers should match up where they were removed from.
This makes sense if you are not replacing the pistons. If the pistons are being replaced, the shop will remove the old pistons, recon and balance the rods, and then press on the new pistons. Once the rods have been reconditioned and the crank turned, the numbers really don't matter. Hopefully, he will take note of the numbers and put 4 one way, 4 the other, in the correct orientation.

NOTE: Not sure if this applies, but at our shop we scribed the numbers on rather than beating them on with a whammer. Probably not an issue on a street engine, but just another of those little things that can add up. Obviously, if you stamp the numbers BEFORE reconning, it won't be an issue.

Last edited by captjim; June 29th, 2013 at 02:05 PM.
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Old June 29th, 2013, 03:41 PM
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Originally Posted by captjim
This makes sense if you are not replacing the pistons. If the pistons are being replaced, the shop will remove the old pistons, recon and balance the rods, and then press on the new pistons. Once the rods have been reconditioned and the crank turned, the numbers really don't matter. Hopefully, he will take note of the numbers and put 4 one way, 4 the other, in the correct orientation.

NOTE: Not sure if this applies, but at our shop we scribed the numbers on rather than beating them on with a whammer. Probably not an issue on a street engine, but just another of those little things that can add up. Obviously, if you stamp the numbers BEFORE reconning, it won't be an issue.
You hit the nail on the head. The engine builder told me to not worry with marking the rods since he was reconditioning them and we were installing new pistons and we were balancing the assy. I guess I will,go,ask,him about it Monday. Engine is in the car and the car is at the body shop so it isn't as simple as dropping the pan to find out.
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Old July 2nd, 2013, 09:55 AM
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Went and talked to the engine shop today and he said it could be a problem. He is going to pull a couple of Olds rods and look at them to be sure. And give me a call. I am really going to hate pulling this thing back out of a freshly painted car to figure this out? There were a couple of comments in this thread that it really doesn't matter. Any opinions on this would be appreciated. My engine is a 350 not a 455.
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Old July 2nd, 2013, 01:38 PM
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Originally Posted by captjim
I heard the same thing a couple of times. I am not positive, but I don't think there is a radius/chamfer issur like on some cranks and rods.
Hey Jim,
Do you know of anyway to verify this?
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