External balance for even fire 231

MacDiesel

Newbie
I am hoping one of you can help me. My CJ had an engine swap done by the previous owner to an odd fire Buick 231. I am now replacing that engine with an even fire 231. My new engine should be here on Friday, but I do not know how to correctly install the flex plate.

I do know that both the odd and even fire engines are externally balanced, and I have purchased the correct flex plate and harmonic balancer for the new even fire engine. The problem I am having is the bolt pattern on the flex plate is not (or does not appear to be) asymmetrical, and I am worried I will not have this installed correctly. Everything I have found talks about marking the old flex plate / flywheel and installing the new one in the same orientation. I still have the old odd fire engine and flex plate and I had marked them, but I am guessing that the orientation is different.

Does anyone know what the correct orientation is for the flex plate? I have emailed the vendor I ordered my engine through several times, but they have been unable to help with this.

The new even fire flex plate has several letters / numbers stamped around the outside edge. If I have it sitting with the number 3 (at the 12:00 position), the numbers going around are 5 at roughly 2:00, S at around 4:00 followed closely by a 7, 6 at 6:00, 11 at around 8:00, and 1 at around 10:00. I'm hoping that when you set the engine to TDC for the number 1 cylinder there is an identifiable way to correctly index this flex plate to the engine. If it helps the flex plate appears to be weighted heavier (less material removed) between the 6 and 11 at around 7:00 as I have it sitting.
 
I am hoping one of you can help me. My CJ had an engine swap done by the previous owner to an odd fire Buick 231. I am now replacing that engine with an even fire 231. My new engine should be here on Friday, but I do not know how to correctly install the flex plate.

I do know that both the odd and even fire engines are externally balanced, and I have purchased the correct flex plate and harmonic balancer for the new even fire engine. The problem I am having is the bolt pattern on the flex plate is not (or does not appear to be) asymmetrical, and I am worried I will not have this installed correctly. Everything I have found talks about marking the old flex plate / flywheel and installing the new one in the same orientation. I still have the old odd fire engine and flex plate and I had marked them, but I am guessing that the orientation is different.

Does anyone know what the correct orientation is for the flex plate? I have emailed the vendor I ordered my engine through several times, but they have been unable to help with this.

The new even fire flex plate has several letters / numbers stamped around the outside edge. If I have it sitting with the number 3 (at the 12:00 position), the numbers going around are 5 at roughly 2:00, S at around 4:00 followed closely by a 7, 6 at 6:00, 11 at around 8:00, and 1 at around 10:00. I'm hoping that when you set the engine to TDC for the number 1 cylinder there is an identifiable way to correctly index this flex plate to the engine. If it helps the flex plate appears to be weighted heavier (less material removed) between the 6 and 11 at around 7:00 as I have it sitting.
If it helps I have36B4EBD6-C2FA-4C7E-9E80-95544E528735.jpeg attached a picture of the flex plate off my old odd fire engine. With the number 1 cylinder at TDC the heavier part of the flex plate between 6 and 11 is at the 12:00 position when installed on the engine.
 
I am not familiar with the even/odd v-6's. The '67 parts book shows different numbers for the odd and even fire.
Looking on ebay at odd and even fire flywheels there appears that there may be some difference.
I would suspect some difference because of the crankshaft configuration.
The offset bolt hole should only allow the flywheel to bolt on in one position.

They don't appear to be expensive:

even fire flywheel, click here
1


odd fire flywheel, click here
1
 
You can't install it the wrong way. It will only bolt on one way. That's the reason for the asymmetrical bolt pattern.
 
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