I have two Subaru EZ30 engines bolted together. One is at TDC on cylinder one and the other is TDC cylinder six. They fire at the same time. I did this thinking it would Balance or cancel each other out for smooth running. The engines have a bad vibration. I don't think it is the connector as it includes two flex plates bolted together rim to rim. I'm thinking that the detonation is pushing the rear engine to the right and the front engine to the left and causing the vibration. Does this sound right?


If it would be better to have cylinders on the same side firing, here is my dilemma. The connector to the flex plates has the eight bolts like the flex plate. I could only rotate it 45, 90 and 135 degrees. I have heard that rotating one engine 30 degrees would put that engine out of sync with the other one so I could fire one cylinder at a time out of the 12 cylinders. If 30 degrees Is the Odd number, then would 90 get me into the same predicament?

If so, I have to modify the connector$$$ or brace the two engines better to the chassis. There might be some play. What do you guys think?

Thanks,

Jack

https://www.youtube.com/watch?v=bBsSs8bPrO8