OK, now I can understand why you mentioned the timing chain. Yes, if plastic pieces are found in the screen or bottom of the pan in the sludge I agree with you that the timing gear would need replaced or the oil fill screen will plug up again with more plastic.

When I replaced my 318 with the 360 I used a true double roller steel chain and gears without any plastic cover. As far as I know this is probably the best set-up when considering performance, reliability, and noise. I can be under the hood and barely hear any timing chain noise. I've attached a photo of my engine showing the timing gears and chain. Haven't had any experience with a total gear drive setup.

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