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Gentleman; those of you out there with what you think is the orig timing tab on your 396's(Vette only), please have a look at it and post a description. i'm particurly interested in the shape of the exposed portion of the tab, not the side that's tack welded to the cover.BTW, if you're cover has holes drilled for alignment plugs and/or its got a captive nut to bolt the oil pan to the cover, go no further as you probably don't have an orig 396 cover. thanks guys, mike
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Re: 396 timing chain cover timing tab
Mike -- Per '65 Tech Manual, the 396 oil pan and timing cover SHOULD have the hole and square captive nut (respectively) for securing the front of the pan to the cover. I'm under the impression that this carried on through the 1966 model year. -
Is either one of the marks pictured on
pages 6-9 or 6-28 of the 1965 Interim Shop Manual correct? No speakie
Boat motors....Comment
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Re: 396 timing chain cover timing tab
Wayne; you're correct. i had it ass backwards--i blame it on old flatus. anyway, what i need to now is the shape of the exposed side of the tab: is it rectangular or L-shaped? thanks for catching my mistake. mikeComment
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Re: Is either one of the marks pictured on
Loren: Photo in fig. 14, 6-9 of interim sm doesn't include the lower 10 to 20 % of tyhe exposed tab that i have questions about. seems the other cover in fig 16V is way too blurry for exam. thnks, mikeComment
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Re: 396 timing chain cover timing tab
Mike-----
Known original timing covers for 1965 L-78s that I've examined have a completely rectangular shape for the timing tab. This is unlike some reproductions that I've seen which have an angled top edge. Also,reproductions have a small, circular "relief" at the lower edge of the tab's bent over portion. This "relief" was not present on originals I've seen. It is possible, though, that tabs like the reproductions were also used.
It's hard to say if ALL of these L-78 tabs were configured as I described. Only one cover part number was ever used for 1965 L-78s, GM #3860068, but it's possible that the tab varied. Perhaps others can shed some light on this with some more "empirical evidence".In Appreciation of John HinckleyComment
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Re: 396 timing chain cover timing tab
Joe: in anticipation of assemblying the 396 for my coupe, i drug out the pile of Mark 4 timing chain covers and i have three tab styles on the non-drilled for index type covers. My 396 conv with 37k miles on its got a perfectly rectangular exposed tab, not l-shaped, not angled on top, nor not arc cut on lower inside edge(like a 66 and 67 BB ought to have--ie, arc'd)Lets see what the rest of the gang comes up with on tab morphology. thanks, mikeComment
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Re: 396 timing chain cover timing tab
Mike the one I have off of 16120 has squared smooth edges 1 1/2"long with 11 degree marks stamped O being the 3rd mark from the bottom.this is a 65 only part. 66 425s were different. I dont know when the change was made .I would think there would be some overlap ? these are very hard to find .the repro tabs I have seen are not correct. and most cars I have looked at do not have the orig.
When you get to the main bearing bolts see how the windage tray is held on ? 16120 had hollow main bolt ends with bolts, not nuts holding the tray . Also the pans are a little different to . Good luck Bill. PS I can E mail photos if needed.Comment
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Re: 396 timing chain cover timing tab
Bill ; thanks for input . could you email a pic of the tab? mikeComment
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Re: 396 timing chain cover timing tab
Mikie, is it possible that the 396 in question is another "Honest Uncle Billy Clements" creation?????Dick WhittingtonComment
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Re: 396 timing chain cover timing tab
It's a D Q creation. mikeComment
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Re: 396 timing chain cover timing tab
Mike, I checked what I believe to be the original timing cover on 20720 and it has the rectangular shape (does not have an 'R' stamped on it, very short below '0'). Also checked a timing cover for a 7" balancer (hydraulic 66 390 HP car) and it is 'L' shaped. Have a cover for a 8" balancer (solid 66/maybe solid 67 car) and it has the tapered top with the circular relief cut near the bottom. Hope this helps; can send pics.Comment
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Re: 396 timing chain cover timing tab
Dan: thanks for the info--it agrees with my feel for the tabs on the 65, 66 and 67 BB. mikeComment
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