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1937 timing hole cover

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Vintiage Pontiac Flathead Owners:


In another thread Paul asked if I had a 1937 Pontiac timing hole cover and, if so, could I share pictures.  I think that I have a two part answer: (1) Yes, I have a timing hole cover and (2) No, it is not from a 1937.


Here is a picture of the metal timing hole cover that I have:  It measures 1 9/16" in length and 1 5/16" in width (approximately).  I have also included a side and oblique view to show a bit more detail.











Finally, I have included the drawing of the clutch housing from my collection of multi-year Pontiac Master Parts books.  The drawing for the 1937-38 clutch housing does not show the actual timing hole cover (part group 0.714), but it does show that all 1926-1936 Pontiac engines used part number 487833.  It then lists 1938-1939 as part number 501383.  The 1939 clutch housing drawing shows a rubber timing hole cover ... so the 1938 (and, I suspect, the 1937) used the rubber timing hole cover.  Finally, the drawing for the 1041-1942 clutch housing shows the metal timing hole cover that I appear to incorrectly have on my 1937 6-cylinder engine.  I don't know how far beyond 1942 they used the same metal timing hole cover.











If anyone has more details, I'm sure we'd appreciate learning something further.






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Nice sleuth work on the rubber timing hole cover John.    I've looked into it in the past and found that Steele Rubber doesn't make a reproduction of the rubber cover.    I was figuring they for sure would have one on their rubber item list since that's their specialty but I guess not.    I also looked into California  Pontiac  Restoration and Kanter Auto Parts out east  but they don't have it either.    I was hoping someone made a reproduction of it but I guess I'll still be looking.   I imagine few timing hole covers survived due to years of under the hood heat that dries out the rubber and makes it stiff and brittle.    Which is probably why they simply shrink a bit and fall out of the hole over time.   I'll keep looking though anyway.


Thanks for the research.  Maybe someone will chime in with more insight!!



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  • 2 weeks later...



Thanks for that input. At this point, my working theory is that Pontiac 6 and 8 used the metal timing hole cover starting in ‘41 through the end of the flathead era. I also thing that the ‘37-‘39 used the rubber cover, with 1940 being unknown. 


Of course, I may be wrong and hope that anyone who knows differently will enlighten me. 


Thanks again, John, for your response. 



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Thanks for the pix, PP.    You've shown us these before in a previous post but this time with measurements.   That definitely helps!   I'm wondering if the strap across the front, which I assume is to pull it out of the timing hole, is made of the same foam rubber or is it made of something else?    It's hard to tell from the pix.   I'm also wondering if one could fabricate a copy with a 3D printer using a denser plastic that can be printed, which requires some serious heating of the plastic to liquefy it, and end up with a hole cover that can handle the under-the-hood heat buildup?    Guess I'd have to know more about 3D printers and certain plastic's properties.    Anyway, just a thought.


I'm amazed your timing hole cover looks that good with almost no deterioration after all these years.



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PP and Paul:


Thanks for those nice photos and discussion. When I have a chance, I’m going to talk to some folks that know a lot about 3D printing. I’m not sure they will do something like this for me. However, if I am not mistaken, the process is roughly:


1. Use a 3D printer to print a model  in just about any material. 


2. Send the model to someone like Steele Rubber. They make a mold from the original model and then use that to make parts out of their standard rubber material. 


I don’t know what they charge for setup … and what the resulting per part would cost, but it seems as if it is worth exploring …


Thanks again for those photos. 



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  • 4 months later...

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