Author Topic: Modifying an Offenhauser cast aluminum valve cover --  (Read 2416 times)

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Offline goodfellow

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Modifying an Offenhauser cast aluminum valve cover --
« on: November 14, 2009, 08:46:10 PM »
It's not a big deal, but when most people think of a "small milling job" rarely do they realize the amount of time that setup and preparation work requires. This job took almost two hours, and most of it was spent on setup and planning the cuts, -- especially the finish cuts. Nevertheless, it was a fun time in the machine shop this afternoon.

It's an Offy cast aluminum cover for a 67 Chevelle six banger. The original stamped cover has a second opening for the PCV valve, and this one needed to follow suit.

Offenhauser does make nice products and I hated to cut it, but that's what was required.



This is the OEM oil filler and it needed a second opening further down for the PCV valve -- it also needed to be spaced right so that the valve train doesn't interfere with the PCV valve once it's seated in place.





The hardest part was coming up with a clamping setup to hold this thing steady and true.



Once that hurdle was covered, the milling is straight forward -- work from the inside out with a fast speed and slow feed. A bit of Marvel Mystery Oil is a good lubricant and makes for easy cutting.





After "hogging" all the aluminum you can see the mess. I kept a steady stream of compressed air flowing to blow away any chip buildup. Chip buildup can ruin an aluminum finish very quickly.



This is the roughed in pocket  --



Next we mark center and use a hole saw to cut the PCV opening (very slow speed  -- 75 RPM on this geared head mill) and lots of Marvel Oil.





One final pass under the mill for a finish "shave" and this is the end result --




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Modifying an Offenhauser cast aluminum valve cover --
« on: November 14, 2009, 08:46:10 PM »

Offline rusty

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Re: Modifying an Offenhauser cast aluminum valve cover --
« Reply #1 on: November 14, 2009, 08:52:56 PM »
Very nice work. Getting the radius to match the oil fill will be a bear.
Tool do job=Good tool

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Offline goodfellow

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Re: Modifying an Offenhauser cast aluminum valve cover --
« Reply #2 on: November 14, 2009, 09:11:20 PM »
Glad I won't have to do it since I don't have any roundover cutter tooling. Well, not yet at least -- I ordered a set from Enco just this evening .  Until then, -- my friend will have to work with a Dremel to do match it up.

Offline rusty

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Re: Modifying an Offenhauser cast aluminum valve cover --
« Reply #3 on: November 14, 2009, 09:19:39 PM »
Ye gods, I hope he has steadier hands then I do to try that!!!
Tool do job=Good tool

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Offline goodfellow

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Re: Modifying an Offenhauser cast aluminum valve cover --
« Reply #4 on: November 30, 2009, 08:55:45 AM »
This is the finished product. The owner did an excellent job in finishing the engine and the valve cover. It looks very professional and gives that inline six Chevy motor a clean "old school" look. The fit/finish is very well done.  :spincl:




Offline rusty

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Re: Modifying an Offenhauser cast aluminum valve cover --
« Reply #5 on: November 30, 2009, 02:25:58 PM »
Very nice job! It looks excellent. Now what is it going into?
Tool do job=Good tool

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Offline goodfellow

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Re: Modifying an Offenhauser cast aluminum valve cover --
« Reply #6 on: November 30, 2009, 02:53:40 PM »
Very nice job! It looks excellent. Now what is it going into?


'67 Chevelle 4-door --

http://www.garagehangout.com/forum/index.php?topic=1923.0

The car is in this GH thread. Very basic --, but a true survivor and the owner is putting some good money into the resto.
« Last Edit: November 30, 2009, 02:55:52 PM by goodfellow »