What's the difference? (Timing cover)

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WinginEngineer
Posts: 150
Joined: Sat Sep 03, 2016 3:31 pm

What's the difference? (Timing cover)

Post by WinginEngineer »

My ignorance is going shine through bright again...

I'm tearing my engine(s) down for rebuild and noticed something. I'm not sure what to call the cover/housing on the "back" of the motor. It doesn't actually house the timing set, but since it still houses the distributor I guess I'll still call it a timing cover.

Regardless, the "timing cover" is different between the two motors. Both are '62 (supposedly). So what's the difference here and which one should I be using on the finished product?

Here are pictures of the visible differences...
Attachments
20170611_102423.jpg
20170611_102430.jpg
Kevin - Phoenix/Mesa, AZ
1962 Corvair 700
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bbodie52
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Re: What's the difference? (Timing cover)

Post by bbodie52 »

I noticed the same thing when I started rebuilding Corvair engines as a teenager back in the 1960s. They are simply called the "rear housing". Some of them were produced with a rough casting and were machined differently as a part of the production process. The remainder have a smoother aluminum casting and slight variations in the way they were machined and finished. All were interchangeable, but I think you need to watch the oil pump gear clearances — especially if you move the pump years from one housing to another. There is a procedure to utilize Plastigauge to measure the pump clearance to the oil pump cover. There are actually a range of gaskets in different thicknesses to allow the clearance to be adjusted. Also, as shown in the photo below, the rear housings that were installed on the turbocharged engines that were produced from 1962 to 1966 had a different timing scale riveted to the housing (to increase the scale up to 24°). Clark's Corvair Parts also lists a different part number for their used rear housings for the 1960 Corvair — indicating that it has a "solid upper casting".

Early rear covers are sand cast aluminum, while later rear housings are die cast. Sand cast covers are heavier.

Corvair Rear Housing Timing Marks.jpg
Rear Housing Vairiations.jpg
Rear Housing Vairiations (2).jpg
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible
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