V8 Camshaft Bolt Pattern

Biggles, you can order a digital copy of the part drawing from the Benson Ford Research Center, $30/per drawing. I am trying it for the first time this week and they said I should get a digital copy of the drawing I requested shortly after the first of the year.
 
Thank you, that will be a great help.

I'm making a jig/tool to re-drill the camshaft mounting holes in the timing gear to enable the camshaft to be advanced or retarded anything up to five degrees.

Why? Because by degreeing various camshafts it has been discovered that some are as much as 3 degrees away from specification. For example:

Max-1-data.jpg
 
Biggles said:
Thank you, that will be a great help.

I'm making a jig/tool to re-drill the camshaft mounting holes in the timing gear to enable the camshaft to be advanced or retarded anything up to five degrees.

Why? Because by degreeing various camshafts it has been discovered that some are as much as 3 degrees away from specification. For example:

Max-1-data.jpg
Click to expand...

There's an easy way, we use the SBC "pills" to adjust the timing!

I'll put some shots below!

Thanks, Gary in N.Y.

P.S. With our method you can get more than 5* if needed?
 

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  • Flathead Cam Gear Drilled For Pin-Letter E Drill.jpg
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I've filed the holes and used star washers if I thought changing the cam timing would help. However, for mosy applications, I don't think 2 or 3 degrees makes much difference.
Gramps
 
Biggles said:
Thank you, that will be a great help.

I'm making a jig/tool to re-drill the camshaft mounting holes in the timing gear to enable the camshaft to be advanced or retarded anything up to five degrees.

Why? Because by degreeing various camshafts it has been discovered that some are as much as 3 degrees away from specification. For example:

Max-1-data.jpg
Click to expand...

If you did a lot of them, you would find some are off more than 3 degrees.
From your profile I see you are qualified to figure out the math and I assume you have the shop equipment to do the work so why not just set the gear up on the turntable and drill it where you need it?
If you are careful you can drill 3 new offset set of holes.
 
Here is what you need - I cut if from a PDF that came from a fellow flathead racer. When I checked my CAD model, I did not have the bolt pattern detailed as of yet and I don't have time to get to it - so a raster image will have to do.

This should give you everything you need (you may need to zoom in).

Flathead-21A-CAM-Front.jpg
 
That cam end drawing looks very interesting. Lots of useful info there.

I can't speak of all the dimensions, I would like to believe they are ok, but the thread callout as 1/4-28 is an error It's 5/16-24.

Mart.
 
Mart said:
That cam end drawing looks very interesting. Lots of useful info there.

I can't speak of all the dimensions, I would like to believe they are ok, but the thread callout as 1/4-28 is an error It's 5/16-24.

Mart.
Click to expand...

Yep - I didn't catch that, but I have the correct threaded holes in my 3D CAD model - just didn't have time to do the 2D detail drawings and modify the snout for the earlier t-slot setup.
 
To me, it is an easy job with a rotary table and a 'pointer' to a cam tooth (marked as the install tooth). Once you setup on the stock locations and the pointer on the stock 'indexed tooth" - then determine where the first hole is, then you can select a "new tooth" to be the indexed tooth and use the degree markings to know where to drill each hole (advanced or retarded). Easy peasy! LOL

I'd probably make a quick aluminum "centering mandrel" - that fits in the hole on my rotary table and picks up the center hole on the cam gear (with a drilled/tapped hole in the center to hold down the cam gear) - making it very easy to pop one on the table and have things ready to rock.

Heck, since I'm going to be putting a 302 CI flathead together in January, might just have to set this up for shits and giggles - will post back to this thread.
 
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Bored&Stroked said:
Heck, since I'm going to be putting a 302 CI flathead together in January, might just have to set this up for shits and giggles - will post back to this thread.
Click to expand...

Got all you said, B&S.

Heck, since I'm putting together a 286 CI 21-stud, there may be no time for messing with cam jigs, even for sh*ts and giggles. :)

Look forward to your post back - me too.
Thanks, all.
 
Biggles said:
Got all you said, B&S.

Heck, since I'm putting together a 286 CI 21-stud, there may be no time for messing with cam jigs, even for sh*ts and giggles. :)

Look forward to your post back - me too.
Thanks, all.
Click to expand...

How are you getting a big enough bore for 286 cubes?
 
One thought : He's in England so he's probably working with a Pilot engine. The only thing I really know about them is that they were also produced after the war. Do you suppose that could make any difference?
 
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