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Base Circle Dimension

Started by Ohio HD, October 30, 2023, 04:36:27 PM

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Ohio HD

Does anyone know the base circle for the stock HD cams in the M8?

hrdtail78

Which lope?  All lopes are not the same.
Semper Fi

Ohio HD

If there are different base circles I'd like to know what they all are.

hrdtail78

Front to rear. 
FE 1.510
RE 1.3615
FI 1.424
RI 1.5

Sorry, I got busy.   DM me your address and I will send you a take out if you want one.
Semper Fi

Ohio HD

No problem, thanks Jason. I didn't know they were made with different base circles, but I guess that works with trying to balance front to rear pushrods and lifter depths.

I appreciate it.

Ohio HD

November 14, 2023, 05:08:15 PM #5 Last Edit: November 15, 2023, 09:10:15 AM by Ohio HD
So I had a chance today to look over the M8 cam that hrdtail78 sent me, thanks Jason.

This may be old news to some, but it's the first M8 OEM cam I've had my hands on. As best as I can tell the cam is made from seven different parts. The inner end of the cam looks like there's a pressed on bearing race, and then looks to we welded, resistance welded. Also the outer end of the cam, the spline and race look to be pressed on. The lobes are pressed on. And there's an ID dimple on each lobe, at a different place on each lobe to identify which one is what for assembly purposes.

My guess is they machine each lobe from a longer length of stock, and possibly wire EDM cut to width. That may not be what they do, but it would be one way to make make lobes with less grinder time. 

When making lots of cams, this is a less costly way to do it.











cheech

Quote from: Ohio HD on November 14, 2023, 05:08:15 PMMy guess is they machine each lobe from a longer length of stock, and possibly wire EDM cut to width. That may not be what they do, but it would be one way to make make lobes with less grinder time. 
Nice info.

Although the way those dimples appear and the surface finish on the side of the lobes, my first guess would be pressing those out of powdered metal like all the auto OEM's are doing for connecting rods it seems these days.

No argument, just that's my first guess.
One of us may be right or none.   :nix:

Actually, came across these as a result of wondering about it.

Lobe Producer
SAE paper

Ohio HD

November 19, 2023, 09:57:22 AM #7 Last Edit: November 19, 2023, 10:03:03 AM by Ohio HD
That's actually a good possibility.

Powdered metals have come a long way in the 15 years. When I was still working we sourced all of our raw steel from a powdered metal supplier in Germany, and had the blanks machined and heat treated in Italy. That was some tough steel. When we got them we would EDM the shapes needed for our customers.

If you ever saw a powdered metal press, some are huge. They sometimes go into the floor up to two stories in some cases.

https://www.e-ci.com/pm-presses

https://www.e-ci.com/power-die-change-compacting-pm-presses

FSG

QuoteAlthough the way those dimples appear and the surface finish on the side of the lobes, my first guess would be pressing those out of powdered metal like all the auto OEM's are doing for connecting rods it seems these days.

HD has done it that way in the past ......  remember the CVO Cams and others with incorrectly positioned lobes ?  There was a SB Bulletin covering them.

Ohio HD

I must have missed that, was it early CVO bikes?

hrdtail78

I have pulled TC cams that are manufactured like this.  I really can't recall out of which bikes though.  Just noticed the lopes looked pressed on. 
Semper Fi