what are possible causes of cams breaking
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what are possible causes of cams breaking
SBC and BBC billet cams that break towards the rear of the cam, but in front of the gear.
What could be causing this?
What could be causing this?
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Re: what are possible causes of cams breaking
Sounds like they need to increase the radius in the corner of the relief cuts.
Re: what are possible causes of cams breaking
1. High volume/high pressure oil pump
2. High valve spring pressures
3. High intensity lobe profiles
4. High lift lobe profile on a small diameter cam core.
2. High valve spring pressures
3. High intensity lobe profiles
4. High lift lobe profile on a small diameter cam core.
Jack Vines
Studebaker-Packard V8 Limited
Obsolete Engineering
Studebaker-Packard V8 Limited
Obsolete Engineering
Re: what are possible causes of cams breaking
There are multiple reasons, you can have a cam break, but the most common problem, is the induction hardened cores, some companies use.
A proper core, has the lobes and journals hardened, and the material between the lobes and journals(the barrel), left soft, so it's less brittle.
This allows the cam to flex and twist, without breaking.
On the mass-produced, induction hardened cams, the coils that heat treat the lobes, aren't always exactly over the lobes, and sometimes harden the area between the lobes. This is what causes them to crack and break between the lobes. The reason most SBC's and BBC's break at the back, is because the largest span between to journals is between the rear 2 journals.
Mike Jones
Jones Cam Designs
Denver, NC
jonescams@bellsouth.net
http://www.jonescams.com
Jones Cam Designs' HotPass Vendors Forum: viewforum.php?f=44
(704)489-2449
Jones Cam Designs
Denver, NC
jonescams@bellsouth.net
http://www.jonescams.com
Jones Cam Designs' HotPass Vendors Forum: viewforum.php?f=44
(704)489-2449
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Re: what are possible causes of cams breaking
Most of the ones I've seen come from the core manufacturer, Engine Power Components. They are Comp's biggest supplier, but sell to almost all cam companies.
Mike Jones
Jones Cam Designs
Denver, NC
jonescams@bellsouth.net
http://www.jonescams.com
Jones Cam Designs' HotPass Vendors Forum: viewforum.php?f=44
(704)489-2449
Jones Cam Designs
Denver, NC
jonescams@bellsouth.net
http://www.jonescams.com
Jones Cam Designs' HotPass Vendors Forum: viewforum.php?f=44
(704)489-2449
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Re: what are possible causes of cams breaking
How fast are you spinning this engine ? what are you driving the camshaft with chain, belt, gears ?
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Re: what are possible causes of cams breaking
That's what I was getting at. The few I have seen break, were comps. They were small base circle sbc cams though, with a fair bit of spring, and running a fair bit of rpm.
Re: what are possible causes of cams breaking
I’ve seen oil pump driveshafts forced down with distributor clamp twist, cam gears worn off off and pump gears ruined from lack of clearance.
Could be your breaking cams.? ...is pump shaft jammed tight with distributor clamp?
Could be your breaking cams.? ...is pump shaft jammed tight with distributor clamp?
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Re: what are possible causes of cams breaking
Broke two Comp cams on a blown BBC with a dry sump. No oil pump driven off the distributor. In fact engine uses a front drive distributor.
Both cams broke just past the last lobe in the rear.
Both cams broke just past the last lobe in the rear.