I agree with all your guys concerns.

I also wonder why there are no hollow aftermarket cams available.


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http://www.takakaira.co.jp/

you can find anything there.
and they ship anywhere.

 

mostly you worry about the thickness for structural integrity, once you have that measurement... you're done. all you ahve to do is see how large the bore is on a stock cam.

as for being balanced... that's a trick but how do they balance solid ones? you just use ultra uniform billets. if you have it machined correctly... then it should maintain its balance (THIS IS THE TRICK THO, the hardest part, which is why using mitsu billets is better).

you do have to make sure that the angle is correct all teh way through but this goes hand in hand wtih making sure it's balanced.

i guess the million dollar question is where do these blanks come from... and how are they made with what machine. once that's answered if ANYTHINg, this machine can be outsourced... these can be made... cams can be ground.... problem is these are made in japan... not in taiwan, which means if they did come out... they'd be big bucks. unless we can find another manufacturer of cars that puts out hollow cam equipt oem vehicles.... anyone know if corvettes come wtih hollow cams?

 

I had read that HKS was using oem billets. If that is true (HKS are not hollow) then the drilling is done after the fact right. Someone knows about this somewhere, it must be a cost thing. I personally would pay a premium to get hollow oem or better quality cams for future tuning goals. Seems there would be a market for them. We will find out soon enough from Z-1. He seems the only one interested in this thread.

 

So adam what did you find out...?

 

no reply yet...they are typically very slow to answer emails as of late for some reason

 

I think they are cast hollow. Then machined. In addition to reduced mass hollow cams aid in valve train lubrication.

 

I searched in 2003 to see if I could find any hollow camshafts and I could not find any. Adam, if you find some please PM me as I would be most likely to buy them that instant

 

Thanks Adam we will stay tuned!

 

Reducing mass at the center of rotation has virtually no effect on rotational inertia, remember there is no lever arm length at the center.

 

but the overall mass does play into the equation MR^2... since the radius stays the same then the most you can do is change the overall mass... in case you're wondering where i got the MR^2 from it's the moment of inertia for a ring which can be generalized to describe a hollow rod as the rod can be a an infinite sum of thin rings.

 

Does anyone have a good picture of the OEM hollow cam? I would quite like to seem it. Also, some dimensions will be nice.

Where I work, we can do deep hole boring. However, it depends on the hole size/diameter ration and also the sort fo finish you want on the hole surface. If it's too deep and slender, our mahcine might not be able to hadle it. We do have several gun drills, but they are for much smaller holes. If the hole is as big as I think it is, then you might get away with boring from both sides to meet in the middle with really good CNC machine (which we have). It all depends in dimensions. If anyone has a blank they want drilling, we might be interested.

In any case, I think it would probably be simplest of Mitsubishi casts them hollow. I think camshafts goes through a hardening process and so if you drill after all that is done, you'll never get through. I rekon the steps are:

1.) Cast hollow 2.)Machine 3.)Hardening 4.)Grind and balance.

If they're not cast hollow, then you'll drill them before machining.

I don't make cams, so if the steps above are totally wrong, please correct me.

 

deep hole boring... that sounds a lil dirty . but this sounds very promising...

i think the longitudinal balance of a cam shaft is not so important... the cam is held down... i mean so is the crank shaft but the difference is the crank shaft has a huge lever moment and the worst is does is cause vibrations, which yes can be damaging but you see where i'm going... what's the cam gonna do? it's fairly well fixed in there... i think as long as you're not jackass drilling it way sideways it should be fine.

but from here on out it's all about structural integrity... we don't know how much is too much. the aftermarket cams may not be made to the same stregth or hardness that the stock ones are, what if the stockers are more strong to take the hollowness... it's a minor concern. cuz if anything just drill less. but this is all very promising!!!

and while you have all the equipement you don't even have to drill ALL the way through... what if you just made some channels... camshaft lightening... i mean that's waht we're here for anyhow... so if you don't have a long enough gun drill then don't do it all the way through... some is better than none... you can make semihollow cams!!!

 

Been thinking about the bore size,

The thing is, torque capacities of a hollow shaft and a solid one aren't all that different. Obviously it reduces, but not by it's usually more than offset by the weight it removes.

The important bit is the transverse load, the force the follower pushes on the camshaft. The capacity is much decreased. Whether this is important you need to know the shaft size, spring rate, cam shaft profile etc. but i suspect that this isn't all that much.

What I think happens is that when they harden, there's some distortion. I believe there will be more distortion in hollow camshafts than in a solid one. Mitsubishi can afford the greater distortion by leaving more metal for grinding. And they can do this 'cos they probably have about a thousand cam grinders.

So, I propose that the problem is in production, rather than strength.

Oh, btw I think JUN do BOTH solid and hollow camshafts. Strangely, the hollow ones are cheaper.

 

please see my post...they do not offer hollow