also check with forced performance they have new cams out for the evo that may be hollow
http://linux.forcedperformance.net/m...ode=Lancer_EVO

 

I've read the posts. Which is why I did say I _think_ they do both. I don't know what 'lash' type means but on this page http://www.junauto.co.jp/products/cy...aft-4g63.html?
They seem to do 'Lash' type and solid type. Now I think solid means that it's solid, then 'lash' means hollow? In a Japanese english sort of way? Perhaps it means forged as in made from a forged blank as opposed to one machines from a solid cylindrical block.

I really don't know what it means. Strangely it is cheaper which to me suggests that it is likely to be cast hollow (foundries charge mainly by the weight). If it is machined from a forged casting, it should be more expensive due to the forging costs.

Perhaps Lash is a cam terminology? They don't state COLD valve clearance with the solid type, perhaps they are talking abou solid lifters?

 

Lash type is for standard valvetrain, solid type is for use with Solid Lifters (ie very high rpm use)

 

alright, so my _third_ guess was right. Cheers mate.

Any idea why it's more expensive?

 

Using solid lifters allows a properly built motor to reach higher RPM levels without having to shift as quickly. In racing, shifting = lost time. I don't think you can put in solid lifters without some serious planning if you are wanting to rev your 4G63 up to 10k.

Someone correct me if I am wrong, since I am a total amature

 

From looking at stock cams, they look to be cast hollow. There are many relief holes along the whole shaft, which I'm guessing are there to allow the casting material to be released.

 

hey...... is that a hollow cam i see? but their speak is all different from the 272 280 crap we're used to.

 

the small holes are prolly in case if any oil goes in, it comes out easily rather than having to go right to the other end.

 

Interesting ? Good price and specs too.


.

 

I read an article in Motor Trend referring to the cams as "gun drilled". It would make sense to cast the cores hollow and them grind them and balance though.

 

Well i suppose it depends on what you can start off with. If you're Mitsubishi and make loads of these it's probably cheaper to have a whole bunch cast hollow and forged. If you're a cam shaft manufacturer who makes cams for lots of different makes the you might want to start from a cylindrical blank, (gun)drill it, machine the cams, harden then grind. Obviously works out more expensive compared to Mitsubishi, but you're less limited in material choice and there's really no need for a minimum order.

 

I cant see the performance gain between hollow and solid cams really being that significant. since they are only about 1 1/4" diameter the rotational mass weight cant be that much. I just cant see them making more then 1-2 whp if you had the same exact cams, hollow and solid. its not like a lighter wheel/tire combo which is lets say 20" in diameter and the lighter weight will cause so much less centrifugal force. Someone please tell me the weight of an HKS cam and the weight of a stock cam. I have hks cams here and my stock cams at home, i'll have to check myself if no one else knows.

how much more force does it take to rotate a solid pencil, over a pen which is hollow???

 

its not about horsepower its about rotational mass. The cams spin alot faster than the wheels do.

The pencil example is valid, but only because its a lightweight object to begin with. How much more force does it take to rotate a 10 foot circumference solid steel pillar vs one of the same dimensions that is hollow - as the weight of the object in question increases, the differences in rotational mass become more significant

 

Would using aftermarket camshafts require one to change the timing belt earlier than 60,000 miles due to greater wear?

Hopefully mitsu used them because it was, for them, easy to do so and it serves as a good marketing point.

 

on a car that sees frequent trips to higher than stock redline, yes its advisable to do timing belts earlier