I think it is important to have a choice and to know what is available in the aftermarket for cams that are hollow just as the stock cams are. Some of you may not care...I do. So far Z1 tells me: Uh......I don't know about the Tomei (after a previous post by them said they were hollow). Disapointing phone conversation (yes I have spent money with them). Here is what I did find out. Please confirm if you know others.

Jun Cams are hollow

If you as a Vendor would like to contribute a list of known hollow cams that are available or that you sell please chime in. I am really not interested in those that are solid. Please don't post to say how unimportant a hollow cam is or flame the topic if you are not interested in knowing move along. Sorry just a bit frustrated by the lack of reliable information and service that some vendors provide,

 

Not sure who you spoke to today, but it is easy to get confused on this stuff, especially considering it is not a question more than 1 or 2 people have ever asked.....so I will apologize for whomever you spoke with for not knowing the answer to your question.

That being said

HKS - solid
JUN - solid (they use their own material, not OEM blanks as evidenced by this email:

Dear Adam,

I'm sorry for the delay very much.
We don't have camshafts for Evo VIII in stock now. We need 2
weeks for the manufacturing.

Material of camshaft for all 4G63 is our original material. We
don't perform hollowing.

Thank you,
Toshiyuki Takahashi
Tanaka Industrial Co., Ltd

Tomei: my notes say they are, but now I am calling it into question in light of the email from JUN. I will ask Tomei tonight. I would not expect a fast answer as they have been very slow to deal with lately.

Adam

 

Adam, obviously I did not speak to you earlier as you have always shown a responsive attitude and been forthcoming in your statements. I appreciate the follow up. I plan on buying hollow cams and I have used you in the past for product and was very happy. See my other post regarding the Ralliart plug wires you sold me.

Please post as soon as you know for sure which if any are hollow.

Your Follow Thru is Greatly appreciated!
Darren

 

no problem Darren - I emailed Tomei, so we'll see what (if) they say in their reply

 

hey why doesn't someone just make them? gsc is pretty involved here... why don't they just hollow out their cams? is it hard? you just get a very precise machine to machine out the middle right? i mean they're already using very accurate mahcines to make the lobes. granted you have to overcome the length of the shaft... but they have accurate drills right? one that you can pretty much just jig up and drill to total accuracy?

 

Good point not sure about the whole "gun drilling" thing.

 

not to highjack the thread but what is the difference between hollow and solid cams. i understand that one is hollow and the other isnt but performance-wise why would someone choose one over the other? thanks

 

lighter weight = less rotational intertia = more efficient motor = more power

 

Exactamundo!

 

I would imagine drilling out a camshaft is a very tedious bit of engineering. You have to make sure the walls of the cam are still thick enough to withstand the abuse of high rpm usage, you have to make sure they are balanced before and after drilling, and then you'd have to make certain the drill angle was precise all the way through the core as well as measuring the thickness of the walls all the way through afterwards. For a non-conglomerate company like Tomei and HKS, this is going to be more of a cost issue than for Mitsubishi, especially since you are buying cams with no car. Its possible but it may not make as much business sense. Grinding lobes and getting precise lift and duration measurements are no walk in the park either.

 

What about stock cam regrinds is this feasable?

 

The reason HKS and other brands are so desirable is because they aren't stock regrinds. Starting with a blank is more precise.

 

Makes sense. Why wouldn't other vendors start with oem blanks, these would be hollow right? Or are they drilled after the fact?

 

Good point. I don't know. I'm thinking they are drilled after the fact by Mitsubishi.

 

The Nissan 350 uses hollow cams as well. They obviously are viable at the oem level so it just stands to reason that the aftermarket would offer the same in different grinds.