View Full Version : Grinding automotive cams?
04-25-2012, 03:04 PM
It really is far too early for me to consider actually doing anything like this, but I'm curious about whether or not it's something I might eventually be able to do at home...
I'm curious about the process of grinding my own cams. Setting the intricacies of cam profile design aside for the moment, I really want to know what machinery/attachments are necessary to do the job. The reason I ask is that I own a car which aftermerket cams are almost completely unavailable anymore.
Anybody know what's involved, what kind of machinery, etc? I honestly have no idea if it's just a matter of having a lathe/mill with the correct attachments, or if there's some obscure proprietary machinery out there that does nothing but grind cams...
04-25-2012, 09:17 PM
Effectively grinding an automotive camshaft is not something that can be done with normal home shop machines and common attachments. There are, of course, specialized machines for this and I feel sure some people have designed and made their own. The machines are not terribly complex but careful work would be needed to get the needed accuracy and versatility. They have an oversize master cam that rotates in step with the camshaft with a follower and linkage that moves either the camshaft or the grinding wheel back and forth as they rotate. They also have some method of precision indexing the camshaft to grind each cam in the proper angular relationship. And, of course, they have a method of moving the lengthwise positioning of either the camshaft or wheel.
04-25-2012, 11:40 PM
Thanks for that. I figured that was the case but would rather ask to be sure. I know one person with the ability to grind cams. Unfortunately he's in Sweden and has health problems these days. I've been holding onto the faint hope that I could either work toward doing the cams myself or finding an experienced home machinist who could make a set to my specs....
Oh well. Not like I don't have a million other things to keep me busy anyway. Thanks again.
http://www.youtube.com/watch?v=MVGbJ7F3Ias is good plus there are several more in the same neighborhood.
04-26-2012, 01:11 PM
Thanks RWO, seeing the machines helped... Looks as if the old fashioned hand ground cams were sometimes done on a standard lathe with a special attachment that held a small articulating grinder or belt sander and the template; but I couldn't find a detailed enough shot of the machinery (the camera always focused on the cam itself) to tell for sure.
Like I said, even under the best circumstances I'm a long long way from attempting anything that complex. But its fun to think about.
Honestly a more likely solution for me is to find cams from another engine with the same valve spacing (actually pretty common since the cosworth engine I'm playing with is the grandpa of most pent roof 4 cylinders) then modify the bearings and cam drives to fit. Even that's a back burner project though.
04-26-2012, 02:19 PM
During my lunch break I did some "eyes closed" brainstorming and came up with what I thought might be a workable design. Then for giggles started googling terms like "antique cam grinder" and "grinding cam on a lathe" just to see what I could find....
Here's where I eventually landed. Just thought I'd share since it's a subject that's been covered before. Turns out that what I came up with isn't that earth shaking. I'm still a little weak on translating the terminology to a good mental image. But from what I can tell, I think this thread describes the same thing what I was thinking of (look at post #6). Makes me feel pretty good to know that I'm not too far off the mark in terms of figuring the "how" part out. And that others have gone the DIY route with some success.
Edit: I also found this article about offset grinding a cam for a scale model engine. Seems interesting and I'm sure it could be scaled up.
Really, I'm just being nerdy now....
05-01-2012, 05:58 PM
I guess the next question would be what material?