Broken Cams/ How to prevent??

Fireman450

Fireman450

Daring to be diffrent!!
Joined
Nov 24, 2007
Messages
1,606
Guys Ive herd all kinds of stories of people breaking camshafts. My question is what is the reason people are breaking them and what can be done to prevent this from happening to me? This is all for the 12 valve in my sig.
Thanks
Fireman450
 
I think the main thing he is asking is how to keep a Re-Ground stock core performance cam from breaking with a 13mm pump. Also, do you guys think the Dragon Flow 13mm and the matching sticks would be too much fuel for a S465 ETT turbo?
 
Quick like, say, going from 1000 RPM to 2500 RPM instantly by downshifting with a manual valve body?
 
kino_fab said:
I think the main thing he is asking is how to keep a Re-Ground stock core performance cam from breaking with a 13mm pump. Also, do you guys think the Dragon Flow 13mm and the matching sticks would be too much fuel for a S465 ETT turbo?
Click to expand...

Yea what he said... Thanks Bragg :Cheer:
 
Downshifting isn't such a problem because you are already out of the throttle, guys that like to free rev their engines and pullers (especially autos) who snap off the throttle at the end of the track are more prone to it, but there are also other factors to consider, like valvesprings, size of P&B's in the pump and if you run a retainer bolt on the end of the cam.
 
There are a few ways to keep your cam from breaking, first keep the RPM spikes to a minimum. But if you can't seem to do that, then first do the bolt on retainer to keep the gear snug. If the gear walks forward at all it acts like a prybar with a long handle. It WILL snap the cam if it is walking forward and you have a healthy 12mm or 13mm pump, and are running the big R's. The second is to take the cam to a machine shop and have it radiused in between the first journal and the first lobe, in between the first two lobes, and inbetween the second lobe and the second journal. This eliminates the stress risers and will allow the cam to flex without fracturing. The cummins cam is a good piece, it just was not designed to run 5k and drive 1000cc p pumps with crazy RPM spikes. Do the radius and the bolt on retainer and it should be fine. Also If you want to spend some big money scheid has a billet aluminum front cover that has a bearing support that the cam rides in. Hope this helps.

Zach
 
This is ONLY 100% fix for a broken cam that is stressed from either too much load and harmonics or an unloading condition.

Billet Steel, hardened properly, surfaced properly, and uses a bolt on cam gear system to permanantly hold the gear in place.
 

Attachments

  • cam201.jpg
    cam201.jpg
    65.3 KB · Views: 61
  • cam202.jpg
    cam202.jpg
    69 KB · Views: 74
Using large a radius to transition from the lobes and journals to the main shaft adds strength. The journals and lobes are mirror finished to a Rougnness Average of under 4!!!!!!!!! This is an exclusive to F1 Billets.
 

Attachments

  • cam005.jpg
    cam005.jpg
    57 KB · Views: 60
Finally a comparison between the "others" Billet cam and a F1 Billet cam.

1) The F1 cam uses a bolt-on style retainer system to hold the gear on the cam nose. This keeps the gear from walking forward. The other shown uses a press on gear that can press back off under heavy load.

2) The F1 cam has a thicker diameter between journal 1 and 2. The other shown uses a skinny diameter between journals 1 and 2.

The F1 cam is the on the right.
 

Attachments

  • Billet_jpg_w560h747.jpg
    Billet_jpg_w560h747.jpg
    31.6 KB · Views: 82
  • cam004.jpg
    cam004.jpg
    23.3 KB · Views: 78
How are you don? It has been a while since I have argued with you. Just wanted to let you know that the HD cams have the bolt on retainer as well, and that they are thick as they can possibly be between 1 and 2 with the lift we are running. I have always liked a little more lift than what you run.

Zach
 
Soup Nazi said:
Finally a comparison between the "others" Billet cam and a F1 Billet cam.

1) The F1 cam uses a bolt-on style retainer system to hold the gear on the cam nose. This keeps the gear from walking forward. The other shown uses a press on gear that can press back off under heavy load.

2) The F1 cam has a thicker diameter between journal 1 and 2. The other shown uses a skinny diameter between journals 1 and 2.

The F1 cam is the on the right.
Click to expand...

That is mine, as you well know Don. You should also know that it comes with a bolt on retainer. That billet steel, has to do alot of moving for it to break, unlike a casting. Most in the know are smart enough to realize that.

Must be time for you to release your billet cams, good luck!
 
Thats not just your cam. Actually, that skinny one was used by another vendor long before you arrived on the scene.

I think the larger diameter is indicated in a 12 Valve application. So, it is used on the F1 cam.

The skinny cam in the photo is a press on design. Just like the last one I saw from the original vendor. Did you source their same supplier?
 
It is a press on with a bolt on retainer. I make the retainer plates from hardened steel, the nose is counterbored then tapped. These are made by a company that supplies a very large amount of Billets to the aftermarket. I fully believe that with their engineering background they are in the know on camshafts. As many that are sold with never a problem, seems to be good feeback. I am sure if it were necessary to generously radius and add thickness to the front section, it can be done at no extra cost. I am just saying I don't believe it is necessary in a billet, in a casting YES!
 
You must log in or register to reply here.
Back
Top