BROKEN KEYWAY ON BILLET CAM

8

87GN_Bart

Active Member
Joined
Jul 12, 2016
I have broken 2 keyway inserts on my 224 billet comp cam, i was lucky the pistons were relieved therefore the damage was only bent valves in the heads. Is there something i am over looking, the chain in each case never broke however the keyway was broken. I would appreciate any ideas how to resolve this issue. The motor is a stage2 off center 3.8 with GN1 heads.
 
Yes it sheared the key in both cases which has me concerned as i do not want to go through this again.
 
Thanks guys, i will make sure to check the clamp up with stack up of the cam gear and the torque of the cam bolt. Much appreciated.
 
What cam thrust set up are you running? I was running a Danny Bee type set up with a Rollmaster timing set and had the cam gear come loose and break the woodruff key.

Neal
 
750H.P.V6 said:
What cam thrust set up are you running? I was running a Danny Bee type set up with a Rollmaster timing set and had the cam gear come loose and break the woodruff key.

Neal
Click to expand...
Lol that's the exact same setup I'm planning to use
 
750H.P.V6 said:
If you haven't already machined the nose of the cam. I'd tell you to take a look at the Webber set up.

Neal
Click to expand...

One of these gizmos?

image.jpg

I have a TA block, I think I'm pretty much stuck with the danny bee thrust. Haven't checked yet but I imagine the front gallery plugs (O-ring ports) would probably be in the way of the roller bearing thrust setup.
 
Last edited:
Beatav8 that is the set up i have been using for years for my cams however recently it is causing me problems. Neal thanks for the input, I was told by the engine builder that he prefers the Webber set up because is it beefier.
 
Perhaps we need a chrome moly steel key to be safe, lol.

Notes:
steel spacer, not aluminum
hardened key
bolt torque / tension, no premature bottoming out due to stack up.

pinning the assembly is a good idea too
 
Last edited:
After I had this happen I delved way into the design of the Danny Bee set up. I'm lucky enough to work at an engine R&D company so there are some really sharp engineers working here along with some very well qualified engine builders with background in various forms of racing. What we determined is with the Danny Bee type set up there is a lack of contact area between the back of the cam gear and the nose of the cam. This is partly due to having to cut down the cam to such a small diameter and also the fact that the Rollmaster timing chain set has a very large chamfer on the I.D. of the upper gear. I would say the whole design is marginal if running a stock type heads with a hydraulic roller. I run Stage II heads with a solid roller cam and a lot more spring pressure. In my instance when I pulled the front cover the bolt was still tight and loctited in place yet there had been enough movement that the key had broken and the spacer split open along the keyway.

FWIW, a different key material isn't the answer. The key is to align the parts not prevent them from spinning. One of our engineers said they had similar problems with cams during the Viper racing program once they pinned the cam / gear the issues went away.

Neal
 
another thing after eating cam sensor gears over and over i ended up making an oil line to feed the gears and set the gap at .020
 
Interesting thread. I am going to be using a billet roller with the Danny Bee retainer. Good info. Pinning the gear doesn't sound like a bad idea.
 
Bobby " thanks for the thread" it has shed alot of light on my problem and i know now what to look for and how to fix the problem. This community is AWESOME thanks to all. Cheers
 
One of the high strength loctite retaining compounds (like 620, 638 or 680) might be a good insurance policy for a properly assembled joint as well.
 
If you plan on using the Danny Bee type setup I'd suggest you go with at 75 ft lbs on the bolt and cross your fingers. I ended up designing some different components and having them fabricated in our machine shop to increase the contact surface are between gear face and the cam nose.

Neal
 
You must log in or register to reply here.

Similar threads

J
TA Billet Cam for sale-needs repair on one lobe
Replies
11
Views
2K
jmendlik
J
X
Need rec on new cam and turbo
Replies
11
Views
2K
TType85
TType85
O
billet roller 210/210; short travel or stands johnson lifters?
2
Replies
21
Views
2K
outatime86
O
turbobuick
Billet Roller Camshafts
Replies
4
Views
1K
modular46
M
X
Broken Crank
2 3
Replies
45
Views
5K
Chuck Leeper
Chuck Leeper
Top