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hmmm odd.

It could even be the fact the cams probably advanced 2 degrees with the new chain setup l67 can sprockets had 2 degrees of retard over ecotec ones or the 10:1 fueling to rich can knock and rattle

I installed the rollmaster cs6150 and set it at +6 degrees. When I had the wideband installed it would read 10.0 at wot I'm sure it would read lower but my gauge only goes down to 10.0.

Why +6 that's a lot of advance

People on l67 torque say to set it at +6


( Quote from l67 torque )
I have read on many occasions this +2 degrees been machined into the genuine GMH Supercharged V6 L67 CAM shaft sprocket. Where did ths + 2 degree figure come from? I am wondering if this figure is more like + 6 degrees.

To explain here is my resent experience dialing in my existing cam using a Rollmaster CS6150 after the failure of my chain tensioner on factory single row chain.

Firstly my car ran very well even though the tensioner was gone so I spent considerable time with degree wheel and dail indicator making extensive notes even plotting the original cam position in an XLS spread sheet. The last thing I wanted was to lose the performance I had by getting the dial in wrong with the Rollmaster. Before I removed the old chain and timing gears I noted that it was dot to dot as expected. From the XLS spreed sheet the cam timing was spot on in every detail.

Fitted the Rollmaster and decided to start at +2 degrees and timing was along way out. Was not happy at all as the Crank sproket was as some know here very hard to move. Ended up at + 6 degrees and this is as close to where I can get compared with the original dial in. Rang Rollmaster to query my findings and they said they were aware of the problem with the L67 and I was the first one to ring and supply dial in figures. Car is running well again at + 6 degrees.

I wonder if that's why the new engine in vb ran different we swapped from single row to double row rollmaster on 0 and shifted power up the rpm band compared to the old engine maybe they are just made way outta wack

I am sure that the timing set I used as well and mine was only out 1º. I retarded it by 2º to get a neg 1 from spec iirc. Certainly not 6. That was on a buick though. I did notice rollmaster said this does not fit SC engine, maybe this is the reason?

This is the handy work of OZ38

The Super6 Cam chain sprocket keyway is advanced 5 degrees compared to the N/A Cam chain sprocket.

N/A cam Gear
Intake @ 0.050"
27.5° After TDC opens
32.0° After BDC closes
119° C/L

Super6 Cam Gear
Intake @ 0.050"
22.5° After TDC opens
27.0° After BDC closes
114° C/L


So I now know you can run a CC VS cam at least 5° Advanced using the Rollmaster Timing Chain sets .

Interesting fact though, Dick guest about up to 6 degrees advanced over the N/A sometime back in another thread. Good guess.

Did you end up finding the cause of the rattle?

Nah mate gave up trying and wasting money on it, guess I'll find out when it goes bang