Racecar Project - New High Lift Camshaft
01-16-2009, 11:07 AM
#1
Nordschleife Master
Thread Starter
Racecar Project - New High Lift Camshaft
You may remember the 9M DLC Rocker Arm validation thread https://rennlist.com/forums/showthre...eferrerid=4234 where I mentioned that I had sent the 9M rocker to my camshaft manufacturer for some testing and input into a new camshaft design for my engine.
That process is complete and here is a picture of the high lift camshafts for my new engine. After the 100 hour test was complete on the engine and I found a more optimum length of the intake runner stack than I had previously been running I went back and did some additional component testing. I bought a brand new set of the 9M heads with the 9M high lift valvetrain package. I did some machining on the valves to improve flow and put the entire assembly back on the flow bench to test against what I had for the preproduction heads I was running. This testing, combined with the rocker arm validation and camshaft geometry testing we were able to produce a new camshaft for my engine that represents the best of what I've done so far.
This camshaft is manufacturered from billet steel, not from chill cast cores like we've done in the past. There is nothing wrong with chill cast core camshafts and I will continue to use them in engines, however, in my engine I wanted to reduce the camshaft bending that occurs. The billet core is stiffer than a chill cast core with a weight penalty. These camshafts have been nitrided so they are harder than normal and it will reduce the likelyhood that the DLC (Diamond Like Carbon) coating on the rocker arm will wear the camshaft. The camshaft has also been highly polished to 1.0-1.2 micro inches. This superfinishing of the camshaft will assist with oil lubrication, reduce friction, and reduce wear. On my camshaft manufacturer's spintron machine, this has been shown to reduce friction enough to gain 4-5hp on a 400hp engine.
The lift on the camshafts is so large that the lobes are larger than the bearing bores of the cam towers. This necessitated that the lobes be offset through a reduction in base circle. It is interesting that these camshafts are similar in specification to the ones Colin came up with on his initial high lift valvetrain package, once again validating the work 9M has done. These camshafts have significantly more "lift area under the curve" than my old camshafts, and can only be accomplished with the 9M high lift rocker arm. These camshfts will not work with a stock rocker arm.
That process is complete and here is a picture of the high lift camshafts for my new engine. After the 100 hour test was complete on the engine and I found a more optimum length of the intake runner stack than I had previously been running I went back and did some additional component testing. I bought a brand new set of the 9M heads with the 9M high lift valvetrain package. I did some machining on the valves to improve flow and put the entire assembly back on the flow bench to test against what I had for the preproduction heads I was running. This testing, combined with the rocker arm validation and camshaft geometry testing we were able to produce a new camshaft for my engine that represents the best of what I've done so far.
This camshaft is manufacturered from billet steel, not from chill cast cores like we've done in the past. There is nothing wrong with chill cast core camshafts and I will continue to use them in engines, however, in my engine I wanted to reduce the camshaft bending that occurs. The billet core is stiffer than a chill cast core with a weight penalty. These camshafts have been nitrided so they are harder than normal and it will reduce the likelyhood that the DLC (Diamond Like Carbon) coating on the rocker arm will wear the camshaft. The camshaft has also been highly polished to 1.0-1.2 micro inches. This superfinishing of the camshaft will assist with oil lubrication, reduce friction, and reduce wear. On my camshaft manufacturer's spintron machine, this has been shown to reduce friction enough to gain 4-5hp on a 400hp engine.
The lift on the camshafts is so large that the lobes are larger than the bearing bores of the cam towers. This necessitated that the lobes be offset through a reduction in base circle. It is interesting that these camshafts are similar in specification to the ones Colin came up with on his initial high lift valvetrain package, once again validating the work 9M has done. These camshafts have significantly more "lift area under the curve" than my old camshafts, and can only be accomplished with the 9M high lift rocker arm. These camshfts will not work with a stock rocker arm.
01-16-2009, 12:25 PM
#3
Nordschleife Master
Thread Starter
These are not the same specification as the 9M cams and were developed as a separate effort specific to my engine requirements. I expect a similar rev range as my old engine. The seat duration and lift specifications really don't tell the entire picture of the camshaft.
