Cam Timing 2
Q. just one question Ken, how hard is it to set the cam timing other than buying a degree wheel. I got the nut off, I welded a bar to the steel plate to lock the hub and then used a impact wrench.
A. You need a degree wheel, a Top dead center stop, and a Dial indicator set up with a tip to fit on top of the spring retainer.
And building a engine like yours, it is not like putting together a puzzle where all the pieces fit perfectly once you determined the correct location.
You will need to check and set:
Piston to Head clearance,
Piston to Valve clearance,
Then time the cams, I suggest finding a good mechanic, this is not easy, doubt me, ASK JEREMY how hard it is to build something like you are building.
One slight screw up on that cam timing, and the first time you hit the start button and its all over. Make SURE you are SURE, before you crank it! Or you will be heart broke for a long time.
I have found that in all instances, 104/105, and 104/107 work best on all 91-00 7s. The 104/107 seems to give a tad more on top with highly modified motors, with some loss of midrange, this is why i call these #s Daytona #s.
Muzzy recommends 105/105. Most ZX7s I checked stock measure 107/104 or 108/104. This is all so subjective and is based in how the individual measures it I realize. I use .040″ lift on open and close,
Why the computer model, which uses stroke and connecting rod length to determine optimum intake cam timing lobe center, draws most heavily on Rod length, I do not know. As I stated, its all based on Math, physics, mechanical rotation, etc.
In Jeremy’s case a 9mm stroke increase with a 100mm rod only made a difference of a 3/4 degree which is nothing. It appears that it takes about a 10mm stroke difference to make a 1 degree lobe center change, and about 2.5mm in rod length to make a 1 degree change.