What are the symptoms of the cam timing being off by a tooth or two? My new L98 is giving me some grief and this is the last thing that I can think of.

 

also, how can the cam timing be checked with the motor assembled? Thx.

 

Pull the odd bank valve cover (1, 3, 5, 7). Put the number one cylinder at TDC on compression stroke (use the ignition timing mark on the damper if you trust it, or use a TDC piston stop in the number one plug hole). You may have to rotate around a couple of times to make sure you're on compression stroke TDC and not intake stroke (watch your valves open and close to be sure). Set up a dregree wheel on the crank, set the pointer to zero. Set up a dial indicator on the exhaust rocker. Compare with the specs you used when you assembled the engine the first time (degrees turned to open valve), or you should be able to find the "straight up" specs from your cam manufacturer to go from.

I had a similar problem when I had a local engine builder assemble my short block for my old Pontiac. He advanced the cam 4 degrees (lowers TQ/HP curve RPM) instead of retarding it 4 (raises the curve) degrees like he was supposed to. He was embarrased!

Good luck!

 

Do a search on the topic, I just confirmed the exact same problem. I ended up taking off the timing chain cover and the cam was installed correclty. You will need a dial indicator and a degree wheel and also, you must know the spec's of your cam. ie, cam center lobe for intake and exhaust.

 

What do you mean you confirmed the same problem? What turned out to be the problem if the cam was right afterall?

 

I had a valve too tight one time when I put a new 350 in my 89 RS and it caused low vaccume and timng to jump around. Check you Vac. level first and then see where you are at.


Brian Felts