Side to side cam variation - what's "acceptable"

[JoeMag]

Timing up new set of cams and here's centerline I'm getting at 0.050" lift (rounding to nearest half degree):

Right intake 104.5
Right exh 106.0

Left intake 104.5
Left exh 110.0

Right separation angle: 210.5
Left separation angle: 214.5

I'm using an 18" degree wheel.

What is considered to be acceptable difference side to side?

[stownsen914]

I discovered a similar discrepancy years ago when I built my first 911 race engine. I think the difference was about 4-5 degrees between the left and right banks. I didn't want to pull the cams and regrind them at that point, so I "split the difference" by advancing the cam a couple degrees on one side.

You probably did this, but make sure you've got all the slack out of the chains, and take measurements a few times.

[JoeMag]

Thx... have not split the difference yet. Using stomski chain tensioners.

[Neil Harvey]

Measuring your cam's 0.050" duration on the engine is fright with error opportunities.

However, the fact you are measuring the Intake centerlines the same, is pointing to some poor exhaust lobe positioning on the shaft.

An acceptable difference in the actual camshaft is zero and the acceptable timing in the engine could be as high as 0.25°. Preferably zero again.

Your engine, I assume is a 6 cylinder. Not all cylinders are making the same Torque. This is due to intake air flow variances, CAM TIMING, ignition variances etc. There can be up to 5- 10 HP difference from one cylinder to another.

So, accepting cams with your LSA differences is accepting a lower engine performance. Don't split the difference, get two cams with the same LSA.

If I had to take a guess here, you received 2 different cams from 2 different sets.