Camtiming tolerance factory spec

[Classic 911]

Hi.

Does anyone have the factory tolerance spec side-to-side when timing camshafts ?

[buster73]

Both sides should be within the lift range specified by Porsche resp. the cam manufacturer (if custom cams are used). For example a Euro 3.0 SC should be between 0.9 to 1.1 mm (check specs for your engine and specific cam). Of course it is beneficial if the difference between left and right bank is as small as possible. With the standard timing procedure you will hardly be able to achieve a perfect match between both sides. However fine tuning of cam timing is possible with some extra efforts and you will find several ways how to do this described in this forum. Probably overkill for a stock engine but worth to look into if you are going for a highly tuned and optimized engine.

[dannobee]

I've never seen a side to side spec, but if you're really anal about it, you can use the slop between the pin and vernier sprocket to "fine tune" it by carefully backing off the big nut and ever so slightly rotate the cam to the proper setting, then locking the nut back down. It won't make it run any different, but it'll make you happier if you're one of those types.

[Jeff Alton]

I am guessing Classic 911 was wondering what the tolerance side to side is with both cams being within the spec range??

Get as close as you can left to right. It is a rare day when they are the exact same.

That said, don't be on the low spec on one side and the high spec on the other side, as better can be achieved.... If that makes sense.

Cheers

[Classic 911]

Originally Posted by Jeff Alton

I am guessing Classic 911 was wondering what the tolerance side to side is with both cams being within the spec range??

Get as close as you can left to right. It is a rare day when they are the exact same.

That said, don't be on the low spec on one side and the high spec on the other side, as better can be achieved.... If that makes sense.

Cheers

Hi,

Yes that’s right.

The spec for my camshaft is 5.2mm at overlap.
After checking again, this time with a digital clock, the left side (1-2-3) is at 5.24mm and the right 4-5-6) is at 5.30.

That’s a 0.06mm or 0.0023" difference side-to-side.

[stownsen914]

Less than .1 mm difference is pretty good. You might be hard pressed to do better, and honestly it's probably within margin of error when you consider chain slop, etc. despite our best efforts to eliminate it.

[buster73]

Originally Posted by Classic 911

After checking again, this time with a digital clock, the left side (1-2-3) is at 5.24mm and the right 4-5-6) is at 5.30. That’s a 0.06mm or 0.0023" difference side-to-side.

Good job. That`s a pretty close match. You can relax and enjoy.

[Jeff Alton]

Originally Posted by Classic 911

Hi,

Yes that’s right.

The spec for my camshaft is 5.2mm at overlap.
After checking again, this time with a digital clock, the left side (1-2-3) is at 5.24mm and the right 4-5-6) is at 5.30.

That’s a 0.06mm or 0.0023" difference side-to-side.

That is good work, set well.

Cheers

[Alan L]

I have spent hrs trying to get better than that - often with no luck. Consider it a good day.
Alan

[Jeff Alton]

That delta between left and right is in the "noise" of the measurement.....

There is only so much adustment in using the factory sprockets and hardware....

Mosts modern cars from the factory allow min 5 degrees of deviation per cam, some up to 10 degress, before a CEL is tripped.

Cheers

[Henry Schmidt]

I once set the cam timing on a 911 race engine at the track by eye. Of course having the proper tools would have been preferable but at the track, sometimes you go with what you have.
The engine performed with no noticeable change in performance. Your results are great, good job.