Cam Degreeing Questions

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Pompis

Pompis

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Today when I was degreeing my cam I bumped into some problems and have some questions. The cam is a Comp XE250H and have 106° intake centerline. I installed the brand new Comp Cams timing chain and sprockets with the 2 dots lined up. When I then was degreeing the cam I've got 59° 0.05" before max lift and 146° 0.05" after max lift. 59+146=205, 205/2=102.5°.So I've got 102.5° intake centerline with the dots lined up. So I had to retard the sprocket 4 degrees. With that adjustment I've landed on 106.5° which is great. My question is the original timing chain and gear retarded or advanced? Are this why I had to retard the crank gear 4 degrees or is this a manufacture error on the cam or the timing set or is it me doing something wrong? But I am sure I have done exactly like Comp Cams instructions. I repeated the reading 2-3 times at both crank gear setting and I readjusted the dial indicator parallel with the lifter as best I could. I've taped 2 lifters together with the plungers facing each other for the dial indicator to take reading from. Would appreciate some input what you guys think.

Here are some pictures how I did my setup.
DSC_2002_zps9bd9a796.jpg


DSC_2004_zpsd1dbcb6b.jpg


DSC_2005_zps93b0bccb.jpg


DSC_2007_zps6788d735.jpg


Thanks FABO
 
"Why is there air?"

It's why advance retard drive sets are made.
 
Should be good. Check your valve timing events @ .050 against the cam card, for good measure. Last cam I degreed the timing set was 8 degrees off
 
Thanks, I understand but I wanted to be sure.

"Check your valve timing events @ .050 against the cam card, for good measure" Does this mean .050" before or after max lift or is it .050" up from bottom of the lobe?

Thanks FABO
 
Pompis said:
Thanks, I understand but I wanted to be sure.

"Check your valve timing events @ .050 against the cam card, for good measure" Does this mean .050" before or after max lift or is it .050" up from bottom of the lobe?

You should have valve opening/ closing points on your cam card @ .050
Click to expand...
 
Valve timing open/close on my cam card should be measured @ .006 not @ .050. Got confused because on the cam card it says duration @ .050 so I thought you meant that and I missed read the other text about open/close timing. Will measure that tomorrow. Thanks
 
Comp Cams list the open close points at .006" lifter rise, NOT from peak lift. You are getting a false reading trying to go off the nose of the cam, because the lobe is asymmetrical.
19° open 56° close is what your after at .006" lifter rise.
You can make note of the numbers at .050" lift and do the math to check the duration.
 
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