Resolved Base Cam run out degreeing cam

[willyp42]

Hey Everyone, I am trying to degree my cams.
I have a set a kelfords and I have an indicator on top of the piston and one on the back of the valve. I am also using BLE solid lifters with the lash set as close to zero as possible.

My issue is I am seeing about 20 thou run out on the base cam.
I can start my measurements at zero’d get my Valve opening event and lift at tdc correct, also my indicator will read max lift to within a couple thou. But my issue is with the valve closing.
It’s around 5degree retarded to 40thou measurement and then my base cam journal will read about 15thou negative for most the no lift portion only to go back to zero and then repeat my intake closing events.

it’s sounds like a measurement error but I am not sure what to try to fix it. I’ve tried increasing pressure and decreasing on the lifter but doesn’t make a difference.
Thanks,
-Will

 

[AWD-Tony]

Have to watched jafro’s video?

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[willyp42]

Yes, the only thing I’m doing differently Is leaving an indicator in the spark plug hole to confirm TDC each round.
For some reason my cam likes to run out when the valve isn’t open

 

[DSMPT]

It's kind of common that the dial indicator tip gets slipped when the spring starts to be in return action and read wrong only in valve closing event.
Should set the dial indicator rod angle in parallel with valve angle as much as you can. And find more stable location to set the dial indicator tip or/and modify the indicator tip not to slip easily. And rotate crank very very gently.

 

[AWD-Tony]

It's kind of common that the dial indicator tip gets slipped when the spring starts to be in return action and read wrong only in valve closing event.
Should set the dial indicator rod angle in parallel with valve angle as much as you can. And find more stable location to set the dial indicator tip or/and modify the indicator tip not to slip easily. And rotate crank very very gently.

+1 That’s the hardest part, keeping the tip from moving on the retainer. Also to keep the indicator clamp down securely so that doesn’t move. Once you get true tdc, you can remove the tdc finder and the dial gauge.

 

[willyp42]

+1 That’s the hardest part, keeping the tip from moving on the retainer. Also to keep the indicator clamp down securely so that doesn’t move. Once you get true tdc, you can remove the tdc finder and the dial gauge.

Ok thanks, I have a nice starrett indicator base that is one of those string tension ones and a magnet bottom I know it’s not the fixture moving. I swapped back to stock retainer for checker spring as they’re bigger than the kiggly ones. It’s been a real PITA I am going to see if a small magnet will help

 

[AWD-Tony]

It’s a pita so be patient and like Hiroshi said, turn the crank slowly once you find the sweet spot on the retainer.

 

[jakelandry]

I have a set of retainers with a peen mark in them to help the indicator tip seat. It still doesn’t fix the problem but the results are more repeatable.

 

[AWD-Tony]

I have a set of retainers with a peen mark in them to help the indicator tip seat. It still doesn’t fix the problem but the results are more repeatable.

That’s a great idea!!

 

[DSMPT]

I locate the indicator tip on a flat/edge spot (depends on retainer's shape) on retainer where valve keepers go. That would be under rocker arm and it would interfere but using a L shape tip would allow you to clear it. After a couple of trial and errors, everyone would find their own method though.

 

[willyp42]

long story short my "snug" indicator holder needed another quarter turn, when the cam would start to lift the valve it would push up the mic ~20 after i honked it down it was fine.