Jump to content


Photo
- - - - -

Sw5 Valve Lash


  • Please log in to reply
2 replies to this topic

#1 big john

big john

    Passed Test

  • Noobies
  • PipPip
  • 30 posts
  • Location: Jacksonville, Florida

Posted 15 October 2018 - 12:32 PM

I have a Swift Tune SW5 cam in my 1275 and the timing tag that came with it said the lash should be set at .015". My question is: Since Swift Tune says the cam is ideal for 1.5 rockers, is the lash setting the same or should it be opened proportionately over the 1.3 ratio rockers? I calculated that to be .017". Surely there must be a lot of people running this combination. Which do you use?

 

Also, when I adjust the valves by the rule of nine I get one rocker that taps noticeably louder over the others. This is a newly built motor with less than 6K miles on it. While trying to adjust this tapping valve (#1 exhaust) I discovered that the clearance would vary while rotating the crankshaft as if the base circle of the lobe was not even. If I adjusted the lash with the cam just coming off the lobe I would measure .020" whereas rotating it to the position with the #8 rocker fully open it measured at .015". I used to own a BMW R65 motorcycle that did the same thing and I never could figure out why. The base circle should give a constant measurement at all positions off the lobe. If I set it at the spot with the widest clearance the motor quiets down. Will it hurt anything to drive with the valves set this way?  Any ideas or experiences?  Thanks!



#2 guywilko

guywilko

    On The Road

  • Noobies
  • PipPip
  • 46 posts

Posted 16 May 2019 - 05:23 PM

? Bent push rod or worn lifter?

#3 Rorf

Rorf

    One Carb Or Two?

  • Members
  • PipPipPipPipPipPipPip
  • 857 posts
  • Location: Cape Town

Posted 16 May 2019 - 05:41 PM

Yes worn cam follower face or worn cam lobe. Bent push rod would show a consistent tappet clearance. Back in the day they used to say noisy tappets are happy tappets - at least one wouldn't get burnt valves from too tight tappets.






1 user(s) are reading this topic

0 members, 1 guests, 0 anonymous users