[Supras] Whipping noise

[Speedtoys]

Cam noise is 1/2 of engine rpm.   Stuck lifter?


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On Feb 4, 2008, at 3:28 PM, "berniek at technicaldevelop.com" <berniek at technicaldevelop.com 
 > wrote:

> Hmm..  The group has not seemed this dead in a long time.  Is the  
> server
> down?
>
>
> Anyway, my '91 (550cc, Lex, Walbro, upgraded IC, 3" exhaust) makes a
> very loud repetitive cracking sound from someplace near the front of  
> the
> engine on cold startup.  It sounds almost like an amplified arc, or
> cracking of a whip when I listen under the hood.  Most times it occurs
> at random, but if I speed up the idle slightly, it occurs at times in
> sync with what appears to be every other revolution of the engine  
> (i.e.,
> 4 stroke style).  The sound must be outside the engine, since it  
> sounds
> like a cracking whip.  It appeared after about 600 miles on a  
> refreshed
> JDM.  One thing I need to do is check the harmonic balancer bolt.  I  
> did
> not tighten it all the way to the spec, as the pipe used on the  
> breaker
> bar began to bend.  Could it be the balancer moving torsionally on the
> crankshaft against the woodruff key? Strangely, once warmed up it is
> fine.  The stock pistons are fitted loose, and I do have cold piston
> slap as well, expected.  But this noise is far more "in your face"
> regarding high frequency content, not muffled or damped by the block  
> walls.
>
>
> BernieK
>
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