----- Original Message -----
From: Richard Mills <mills.richard@ssd.loral.com>
To: Tiger Maill List <tigers@autox.team.net>
Sent: Wednesday, April 05, 2000 9:58 AM
Subject: 351W head questions
>
> I removed the cover and found a broken rocker arm stud.
Was the stud a screw-in stud? If not then disregard the following:
>
> 1) What might have caused the fatigue and what should I
> pay attention to to avoid this failure.
Check the end of the valve stem to see if it is worn at an angle. This will
tell you if the rocker alignment is off. My experience has been with
screw-in studs that were not properly installed (the threads into the head
were crooked) causing binding with stock-type rockers, especially with high
pressure valve springs. A good machine shop can fix this for you if the
problem is extreme but if the alignnment of the stud to the valve isn't too
bad you can lessen the chance of breakage by using roller rockers.
>
> 3) Any suggestions on a source for the rocker studs?
>
Manley studs seem to be good. I ended up using 7/16" studs with roller
rockers instead of the 3/8" but I run a bit more valve lift and higher
spring pressures than most.
> 4) Any comments on things to do during re-assembly?
>
Coat the threads with Permatex to prevent water leaks.
If using stock-type rockers with a high-lift cam be sure to check the
clearance of the rocker's slot on the stud for any binding at full open and
closed valve.
Bob
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