harland sharp rocker breaks at idle????

[norbs]

What do you think caused this? I was just idling down the street and this happens, no pushrod damage at all spring and valve look fine. If anyone has a 1.55 rocker by harland sharp i need it as soon as possible, i will even buy a few spares if someone has them. Please email me at norbz@sympatico.ca Many thanks



http://www3.sympatico.ca/norbz/rocker.JPG

 

[Granny 2]

Not enough radius on the undercut

 

[norbs]

I cant see any area where they have rubbed, my buick day at the track appearance is doomed i guess now

 

[Fuelie600]

Norbs, Possible there was too much preload on the lifter. How does the wall of the pushrod look, where it passes through the head/ does it show more wear than the others? What length push rods and how much preload were you running? Got to be a reason for this other than bad luck! What track do you race at? I run at Napierville, Quebec. Later Brian

 

[bruce]

Wrong pushrod length, I'll bet.
There's alot of force going past center on moving a rocker.

Did you check the rocker to valve tip pattern?.

Buicks are real fussy about lengths and how that effects gross lift.

While you may have found just the weakest of the set, I'd double check the patterns and gross lift to make sure everythings correct.

I bought a used set of Haplands, from an list member, and then when I went to use some the adjusters were all galled. I then went with T+Ds.

 

[n20junkie]

how many miles of street use are on them, unlike steel, aluminum can only be fatigue cycled so many times, after that life of fatigue cycling is up, they break, so if these rockers have a few years on them, then it was just there time, and you might want to get a whole new set, casuse that first one is just a sign that the rest are getting short on life too.
Grant

 

[norbs]

These rockers are a few years old , and maybe have about 5000 miles on them, but hard miles! The pushrod length is fine the contact is centered this is on solid roller lifters with .007 using a a hyd roller cam. 545 lift 224 duration. I think its a matter of fatigue it looks like. I hope harland sharp stands behind there product i will be calling them monday. The TA rockers look nice also

 

[n20junkie]

5,000 is alot of miles of aluminum, but not that much that i would expect to see a fatigue failure unless those hard miles as you described them include high rpms alot, then it was just too much for them
Grant

 

[bruce]

Originally posted by norbs
These rockers are a few years old , and maybe have about 5000 miles on them, but hard miles! The pushrod length is fine the contact is centered this is on solid roller lifters with .007 using a a hyd roller cam. 545 lift 224 duration. I think its a matter of fatigue it looks like. I hope harland sharp stands behind there product i will be calling them monday. The TA rockers look nice also

Fatique usually shows a polished area where the crack/ stress raiser, first begins. Look real close at the perimeter of the break for a smooth area. If it wasn't from fatique and they had some miles on them then something on the build is off, IMO.

Did you check the wear pattern with one cam and then use another one?.

Is the .545 a measured dimension, or quote from the cam sheet?.
You should be able to multiply the cam lift, by the ratio and get a gross lift number, and then get this same number at the rocker's tip, less any lash or lashing errors.

Did you have the dowel guides in the block?.

I'd be most suspecious of too short of pushrod.

 

[Intercooler]

Norbs,

I did the same exact thing last year! These were brand new out of the pack when I put them on and one split in less than 125 miles. It didn't hurt anything but made some noise! I contacted HS and the style I have was before they redesigned the rockers. Maybe is what you have also? The narrow region at the back has a little less meat than the new design. Unfortunately they don't make the old style 1.55's anymore. I ended up buying a complete half set of the 1.6's to fix my problem. I now have spare 1.55's of the old style if you are interested. Since I was going to get some of your exhaust clamps maybe we can work something out. E-mail me if you are interested.


BTW...... I still the the HS rockers are about the best. Very quite!

 

[Intercooler]

Damn..... I just found your picture and looked at it and the break is almost identical to mine down to .001" I guess it pays to have some spares on this little item!

 

[norbs]

check your email thanks!