Rocker Arm Stud Breakage again! Need some Advice!

-
Jonnylightening

Jonnylightening

Well-Known Member
Joined
Mar 4, 2012
Messages
611
Reaction score
166
Location
Pennsylvania
Hi guys Pulled the truck again (400 BB) got half way down the track and lost all OP and engine missing. I had this happen before (3 times now) 1st time just the stud was broken, 2nd time lifter was blown out of the bore, and this time. I need to get something figured out. I have it where the stud itself has 0-1 threads showing so my geometry is good. Im using Crane Gold 1.6 Roller rockers, Lunati 73100 valve springs, and comp cromoly ball/cup P-rods. Is the double valve spring too much for the rocker or ? Should I get a better quality rocker? If so What?? Any help is appreciated. Thanks Jon
 
I set mine up with 3 threads showing after the shafts are shimmed to where they need to be to get the roller tip where I want it.
 
Jonnylightening said:
Hi guys Pulled the truck again (400 BB) got half way down the track and lost all OP and engine missing. I had this happen before (3 times now) 1st time just the stud was broken, 2nd time lifter was blown out of the bore, and this time. I need to get something figured out. I have it where the stud itself has 0-1 threads showing so my geometry is good. Im using Crane Gold 1.6 Roller rockers, Lunati 73100 valve springs, and comp cromoly ball/cup P-rods. Is the double valve spring too much for the rocker or ? Should I get a better quality rocker? If so What?? Any help is appreciated. Thanks Jon
Click to expand...

Pictures would help us help you.
 
Ill try and get some pictures, but when I set them with an adjustable the roller rode the middle of the valvethoughout the cycle.
 
These are actually the steel adjusters breaking in an aluminum arm??? Or are the arms breaking?
 
The stud itself is breaking. It shears off past the treads and where it is necked down, as soon as it starts making the ball thats where they shear off. Basically half the ball is sheared.
 
Jonnylightening said:
The stud itself is breaking. It shears off past the treads and where it is necked down, as soon as it starts making the ball thats where they shear off. Basically half the ball is sheared.
Click to expand...

That is interesting. Assuming your rocker arms are aluminum I am surprised they don't break first. In either event, I wonder if your push rods are jumping out of the cup enough to catch the lip and break it off. Rods too short or not adjusted correctly? Could be the rods are rubbing on the head someplace setting up a harmonic that makes them jump out.
 
Well got the valve covers off and to my surprise I was right on the money, This time however the lifter wasn't up in the valley. I did get a picture of what it looks like. This is almost exactly how the other two looked. I rechecked my geometry and like I stated above the roller rides the center of the valve tip the whole cycle, and it doesn't seem to have any sort of binding between the p-rod and adj. screw. Also the second time this happened I checked to see if I was getting propper lube through there there was hells of it. So this whole thing has me puzzled, I can't keep doing this or somethings badly gunna happen.
 

Attachments

  • Adj Screw.jpg
    23.4 KB · Views: 193
Call Crane and tell them your problem. They will send you new adjusters free of charge. I had the same problem last year, they told me they had a bad batch get out. They didnt even want me to sent them the old ones back.
 
75dartsport said:
Call Crane and tell them your problem. They will send you new adjusters free of charge. I had the same problem last year, they told me they had a bad batch get out. They didnt even want me to sent them the old ones back.
Click to expand...

You say you had the same problem? I did replace the other broken ones with ones that were a gray color, so far none of those broke. What springs are you runnin? I'm running Lunati Doubles. Did it solve the problem?
 
I was running 550 lift double springs. And the new ones did fix the problem.
 
75dartsport said:
I was running 550 lift double springs. And the new ones did fix the problem.
Click to expand...

I'll try and give them a call again, last time I called they wanted me to send them one, but they already seen the trash. I'm running a .525 lunati with doubles, so if it fixed yours hopefully it fixes mine.
 
Well it seems that the replacement studs are holding up so yes I would replace all the rest. I think your on the right track there.
 
You must log in or register to reply here.
-

Back
Top