Ok, so I've my motor(in my sig) keeps breaking rocker nuts. I have stud mount roller rockers, and the polly lock part of the top of the rocker nut will break off. It's already happened like 2 or 3 times in the past few months, on different valves, but all on the same bank, and I'm not to sure why... It does have a trick flow stage 2 cam, but there is obviously no P/V clearence issues... Before I put the cam in it didn't do this either, and no it will only do it if I over rev on accident...at about 7K, as i usually shift at 6K or 6.5K, but before it also wouln't do this w/ my old cam. My buddy told me that with a big cam like that then I would need shorter pushrods, but I'm not sure. Any help appriciated...
Rocker nuts keep breaking...HELP!!??
- Thread starter my289eatsrice
- Start date
Yes, I do have 3/8th studs, and the heads were just red done with a full valve job, and one of the valves were replaced. If i had P/V clearence, then wouldn't that be evident on all the valves, not just one or two...The poly locks do thread a ways onto the stud, so i don't think that could be it...
Check the valve spring pressures if they are weak and you over rev the cam it will float and you will have PTV issues., Recheck the geometry for the correct pushrod length as well.
If your breaking the nuts you have an issue that you need to find, something is binding. What about radial clearnace on the rockers? What brand rockers? What brand nuts?
If your breaking the nuts you have an issue that you need to find, something is binding. What about radial clearnace on the rockers? What brand rockers? What brand nuts?
The rockers are the ford racing A351's and their 1.6 ratio. The nuts are poly locks and I got them from comp cams. I'm not sure what u mean by radial clearence on the rockers, and the valve springs are 10 years old, from trickflow. I don't know what size the pushrods are, but I just used the same ones I used before with the TW heads, with a smaller cam.
Radial clearance would be between the spring and the rocker, most of the ford rockers are not cut back very far so a 1.46" diameter spring could hit and bind.
You need to verify the pushrod length using a adjustable pushrod, also verfiy the geometry of them as well. 10 year old valve springs usually are very worn especially with a cam like the Stage II thats needs 145lbs or so on the seat. What is the installed height of the spring, do you know your current seat pressures?
My bet is the springs were floating causing it to bind and hit.. When the machine shop fixed your heads did they tell you what they found as to why you bent the valve?
You need to verify the pushrod length using a adjustable pushrod, also verfiy the geometry of them as well. 10 year old valve springs usually are very worn especially with a cam like the Stage II thats needs 145lbs or so on the seat. What is the installed height of the spring, do you know your current seat pressures?
My bet is the springs were floating causing it to bind and hit.. When the machine shop fixed your heads did they tell you what they found as to why you bent the valve?
The valve they replaced was replaced because of excessive carbon buildup due to a broken valve guide, which caused the valve to bend. I have only had the TFS stage 2 cam in for a few months now, and before I had a much smaller cam, not sure which one... How would i measure this radial clearence?
take a quick read and see if anything pertains to you. You have a binding issue somewhere thats not gonna go away by itself
http://sbftech.com/index.php/topic,150.0.html
http://sbftech.com/index.php/topic,150.0.html
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