I think I just might have found my problem...

I had a miss that has slowly been getting worse over the past 6 months, and figured I would check out my rockers again, and as mentioned above, the loctite did NOT hold. I did not have any rockers walk completely off, but they are supposed to be torqued to 20 lb/ft and some were less than 15 and all were less than 20. I retorqued them, but now am off to see if I can find that loctite 518 that PaulS mentioned.

Searching on the internet, I see that Grainger has it for $23 per little tube!!!

Is this a specialty item that needs to be ordered online or purchased at a special store, or will O'Reilly or NAPA be able to get it for me?

 

I found a permatex Hi Temperature Red thread locker #24026 which is different than the #27100 Hi Strength Red you normally get at the local stores. The Hi Temp stuff is good up to 450 degrees.

Do the heads get that hot? I would think 300 max...maybe not that hot, but definitely hotter than the 190 of the coolant temperature.

 

consider that there are temps well above 1000 degrees in the combustion chamber. exhaust temps will be well above 500 degrees.
i dont think the rocker arm pedestals will see that much heat but i do believe that they will see more heat than your coolant temp gauge shows.

make sure the holes in the pedestals are completly dry and have no oil in them to contaminate the loctite.
you may want to look at arp's website. they have a lot of tech on how to torque bolts. they may even address the ford rocker arm pedestal bolts. im thinking that some arp bolt assembly lube under the head of the bolt will give you a better torque reading than putting them in dry or with just motor oil on them.

 

The torque isn't crucial. They are more concerned with how far the bolt turns within a torque range, so that you provide some preload.

So, at 18-20 lb/ft, they want you to have rotated the bolt 1/4-1 full turn after finger tight so that you have given the lifters .040-.060 preload.

What concerns me is that if the torque has reduced over time, then the bolts are, in fact, slowly coming loose. Eventually, I will have one walk off like I did at the beginning of this thread.

I gotta figure out how to lock them down so they don't move. That first time they walked off could have killed the engine permanently, if I wasn't as lucky as I was.

 

Stud and Bearing mount is also an option, but it can be permanent.

 

I would bet the permatex would work. We apply it to military and aerospace applications at my work. Like stuff for NASA. And a lot of our customers have it as a secondary option for the Loctite 518 PaulS mentioned.

 

star lock washer under the bolt? just a idea

never seen a pedastal mount back off maybe the bolts are weak and stretching?

 

Alright...looking for it, but most likely will have to order online.

 

I second having a good look at those bolts. Id replace them.

 

Change it out to studs. Loctite the studs in, then use poly locks on the studs. Only problem, I don't know if you could use your rocker arms. Somebody who knows more than me can tell ya that.:Handshake

If you keep the bolts, I'd definitely go ARP. I used their head bolts and rocker studs on my Vette when I put it back together. Their pieces are very well machined. Supposed to be stronger than stock, too. Well worth the money in my book.

 

I wonder if they have figured out that these are not a great idea?

Crane has a different bolt setup on many of them now...The first one is what mine look like.

 

the second pic is how stud mount rockers looks. i suspect that the first pic is still how the pedestal mount rockers come. i installed some pedestal mounts last summer and they had the allen head bolts.
was the rocker arms loose yet or did you find that the bolts were able to be tightened up a little bit more?

 

The Crane/Ford Cobra rockers used that same hold down bolt as in the first pic. I've got a set of these that have been on at least 4 different builds now and none have ever worked loose in service. The second pic, as Bryant stated is of a stud mount rocker. I once used a Crane kit that converted Cleveland pedestal rockers to stud mount on a 400 build and I did have a couple of those that worked loose (several times with the same rocker and bolt) even though I'd used thread locking compound in the initial installation. I never did figure out why those two bolts kept coming loose. May have been worn threads in the head or insufficient thread locking goop, or a combination of both.

 

Mine are the Crane/Ford Racing ones.

This time, I did not have any come loose enough to have play in the rocker, but they had backed off from the 20 lb/ft I set them at originally.

Also, the blue loctite I used last time was not working. So I guess the heads got to the 200 or so degrees needed to melt it and render it useless. I was able to turn the bolts without any initial resistance from cured loctite.

 

Torque em to 25 ft/lbs, That's what I do.