rocker arm came loose... how much damage?

[rockin_rick]

About 5 mins into the 3rd drive of my car with the new engine, I started to hear what sounded like (with my unexperienced ears) an exhaust leak. It didn't surprise me much, since my headers-to-midpipe didn't line up perfect, and my catback is kinda ghetto (previous owner welded in not straight). A few minutes later I started to hear a loud metal clanking/popping that started out quiet and about 1 clank per 2-3 secs and gradually increased in sound level and time between lessened. I got it pulled over within a minute and never ran the engine over about 2000 rpm when this was happening.

Ends up the stud mounted Scorpion 1.6 #2 exhaust rocker had came loose and was hitting the VC top. The rocker was twisted on the stud but the tip was still 1/2 over the valve stem. The pushrod was still in the cup. The lock was way loose, and the nut was 1 turn from coming off. When I took it off, the rocker, valve, valve retainer, and stud showed no signs of damage or even signs of the rocker tip running off the edge of the valve stem. The pushrod cup and pushrod end showed no signs of the pushrod having came out and danced around on the rocker.

Looking down the pushrod hole of the head, you can see that the Trick Flow 6.300 pushrod is not over the FMS roller hyd. lifter at all and is off the side of the lifter. It is also wedged in there, I can't pull it out with my fingers. I tried rocking the motor back and forth about 15° each way to see if it would loosen. Nope. I know I just have to loosen the stock AFR 165 guideplate to get it out (hopefully).

My questions are:

1.) What did I damage?
2.) Should I replace the lifter and can you just get 1 or 2?
3.) Should I pull the lower intake?
4.) Should I run different lifters?

Thanks,
Rick

 

[88stangmangt]

doesnt look like you did any damage tourque it down and go.!!!!!

 

[hllon4whls]

doesnt look like you did any damage tourque it down and go.!!!!!

I guess you missed the fact that the pushrod is stuck in the lifter offcenter?

 

[hllon4whls]

If you cant get the pushrod out, you are going to have to pull the intake.

 

[rockin_rick]

If I can get it out by loosening the guide plate, do I need to remove the lower intake just to see if the lifter is OK? I don't think that there would be any lifter damage, but I am unexperienced with this.

Thanks for the help,
Rick

 

[rockin_rick]

I guess you missed the fact that the pushrod is stuck in the lifter offcenter?

I think that it is more likely stuck in the head offcenter. Maybe being pushed up by the lifter body into the head??? The bottom of the pushrod is out of the lifter and to the side.

Do you think that the pushrod is re-usable if not bent?

Rick

 

[hllon4whls]

I would be safe by pulling the manifold.

The pushrod is probably bent. Check it by rolling it on a piece of glass or a table that you know is straight. It will be obvious if it is bent. If you see any bend at all, dont use it..

Hopefully you are right and the lift is just jamming it against the guide plate. That would make things fairly easy to fix.

 

[rockin_rick]

I took off the guide plate and the PR was still wedged in there. So I got the vise grips and I used a rubbery piece of plastic (part of a cap that came on my Fluidyne) and it came out without much resistance. Both ends of it looked OK, and there were some rub marks on it where it was having to go up and down against the head. But they wern't deep enough to feel or to catch a nail on, so I should be OK. There was also a mark near the lifter end, probably where it was wedged against the lifter or something. Also couldn't feel anything.

It also may be just the slightest bit bent. I held it next to it's intake PR mate and when turned so it bows up, there might have been .001-.002 gap between the two at one end when the other was flat. I bet that's within production tolerances. I mean it's really hard to tell and it may just be my imagination. Should I still replace it? Can I run it for a while, until I can get a replacement? (Summit says "should ship by 6-22") ARRRRRR...

Looking forward to getting it back together...

Thanks everyone,
Rick

 

[Michael Yount]

We seem to have avoided the initial problem however - why did the rocker come lose Rick? If you have a flat surface Rick - Corian kitchen counter, quality diningroom table or desk top -- lay the pushrod down on it and roll it along the flat surface. Even the slightest bend should show up. You can compare it to the one you believe to be straight - roll them both. Given how wedged it was and what you had to do to get it out, I'd be reluctant to reuse it in any event.

 

[rockin_rick]

When adjusting them, I ran across 4 that when I went to give them the 1/2 turn of preload, they had way less turning resistance than the others. The others had some resistance as I gave them the 1/2 turn. (Coiencendently or not, the first one I encountered like this was the one that came loose.) Before continueing, I went and did a bit of internet research and concluded that the lifter probably wasn't pumped up, and I was just easily compressing the lifter spring. So I went and adjusted it and continued on. I did stop in the middle of my routine and it was late at night, so I may just have forgot to lock it down. I will be sure to do rocker adjustments in the future when I can think clearly.

I did try rolling it on my table and didn't notice anything. Like I said, if it's bent, it's very slight. Is it OK to run easy in the car until I can get a replacement? It is also hardened cromemoly. What can happen from running a slightly bent pushrod? I've only got 75 miles on the motor, so I'm still going easy on it.

Rick

 

[Michael Yount]

Did you use an adjustable pushrod to determine pushrod length for optimum valve geometry when you were putting things together? Perhaps you have a few that are just a bit too short.

If it doesn't appear to be bent, or have any galling/gouges in areas that are in contact when it's in use, I'd put it back in. As for running it hard or easy - I'm not sure that will save you much. I'd guess about as many failures happen at idle, or with the throttle closed as happen with someone really pushing things. Run it at your own risk.

If you're sure the rocker/retainer/valve stem/pushrod aren't damaged - try it again. You might try 3/4 turns on those that were 'loose' and see what happens. Was the lock screw loose when you took the cockeyed one apart?

 

[rockin_rick]

I didn't use one, although I have one. I just followed what someone else (Hairycanary) used on his setup with the same parts. Yeah, I know that the same parts, machining tolerances, etc. can cause differences, and probably should have checked, but the contact patch looks to be OK (not too wide, almost centered). (The pic is of the stem that was involved in this taken right after I took it apart.) Even if a few were a bit too short, it shouldn't cause a stud mounted rockers to loosen, right? Were you referring to ped mount setups? I realize that may not be the optimum length, though. Does my pattern look OK? I thought it was pretty good, but I really don't know. If someone thinks it's necessary, maybe this winter I will experiment with PR length. Is a wear pattern established and changing then (or now) would cause problems?

The lock screw was loose and the nut was 1 turn from falling off. The stud was tight. I am wondering now if I am tightening down the lock screws enough. My mehtod is: find zero lash, ensure lock is WAY backed off, turn nut 1/4 turn less than desired, tighten down the lock about 80-90% as much as I can tighen it with the 3" long allen wrench while holding nut with 5/8 wrench, then turn both equally together the last 1/4 turn. That is about as much as I can turn both of them as they get really tight. I use a 5/8" standard length Craftsman wrench. I am wondering if I am not getting enough leverage (and thus torque) on the allen since it is only 3" long.

I installed the PR last night and readjusted all the valves. I set them to 5/8 turn (first time was 1/2 turn). I pulled every nut, rocker and pushrod out individually (one valve at a time to avoid mixing them up) and carefully inspected each for damage/pluggage/wear. I made a chart of each valve's nut, lock, and stud retorque and methodially checked each off as I went. I also retorqued all the studs. They had loosened a bit from their initial 60 ft-lb, as I didn't back them off and was still able to surpass stiction and turn them ~10-15° to click the clicker at 60. I did take out and examine the 2 studs in the cylinder effected. I also used a flashlight and made sure that I got the PR's back in their lifters correctly. Only the second to last one had that 'easy to turn', plunger compressing feeling. I am also very careful to determine zero lash. I check for rocker rocking, pushrod spinning, and nut botteming. I average all 3, wieghing the first 2 more (something like 40/40/20) and call that zero lash. I am confident that I am finding zero lash correctly. Tell me if I'm wrong!

I'll probably pull out those 2 again and roll them again. I think that if I were to get down to the same plane as the pushrod and light it well, I could probably spot a slight up and down warble (or not) as it's rolled. I didn't do that the first time. I'll also roll another one for a reference.

Thanks Mike,
Rick

 

[Michael Yount]

You certainly sound like you're thinking you're way through it carefully. My guess is a short pushrod or two (slight) which wanted a bit more than 1/2 turn to get that rocker tight. The problem with tightening the set screw before you're set is that you can't get a 'feel' for what the nut is doing. It feels tight because it's wedged against the lock screw. People I respect use that technique - it seems tried and true. But were it me, I think I'd try 5/8's to 3/4 turn on the nut; and then put a drop or two of loctite on the set screw. Just thinkin' out loud.

 

[rockin_rick]

Does loctite need the oil cleaned off of the stud and nut and lock to work correctly?

Again, I guess I don't understand the short pushrod theory. It's my understanding that even if a PR was short, the rocker would just sit lower, and tighen the same. The tightening is simply just preloading the lifter, right? It seems that you are thinking of a ped mount setup? Correct me if I am wrong

Rick

 

[Michael Yount]

Wasn't thinking of pedestal mounts - you clearly stated you had stud mounts from the very beginning. But there is a limit to how short a pushrod can be, right? At some point you can tighten the stud til you're on the verge of wringing it off - and if you're not at zero lash yet - then you're gonna have gap -- your pushrod is too short. I'm not concluding some of yours are - I'm concluding it's possible. And if you've got just a little gap there, well it's amazing how that hammering can loosen up things.

One of the issues is that a lot of folks think that our rocker systems (pedestal and stud) are adjustable. Most of them aren't. There are some truly adjustable rockers out there - they have a threaded cup on the pushrod end - like we've all set the lash on solid lifters from time to time. But you hardly ever come across them -- that's what the hydraulic lifter is for. It has some automatic adjustability built in -- but it is limited. And when people start changing heads, valves, springs, cams, rockers, pushrods - well sometimes all those tight tolerances don't quite add up the way they should.

I helped my buddy do a cam degree on an FTI cam/AFR head/Scorpian stud mount rocker set up. After everything else was buttoned up, one set at a time, we installed the rockers with the lifters on the base circle, tightened the nuts to zero lash (til the rocker just touched on the valve and pushrod ends), and then put 1/2 turn on them. After the half turn, we tightened the set screw as much as could by hand with the allen wrench. In retrospect, I'd've used an allen socket and torque wrench, but he didn't have the socket in his shop. It cranked right up, and has stayed quiet. Hasn't required any maintenance at all that I know of. I think if all the dimensions are correct, that is the outcome. Conversely, if things are coming loose - then it's likely that either the installation process was flawed, or something is off dimensionally. And given that one of your pushrods got cocked in the lifter (as if it were able to 'bounce' around in there), it seems likely to me that it was too short. Whether it was too short to start with, or whether it 'became' too short because the rocker loosend up, or whether the rocker loosened up because it was too short -- well, I think that's what you're trying to figure out. Not sure I can conclude anything without being there looking at it with you. And even then, we might both have to give it our best guess, put it back together and see what happens.

 

[rockin_rick]

Yeah, I see what you're saying. I was also thinking of getting a allen socket so I could put the torque wrench on it. Actually, last night I was at sears, but they was sold out of the 3/16 allen to 3/8 drive sockets. I'm going to try the other sears today. Got the longer handled allen wrench, though.

If I tighten the nut to desired setting then torque the lock down while holding the nut steady, how much torque should I put on the locks?

I rolled those again and the one is slightly bent, so I'll be looking to get a replacement today (and a couple spares!). With good backlight and looking under the PR, you can easily see the slight warble. The gap in the middle goes up and down about .010. Too much to temporarially run until a spare is acquired?

Thanks for the wisdom-
Rick

 

[Michael Yount]

I wouldn't run if if it were mine Rick - if it should do some damage, it can really take out a bunch of stuff - even more $$$. I'd get ahold of the folks at Scorpion and ask them what the torque spec is on the lock screw.