My adjustable rocker arms keep falling off!! HELP!!

[mustanggt94]

I've got this motor that was a friend of mine's and we put it in my car, and I don't know if he adjusted the rockers correctly when it was in his car but one of the rocker arms was just sitting in the valve cover when we took the engine out of his car! Anyway I assumed he didn't do it correctly, so I adjusted them the was Comp Cams says so, which is very similar to the instructions I found on here when I searched.

Okay, what's happening is when I adjust them to where there is resistance on the pushrod, then turn the nut a 1/2 turn, on some of them it feels much tighter than others. This worried me at first, but I figured, "well it's what the instructions say!" Okay after I did that, we finally got the engine running, and after a quick test drive we knew something was wrong, and took off the valve covers....TWO of them had fallen off and others had loosened up!!! WTF??? :damnit: So now I adjusted them, but put the ones that felt loose a little tighter, and I also used locktite on the bolts and set screws. Now I drive the car and it has no power at all, and it could be my tune as I am still messing with the Tweecer, but it's really bad, when you floor it it takes forever to get up to speed! I think maybe I overtightened the rocker arms....What should I do? Should I just follow the instructions AND use locktite? The instructions do not say to use locktite so I don't understand why they are falling off! HELP!

 

[Rick 91GT]

I would assume it is a pushrod length issue. Are you sure you are on the base circle on the cam when setting the rockers?

How does the geometry look? What length pushrod are you using? What head? What rocker? Stud mount or ped mount?

 

[EMW150]

Are you sure you are on the base circel on the cam when setting the rockers?

I think this is what's happening. Some weren't on the heel of the cam. That's the only way one would feel tighter than others. Try adjusting one at a time in the firing order and concentrate on having all on TDC compression stroke as you go.

 

[mustanggt94]

I'm not certain on the pushrod length, but I know that is what Brothers had sold him for this combo. They are stud mount on Edelbrock Victor Jr. heads with Crane Cams roller rockers. I guess I'm kinda new at this...what is the base circle mean? How can I get it to TDC Compression stroke FOR SURE on each cylinder? Thanks!

 

[EMW150]

I'm not certain on the pushrod length, but I know that is what Brothers had sold him for this combo. They are stud mount on Edelbrock Victor Jr. heads with Crane Cams roller rockers. I guess I'm kinda new at this...what is the base circle mean? How can I get it to TDC Compression stroke FOR SURE on each cylinder? Thanks!

Get in on #1 cylinder compression (both valves closed), you can use a pocket screwdriver or something in the spark plug hole and feel the piston as you turn it over till the piston is at the top. Then adjust both valves for that cylinder. Then follow in the firing order to each cylinder in order and do the same. There is another procedure that you can use also but this one works for the majority of cams.

 

[EMW150]

Here's a good description of 2 different ways.

Valve Lash Adjustment Procedures
by Brian Tooley

There are numerous ways to lash valves in an engine. We will discuss only what we feel are the best ways. The method that we prefer will work on any camshaft type, the only difference is the amount of lash that will be used. We use the "firing order method" of lashing valves. We can lash the valves on an engine stand and never have to readjust them once run in the car.

Step #1 Find top dead center for piston #1
A lot of people think that if the timing pointer is on the balancer mark that this is TDC #1. This is not necessarily true, it can be TDC #6. This is because there are 720 degrees crankshaft rotation in one complete firing sequence. There are two ways to find TDC #1. First is by pulling the #1 spark plug, holding your finger over the hole and turning the crankshaft until it tries to blow your finger away, then once the timing mark comes up this will be TDC #1. The other method requires the valve cover or intake to be off. You can look at the lifters or rockers of #1 and #6 cylinders. When #1 is at TDC, #6 has both valves open slighty. If you move the balancer timing mark to each side of the timing pointer, you should see both lifters or rockers of #6 moving up and down and #1 should remain stationary. If it is vice versa then you are on TDC #6 and need to move the crankshaft 360 degrees or one full turn.

Step #2 Adjust the the lash of #1 cylinder
This is where you have to determine the lash you will use. If it is a solid or solid roller application then the lash will generally be between .016" and .030". For hydraulic and hydraulic roller applications we prefer to go 1/4 turn more than "0". We turn the poly lock while moving the rocker arm up and down on the valve. Once all play is taken out go 1/4 turn more and then lock down the inner set screw. Another thing you can do at this point is go just shy of 1/4 turn, lock down the inner set screw and then put the wrench on the poly lock and turn it as far as you can, within reason. This helps lock down the poly lock to keep it from backing off.

Step #3 Turn the crankshaft 90 degrees
Turn the crankshaft 90 degrees or 1/4 turn to the next cylinder in the firing order. Repeat Step #2. The next one in the firing order is obviously dependent on the engine you have. All V8 Chevys (small block and big block) are 1-8-4-3-6-5-7-2. 302HO and 351W are 1-3-7-2-6-5-4-8. Non-HO 302 and 289 are 1-5-4-2-6-3-7-8.

Step #4 Keep going
Keep turning the crank in 90 degree increments and lashing the valves for that cylinder until all 8 cylinders have been adjusted. At that point you should have to turn the crank one more 90 degree turn and you will be back on #1 TDC.

For you serious race car guys with gross duration figures in the 320 plus region you can use the firing order sequence but instead of adjusting the #1 valves at TDC #1 adjust the previous intake rocker and the next exhaust rocker. This ensures that the lifter is on the absolute base circle of the camshaft.

 

[mustanggt94]

That makes sense, but why the heck does the instructions from Crane Cams and the instructions I've found on Stanget say to turn the motor until the exhaust is just starting to open, then adjust the intake....then turn until the intake is almost CLOSED, adjust the intake valve....this is very tough procedure to get accuratly and obviously is not working for me! Just wondering why they say to do that???

 

[04sleeper]

I have always found that doing 2 rockers (1 cylinder) at a time works just fine and takes less time.

I "Bump" the starter a little at a time until the intake valve on that cylinder opens and closes, then the exhaust valve opens and closes all the way. Then I adjust both rockers for that cylinder by tightening down the rocker nut (with the set screw loosened all the way) by hand with a rag until I can't tighten it anymore by hand. Then I give an aditional 1/4 to 1/2 turn with a wrench and tighten the set screw.

Then I go to the next cylinder and repeat the same procedure.

I have never had to use loctite on either the nut or set screw.

 

[EMW150]

That makes sense, but why the heck does the instructions from Crane Cams and the instructions I've found on Stanget say to turn the motor until the exhaust is just starting to open, then adjust the intake....then turn until the intake is almost CLOSED, adjust the intake valve....this is very tough procedure to get accuratly and obviously is not working for me! Just wondering why they say to do that???

That method should work. Personally, I've never used it.

 

[Rick 91GT]

I've done it all the way mentioned above..lol

I like to do one cylinder at a time, easier and more accurate for me. I use a small bit of blue loctite on the set screws to ensure none come loose, I've seen what they do when they come loose.

 

[mustanggt94]

Here's a good description of 2 different ways.


Step #2 Adjust the the lash of #1 cylinder
This is where you have to determine the lash you will use. If it is a solid or solid roller application then the lash will generally be between .016" and .030". For hydraulic and hydraulic roller applications we prefer to go 1/4 turn more than "0". We turn the poly lock while moving the rocker arm up and down on the valve. Once all play is taken out go 1/4 turn more and then lock down the inner set screw. Another thing you can do at this point is go just shy of 1/4 turn, lock down the inner set screw and then put the wrench on the poly lock and turn it as far as you can, within reason. This helps lock down the poly lock to keep it from backing off.

Is the POLY LOCK just the large nut? This is what is actally adjusted, right? The allen screw in the middle just needs to lock it down, right? I know I sound like an idiot but I do not want to have to do this again! Going to do this after work today! Also, how tight should the set screw be? Thanks!

 

[EMW150]

Correct, I just turn the set screw about as tight as I can get it (within reason) with the allen wrench.

 

[mustanggt94]

UPDATE:


Well, well....I took the car out today after messing with the Tweecer tune, hoping it would fix the sluggish problems....and the car was running decent, and all I did was go around the block and the car crapped out on me and would barely run! Well I heard a lot of noise so I shut the car off and towed it home. Well one of the rocker arms fell off again, but this time it broke the stud in half on my edelbrock heads. Anyone know why it would do this?

 

[Rick 91GT]

Did you re-set the rockers?

 

[04sleeper]

Sounds to me like you have too long of a pushrod. If the lifters are bottoming out and have no more room something has to give. Not good.

Could you get a few pictures of the heads as they are right now so we can see your rockers and how they sit on the valve?

It may help.

 

[mustanggt94]

Well I was dumb and decided to take it around the block to see if the tune was better before I re-set the rockers, obviously not a good idea! I think I might have overtightened them this last time....do you think that would cause it to break like that? I will post pictures once I get to my garage.

 

[mustanggt94]

Here are the pics of the side that has been giving me all these problems!

http://home.comcast.net/~yellowmustang94/mustang/DCP_4316.jpg

http://home.comcast.net/~yellowmustang94/mustang/DCP_4317.jpg

 

[Stang8URMPRT]

Ouch man! I have always been taught to adjust the rocker, then turn it 1/4 of a turn, then LOCK the allen head, then go ANOTHER 1/4 of a turn. This positivly locks that allen head screw into the stud and it won't come loose. Good luck.

 

[mustanggt94]

That makes sense....Well I just picked up a whole set (only come in a set of 16, dammit!) of rocker arm studs from my local machine shop today. I'd like to get this thing running this weekend if possible, but I'm afraid to put it all back together if something else is wrong, like the pushrods were too long ect. This is the only thing I can think of but I do not know what they are supposed to be at....my cam has intake lift of .542, exhaust lift of .563, and I have Comp Cams Pro-Magnum 1.6 roller rockers on Edelbrock Victor Jr. Heads.....does anyone know how to figure out what the correct pushrod length should be? The pushrods that are currently on there are 6.875 5/16" Crane Cams Chromoly Pushrods.

 

[Stang8URMPRT]

Holy **** batman. Do you have any reason for that long of a pushrod? THat's a Flat Tappet Cam Pushrod length. Stock roller cam pushrod length is 6.250 inchs. You've got over 1/2 an inch longer pushrods. Those are most likely WAY too long.

You need to get a push rod length checking tool. This is the only way you'll get the right size pushrod.