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rocker arms problem


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praza's Avatar
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June 19th, 2013, 11:53 AM   #1  
rocker arms problem

I have a problem with my 87 caprice. I torn apart the engine, and IMHO I found something unusual. The side aligment of rocker arms have a huge side allowance. The rocker arms are moving from side to side, even using just using just pushrods, although they were adjusted. One side of the engine is better then other.

I feel the new rocker arm kit is a solution, but what could cause this behavior and what allows it?

Please check videos below


 
SWHouston's Avatar
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June 20th, 2013, 2:19 AM   #2  
If you had the Rocker Arms adjusted properly, how is it that there was a sufficient LACK of pressure on them, to allow you to turn them back and forth like that ? I could see that there may be one or two Valves on low Cam, but not all of them.

Now, if you've intentionally loosened the Rockers just to show us how loose they are, then that's ok, but...
You need to watch them operating, and see if that slack is really messing with the Geometry.
IF they don't wobble around when the engine is running, then you're ok, but...

If they do wobble, then your choice is only to replace them...ALL of them, Pivot ***** and Nuts too.
You know that you can buy Arms with grooved Pivot *****, and eliminate that wobble completely.

Ref:
http://www.summitracing.com/search/d...7?autoview=SKU
This reference may not be the exact Rocker for your ride, check it closely.


Last edited by SWHouston; June 20th, 2013 at 3:12 AM.
 
old dog's Avatar
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June 20th, 2013, 2:59 PM   #3  
look's like a old worn out engine .like mentened before if the lifters are holding pressure and adjusted right it will be at a minamum. but rocker arm stud's can get cut from the rocker's ,and the guide slot's in the cylinder head for the push rod's can get egged out and let them wobble in combination with cut stud's .

 
praza's Avatar
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June 22nd, 2013, 9:42 AM   #4  
Thank you everyone for your feedback.

For the reference, this is suppost to be stock GM engine in 87 Caprice, which I own for about 5 years. Its now my weekend car, but as dd it servers me about 20k miles up to total around 150k miles.

Back to the problem:
Rocker arms clearance on one side of the engine is greater than the other one. The posted video was taken after careful adjustment of both sides.

Pushrods of some valves even lean on the wall in the cylinder head hole, which I do not like to see.

Today I checked everything carefully, the length and diameter of all pushrods are identical.I changed rocker arms of the "good" side and put them on the "wrong" side and vice versa. This does not changed anything, the allowance on the one side of cylinders is larger, then other side.
Therefore the reason is not rocker arms.

After closer examination I have discovered a mystery.
The "good" head have in the holes for the pushrods guide tabs on the sides.
The "bad" head have a circular holes and side allowance is therefore greater.

Both heads have the same part number, but 1 was in past exchanged for replacement part from 88 Caprice due the cracked head.

Excessive lateral allowance of the rockers would be diminished, if I install the pushrods with a larger diameter. Do you know if there are pushrods with different diameters?

I disassembled the engine for several oil seal leaks and also, when the engine was running, I was able to hear irregular knocking of timing chain. Therefore I wanted to check the rocker arms.

Now I wonder, if its worth to deal with this large laterel allowance, or not.

I appriciate the time you are spending reading and thinking about my problems, thank you


 
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June 22nd, 2013, 12:25 PM   #5  
Praza, you said...

"Therefore the reason is not rocker arms"
I understand that this appears to be true, but, if you buy and place Rocker Arms which have the Groves, this will correct the problem on both heads. The lateral looseness will be corrected by new Arms.

"Do you know if there are pushrods with different diameters?"
The Pushrods should all be the same diameter. You have checked those there, and they would be usable with new Rocker Arms.

"I was able to hear irregular knocking of timing chain"
This is not good, you should repair as soon as possible. If either Gear or the Chain were to break, it could destroy the Engine.

"Now I wonder, if its worth to deal with this large laterel allowance, or not."
I can not speak to this. You must decide how much money you wish to spend on the car. IF you intend to keep it, then yes, the Rocker Arms should be replaced, and that WILL correct the lateral wobble of all the Arms.

However, the Timing Chain looseness is a much greater threat, and should receive priority !


Last edited by SWHouston; June 22nd, 2013 at 12:28 PM.
 
praza's Avatar
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July 1st, 2013, 3:57 PM   #6  
Thanks for respond, I purchased the correct set of rocker arms and will clear custom soon, so will keep you updated. Unfortunatelly nobody during repair reallized, that replaced head needs different rocker arms with self aligning.
Well now have it corrected.

I used a incorrect expression about the irregular knocking noise. The noise was from the top end, (rocker arms) not the timing chain. This was replaced with new part during the head exchange about 1000 miles ago.

 
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